decssasub: allow out of order timestamps

Out of order timestamps is allowed by the spec.

Switch from out internal demuxer to ffmpeg's ssa demux.  ffmpeg already
handles out of order timestamps.

Fixes https://github.com/HandBrake/HandBrake/issues/2906

1 files changed, 77 insertions, 266 deletions

diff --git a/libhb/decssasub.c b/libhb/decssasub.c
index 2e8e2ae05..5175ca7a6 100644
--- a/libhb/decssasub.c
+++ b/libhb/decssasub.c
@@ -23,92 +23,45 @@
  *
  * @author David Foster (davidfstr)
  */
-#include <stdlib.h>
-#include <stdio.h>
-#include <ctype.h>
-#include "handbrake/handbrake.h"
 
-#include <ass/ass.h>
+#include "handbrake/handbrake.h"
 #include "handbrake/decavsub.h"
-#include "handbrake/colormap.h"
+#include "libavformat/avformat.h"
 
 struct hb_work_private_s
 {
+    AVFormatContext    * ic;
     hb_avsub_context_t * ctx;
-    hb_job_t      * job;
-    hb_subtitle_t * subtitle;
-
-    // SSA Import
-    FILE          * file;
-    int             readOrder;
+    AVPacket             avpkt;
+    hb_subtitle_t      * subtitle;
 
     // Time of first desired subtitle adjusted by reader_pts_offset
     uint64_t start_time;
     uint64_t stop_time;
 };
 
-#define SSA_VERBOSE_PACKETS 0
-
 static int extradataInit( hb_work_private_t * pv )
 {
-    int    events = 0;
-    char * events_tag = "[Events]";
-    char * format_tag = "Format:";
-    int    events_len = strlen(events_tag);;
-    int    format_len = strlen(format_tag);;
-    char * header = NULL;
-
-    while (1)
+    if (pv->ic->nb_streams < 1)
     {
-        char    * line = NULL;
-        ssize_t   len;
-        size_t    size = 0;
-
-        len = hb_getline(&line, &size, pv->file);
-        if (len < 0)
-        {
-            // Incomplete SSA header
-            free(header);
-            return 1;
-        }
-        if (len > 0 && line != NULL)
-        {
-            if (header != NULL)
-            {
-                char * tmp = header;
-                header = hb_strdup_printf("%s%s", header, line);
-                free(tmp);
-            }
-            else
-            {
-                header = strdup(line);
-            }
-            if (!events)
-            {
-                if (len >= events_len &&
-                    !strncasecmp(line, events_tag, events_len))
-                {
-                    events = 1;
-                }
-            }
-            else
-            {
-                if (len >= format_len &&
-                    !strncasecmp(line, format_tag, format_len))
-                {
-                    free(line);
-                    break;
-                }
-                // Improperly formatted SSA header
-                free(header);
-                return 1;
-            }
-        }
-        free(line);
+        hb_error("SSA demux found no streams");
+        return 1;
     }
-    pv->subtitle->extradata = (uint8_t*)header;
-    pv->subtitle->extradata_size = strlen(header) + 1;
 
+    AVStream * st = pv->ic->streams[0];
+    if (st->codecpar->codec_id != AV_CODEC_ID_ASS)
+    {
+        hb_error("SSA demux found wrong codec_id %x", st->codecpar->codec_id);
+        return 1;
+    }
+    if (st->codecpar->extradata != NULL)
+    {
+        pv->subtitle->extradata = malloc(st->codecpar->extradata_size + 1);
+        memcpy(pv->subtitle->extradata,
+               st->codecpar->extradata, st->codecpar->extradata_size);
+        pv->subtitle->extradata[st->codecpar->extradata_size] = 0;
+        pv->subtitle->extradata_size = st->codecpar->extradata_size + 1;
+    }
     return 0;
 }
 
@@ -117,35 +70,33 @@ static int decssaInit( hb_work_object_t * w, hb_job_t * job )
     hb_work_private_t * pv;
     int                 ii;
 
-    pv              = calloc( 1, sizeof( hb_work_private_t ) );
-    if (pv == NULL)
+    if (w->subtitle->config.src_filename == NULL)
     {
+        hb_error("No SSA subtitle file specified");
         goto fail;
     }
-    w->private_data = pv;
-    pv->ctx = decavsubInit(w, job);
-    if (pv->ctx == NULL)
+
+    pv = calloc( 1, sizeof( hb_work_private_t ) );
+    if (pv == NULL)
     {
         goto fail;
     }
-    pv->job         = job;
+    w->private_data = pv;
     pv->subtitle    = w->subtitle;
-
-    if (pv->subtitle->config.src_filename == NULL)
+    av_init_packet(&pv->avpkt);
+    if (avformat_open_input(&pv->ic, pv->subtitle->config.src_filename,
+        NULL, NULL ) < 0 )
     {
-        hb_error("No SSA subtitle file specified");
+        hb_error("Could not open the SSA subtitle file '%s'\n",
+                 pv->subtitle->config.src_filename);
         goto fail;
     }
-
-    pv->file = hb_fopen(pv->subtitle->config.src_filename, "r");
-    if(pv->file == NULL)
+    pv->ctx = decavsubInit(w, job);
+    if (pv->ctx == NULL)
     {
-        hb_error("Could not open the SSA subtitle file '%s'\n",
-                 pv->subtitle->config.src_filename);
         goto fail;
     }
 
-    // Read SSA header and store in subtitle extradata
     if (extradataInit(pv))
     {
         goto fail;
@@ -192,10 +143,11 @@ static int decssaInit( hb_work_object_t * w, hb_job_t * job )
 fail:
     if (pv != NULL)
     {
+        av_packet_unref(&pv->avpkt);
         decavsubClose(pv->ctx);
-        if (pv->file != NULL)
+        if (pv->ic)
         {
-            fclose(pv->file);
+            avformat_close_input(&pv->ic);
         }
         free(pv);
         w->private_data = NULL;
@@ -203,146 +155,67 @@ fail:
     return 1;
 }
 
-#define SSA_2_HB_TIME(hr,min,sec,centi) \
-    ( 90LL * ( hr    * 1000LL * 60 * 60 +\
-              min   * 1000LL * 60 +\
-              sec   * 1000LL +\
-              centi * 10LL ) )
-
-/*
- * Parses the start and stop time from the specified SSA packet.
- *
- * Returns true if parsing failed; false otherwise.
- */
-static int parse_timing( char *line, int64_t *start, int64_t *stop )
+static hb_buffer_t * ssa_read( hb_work_private_t * pv )
 {
-    /*
-     * Parse Start and End fields for timing information
-     */
-    int start_hr, start_min, start_sec, start_centi;
-    int   end_hr,   end_min,   end_sec,   end_centi;
-    // SSA subtitles have an empty layer field (bare ',').  The scanf
-    // format specifier "%*128[^,]" will not match on a bare ','.  There
-    // must be at least one non ',' character in the match.  So the format
-    // specifier is placed directly next to the ':' so that the next
-    // expected ' ' after the ':' will be the character it matches on
-    // when there is no layer field.
-    int numPartsRead = sscanf(line, "Dialogue:%*128[^,],"
-        "%d:%d:%d.%d,"  // Start
-        "%d:%d:%d.%d,", // End
-        &start_hr, &start_min, &start_sec, &start_centi,
-          &end_hr,   &end_min,   &end_sec,   &end_centi );
-    if ( numPartsRead != 8 )
-        return 1;
-
-    *start = SSA_2_HB_TIME(start_hr, start_min, start_sec, start_centi);
-    *stop  = SSA_2_HB_TIME(  end_hr,   end_min,   end_sec,   end_centi);
-
-    return 0;
-}
+    int           err;
+    hb_buffer_t * out;
 
-static char * find_field( char * pos, char * end, int fieldNum )
-{
-    int curFieldID = 1;
-    while (pos < end)
+    if ((err = av_read_frame(pv->ic, &pv->avpkt)) < 0)
     {
-        if ( *pos++ == ',' )
+        if (err != AVERROR_EOF)
         {
-            curFieldID++;
-            if ( curFieldID == fieldNum )
-                return pos;
+            hb_error("SSA demux read error %d", err);
         }
+        return hb_buffer_eof_init();
     }
-    return NULL;
-}
+    AVStream * st = pv->ic->streams[pv->avpkt.stream_index];
 
-/*
- * SSA line format:
- *   Dialogue: Marked,Start,End,Style,Name,MarginL,MarginR,MarginV,Effect,Text '\0'
- *             1      2     3   4     5    6       7       8       9      10
- *
- * MKV-SSA packet format:
- *   ReadOrder,Marked,          Style,Name,MarginL,MarginR,MarginV,Effect,Text '\0'
- *   1         2                3     4    5       6       7       8      9
- */
-static hb_buffer_t *
-decode_line_to_mkv_ssa( hb_work_private_t * pv, char * line, int size )
-{
-    hb_buffer_t * out;
+    out = hb_buffer_init(pv->avpkt.size + 1);
+    memcpy(out->data, pv->avpkt.data, pv->avpkt.size);
+    out->data[pv->avpkt.size] = 0;
+    out->size = pv->avpkt.size;
 
-    // Trim trailing CR/LF
-    while (size > 0 && (line[size - 1] == '\n' || line[size - 1] == '\r'))
+    double tsconv = (double)90000. * st->time_base.num / st->time_base.den;
+    if (pv->avpkt.pts != AV_NOPTS_VALUE)
     {
-        line[--size] = 0;
+        out->s.start = pv->avpkt.pts * tsconv;
     }
-
-    int64_t start, stop;
-    if (parse_timing(line, &start, &stop))
+    if (pv->avpkt.dts != AV_NOPTS_VALUE)
     {
-        goto fail;
+        out->s.renderOffset = pv->avpkt.dts * tsconv;
     }
-
-    // Convert the SSA packet to MKV-SSA format, which is what libass expects
-    char * mkvSSA;
-    int    numPartsRead;
-    char * styleToTextFields;
-    char * layerField = malloc(size);
-
-    // SSA subtitles have an empty layer field (bare ',').  The scanf
-    // format specifier "%*128[^,]" will not match on a bare ','.  There
-    // must be at least one non ',' character in the match.  So the format
-    // specifier is placed directly next to the ':' so that the next
-    // expected ' ' after the ':' will be the character it matches on
-    // when there is no layer field.
-    numPartsRead = sscanf( (char *)line, "Dialogue:%128[^,],", layerField );
-    if ( numPartsRead != 1 )
+    if (out->s.renderOffset >= 0 && out->s.start == AV_NOPTS_VALUE)
     {
-        free(layerField);
-        goto fail;
+        out->s.start = out->s.renderOffset;
     }
-
-    styleToTextFields = find_field( line, line + size, 4 );
-    if ( styleToTextFields == NULL ) {
-        free( layerField );
-        goto fail;
+    else if (out->s.renderOffset == AV_NOPTS_VALUE && out->s.start >= 0)
+    {
+        out->s.renderOffset = out->s.start;
     }
-
-    // The sscanf conversion above will result in an extra space
-    // before the layerField.  Strip the space.
-    char *stripLayerField = layerField;
-    for(; *stripLayerField == ' '; stripLayerField++);
-
-    out = hb_buffer_init( size + 1 );
-    mkvSSA = (char*)out->data;
-
-    mkvSSA[0] = '\0';
-    sprintf(mkvSSA, "%d", pv->readOrder++);
-    strcat( mkvSSA, "," );
-    strcat( mkvSSA, stripLayerField );
-    strcat( mkvSSA, "," );
-    strcat( mkvSSA, (char *)styleToTextFields );
-
-    out->size           = strlen(mkvSSA) + 1;
-    out->s.frametype    = HB_FRAME_SUBTITLE;
-    out->s.start        = start + pv->subtitle->config.offset * 90;
-    out->s.duration     = stop - start;
-    out->s.stop         = stop + pv->subtitle->config.offset * 90;
-
-    if (out->size == 0)
+    int64_t pkt_duration = pv->avpkt.duration;
+    if (pkt_duration != AV_NOPTS_VALUE)
     {
-        hb_buffer_close(&out);
+        out->s.duration = pkt_duration * tsconv;
+        out->s.stop = out->s.start + out->s.duration;
     }
-    else if (out->s.stop  <= pv->start_time ||
-             out->s.start >= pv->stop_time)
+    else
+    {
+        out->s.duration = (int64_t)AV_NOPTS_VALUE;
+    }
+    out->s.type = SUBTITLE_BUF;
+    av_packet_unref(&pv->avpkt);
+
+    if (out->s.stop  <= pv->start_time || out->s.start >= pv->stop_time)
     {
-        // Drop subtitles that end before the start time
-        // or start after the stop time
+        // Drop subtitles that end before the PtoP start time
+        // or start after the PtoP stop time
         hb_deep_log(3, "Discarding SSA at time start %"PRId64", stop %"PRId64,
                     out->s.start, out->s.stop);
         hb_buffer_close(&out);
     }
     else
     {
+        // Adjust start/stop for subtitles that span PtoP start/stop
         if (out->s.start < pv->start_time)
         {
             out->s.start = pv->start_time;
@@ -354,69 +227,6 @@ decode_line_to_mkv_ssa( hb_work_private_t * pv, char * line, int size )
         out->s.start -= pv->start_time;
         out->s.stop  -= pv->start_time;
     }
-
-
-    free( layerField );
-
-    return out;
-
-fail:
-    hb_log( "decssasub: malformed SSA subtitle packet: %.*s\n", size, line );
-    return NULL;
-}
-
-/*
- * Read the SSA file and put the entries into the subtitle fifo for all to read
- */
-static hb_buffer_t * ssa_read( hb_work_private_t * pv )
-{
-    hb_buffer_t * out;
-
-    if (!pv->file)
-    {
-        return hb_buffer_eof_init();
-    }
-
-    if (pv->job->reader_pts_offset == AV_NOPTS_VALUE)
-    {
-        // We need to wait for reader to initialize it's pts offset so that
-        // we know where to start reading SSA.
-        return NULL;
-    }
-    if (pv->start_time == AV_NOPTS_VALUE)
-    {
-        pv->start_time = pv->job->reader_pts_offset;
-        if (pv->job->pts_to_stop > 0)
-        {
-            pv->stop_time = pv->job->pts_to_start + pv->job->pts_to_stop;
-        }
-    }
-    while (!feof(pv->file))
-    {
-        char    * line = NULL;
-        ssize_t   len;
-        size_t    size = 0;
-
-        len = hb_getline(&line, &size, pv->file);
-        if (len > 0 && line != NULL)
-        {
-            out = decode_line_to_mkv_ssa(pv, line, len);
-            if (out != NULL)
-            {
-                free(line);
-                return out;
-            }
-        }
-        free(line);
-        if (len < 0)
-        {
-            // Error or EOF
-            out = hb_buffer_eof_init();
-            return out;
-        }
-    }
-    out = hb_buffer_eof_init();
-
     return out;
 }
 
@@ -447,7 +257,8 @@ static void decssaClose( hb_work_object_t * w )
     if (pv != NULL)
     {
         decavsubClose(pv->ctx);
-        fclose(pv->file);
+        av_packet_unref(&pv->avpkt);
+        avformat_close_input(&pv->ic);
         free(pv);
     }
     w->private_data = NULL;