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|
/* decvobsub.c
Copyright (c) 2003-2017 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
*/
/*
* Decoder for DVD bitmap subtitles, also known as "VOB subtitles" within the HandBrake source code.
*
* Input format of the subtitle packets is described here:
* http://sam.zoy.org/writings/dvd/subtitles/
*
* An auxiliary input is the color palette lookup table, in 'subtitle->palette'.
* The demuxer implementation must fill out this table appropriately.
* - In the case of a true DVD input, the palette is read from the IFO file.
* - In the case of an MKV file input, the palette is read from the codec private data of the subtitle track.
*
* Output format of this decoder is PICTURESUB, which is:
* struct PictureSubPacket {
* uint8_t lum[pixelCount]; // Y
* uint8_t alpha[pixelCount]; // alpha (max = 16)
* uint8_t chromaU[pixelCount]; // Cb
* uint8_t chromaV[pixelCount]; // Cr
* }
*/
#include "hb.h"
struct hb_work_private_s
{
hb_job_t * job;
hb_buffer_t * buf;
int size_sub;
int size_got;
int size_rle;
int64_t pts;
int current_scr_sequence;
int64_t pts_start;
int64_t pts_stop;
int scr_sequence;
int pts_forced;
int x;
int y;
int width;
int height;
int stream_id;
int offsets[2];
uint8_t lum[4];
uint8_t chromaU[4];
uint8_t chromaV[4];
uint8_t alpha[4];
uint8_t palette_set;
};
static hb_buffer_t * Decode( hb_work_object_t * );
int decsubInit( hb_work_object_t * w, hb_job_t * job )
{
hb_work_private_t * pv;
pv = calloc( 1, sizeof( hb_work_private_t ) );
w->private_data = pv;
pv->job = job;
pv->pts = 0;
// Warn if the input color palette is empty
pv->palette_set = w->subtitle->palette_set;
if ( pv->palette_set )
{
// Make sure the entries in the palette are not all 0
pv->palette_set = 0;
int i;
for (i=0; i<16; i++)
{
if (w->subtitle->palette[i])
{
pv->palette_set = 1;
break;
}
}
}
if (!pv->palette_set) {
hb_log( "decvobsub: input color palette is empty!" );
}
return 0;
}
int decsubWork( 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;
int size_sub, size_rle;
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;
}
pv->stream_id = in->s.id;
size_sub = ( in->data[0] << 8 ) | in->data[1];
size_rle = ( in->data[2] << 8 ) | in->data[3];
if( !pv->size_sub )
{
/* We are looking for the start of a new subtitle */
if( size_sub && size_rle && size_sub > size_rle &&
in->size <= size_sub )
{
/* Looks all right so far */
pv->size_sub = size_sub;
pv->size_rle = size_rle;
pv->buf = hb_buffer_init( 0xFFFF );
memcpy( pv->buf->data, in->data, in->size );
pv->buf->s.id = in->s.id;
pv->buf->s.frametype = HB_FRAME_SUBTITLE;
pv->size_got = in->size;
if( in->s.start >= 0 )
{
pv->pts = in->s.start;
pv->current_scr_sequence = in->s.scr_sequence;
}
}
}
else
{
/* We are waiting for the end of the current subtitle */
if( in->size <= pv->size_sub - pv->size_got )
{
memcpy( pv->buf->data + pv->size_got, in->data, in->size );
pv->buf->s.id = in->s.id;
pv->size_got += in->size;
if( in->s.start >= 0 )
{
pv->pts = in->s.start;
pv->current_scr_sequence = in->s.scr_sequence;
}
}
else
{
// bad size, must have lost sync
// force re-sync
if ( pv->buf != NULL )
hb_buffer_close( &pv->buf );
pv->size_sub = 0;
}
}
*buf_out = NULL;
if( pv->size_sub && pv->size_sub == pv->size_got )
{
pv->buf->size = pv->size_sub;
/* We got a complete subtitle, decode it */
*buf_out = Decode( w );
if( buf_out && *buf_out )
{
(*buf_out)->s.id = in->s.id;
}
/* Wait for the next one */
pv->size_sub = 0;
pv->size_got = 0;
pv->size_rle = 0;
if ( pv->pts_stop != AV_NOPTS_VALUE )
{
// If we don't get a valid next timestamp, use the stop time
// of the current sub as the start of the next.
// This can happen if reader invalidates timestamps while
// waiting for an audio to update the SCR.
pv->pts = pv->pts_stop;
pv->current_scr_sequence = pv->scr_sequence;
}
}
return HB_WORK_OK;
}
void decsubClose( hb_work_object_t * w )
{
hb_work_private_t * pv = w->private_data;
if ( pv->buf )
hb_buffer_close( &pv->buf );
free( w->private_data );
}
hb_work_object_t hb_decvobsub =
{
WORK_DECVOBSUB,
"VOBSUB decoder",
decsubInit,
decsubWork,
decsubClose
};
/***********************************************************************
* ParseControls
***********************************************************************
* Get the start and end dates (relative to the PTS from the PES
* header), the width and height of the subpicture and the colors and
* alphas used in it
**********************************************************************/
static int ParseControls( hb_work_object_t * w )
{
hb_work_private_t * pv = w->private_data;
uint8_t * buf = pv->buf->data;
int i;
int command;
int date, next;
pv->pts_start = AV_NOPTS_VALUE;
pv->pts_stop = AV_NOPTS_VALUE;
pv->pts_forced = 0;
pv->alpha[3] = 0;
pv->alpha[2] = 0;
pv->alpha[1] = 0;
pv->alpha[0] = 0;
for( i = pv->size_rle; ; )
{
if ( i + 1 >= pv->buf->size )
{
return 1;
}
date = ( buf[i] << 8 ) | buf[i+1]; i += 2;
next = ( buf[i] << 8 ) | buf[i+1]; i += 2;
for( ;; )
{
if ( i >= pv->buf->size )
{
return 1;
}
command = buf[i++];
/*
* There are eight commands available for
* Sub-Pictures. The first SP_DCSQ should contain, as a
* minimum, SET_COLOR, SET_CONTR, SET_DAREA, and
* SET_DSPXA
*/
if( command == 0xFF ) // 0xFF - CMD_END - ends one SP_DCSQ
{
break;
}
switch( command )
{
case 0x00: // 0x00 - FSTA_DSP - Forced Start Display, no arguments
pv->pts_start = pv->pts + date * 1024;
pv->scr_sequence = pv->current_scr_sequence;
pv->pts_forced = 1;
w->subtitle->hits++;
w->subtitle->forced_hits++;
break;
case 0x01: // 0x01 - STA_DSP - Start Display, no arguments
pv->pts_start = pv->pts + date * 1024;
pv->scr_sequence = pv->current_scr_sequence;
pv->pts_forced = 0;
w->subtitle->hits++;
break;
case 0x02: // 0x02 - STP_DSP - Stop Display, no arguments
if (pv->pts_stop == AV_NOPTS_VALUE)
{
pv->pts_stop = pv->pts + date * 1024;
pv->scr_sequence = pv->current_scr_sequence;
}
break;
case 0x03: // 0x03 - SET_COLOR - Set Colour indices
{
/*
* SET_COLOR - provides four indices into the CLUT
* for the current PGC to associate with the four
* pixel values
*/
int colors[4];
int j;
if ( i + 1 >= pv->buf->size )
{
return 1;
}
colors[0] = (buf[i+0]>>4)&0x0f;
colors[1] = (buf[i+0])&0x0f;
colors[2] = (buf[i+1]>>4)&0x0f;
colors[3] = (buf[i+1])&0x0f;
for( j = 0; j < 4; j++ )
{
/*
* Not sure what is happening here, in theory
* the palette is in YCbCr. And we want YUV.
*
* However it looks more like YCrCb (according
* to pgcedit). And the scalers for YCrCb don't
* work, but I get the right colours by doing
* no conversion.
*/
uint32_t color = w->subtitle->palette[colors[j]];
uint8_t Cr, Cb, y;
y = (color>>16) & 0xff;
Cr = (color>>8) & 0xff;
Cb = (color) & 0xff;
pv->lum[3-j] = y;
pv->chromaU[3-j] = Cb;
pv->chromaV[3-j] = Cr;
/* hb_log("color[%d] y = %d, u = %d, v = %d",
3-j,
pv->lum[3-j],
pv->chromaU[3-j],
pv->chromaV[3-j]);
*/
}
i += 2;
break;
}
case 0x04: // 0x04 - SET_CONTR - Set Contrast
{
/*
* SET_CONTR - directly provides the four contrast
* (alpha blend) values to associate with the four
* pixel values
*/
uint8_t alpha[4];
if ( i + 1 >= pv->buf->size )
{
return 1;
}
alpha[3] = ((buf[i+0] >> 4) & 0x0f) << 4;
alpha[2] = ((buf[i+0] ) & 0x0f) << 4;
alpha[1] = ((buf[i+1] >> 4) & 0x0f) << 4;
alpha[0] = ((buf[i+1] ) & 0x0f) << 4;
int lastAlpha = pv->alpha[3] + pv->alpha[2] + pv->alpha[1] + pv->alpha[0];
int currAlpha = alpha[3] + alpha[2] + alpha[1] + alpha[0];
// fading-in, save the highest alpha value
if( currAlpha > lastAlpha )
{
pv->alpha[3] = alpha[3];
pv->alpha[2] = alpha[2];
pv->alpha[1] = alpha[1];
pv->alpha[0] = alpha[0];
}
// fading-out
if (currAlpha < lastAlpha && pv->pts_stop == AV_NOPTS_VALUE)
{
pv->pts_stop = pv->pts + date * 1024;
pv->scr_sequence = pv->current_scr_sequence;
}
i += 2;
break;
}
case 0x05: // 0x05 - SET_DAREA - defines the display area
{
if ( i + 4 >= pv->buf->size )
{
return 1;
}
pv->x = (buf[i+0]<<4) | ((buf[i+1]>>4)&0x0f);
pv->width = (((buf[i+1]&0x0f)<<8)| buf[i+2]) - pv->x + 1;
pv->y = (buf[i+3]<<4)| ((buf[i+4]>>4)&0x0f);
pv->height = (((buf[i+4]&0x0f)<<8)| buf[i+5]) - pv->y + 1;
i += 6;
break;
}
case 0x06: // 0x06 - SET_DSPXA - defines the pixel data addresses
{
pv->offsets[0] = ( buf[i] << 8 ) | buf[i+1]; i += 2;
pv->offsets[1] = ( buf[i] << 8 ) | buf[i+1]; i += 2;
break;
}
}
}
if( i > next )
{
break;
}
i = next;
}
// Generate timestamps if they are not set
if( pv->pts_start == AV_NOPTS_VALUE )
{
// Set pts to end of last sub if the start time is unknown.
pv->pts_start = pv->pts;
pv->scr_sequence = pv->current_scr_sequence;
}
return 0;
}
/***********************************************************************
* CropSubtitle
***********************************************************************
* Given a raw decoded subtitle, detects transparent borders and
* returns a cropped subtitle in a hb_buffer_t ready to be used by
* the renderer, or NULL if the subtitle was completely transparent
**********************************************************************/
static int LineIsTransparent( hb_work_object_t * w, uint8_t * p )
{
hb_work_private_t * pv = w->private_data;
int i;
for( i = 0; i < pv->width; i++ )
{
if( p[i] )
{
return 0;
}
}
return 1;
}
static int ColumnIsTransparent( hb_work_object_t * w, uint8_t * p )
{
hb_work_private_t * pv = w->private_data;
int i;
for( i = 0; i < pv->height; i++ )
{
if( p[i*pv->width] )
{
return 0;
}
}
return 1;
}
// Brain dead resampler. This should really use swscale...
// Uses Bresenham algo to pick source samples for averaging
static void resample( uint8_t * dst, uint8_t * src, int dst_w, int src_w )
{
int dst_x, src_x, err, cnt, sum, val;
if( dst_w < src_w )
{
// sample down
err = 0;
sum = 0;
val = 0;
cnt = 0;
err = src_w / 2;
dst_x = 0;
for( src_x = 0; src_x < src_w; src_x++ )
{
sum += src[src_x];
cnt++;
err -= dst_w;
if( err < 0 )
{
val = sum / cnt;
dst[dst_x++] = val;
sum = cnt = 0;
err += src_w;
}
}
for( ; dst_x < dst_w; dst_x++ )
{
dst[dst_x] = val;
}
}
else
{
// sample up
err = 0;
err = dst_w / 2;
src_x = 0;
for( dst_x = 0; dst_x < dst_w; dst_x++ )
{
dst[dst_x] = src[src_x];
err -= src_w;
if( err < 0 )
{
src_x++;
err += dst_w;
}
}
}
}
static hb_buffer_t * CropSubtitle( hb_work_object_t * w, uint8_t * raw )
{
hb_work_private_t * pv = w->private_data;
int i;
int crop[4] = { -1,-1,-1,-1 };
uint8_t * alpha;
int realwidth, realheight;
hb_buffer_t * buf;
uint8_t * lum_in, * alpha_in, * u_in, * v_in;
alpha = raw + pv->width * pv->height;
/* Top */
for( i = 0; i < pv->height; i++ )
{
if( !LineIsTransparent( w, &alpha[i*pv->width] ) )
{
crop[0] = i;
break;
}
}
if( crop[0] < 0 )
{
/* Empty subtitle */
return NULL;
}
/* Bottom */
for( i = pv->height - 1; i >= 0; i-- )
{
if( !LineIsTransparent( w, &alpha[i*pv->width] ) )
{
crop[1] = i;
break;
}
}
/* Left */
for( i = 0; i < pv->width; i++ )
{
if( !ColumnIsTransparent( w, &alpha[i] ) )
{
crop[2] = i;
break;
}
}
/* Right */
for( i = pv->width - 1; i >= 0; i-- )
{
if( !ColumnIsTransparent( w, &alpha[i] ) )
{
crop[3] = i;
break;
}
}
realwidth = crop[3] - crop[2] + 1;
realheight = crop[1] - crop[0] + 1;
buf = hb_frame_buffer_init( AV_PIX_FMT_YUVA420P, realwidth, realheight );
buf->s.frametype = HB_FRAME_SUBTITLE;
buf->s.start = pv->pts_start;
buf->s.stop = pv->pts_stop;
buf->s.scr_sequence = pv->scr_sequence;
buf->f.x = pv->x + crop[2];
buf->f.y = pv->y + crop[0];
buf->f.window_width = w->subtitle->width;
buf->f.window_height = w->subtitle->height;
lum_in = raw + crop[0] * pv->width + crop[2];
alpha_in = lum_in + pv->width * pv->height;
u_in = alpha_in + pv->width * pv->height;
v_in = u_in + pv->width * pv->height;
uint8_t *dst;
for( i = 0; i < realheight; i++ )
{
// Luma
dst = buf->plane[0].data + buf->plane[0].stride * i;
memcpy( dst, lum_in, realwidth );
if( ( i & 1 ) == 0 )
{
// chroma U (resample to YUV420)
dst = buf->plane[1].data + buf->plane[1].stride * ( i >> 1 );
resample( dst, u_in, buf->plane[1].width, realwidth );
// chroma V (resample to YUV420)
dst = buf->plane[2].data + buf->plane[2].stride * ( i >> 1 );
resample( dst, v_in, buf->plane[2].width, realwidth );
}
// Alpha
dst = buf->plane[3].data + buf->plane[3].stride * i;
memcpy( dst, alpha_in, realwidth );
lum_in += pv->width;
alpha_in += pv->width;
u_in += pv->width;
v_in += pv->width;
}
return buf;
}
static hb_buffer_t * Decode( hb_work_object_t * w )
{
hb_work_private_t * pv = w->private_data;
int code, line, col;
int offsets[2];
int * offset;
hb_buffer_t * buf;
uint8_t * buf_raw = NULL;
hb_job_t * job = pv->job;
/* Get infos about the subtitle */
if ( ParseControls( w ) )
{
/*
* Coudln't parse the info
*/
hb_deep_log( 2, "decvobsub: Could not parse info!" );
hb_buffer_close( &pv->buf );
return NULL;
}
if( job->indepth_scan || ( w->subtitle->config.force && pv->pts_forced == 0 ) )
{
/*
* Don't encode subtitles when doing a scan.
*
* When forcing subtitles, ignore all those that don't
* have the forced flag set.
*/
hb_buffer_close( &pv->buf );
return NULL;
}
if (w->subtitle->config.dest == PASSTHRUSUB)
{
pv->buf->s.start = pv->pts_start;
pv->buf->s.stop = pv->pts_stop;
pv->buf->s.scr_sequence = pv->scr_sequence;
buf = pv->buf;
pv->buf = NULL;
return buf;
}
/* Do the actual decoding now */
buf_raw = malloc( ( pv->width * pv->height ) * 4 );
#define GET_NEXT_NIBBLE code = ( code << 4 ) | ( ( ( *offset & 1 ) ? \
( pv->buf->data[((*offset)>>1)] & 0xF ) : ( pv->buf->data[((*offset)>>1)] >> 4 ) ) ); \
(*offset)++
offsets[0] = pv->offsets[0] * 2;
offsets[1] = pv->offsets[1] * 2;
for( line = 0; line < pv->height; line++ )
{
/* Select even or odd field */
offset = ( line & 1 ) ? &offsets[1] : &offsets[0];
for( col = 0; col < pv->width; col += code >> 2 )
{
uint8_t * lum, * alpha, * chromaU, * chromaV;
code = 0;
GET_NEXT_NIBBLE;
if( code < 0x4 )
{
GET_NEXT_NIBBLE;
if( code < 0x10 )
{
GET_NEXT_NIBBLE;
if( code < 0x40 )
{
GET_NEXT_NIBBLE;
if( code < 0x100 )
{
/* End of line */
code |= ( pv->width - col ) << 2;
}
}
}
}
lum = buf_raw;
alpha = lum + pv->width * pv->height;
chromaU = alpha + pv->width * pv->height;
chromaV = chromaU + pv->width * pv->height;
memset( lum + line * pv->width + col,
pv->lum[code & 3], code >> 2 );
memset( alpha + line * pv->width + col,
pv->alpha[code & 3], code >> 2 );
memset( chromaU + line * pv->width + col,
pv->chromaU[code & 3], code >> 2 );
memset( chromaV + line * pv->width + col,
pv->chromaV[code & 3], code >> 2 );
}
/* Byte-align */
if( *offset & 1 )
{
(*offset)++;
}
}
hb_buffer_close( &pv->buf );
/* Crop subtitle (remove transparent borders) */
buf = CropSubtitle( w, buf_raw );
free( buf_raw );
return buf;
}
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