path: root/libhb/decavcodec.c

/* decavcodec.c

   Copyright (c) 2003-2016 HandBrake Team
   This file is part of the HandBrake source code
   Homepage: <http://handbrake.fr/>.
   It may be used under the terms of the GNU General Public License v2.
   For full terms see the file COPYING file or visit http://www.gnu.org/licenses/gpl-2.0.html
 */

/* This module is Handbrake's interface to the ffmpeg decoder library
   (libavcodec & small parts of libavformat). It contains four Handbrake
   "work objects":

    decavcodeca connects HB to an ffmpeg audio decoder
    decavcodecv connects HB to an ffmpeg video decoder

        (Two different routines are needed because the ffmpeg library
        has different decoder calling conventions for audio & video.
        These work objects are self-contained & follow all
        of HB's conventions for a decoder module. They can be used like
        any other HB decoder

    These decoders handle 2 kinds of input.  Streams that are demuxed
    by HandBrake and streams that are demuxed by libavformat.  In the
    case of streams that are demuxed by HandBrake, there is an extra
    parse step required that happens in decodeVideo and decavcodecaWork.
    In the case of streams that are demuxed by libavformat, there is context
    information that we need from the libavformat.  This information is
    propagated from hb_stream_open to these decoders through title->opaque_priv.

    A consequence of the above is that the streams that are demuxed by HandBrake
    *can't* use information from the AVStream because there isn't one - they
    get their data from either the dvd reader or the mpeg reader, not the ffmpeg
    stream reader. That means that they have to make up for deficiencies in the
    AVCodecContext info by using stuff kept in the HB "title" struct. It
    also means that ffmpeg codecs that randomly scatter state needed by
    the decoder across both the AVCodecContext & the AVStream (e.g., the
    VC1 decoder) can't easily be used by the HB mpeg stream reader.
 */

#include "hb.h"
#include "hbffmpeg.h"
#include "audio_resample.h"

#ifdef USE_QSV
#include "qsv_common.h"
#endif

static void compute_frame_duration( hb_work_private_t *pv );
static void flushDelayQueue( hb_work_private_t *pv );
static int  decavcodecaInit( hb_work_object_t *, hb_job_t * );
static int  decavcodecaWork( hb_work_object_t *, hb_buffer_t **, hb_buffer_t ** );
static void decavcodecClose( hb_work_object_t * );
static int decavcodecaInfo( hb_work_object_t *, hb_work_info_t * );
static int decavcodecaBSInfo( hb_work_object_t *, const hb_buffer_t *, hb_work_info_t * );

hb_work_object_t hb_decavcodeca =
{
    .id = WORK_DECAVCODEC,
    .name = "Audio decoder (libavcodec)",
    .init = decavcodecaInit,
    .work = decavcodecaWork,
    .close = decavcodecClose,
    .info = decavcodecaInfo,
    .bsinfo = decavcodecaBSInfo
};

#define HEAP_SIZE 8
typedef struct {
    // there are nheap items on the heap indexed 1..nheap (i.e., top of
    // heap is 1). The 0th slot is unused - a marker is put there to check
    // for overwrite errs.
    int64_t h[HEAP_SIZE+1];
    int     nheap;
} pts_heap_t;

struct hb_work_private_s
{
    hb_job_t             * job;
    hb_title_t           * title;
    AVCodecContext       * context;
    AVCodecParserContext * parser;
    AVFrame              * frame;
    hb_buffer_t          * palette;
    int                    threads;
    int                    video_codec_opened;
    hb_buffer_list_t       list;
    double                 duration;        // frame duration (for video)
    double                 field_duration;  // field duration (for video)
    double                 pts_next;        // next pts we expect to generate
    int64_t                chap_time;       // time of next chap mark (if new_chap != 0)
    int                    new_chap;        // output chapter mark pending
    uint32_t               nframes;
    uint32_t               ndrops;
    uint32_t               decode_errors;
    int64_t                prev_pts;
    int                    brokenTS; // video stream may contain packed b-frames
    hb_buffer_t*           delayq[HEAP_SIZE];
    int                    queue_primed;
    pts_heap_t             pts_heap;
    void*                  buffer;
    struct SwsContext    * sws_context; // if we have to rescale or convert color space
    int                    sws_width;
    int                    sws_height;
    int                    sws_pix_fmt;
    int                    cadence[12];
    int                    wait_for_keyframe;
    hb_audio_resample_t  * resample;

#ifdef USE_QSV
    // QSV-specific settings
    struct
    {
        int                decode;
        av_qsv_config      config;
        const char       * codec_name;
#define USE_QSV_PTS_WORKAROUND // work around out-of-order output timestamps
#ifdef  USE_QSV_PTS_WORKAROUND
        hb_list_t        * pts_list;
#endif
    } qsv;
#endif

    hb_list_t            * list_subtitle;
};

#ifdef USE_QSV_PTS_WORKAROUND
// save/restore PTS if the decoder may not attach the right PTS to the frame
static void hb_av_add_new_pts(hb_list_t *list, int64_t new_pts)
{
    int index = 0;
    int64_t *cur_item, *new_item;
    if (list != NULL && new_pts != AV_NOPTS_VALUE)
    {
        new_item = malloc(sizeof(int64_t));
        if (new_item != NULL)
        {
            *new_item = new_pts;
            // sort chronologically
            for (index = 0; index < hb_list_count(list); index++)
            {
                cur_item = hb_list_item(list, index);
                if (cur_item != NULL)
                {
                    if (*cur_item == *new_item)
                    {
                        // no duplicates
                        free(new_item);
                        return;
                    }
                    if (*cur_item > *new_item)
                    {
                        // insert here
                        break;
                    }
                }
            }
            hb_list_insert(list, index, new_item);
        }
    }
}
static int64_t hb_av_pop_next_pts(hb_list_t *list)
{
    int64_t *item, next_pts = AV_NOPTS_VALUE;
    if (list != NULL && hb_list_count(list) > 0)
    {
        item = hb_list_item(list, 0);
        if (item != NULL)
        {
            next_pts = *item;
            hb_list_rem(list, item);
            free(item);
        }
    }
    return next_pts;
}
#endif

static void decodeAudio( hb_audio_t * audio, hb_work_private_t *pv, uint8_t *data, int size, int64_t pts );


static int64_t heap_pop( pts_heap_t *heap )
{
    int64_t result;

    if ( heap->nheap <= 0 )
    {
        return AV_NOPTS_VALUE;
    }

    // return the top of the heap then put the bottom element on top,
    // decrease the heap size by one & rebalence the heap.
    result = heap->h[1];

    int64_t v = heap->h[heap->nheap--];
    int parent = 1;
    int child = parent << 1;
    while ( child <= heap->nheap )
    {
        // find the smallest of the two children of parent
        if (child < heap->nheap && heap->h[child] > heap->h[child+1] )
            ++child;

        if (v <= heap->h[child])
            // new item is smaller than either child so it's the new parent.
            break;

        // smallest child is smaller than new item so move it up then
        // check its children.
        int64_t hp = heap->h[child];
        heap->h[parent] = hp;
        parent = child;
        child = parent << 1;
    }
    heap->h[parent] = v;
    return result;
}

static void heap_push( pts_heap_t *heap, int64_t v )
{
    if ( heap->nheap < HEAP_SIZE )
    {
        ++heap->nheap;
    }

    // stick the new value on the bottom of the heap then bubble it
    // up to its correct spot.
    int child = heap->nheap;
    while (child > 1) {
        int parent = child >> 1;
        if (heap->h[parent] <= v)
            break;
        // move parent down
        int64_t hp = heap->h[parent];
        heap->h[child] = hp;
        child = parent;
    }
    heap->h[child] = v;
}

/***********************************************************************
 * hb_work_decavcodec_init
 ***********************************************************************
 *
 **********************************************************************/
static int decavcodecaInit( hb_work_object_t * w, hb_job_t * job )
{
    AVCodec * codec;

    hb_work_private_t * pv = calloc( 1, sizeof( hb_work_private_t ) );
    w->private_data = pv;

    pv->job = job;
    if (job)
        pv->title = job->title;
    else
        pv->title = w->title;
    hb_buffer_list_clear(&pv->list);

    codec       = avcodec_find_decoder(w->codec_param);
    pv->context = avcodec_alloc_context3(codec);

    if (pv->title->opaque_priv != NULL)
    {
        AVFormatContext *ic = (AVFormatContext*)pv->title->opaque_priv;
        avcodec_copy_context(pv->context, ic->streams[w->audio->id]->codec);
        // libav's eac3 parser toggles the codec_id in the context as
        // it reads eac3 data between AV_CODEC_ID_AC3 and AV_CODEC_ID_EAC3.
        // It detects an AC3 sync pattern sometimes in ac3_sync() which
        // causes it to eventually set avctx->codec_id to AV_CODEC_ID_AC3
        // in ff_aac_ac3_parse(). Since we are parsing some data before
        // we get here, the codec_id may have flipped.  This will cause an
        // error in hb_avcodec_open().  So flip it back!
        pv->context->codec_id = w->codec_param;
    }
    else
    {
        pv->parser = av_parser_init(w->codec_param);
    }
    hb_ff_set_sample_fmt(pv->context, codec, AV_SAMPLE_FMT_FLT);

    /* Downmixing & sample_fmt conversion */
    if (!(w->audio->config.out.codec & HB_ACODEC_PASS_FLAG))
    {
        pv->resample =
            hb_audio_resample_init(AV_SAMPLE_FMT_FLT,
                                   w->audio->config.out.mixdown,
                                   w->audio->config.out.normalize_mix_level);
        if (pv->resample == NULL)
        {
            hb_error("decavcodecaInit: hb_audio_resample_init() failed");
            return 1;
        }
        /*
         * Some audio decoders can downmix using embedded coefficients,
         * or dedicated audio substreams for a specific channel layout.
         *
         * But some will e.g. use normalized mix coefficients unconditionally,
         * so we need to make sure this matches what the user actually requested.
         */
        int avcodec_downmix = 0;
        switch (w->codec_param)
        {
            case AV_CODEC_ID_AC3:
            case AV_CODEC_ID_EAC3:
                avcodec_downmix = w->audio->config.out.normalize_mix_level != 0;
                break;
            case AV_CODEC_ID_DTS:
                avcodec_downmix = w->audio->config.out.normalize_mix_level == 0;
                break;
            case AV_CODEC_ID_TRUEHD:
                avcodec_downmix = (w->audio->config.out.normalize_mix_level == 0     ||
                                   w->audio->config.out.mixdown == HB_AMIXDOWN_MONO  ||
                                   w->audio->config.out.mixdown == HB_AMIXDOWN_DOLBY ||
                                   w->audio->config.out.mixdown == HB_AMIXDOWN_DOLBYPLII);
                break;
            default:
                break;
        }
        if (avcodec_downmix)
        {
            switch (w->audio->config.out.mixdown)
            {
                // request 5.1 before downmixing to dpl1/dpl2
                case HB_AMIXDOWN_DOLBY:
                case HB_AMIXDOWN_DOLBYPLII:
                    pv->context->request_channel_layout = AV_CH_LAYOUT_5POINT1;
                    break;
                // request the layout corresponding to the selected mixdown
                default:
                    pv->context->request_channel_layout =
                        hb_ff_mixdown_xlat(w->audio->config.out.mixdown, NULL);
                    break;
            }
        }
    }

    // libavcodec can't decode TrueHD Mono (bug #356)
    // work around it by requesting Stereo and downmixing
    if (w->codec_param                     == AV_CODEC_ID_TRUEHD &&
        w->audio->config.in.channel_layout == AV_CH_LAYOUT_MONO)
    {
        pv->context->request_channel_layout = AV_CH_LAYOUT_STEREO;
    }

    // Set decoder opts...
    AVDictionary * av_opts = NULL;
    av_dict_set( &av_opts, "refcounted_frames", "1", 0 );

    // Dynamic Range Compression
    if (w->audio->config.out.dynamic_range_compression >= 0.0f &&
        hb_audio_can_apply_drc(w->audio->config.in.codec,
                               w->audio->config.in.codec_param, 0))
    {
        float drc_scale_max = 1.0f;
        /*
         * avcodec_open will fail if the value for any of the options is out of
         * range, so assume a conservative maximum of 1 and try to determine the
         * option's actual upper limit.
         */
        if (codec != NULL && codec->priv_class != NULL)
        {
            const AVOption *opt;
            opt = av_opt_find2((void*)&codec->priv_class, "drc_scale", NULL,
                               AV_OPT_FLAG_DECODING_PARAM|AV_OPT_FLAG_AUDIO_PARAM,
                               AV_OPT_SEARCH_FAKE_OBJ, NULL);
            if (opt != NULL)
            {
                drc_scale_max = opt->max;
            }
        }
        if (w->audio->config.out.dynamic_range_compression > drc_scale_max)
        {
            hb_log("decavcodecaInit: track %d, sanitizing out-of-range DRC %.2f to %.2f",
                   w->audio->config.out.track,
                   w->audio->config.out.dynamic_range_compression, drc_scale_max);
            w->audio->config.out.dynamic_range_compression = drc_scale_max;
        }

        char drc_scale[5]; // "?.??\n"
        snprintf(drc_scale, sizeof(drc_scale), "%.2f",
                 w->audio->config.out.dynamic_range_compression);
        av_dict_set(&av_opts, "drc_scale", drc_scale, 0);
    }

    if (hb_avcodec_open(pv->context, codec, &av_opts, 0))
    {
        av_dict_free( &av_opts );
        hb_log("decavcodecaInit: avcodec_open failed");
        return 1;
    }
    // avcodec_open populates av_opts with the things it didn't recognize.
    AVDictionaryEntry *t = NULL;
    while ((t = av_dict_get(av_opts, "", t, AV_DICT_IGNORE_SUFFIX)) != NULL)
    {
            hb_log("decavcodecaInit: unknown option '%s'", t->key);
    }
    av_dict_free( &av_opts );

    pv->frame = av_frame_alloc();
    if (pv->frame == NULL)
    {
        hb_log("decavcodecaInit: av_frame_alloc failed");
        return 1;
    }

    return 0;
}

/***********************************************************************
 * Close
 ***********************************************************************
 *
 **********************************************************************/
static void closePrivData( hb_work_private_t ** ppv )
{
    hb_work_private_t * pv = *ppv;

    if ( pv )
    {
        flushDelayQueue( pv );
        hb_buffer_list_close(&pv->list);

        if ( pv->job && pv->context && pv->context->codec )
        {
            hb_log( "%s-decoder done: %u frames, %u decoder errors, %u drops",
                    pv->context->codec->name, pv->nframes, pv->decode_errors,
                    pv->ndrops );
        }
        av_frame_free(&pv->frame);
        if ( pv->sws_context )
        {
            sws_freeContext( pv->sws_context );
        }
        if ( pv->parser )
        {
            av_parser_close(pv->parser);
        }
        if ( pv->context && pv->context->codec )
        {
#ifdef USE_QSV
            /*
             * FIXME: knowingly leaked.
             *
             * If we're using our Libav QSV wrapper, qsv_decode_end() will call
             * MFXClose() on the QSV session. Even if decoding is complete, we
             * still need that session for QSV filtering and/or encoding, so we
             * we can't close the context here until we implement a proper fix.
             */
            if (!pv->qsv.decode)
#endif
            {
                hb_avcodec_close(pv->context);
            }
        }
        if ( pv->context )
        {
            av_freep( &pv->context->extradata );
            av_freep( &pv->context );
        }
        hb_audio_resample_free(pv->resample);

#ifdef USE_QSV_PTS_WORKAROUND
        if (pv->qsv.decode && pv->qsv.pts_list != NULL)

        {
            while (hb_list_count(pv->qsv.pts_list) > 0)
            {
                int64_t *item = hb_list_item(pv->qsv.pts_list, 0);
                hb_list_rem(pv->qsv.pts_list, item);
                free(item);
            }
            hb_list_close(&pv->qsv.pts_list);
        }
#endif

        free(pv);
    }
    *ppv = NULL;
}

static void decavcodecClose( hb_work_object_t * w )
{
    hb_work_private_t * pv = w->private_data;

    if ( pv )
    {
        closePrivData( &pv );
        w->private_data = NULL;
    }
}

/***********************************************************************
 * Work
 ***********************************************************************
 *
 **********************************************************************/
static int decavcodecaWork( hb_work_object_t * w, hb_buffer_t ** buf_in,
                    hb_buffer_t ** buf_out )
{
    hb_work_private_t * pv = w->private_data;
    hb_buffer_t * in = *buf_in;

    // libavcodec/mpeg12dec.c requires buffers to be zero padded.
    // If not zero padded, it can get stuck in an infinite loop.
    // It's likely there are other decoders that expect the same.
    if (in->data != NULL)
    {
        memset(in->data + in->size, 0, in->alloc - in->size);
    }

    if (in->s.flags & HB_BUF_FLAG_EOF)
    {
        /* EOF on input stream - send it downstream & say that we're done */
        *buf_out = in;
        *buf_in = NULL;
        return HB_WORK_DONE;
    }

    *buf_out = NULL;

    if ( in->s.start < 0 && pv->pts_next <= 0 )
    {
        // discard buffers that start before video time 0
        return HB_WORK_OK;
    }

    int pos, len;
    for ( pos = 0; pos < in->size; pos += len )
    {
        uint8_t *pout;
        int pout_len;
        int64_t cur;

        cur = in->s.start;

        if ( pv->parser != NULL )
        {
            len = av_parser_parse2( pv->parser, pv->context, &pout, &pout_len,
                                in->data + pos, in->size - pos, cur, cur, 0 );
            cur = pv->parser->pts;
        }
        else
        {
            pout = in->data;
            len = pout_len = in->size;
        }
        if (pout != NULL && pout_len > 0)
        {
            decodeAudio( w->audio, pv, pout, pout_len, cur );
        }
    }
    *buf_out = hb_buffer_list_clear(&pv->list);
    return HB_WORK_OK;
}

static int decavcodecaInfo( hb_work_object_t *w, hb_work_info_t *info )
{
    hb_work_private_t *pv = w->private_data;

    memset( info, 0, sizeof(*info) );

    if ( pv && pv->context )
    {
        AVCodecContext *context = pv->context;
        info->bitrate = context->bit_rate;
        info->rate.num = context->time_base.num;
        info->rate.den = context->time_base.den;
        info->profile = context->profile;
        info->level = context->level;
        return 1;
    }
    return 0;
}

static int decavcodecaBSInfo( hb_work_object_t *w, const hb_buffer_t *buf,
                             hb_work_info_t *info )
{
    hb_work_private_t *pv = w->private_data;
    int ret = 0;
    hb_audio_t *audio = w->audio;

    memset( info, 0, sizeof(*info) );

    if ( pv && pv->context )
    {
        return decavcodecaInfo( w, info );
    }

    AVCodec *codec = avcodec_find_decoder( w->codec_param );
    if ( ! codec )
    {
        // there's no ffmpeg codec for this audio type - give up
        return -1;
    }

    static char codec_name[64];
    info->name =  strncpy( codec_name, codec->name, sizeof(codec_name)-1 );

    AVCodecContext *context      = avcodec_alloc_context3(codec);
    AVCodecParserContext *parser = NULL;

    if (w->title && w->title->opaque_priv != NULL)
    {
        AVFormatContext *ic = (AVFormatContext*)w->title->opaque_priv;
        avcodec_copy_context(context, ic->streams[audio->id]->codec);
        // libav's eac3 parser toggles the codec_id in the context as
        // it reads eac3 data between AV_CODEC_ID_AC3 and AV_CODEC_ID_EAC3.
        // It detects an AC3 sync pattern sometimes in ac3_sync() which
        // causes it to eventually set avctx->codec_id to AV_CODEC_ID_AC3
        // in ff_aac_ac3_parse(). Since we are parsing some data before
        // we get here, the codec_id may have flipped.  This will cause an
        // error in hb_avcodec_open().  So flip it back!
        context->codec_id = w->codec_param;
    }
    else
    {
        parser = av_parser_init(codec->id);
    }

    hb_ff_set_sample_fmt( context, codec, AV_SAMPLE_FMT_FLT );

    AVDictionary * av_opts = NULL;
    av_dict_set( &av_opts, "err_detect", "crccheck+explode", 0 );
    if ( hb_avcodec_open( context, codec, &av_opts, 0 ) )
    {
        av_dict_free( &av_opts );
        return -1;
    }
    av_dict_free( &av_opts );
    unsigned char *parse_buffer;
    int parse_pos, dec_pos, parse_buffer_size;

    while (buf != NULL && !ret)
    {
        parse_pos = 0;
        while (parse_pos < buf->size)
        {
            int parse_len, truehd_mono = 0;

            if (parser != NULL)
            {
                parse_len = av_parser_parse2(parser, context,
                                &parse_buffer, &parse_buffer_size,
                                buf->data + parse_pos, buf->size - parse_pos,
                                buf->s.start, buf->s.start, 0);
            }
            else
            {
                parse_buffer = buf->data + parse_pos;
                parse_len = parse_buffer_size = buf->size - parse_pos;
            }

            // libavcodec can't decode TrueHD Mono (bug #356)
            // work around it by requesting Stereo before decoding
            if (context->codec_id == AV_CODEC_ID_TRUEHD &&
                context->channel_layout == AV_CH_LAYOUT_MONO)
            {
                truehd_mono                     = 1;
                context->request_channel_layout = AV_CH_LAYOUT_STEREO;
            }
            else
            {
                context->request_channel_layout = 0;
            }

            dec_pos = 0;
            while (dec_pos < parse_buffer_size)
            {
                int dec_len;
                int got_frame;
                AVFrame *frame = av_frame_alloc();
                AVPacket avp;
                av_init_packet(&avp);
                avp.data = parse_buffer + dec_pos;
                avp.size = parse_buffer_size - dec_pos;

                dec_len = avcodec_decode_audio4(context, frame, &got_frame, &avp);
                if (dec_len < 0)
                {
                    av_frame_free(&frame);
                    break;
                }
                if (dec_len > 0 && got_frame)
                {
                    // libavcoded doesn't consistently set frame->sample_rate
                    if (frame->sample_rate != 0)
                    {
                        info->rate.num = frame->sample_rate;
                    }
                    else
                    {
                        info->rate.num = context->sample_rate;
                        hb_log("decavcodecaBSInfo: warning: invalid frame sample_rate! Using context sample_rate.");
                    }
                    info->rate.den          = 1;
                    info->samples_per_frame = frame->nb_samples;
                    info->sample_bit_depth  = context->bits_per_raw_sample;

                    int bps = av_get_bits_per_sample(context->codec_id);
                    int channels = av_get_channel_layout_nb_channels(frame->channel_layout);
                    if (bps > 0)
                    {
                        info->bitrate = bps * channels * info->rate.num;
                    }
                    else if (context->bit_rate > 0)
                    {
                        info->bitrate = context->bit_rate;
                    }
                    else
                    {
                        info->bitrate = 1;
                    }

                    if (truehd_mono)
                    {
                        info->channel_layout = AV_CH_LAYOUT_MONO;
                        info->matrix_encoding = AV_MATRIX_ENCODING_NONE;
                    }
                    else
                    {
                        AVFrameSideData *side_data;
                        if ((side_data =
                             av_frame_get_side_data(frame,
                                                    AV_FRAME_DATA_MATRIXENCODING)) != NULL)
                        {
                            info->matrix_encoding = *side_data->data;
                        }
                        else
                        {
                            info->matrix_encoding = AV_MATRIX_ENCODING_NONE;
                        }
                        if (info->matrix_encoding == AV_MATRIX_ENCODING_DOLBY ||
                            info->matrix_encoding == AV_MATRIX_ENCODING_DPLII)
                        {
                            info->channel_layout = AV_CH_LAYOUT_STEREO_DOWNMIX;
                        }
                        else
                        {
                            info->channel_layout = frame->channel_layout;
                        }
                    }
                    if (context->codec_id == AV_CODEC_ID_AC3 ||
                        context->codec_id == AV_CODEC_ID_EAC3)
                    {
                        if (context->audio_service_type == AV_AUDIO_SERVICE_TYPE_KARAOKE)
                        {
                            info->mode = 7;
                        }
                        else
                        {
                            info->mode = context->audio_service_type;
                        }
                    }
                    else if (context->codec_id == AV_CODEC_ID_AAC &&
                             context->extradata_size == 0)
                    {
                        // Parse ADTS AAC streams for AudioSpecificConfig.
                        // This data is required in order to write
                        // proper headers in MP4 and MKV files.
                        AVBitStreamFilterContext* aac_adtstoasc;
                        aac_adtstoasc = av_bitstream_filter_init("aac_adtstoasc");
                        if (aac_adtstoasc)
                        {
                            int ret, size;
                            uint8_t *data;
                            ret = av_bitstream_filter_filter(aac_adtstoasc, context,
                                    NULL, &data, &size, avp.data, avp.size, 0);
                            if (ret >= 0 &&
                                context->extradata_size > 0 &&
                                audio->priv.config.extradata.length == 0)
                            {
                                int len;
                                len = MIN(context->extradata_size, HB_CONFIG_MAX_SIZE);
                                memcpy(audio->priv.config.extradata.bytes,
                                       context->extradata, len);
                                audio->priv.config.extradata.length = len;
                            }
                            av_bitstream_filter_close(aac_adtstoasc);
                        }
                    }

                    ret = 1;
                    av_frame_free(&frame);
                    break;
                }
                dec_pos += dec_len;
                av_frame_free(&frame);
            }
            parse_pos += parse_len;
        }
        buf = buf->next;
    }

    info->profile = context->profile;
    info->level = context->level;
    info->channel_map = &hb_libav_chan_map;

    if ( parser != NULL )
        av_parser_close( parser );
    hb_avcodec_close( context );
    av_freep( &context->extradata );
    av_freep( &context );
    return ret;
}

/* -------------------------------------------------------------
 * General purpose video decoder using libavcodec
 */

static uint8_t *copy_plane( uint8_t *dst, uint8_t* src, int dstride, int sstride,
                            int h )
{
    if ( dstride == sstride )
    {
        memcpy( dst, src, dstride * h );
        return dst + dstride * h;
    }
    int lbytes = dstride <= sstride? dstride : sstride;
    while ( --h >= 0 )
    {
        memcpy( dst, src, lbytes );
        src += sstride;
        dst += dstride;
    }
    return dst;
}

// copy one video frame into an HB buf. If the frame isn't in our color space
// or at least one of its dimensions is odd, use sws_scale to convert/rescale it.
// Otherwise just copy the bits.
static hb_buffer_t *copy_frame( hb_work_private_t *pv )
{
    AVCodecContext *context = pv->context;
    int w, h;
    if ( ! pv->job )
    {
        // HandBrake's video pipeline uses yuv420 color.  This means all
        // dimensions must be even.  So we must adjust the dimensions
        // of incoming video if not even.
        w = context->width & ~1;
        h = context->height & ~1;
    }
    else
    {
        w = pv->job->title->geometry.width;
        h = pv->job->title->geometry.height;
    }

    hb_buffer_t *out = hb_video_buffer_init( w, h );

#ifdef USE_QSV
    // no need to copy the frame data when decoding with QSV to opaque memory
    if (pv->qsv.decode &&
        pv->qsv.config.io_pattern == MFX_IOPATTERN_OUT_OPAQUE_MEMORY)
    {
        out->qsv_details.qsv_atom = pv->frame->data[2];
        out->qsv_details.ctx      = pv->job->qsv.ctx;
        return out;
    }
#endif

    uint8_t *dst = out->data;

    if (context->pix_fmt != AV_PIX_FMT_YUV420P || w != context->width ||
        h != context->height)
    {
        // have to convert to our internal color space and/or rescale
        uint8_t * data[4];
        int       stride[4];
        hb_picture_fill(data, stride, out);

        if (pv->sws_context == NULL            ||
            pv->sws_width   != context->width  ||
            pv->sws_height  != context->height ||
            pv->sws_pix_fmt != context->pix_fmt)
        {
            if (pv->sws_context != NULL)
                sws_freeContext(pv->sws_context);
            pv->sws_context = hb_sws_get_context(context->width,
                                                 context->height,
                                                 context->pix_fmt,
                                                 w, h, AV_PIX_FMT_YUV420P,
                                                 SWS_LANCZOS|SWS_ACCURATE_RND);
            pv->sws_width   = context->width;
            pv->sws_height  = context->height;
            pv->sws_pix_fmt = context->pix_fmt;
        }
        sws_scale(pv->sws_context,
                  (const uint8_t* const *)pv->frame->data,
                  pv->frame->linesize, 0, context->height, data, stride);
    }
    else
    {
        w = out->plane[0].stride;
        h = out->plane[0].height;
        dst = out->plane[0].data;
        copy_plane( dst, pv->frame->data[0], w, pv->frame->linesize[0], h );
        w = out->plane[1].stride;
        h = out->plane[1].height;
        dst = out->plane[1].data;
        copy_plane( dst, pv->frame->data[1], w, pv->frame->linesize[1], h );
        w = out->plane[2].stride;
        h = out->plane[2].height;
        dst = out->plane[2].data;
        copy_plane( dst, pv->frame->data[2], w, pv->frame->linesize[2], h );
    }

    return out;
}

static void log_chapter( hb_work_private_t *pv, int chap_num, int64_t pts )
{
    hb_chapter_t *c;

    if ( !pv->job )
        return;

    c = hb_list_item( pv->job->list_chapter, chap_num - 1 );
    if ( c && c->title )
    {
        hb_log( "%s: \"%s\" (%d) at frame %u time %"PRId64,
                pv->context->codec->name, c->title, chap_num, pv->nframes, pts );
    }
    else
    {
        hb_log( "%s: Chapter %d at frame %u time %"PRId64,
                pv->context->codec->name, chap_num, pv->nframes, pts );
    }
}

static void flushDelayQueue( hb_work_private_t *pv )
{
    hb_buffer_t *buf;
    int slot = pv->queue_primed ? pv->nframes & (HEAP_SIZE-1) : 0;

    // flush all the video packets left on our timestamp-reordering delay q
    while ((buf = pv->delayq[slot]) != NULL)
    {
        buf->s.start = heap_pop(&pv->pts_heap);
        hb_buffer_list_append(&pv->list, buf);
        pv->delayq[slot] = NULL;
        slot = ( slot + 1 ) & (HEAP_SIZE-1);
    }
}

// send cc_buf to the CC decoder(s)
static void cc_send_to_decoder(hb_work_private_t *pv, hb_buffer_t *buf)
{
    if (buf == NULL)
        return;

    // if there's more than one decoder for the captions send a copy
    // of the buffer to all.
    hb_subtitle_t *subtitle;
    int ii = 0, n = hb_list_count(pv->list_subtitle);
    while (--n > 0)
    {
        // make a copy of the buf then forward it to the decoder
        hb_buffer_t *cpy = hb_buffer_dup(buf);

        subtitle = hb_list_item(pv->list_subtitle, ii++);
        hb_fifo_push(subtitle->fifo_in, cpy);
    }
    subtitle = hb_list_item(pv->list_subtitle, ii);
    hb_fifo_push( subtitle->fifo_in, buf );
}

static hb_buffer_t * cc_fill_buffer(hb_work_private_t *pv, uint8_t *cc, int size, int64_t pts)
{
    int cc_count[4] = {0,};
    int ii;
    hb_buffer_t *buf = NULL;

    for (ii = 0; ii < size; ii += 3)
    {
        if ((cc[ii] & 0x04) == 0)    // not valid
            continue;
        if ((cc[ii+1] & 0x7f) == 0 && (cc[ii+2] & 0x7f) == 0) // stuffing
            continue;
        int type = cc[ii] & 0x03;
        cc_count[type]++;
    }

    // Only handles CC1 for now.
    if (cc_count[0] > 0)
    {
        buf = hb_buffer_init(cc_count[0] * 2);
        buf->s.start = pts;
        int jj = 0;
        for (ii = 0; ii < size; ii += 3)
        {
            if ((cc[ii] & 0x04) == 0)    // not valid
                continue;
            if ((cc[ii+1] & 0x7f) == 0 && (cc[ii+2] & 0x7f) == 0) // stuffing
                continue;
            int type = cc[ii] & 0x03;
            if (type == 0)
            {
                buf->data[jj++] = cc[ii+1];
                buf->data[jj++] = cc[ii+2];
            }
        }
    }
    return buf;
}

static int get_frame_type(int type)
{
    switch(type)
    {
        case AV_PICTURE_TYPE_I:
            return HB_FRAME_I;
        case AV_PICTURE_TYPE_B:
            return HB_FRAME_B;
        case AV_PICTURE_TYPE_P:
            return HB_FRAME_P;
    }
    return 0;
}

/*
 * Decodes a video frame from the specified raw packet data
 *      ('data', 'size').
 * The output of this function is stored in 'pv->list', which contains a list
 * of zero or more decoded packets.
 *
 * The returned packets are guaranteed to have their timestamps in the correct
 * order, even if the original packets decoded by libavcodec have misordered
 * timestamps, due to the use of 'packed B-frames'.
 *
 * Internally the set of decoded packets may be buffered in 'pv->delayq'
 * until enough packets have been decoded so that the timestamps can be
 * correctly rewritten, if this is necessary.
 */
static int decodeFrame( hb_work_object_t *w, uint8_t *data, int size, int64_t pts, int64_t dts, uint8_t frametype )
{
    hb_work_private_t *pv = w->private_data;
    int got_picture, oldlevel = 0;
    AVPacket avp;

    if ( global_verbosity_level <= 1 )
    {
        oldlevel = av_log_get_level();
        av_log_set_level( AV_LOG_QUIET );
    }

    av_init_packet(&avp);
    avp.data = data;
    avp.size = size;
    avp.pts  = pts;
    avp.dts  = dts;

    if (pv->palette != NULL)
    {
        uint8_t * palette;
        int size;
        palette = av_packet_new_side_data(&avp, AV_PKT_DATA_PALETTE,
                                          AVPALETTE_SIZE);
        size = MIN(pv->palette->size, AVPALETTE_SIZE);
        memcpy(palette, pv->palette->data, size);
        hb_buffer_close(&pv->palette);
    }

    /*
     * libav avcodec_decode_video2() needs AVPacket flagged with AV_PKT_FLAG_KEY
     * for some codecs. For example, sequence of PNG in a mov container.
     */
    if ( frametype & HB_FRAME_KEY )
    {
        avp.flags |= AV_PKT_FLAG_KEY;
    }

#ifdef USE_QSV_PTS_WORKAROUND
    /*
     * The MediaSDK decoder will return decoded frames in the correct order,
     * but *sometimes* with the incorrect timestamp assigned to them.
     *
     * We work around it by saving the input timestamps (in chronological order)
     * and restoring them after decoding.
     */
    if (pv->qsv.decode && avp.data != NULL)
    {
        hb_av_add_new_pts(pv->qsv.pts_list, avp.pts);
    }
#endif

    if ( avcodec_decode_video2( pv->context, pv->frame, &got_picture, &avp ) < 0 )
    {
        ++pv->decode_errors;
    }

#ifdef USE_QSV
    if (pv->qsv.decode && pv->job->qsv.ctx == NULL && pv->video_codec_opened > 0)
    {
        // this is quite late, but we can't be certain that the QSV context is
        // available until after we call avcodec_decode_video2() at least once
        pv->job->qsv.ctx = pv->context->priv_data;
    }
#endif

#ifdef USE_QSV_PTS_WORKAROUND
    if (pv->qsv.decode && got_picture)
    {
        // we got a decoded frame, restore the lowest available PTS
        pv->frame->pkt_pts = hb_av_pop_next_pts(pv->qsv.pts_list);
    }
#endif

    if ( global_verbosity_level <= 1 )
    {
        av_log_set_level( oldlevel );
    }
    if( got_picture )
    {
        uint16_t flags = 0;

        // ffmpeg makes it hard to attach a pts to a frame. if the MPEG ES
        // packet had a pts we handed it to av_parser_parse (if the packet had
        // no pts we set it to AV_NOPTS_VALUE, but before the parse we can't
        // distinguish between the start of a video frame with no pts & an
        // intermediate packet of some frame which never has a pts). we hope
        // that when parse returns the frame to us the pts we originally
        // handed it will be in parser->pts. we put this pts into avp.pts so
        // that when avcodec_decode_video finally gets around to allocating an
        // AVFrame to hold the decoded frame, avcodec_default_get_buffer can
        // stuff that pts into the it. if all of these relays worked at this
        // point frame.pts should hold the frame's pts from the original data
        // stream or AV_NOPTS_VALUE if it didn't have one. in the latter case
        // we generate the next pts in sequence for it.

        // recompute the frame/field duration, because sometimes it changes
        compute_frame_duration( pv );

        double pts;
        double frame_dur = pv->duration;
        if ( pv->frame->repeat_pict )
        {
            frame_dur += pv->frame->repeat_pict * pv->field_duration;
        }

        // If there was no pts for this frame, assume constant frame rate
        // video & estimate the next frame time from the last & duration.
        if (pv->frame->pkt_pts == AV_NOPTS_VALUE)
        {
            pts = pv->pts_next;
        }
        else
        {
            pts = pv->frame->pkt_pts;
            // Detect streams with broken out of order timestamps
            if (!pv->brokenTS && pv->frame->pkt_pts < pv->prev_pts)
            {
                hb_log("Broken timestamps detected.  Reordering.");
                pv->brokenTS = 1;
            }
            pv->prev_pts = pv->frame->pkt_pts;
        }

        pv->pts_next = pts + frame_dur;

        if ( pv->frame->top_field_first )
        {
            flags |= PIC_FLAG_TOP_FIELD_FIRST;
        }
        if ( !pv->frame->interlaced_frame )
        {
            flags |= PIC_FLAG_PROGRESSIVE_FRAME;
        }
        if ( pv->frame->repeat_pict == 1 )
        {
            flags |= PIC_FLAG_REPEAT_FIRST_FIELD;
        }
        if ( pv->frame->repeat_pict == 2 )
        {
            flags |= PIC_FLAG_REPEAT_FRAME;
        }
        int frametype = get_frame_type(pv->frame->pict_type);

        // Check for CC data
        AVFrameSideData *sd;
        sd = av_frame_get_side_data(pv->frame, AV_FRAME_DATA_A53_CC);
        if (sd != NULL)
        {
            if (!pv->job && pv->title && sd->size > 0)
            {
                hb_subtitle_t *subtitle;
                int i = 0;

                while ((subtitle = hb_list_item(pv->title->list_subtitle, i++)))
                {
                    /*
                     * Let's call them 608 subs for now even if they aren't,
                     * since they are the only types we grok.
                     */
                    if (subtitle->source == CC608SUB)
                    {
                        break;
                    }
                }
                if (subtitle == NULL)
                {
                    subtitle = calloc(sizeof( hb_subtitle_t ), 1);
                    subtitle->track = hb_list_count(pv->title->list_subtitle);
                    subtitle->id = 0;
                    subtitle->format = TEXTSUB;
                    subtitle->source = CC608SUB;
                    subtitle->config.dest = PASSTHRUSUB;
                    subtitle->codec = WORK_DECCC608;
                    subtitle->type = 5;
                    snprintf(subtitle->lang, sizeof( subtitle->lang ),
                             "Closed Captions");
                    /*
                     * The language of the subtitles will be the same as the
                     * first audio track, i.e. the same as the video.
                     */
                    hb_audio_t *audio = hb_list_item(pv->title->list_audio, 0);
                    if (audio != NULL)
                    {
                        snprintf(subtitle->iso639_2, sizeof(subtitle->iso639_2),
                                 "%s", audio->config.lang.iso639_2);
                    } else {
                        snprintf(subtitle->iso639_2, sizeof(subtitle->iso639_2),
                                 "und");
                    }
                    hb_list_add(pv->title->list_subtitle, subtitle);
                }
            }
            if (pv->list_subtitle != NULL && sd->size > 0)
            {
                hb_buffer_t *cc_buf;
                cc_buf = cc_fill_buffer(pv, sd->data, sd->size, pts);
                cc_send_to_decoder(pv, cc_buf);
            }
        }

        hb_buffer_t *buf;

        // if we're doing a scan or this content couldn't have been broken
        // by Microsoft we don't worry about timestamp reordering
        if ( ! pv->job || ! pv->brokenTS )
        {
            buf = copy_frame( pv );
            av_frame_unref(pv->frame);
            buf->s.start = pts;

            buf->s.flags = flags;
            buf->s.frametype = frametype;

            if ( pv->new_chap && buf->s.start >= pv->chap_time )
            {
                buf->s.new_chap = pv->new_chap;
                log_chapter( pv, pv->new_chap, buf->s.start );
                pv->new_chap = 0;
                pv->chap_time = 0;
            }
            hb_buffer_list_append(&pv->list, buf);
            ++pv->nframes;
            return got_picture;
        }

        // XXX This following probably addresses a libavcodec bug but I don't
        //     see an easy fix so we workaround it here.
        //
        // The M$ 'packed B-frames' atrocity results in decoded frames with
        // the wrong timestamp. E.g., if there are 2 b-frames the timestamps
        // we see here will be "2 3 1 5 6 4 ..." instead of "1 2 3 4 5 6".
        // The frames are actually delivered in the right order but with
        // the wrong timestamp. To get the correct timestamp attached to
        // each frame we have a delay queue (longer than the max number of
        // b-frames) & a sorting heap for the timestamps. As each frame
        // comes out of the decoder the oldest frame in the queue is removed
        // and associated with the smallest timestamp. Then the new frame is
        // added to the queue & its timestamp is pushed on the heap.
        // This does nothing if the timestamps are correct (i.e., the video
        // uses a codec that Micro$oft hasn't broken yet) but the frames
        // get timestamped correctly even when M$ has munged them.

        // remove the oldest picture from the frame queue (if any) &
        // give it the smallest timestamp from our heap. The queue size
        // is a power of two so we get the slot of the oldest by masking
        // the frame count & this will become the slot of the newest
        // once we've removed & processed the oldest.
        int slot = pv->nframes & (HEAP_SIZE-1);
        if ( ( buf = pv->delayq[slot] ) != NULL )
        {
            pv->queue_primed = 1;
            buf->s.start = heap_pop( &pv->pts_heap );
            if ( pv->new_chap && buf->s.start >= pv->chap_time )
            {
                buf->s.new_chap = pv->new_chap;
                log_chapter( pv, pv->new_chap, buf->s.start );
                pv->new_chap = 0;
                pv->chap_time = 0;
            }
            hb_buffer_list_append(&pv->list, buf);
        }

        // add the new frame to the delayq & push its timestamp on the heap
        buf = copy_frame( pv );
        av_frame_unref(pv->frame);
        /* Store picture flags for later use by filters */
        buf->s.flags = flags;
        buf->s.frametype = frametype;
        pv->delayq[slot] = buf;
        heap_push( &pv->pts_heap, pts );

        ++pv->nframes;
    }

    return got_picture;
}
static void decodeVideo( hb_work_object_t *w, uint8_t *data, int size, int64_t pts, int64_t dts, uint8_t frametype )
{
    hb_work_private_t *pv = w->private_data;

    /*
     * The following loop is a do..while because we need to handle both
     * data & the flush at the end (signaled by size=0). At the end there's
     * generally a frame in the parser & one or more frames in the decoder
     * (depending on the bframes setting).
     */
    int pos = 0;
    do {
        uint8_t *pout;
        int pout_len, len;
        int64_t parser_pts, parser_dts;
        if ( pv->parser )
        {
            len = av_parser_parse2( pv->parser, pv->context, &pout, &pout_len,
                                    data + pos, size - pos, pts, dts, 0 );
            parser_pts = pv->parser->pts;
            parser_dts = pv->parser->dts;
        }
        else
        {
            pout = data;
            len = pout_len = size;
            parser_pts = pts;
            parser_dts = dts;
        }
        pos += len;

        if ( pout_len > 0 )
        {
            decodeFrame( w, pout, pout_len, parser_pts, parser_dts, frametype );
        }
    } while ( pos < size );

    /* the stuff above flushed the parser, now flush the decoder */
    if (size <= 0)
    {
        while (decodeFrame(w, NULL, 0, AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0))
        {
            continue;
        }
#ifdef USE_QSV
        if (pv->qsv.decode)
        {
            // flush a second time
            while (decodeFrame(w, NULL, 0, AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0))
            {
                continue;
            }
        }
#endif
        flushDelayQueue(pv);
        if (pv->list_subtitle != NULL)
            cc_send_to_decoder(pv, hb_buffer_eof_init());
    }
}

static int decavcodecvInit( hb_work_object_t * w, hb_job_t * job )
{

    hb_work_private_t *pv = calloc( 1, sizeof( hb_work_private_t ) );

    w->private_data = pv;
    pv->wait_for_keyframe = 60;
    pv->job   = job;
    if ( job )
        pv->title = job->title;
    else
        pv->title = w->title;
    hb_buffer_list_clear(&pv->list);

#ifdef USE_QSV
    if (hb_qsv_decode_is_enabled(job))
    {
        // determine which encoder we're using
        hb_qsv_info_t *info = hb_qsv_info_get(job->vcodec);
        pv->qsv.decode = info != NULL;
        if (pv->qsv.decode)
        {
            // setup the QSV configuration
            pv->qsv.config.io_pattern         = MFX_IOPATTERN_OUT_OPAQUE_MEMORY;
            pv->qsv.config.impl_requested     = info->implementation;
            pv->qsv.config.async_depth        = job->qsv.async_depth;
            pv->qsv.config.sync_need          =  0;
            pv->qsv.config.usage_threaded     =  1;
            pv->qsv.config.additional_buffers = 64; // FIFO_LARGE
            if (info->capabilities & HB_QSV_CAP_RATECONTROL_LA)
            {
                // more surfaces may be needed for the lookahead
                pv->qsv.config.additional_buffers = 160;
            }
            pv->qsv.codec_name = hb_qsv_decode_get_codec_name(w->codec_param);
        }
    }
    else
    {
        pv->qsv.decode = 0;
    }
#endif

    if( pv->job && pv->job->title && !pv->job->title->has_resolution_change )
    {
        pv->threads = HB_FFMPEG_THREADS_AUTO;
    }

    AVCodec *codec = NULL;

#ifdef USE_QSV
    if (pv->qsv.decode)
    {
        codec = avcodec_find_decoder_by_name(pv->qsv.codec_name);
    }
    else
#endif
    {
        codec = avcodec_find_decoder(w->codec_param);
    }
    if ( codec == NULL )
    {
        hb_log( "decavcodecvInit: failed to find codec for id (%d)", w->codec_param );
        return 1;
    }

    if ( pv->title->opaque_priv )
    {
        AVFormatContext *ic = (AVFormatContext*)pv->title->opaque_priv;

        pv->context = avcodec_alloc_context3(codec);
        avcodec_copy_context( pv->context, ic->streams[pv->title->video_id]->codec);
        pv->context->workaround_bugs = FF_BUG_AUTODETECT;
        pv->context->err_recognition = AV_EF_CRCCHECK;
        pv->context->error_concealment = FF_EC_GUESS_MVS|FF_EC_DEBLOCK;

#ifdef USE_QSV
        if (pv->qsv.decode)
        {
#ifdef USE_QSV_PTS_WORKAROUND
            pv->qsv.pts_list = hb_list_init();
#endif
            // set the QSV configuration before opening the decoder
            pv->context->hwaccel_context = &pv->qsv.config;
        }
#endif

        // Set encoder opts...
        AVDictionary * av_opts = NULL;
        av_dict_set( &av_opts, "refcounted_frames", "1", 0 );
        if (pv->title->flags & HBTF_NO_IDR)
        {
            av_dict_set( &av_opts, "flags", "output_corrupt", 0 );
        }

        if ( hb_avcodec_open( pv->context, codec, &av_opts, pv->threads ) )
        {
            av_dict_free( &av_opts );
            hb_log( "decavcodecvInit: avcodec_open failed" );
            return 1;
        }
        av_dict_free( &av_opts );

        pv->video_codec_opened = 1;
        // avi, mkv and possibly mp4 containers can contain the M$ VFW packed
        // b-frames abortion that messes up frame ordering and timestamps.
        // XXX ffmpeg knows which streams are broken but doesn't expose the
        //     info externally. We should patch ffmpeg to add a flag to the
        //     codec context for this but until then we mark all ffmpeg streams
        //     as suspicious.
        pv->brokenTS = 1;
    }
    else
    {
        pv->parser = av_parser_init( w->codec_param );
    }

    pv->frame = av_frame_alloc();
    if (pv->frame == NULL)
    {
        hb_log("decavcodecvInit: av_frame_alloc failed");
        return 1;
    }

    /*
     * If not scanning, then are we supposed to extract Closed Captions
     * and send them to the decoder?
     */
    if (job != NULL && hb_list_count(job->list_subtitle) > 0)
    {
        hb_subtitle_t *subtitle;
        int i = 0;

        while ((subtitle = hb_list_item(job->list_subtitle, i++)) != NULL)
        {
            if (subtitle->source == CC608SUB)
            {
                if (pv->list_subtitle == NULL)
                {
                    pv->list_subtitle = hb_list_init();
                }
                hb_list_add(pv->list_subtitle, subtitle);
            }
        }
    }
    return 0;
}

static int setup_extradata( hb_work_object_t *w, hb_buffer_t *in )
{
    hb_work_private_t *pv = w->private_data;

    // we can't call the avstream funcs but the read_header func in the
    // AVInputFormat may set up some state in the AVContext. In particular
    // vc1t_read_header allocates 'extradata' to deal with header issues
    // related to Microsoft's bizarre engineering notions. We alloc a chunk
    // of space to make vc1 work then associate the codec with the context.
    if (pv->context->extradata == NULL)
    {
        if (pv->parser == NULL || pv->parser == NULL ||
            pv->parser->parser->split == NULL)
        {
            return 0;
        }
        else
        {
            int size;
            size = pv->parser->parser->split(pv->context, in->data, in->size);
            if (size > 0)
            {
                pv->context->extradata_size = size;
                pv->context->extradata =
                                av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
                if (pv->context->extradata == NULL)
                    return 1;
                memcpy(pv->context->extradata, in->data, size);
                return 0;
            }
        }
        return 1;
    }

    return 0;
}

static int decavcodecvWork( hb_work_object_t * w, hb_buffer_t ** buf_in,
                            hb_buffer_t ** buf_out )
{
    hb_work_private_t *pv = w->private_data;
    hb_buffer_t *in = *buf_in;
    int64_t pts = AV_NOPTS_VALUE;
    int64_t dts = pts;

    *buf_in = NULL;
    *buf_out = NULL;

    // libavcodec/mpeg12dec.c requires buffers to be zero padded.
    // If not zero padded, it can get stuck in an infinite loop.
    // It's likely there are other decoders that expect the same.
    if (in->data != NULL)
    {
        memset(in->data + in->size, 0, in->alloc - in->size);
    }

    /* if we got an empty buffer signaling end-of-stream send it downstream */
    if (in->s.flags & HB_BUF_FLAG_EOF)
    {
        if (pv->context != NULL && pv->context->codec != NULL)
        {
            decodeVideo(w, in->data, 0, pts, dts, 0);
        }
        hb_buffer_list_append(&pv->list, in);
        *buf_out = hb_buffer_list_clear(&pv->list);
        return HB_WORK_DONE;
    }

    // if this is the first frame open the codec (we have to wait for the
    // first frame because of M$ VC1 braindamage).
    if ( !pv->video_codec_opened )
    {

        AVCodec *codec = NULL;
#ifdef USE_QSV
        if (pv->qsv.decode)
        {
            codec = avcodec_find_decoder_by_name(pv->qsv.codec_name);
        }
        else
#endif
        {
            codec = avcodec_find_decoder(w->codec_param);
        }

        if ( codec == NULL )
        {
            hb_log( "decavcodecvWork: failed to find codec for id (%d)", w->codec_param );
            *buf_out = hb_buffer_eof_init();
            return HB_WORK_DONE;
        }

        pv->context = avcodec_alloc_context3( codec );
        pv->context->workaround_bugs = FF_BUG_AUTODETECT;
        pv->context->err_recognition = AV_EF_CRCCHECK;
        pv->context->error_concealment = FF_EC_GUESS_MVS|FF_EC_DEBLOCK;

        if ( setup_extradata( w, in ) )
        {
            // we didn't find the headers needed to set up extradata.
            // the codec will abort if we open it so just free the buf
            // and hope we eventually get the info we need.
            hb_buffer_close( &in );
            return HB_WORK_OK;
        }

#ifdef USE_QSV
        if (pv->qsv.decode)
        {
#ifdef USE_QSV_PTS_WORKAROUND
            pv->qsv.pts_list = hb_list_init();
#endif
            // set the QSV configuration before opening the decoder
            pv->context->hwaccel_context = &pv->qsv.config;
        }
#endif

        AVDictionary * av_opts = NULL;
        av_dict_set( &av_opts, "refcounted_frames", "1", 0 );
        if (pv->title->flags & HBTF_NO_IDR)
        {
            av_dict_set( &av_opts, "flags", "output_corrupt", 0 );
        }

        // disable threaded decoding for scan, can cause crashes
        if ( hb_avcodec_open( pv->context, codec, &av_opts, pv->threads ) )
        {
            av_dict_free( &av_opts );
            hb_log( "decavcodecvWork: avcodec_open failed" );
            *buf_out = hb_buffer_eof_init();
            return HB_WORK_DONE;
        }
        av_dict_free( &av_opts );
        pv->video_codec_opened = 1;
    }

    if( in->s.start >= 0 )
    {
        pts = in->s.start;
        dts = in->s.renderOffset;
    }
    if ( in->s.new_chap )
    {
        pv->new_chap = in->s.new_chap;
        pv->chap_time = pts >= 0? pts : pv->pts_next;
    }
    if (in->palette != NULL)
    {
        pv->palette = in->palette;
        in->palette = NULL;
    }
    decodeVideo( w, in->data, in->size, pts, dts, in->s.frametype );
    hb_buffer_close( &in );
    *buf_out = hb_buffer_list_clear(&pv->list);
    return HB_WORK_OK;
}

static void compute_frame_duration( hb_work_private_t *pv )
{
    double duration = 0.;
    int64_t max_fps = 64LL;

    // context->time_base may be in fields, so set the max *fields* per second
    if ( pv->context->ticks_per_frame > 1 )
        max_fps *= pv->context->ticks_per_frame;

    if ( pv->title->opaque_priv )
    {
        // If ffmpeg is demuxing for us, it collects some additional
        // information about framerates that is often more accurate
        // than context->time_base.
        AVFormatContext *ic = (AVFormatContext*)pv->title->opaque_priv;
        AVStream *st = ic->streams[pv->title->video_id];
        if ( st->nb_frames && st->duration )
        {
            // compute the average frame duration from the total number
            // of frames & the total duration.
            duration = ( (double)st->duration * (double)st->time_base.num ) /
                       ( (double)st->nb_frames * (double)st->time_base.den );
        }
        // Raw demuxers set a default fps of 25 and do not parse
        // a value from the container.  So use the codec time_base
        // for raw demuxers.
        else if (ic->iformat->raw_codec_id == AV_CODEC_ID_NONE)
        {
            // XXX We don't have a frame count or duration so try to use the
            // far less reliable time base info in the stream.
            // Because the time bases are so screwed up, we only take values
            // in the range 8fps - 64fps.
            AVRational *tb = NULL;
            if ( st->avg_frame_rate.den * 64LL > st->avg_frame_rate.num &&
                 st->avg_frame_rate.num > st->avg_frame_rate.den * 8LL )
            {
                tb = &(st->avg_frame_rate);
                duration =  (double)tb->den / (double)tb->num;
            }
            else if ( st->time_base.num * 64LL > st->time_base.den &&
                      st->time_base.den > st->time_base.num * 8LL )
            {
                tb = &(st->time_base);
                duration =  (double)tb->num / (double)tb->den;
            }
        }
        if ( !duration &&
             pv->context->time_base.num * max_fps > pv->context->time_base.den &&
             pv->context->time_base.den > pv->context->time_base.num * 8LL )
        {
            duration =  (double)pv->context->time_base.num /
                        (double)pv->context->time_base.den;
            if ( pv->context->ticks_per_frame > 1 )
            {
                // for ffmpeg 0.5 & later, the H.264 & MPEG-2 time base is
                // field rate rather than frame rate so convert back to frames.
                duration *= pv->context->ticks_per_frame;
            }
        }
    }
    else
    {
        if ( pv->context->time_base.num * max_fps > pv->context->time_base.den &&
             pv->context->time_base.den > pv->context->time_base.num * 8LL )
        {
            duration =  (double)pv->context->time_base.num /
                            (double)pv->context->time_base.den;
            if ( pv->context->ticks_per_frame > 1 )
            {
                // for ffmpeg 0.5 & later, the H.264 & MPEG-2 time base is
                // field rate rather than frame rate so convert back to frames.
                duration *= pv->context->ticks_per_frame;
            }
        }
    }
    if ( duration == 0 )
    {
        // No valid timing info found in the stream, so pick some value
        duration = 1001. / 24000.;
    }
    pv->duration = duration * 90000.;
    pv->field_duration = pv->duration;
    if ( pv->context->ticks_per_frame > 1 )
    {
        pv->field_duration /= pv->context->ticks_per_frame;
    }
}

static int decavcodecvInfo( hb_work_object_t *w, hb_work_info_t *info )
{
    hb_work_private_t *pv = w->private_data;

    int clock_min, clock_max, clock;
    hb_video_framerate_get_limits(&clock_min, &clock_max, &clock);

    memset( info, 0, sizeof(*info) );

    if (pv->context == NULL)
        return 0;

    info->bitrate = pv->context->bit_rate;
    // HandBrake's video pipeline uses yuv420 color.  This means all
    // dimensions must be even.  So we must adjust the dimensions
    // of incoming video if not even.
    info->geometry.width = pv->context->width & ~1;
    info->geometry.height = pv->context->height & ~1;

    info->geometry.par.num = pv->context->sample_aspect_ratio.num;
    info->geometry.par.den = pv->context->sample_aspect_ratio.den;

    compute_frame_duration( pv );
    info->rate.num = clock;
    info->rate.den = pv->duration * (clock / 90000.);

    info->profile = pv->context->profile;
    info->level = pv->context->level;
    info->name = pv->context->codec->name;

    switch( pv->context->color_primaries )
    {
        case AVCOL_PRI_BT709:
            info->color_prim = HB_COLR_PRI_BT709;
            break;
        case AVCOL_PRI_BT470BG:
            info->color_prim = HB_COLR_PRI_EBUTECH;
            break;
        case AVCOL_PRI_BT470M:
        case AVCOL_PRI_SMPTE170M:
        case AVCOL_PRI_SMPTE240M:
            info->color_prim = HB_COLR_PRI_SMPTEC;
            break;
        default:
        {
            if ((info->geometry.width >= 1280 || info->geometry.height >= 720)||
                (info->geometry.width >   720 && info->geometry.height >  576 ))
                // ITU BT.709 HD content
                info->color_prim = HB_COLR_PRI_BT709;
            else if( info->rate.den == 1080000 )
                // ITU BT.601 DVD or SD TV content (PAL)
                info->color_prim = HB_COLR_PRI_EBUTECH;
            else
                // ITU BT.601 DVD or SD TV content (NTSC)
                info->color_prim = HB_COLR_PRI_SMPTEC;
            break;
        }
    }

    switch( pv->context->color_trc )
    {
        case AVCOL_TRC_SMPTE240M:
            info->color_transfer = HB_COLR_TRA_SMPTE240M;
            break;
        default:
            // ITU BT.601, BT.709, anything else
            info->color_transfer = HB_COLR_TRA_BT709;
            break;
    }

    switch( pv->context->colorspace )
    {
        case AVCOL_SPC_BT709:
            info->color_matrix = HB_COLR_MAT_BT709;
            break;
        case AVCOL_SPC_FCC:
        case AVCOL_SPC_BT470BG:
        case AVCOL_SPC_SMPTE170M:
        case AVCOL_SPC_RGB: // libswscale rgb2yuv
            info->color_matrix = HB_COLR_MAT_SMPTE170M;
            break;
        case AVCOL_SPC_SMPTE240M:
            info->color_matrix = HB_COLR_MAT_SMPTE240M;
            break;
        default:
        {
            if ((info->geometry.width >= 1280 || info->geometry.height >= 720)||
                (info->geometry.width >   720 && info->geometry.height >  576 ))
                // ITU BT.709 HD content
                info->color_matrix = HB_COLR_MAT_BT709;
            else
                // ITU BT.601 DVD or SD TV content (PAL)
                // ITU BT.601 DVD or SD TV content (NTSC)
                info->color_matrix = HB_COLR_MAT_SMPTE170M;
            break;
        }
    }

    info->video_decode_support = HB_DECODE_SUPPORT_SW;
    switch (pv->context->codec_id)
    {
        case AV_CODEC_ID_H264:
            if (pv->context->pix_fmt == AV_PIX_FMT_YUV420P ||
                pv->context->pix_fmt == AV_PIX_FMT_YUVJ420P)
            {
#ifdef USE_QSV
                info->video_decode_support |= HB_DECODE_SUPPORT_QSV;
#endif
            }
            break;

        default:
            break;
    }

    return 1;
}

static int decavcodecvBSInfo( hb_work_object_t *w, const hb_buffer_t *buf,
                              hb_work_info_t *info )
{
    return 0;
}

static void decavcodecvFlush( hb_work_object_t *w )
{
    hb_work_private_t *pv = w->private_data;

    if (pv->context != NULL && pv->context->codec != NULL)
    {
        flushDelayQueue( pv );
        hb_buffer_list_close(&pv->list);
        if ( pv->title->opaque_priv == NULL )
        {
            pv->video_codec_opened = 0;
            hb_avcodec_close( pv->context );
            av_freep( &pv->context->extradata );
            av_freep( &pv->context );
            if ( pv->parser )
            {
                av_parser_close(pv->parser);
            }
            pv->parser = av_parser_init( w->codec_param );
        }
        else
        {
            avcodec_flush_buffers( pv->context );
        }
    }
    pv->wait_for_keyframe = 60;
}

hb_work_object_t hb_decavcodecv =
{
    .id = WORK_DECAVCODECV,
    .name = "Video decoder (libavcodec)",
    .init = decavcodecvInit,
    .work = decavcodecvWork,
    .close = decavcodecClose,
    .flush = decavcodecvFlush,
    .info = decavcodecvInfo,
    .bsinfo = decavcodecvBSInfo
};
static void decodeAudio(hb_audio_t *audio, hb_work_private_t *pv, uint8_t *data,
                        int size, int64_t pts)
{
    AVCodecContext *context = pv->context;
    int loop_limit = 256;
    int pos = 0;

    // If we are given a pts, use it; but don't lose partial ticks.
    if (pts != AV_NOPTS_VALUE && (int64_t)pv->pts_next != pts)
        pv->pts_next = pts;
    while (pos < size)
    {
        int got_frame;
        AVPacket avp;

        av_init_packet(&avp);
        avp.data = data + pos;
        avp.size = size - pos;
        avp.pts  = pv->pts_next;
        avp.dts  = AV_NOPTS_VALUE;

        int len = avcodec_decode_audio4(context, pv->frame, &got_frame, &avp);
        if (len < 0)
        {
            ++pv->decode_errors;
        }
        if ((len < 0) || (!got_frame && !(loop_limit--)))
        {
            return;
        }
        else
        {
            loop_limit = 256;
        }

        pos += len;

        if (got_frame)
        {
            hb_buffer_t *out;
            int samplerate;
            // libavcoded doesn't yet consistently set frame->sample_rate
            if (pv->frame->sample_rate != 0)
            {
                samplerate = pv->frame->sample_rate;
            }
            else
            {
                samplerate = context->sample_rate;
            }
            double duration = (90000. * pv->frame->nb_samples /
                               (double)samplerate);

            if (audio->config.out.codec & HB_ACODEC_PASS_FLAG)
            {
                // Note that even though we are doing passthru, we had to decode
                // so that we know the stop time and the pts of the next audio
                // packet.
                out = hb_buffer_init(avp.size);
                memcpy(out->data, avp.data, avp.size);
            }
            else
            {
                AVFrameSideData *side_data;
                if ((side_data =
                     av_frame_get_side_data(pv->frame,
                                            AV_FRAME_DATA_DOWNMIX_INFO)) != NULL)
                {
                    double surround_mix_level, center_mix_level;
                    AVDownmixInfo *downmix_info = (AVDownmixInfo*)side_data->data;
                    if (audio->config.out.mixdown == HB_AMIXDOWN_DOLBY ||
                        audio->config.out.mixdown == HB_AMIXDOWN_DOLBYPLII)
                    {
                        surround_mix_level = downmix_info->surround_mix_level_ltrt;
                        center_mix_level   = downmix_info->center_mix_level_ltrt;
                    }
                    else
                    {
                        surround_mix_level = downmix_info->surround_mix_level;
                        center_mix_level   = downmix_info->center_mix_level;
                    }
                    hb_audio_resample_set_mix_levels(pv->resample,
                                                     surround_mix_level,
                                                     center_mix_level,
                                                     downmix_info->lfe_mix_level);
                }
                hb_audio_resample_set_channel_layout(pv->resample,
                                                     pv->frame->channel_layout);
                hb_audio_resample_set_sample_fmt(pv->resample,
                                                 pv->frame->format);
                if (hb_audio_resample_update(pv->resample))
                {
                    hb_log("decavcodec: hb_audio_resample_update() failed");
                    av_frame_unref(pv->frame);
                    return;
                }
                out = hb_audio_resample(pv->resample, pv->frame->extended_data,
                                        pv->frame->nb_samples);
            }
            av_frame_unref(pv->frame);

            if (out != NULL)
            {
                out->s.start    = pv->pts_next;
                out->s.duration = duration;
                out->s.stop     = duration + pv->pts_next;
                pv->pts_next    = duration + pv->pts_next;
                hb_buffer_list_append(&pv->list, out);
            }
            ++pv->nframes;
        }
    }
}