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FFmpeg/libavcodec/h263dec.c
Juanjo 644d98a4f2 - Preliminary RTP friendly mode for H.263.
- GOB headers for H.263 coding on RTP mode.
- Improved GOB header detection for H.263 decoder.

Originally committed as revision 222 to svn://svn.ffmpeg.org/ffmpeg/trunk
2001-11-19 02:13:14 +00:00

257 lines
7.1 KiB
C

/*
* H263 decoder
* Copyright (c) 2001 Gerard Lantau.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "dsputil.h"
#include "avcodec.h"
#include "mpegvideo.h"
//#define DEBUG
static int h263_decode_init(AVCodecContext *avctx)
{
MpegEncContext *s = avctx->priv_data;
int i;
s->avctx = avctx;
s->out_format = FMT_H263;
s->width = avctx->width;
s->height = avctx->height;
/* select sub codec */
switch(avctx->codec->id) {
case CODEC_ID_H263:
s->gob_number = 0;
s->first_gob_line = 0;
break;
case CODEC_ID_MPEG4:
s->time_increment_bits = 4; /* default value for broken headers */
s->h263_pred = 1;
break;
case CODEC_ID_MSMPEG4:
s->h263_msmpeg4 = 1;
s->h263_pred = 1;
break;
case CODEC_ID_H263I:
s->h263_intel = 1;
break;
default:
return -1;
}
/* for h263, we allocate the images after having read the header */
if (avctx->codec->id != CODEC_ID_H263)
if (MPV_common_init(s) < 0)
return -1;
/* XXX: suppress this matrix init, only needed because using mpeg1
dequantize in mmx case */
for(i=0;i<64;i++)
s->non_intra_matrix[i] = default_non_intra_matrix[i];
if (s->h263_msmpeg4)
msmpeg4_decode_init_vlc(s);
else
h263_decode_init_vlc(s);
return 0;
}
static int h263_decode_end(AVCodecContext *avctx)
{
MpegEncContext *s = avctx->priv_data;
MPV_common_end(s);
return 0;
}
static int h263_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
UINT8 *buf, int buf_size)
{
MpegEncContext *s = avctx->priv_data;
int ret;
AVPicture *pict = data;
#ifdef DEBUG
printf("*****frame %d size=%d\n", avctx->frame_number, buf_size);
printf("bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
#endif
/* no supplementary picture */
if (buf_size == 0) {
*data_size = 0;
return 0;
}
init_get_bits(&s->gb, buf, buf_size);
/* let's go :-) */
if (s->h263_msmpeg4) {
ret = msmpeg4_decode_picture_header(s);
} else if (s->h263_pred) {
ret = mpeg4_decode_picture_header(s);
} else if (s->h263_intel) {
ret = intel_h263_decode_picture_header(s);
} else {
ret = h263_decode_picture_header(s);
/* After H263 header decode we have the height, width, */
/* and other parameters. So then we could init the picture */
/* FIXME: By the way H263 decoder is evolving it should have */
/* an H263EncContext */
if (!s->context_initialized) {
avctx->width = s->width;
avctx->height = s->height;
if (MPV_common_init(s) < 0)
return -1;
} else if (s->width != avctx->width || s->height != avctx->height) {
/* H.263 could change picture size any time */
MPV_common_end(s);
if (MPV_common_init(s) < 0)
return -1;
}
}
if (ret < 0)
return -1;
MPV_frame_start(s);
#ifdef DEBUG
printf("qscale=%d\n", s->qscale);
#endif
/* decode each macroblock */
for(s->mb_y=0; s->mb_y < s->mb_height; s->mb_y++) {
/* Check for GOB headers on H.263 */
/* FIXME: In the future H.263+ will have intra prediction */
/* and we are gonna need another way to detect MPEG4 */
if (s->mb_y && !s->h263_pred) {
s->first_gob_line = h263_decode_gob_header(s);
}
for(s->mb_x=0; s->mb_x < s->mb_width; s->mb_x++) {
#ifdef DEBUG
printf("**mb x=%d y=%d\n", s->mb_x, s->mb_y);
#endif
//fprintf(stderr,"\nFrame: %d\tMB: %d",avctx->frame_number, (s->mb_y * s->mb_width) + s->mb_x);
/* DCT & quantize */
if (s->h263_msmpeg4) {
msmpeg4_dc_scale(s);
} else if (s->h263_pred) {
h263_dc_scale(s);
} else {
/* default quantization values */
s->y_dc_scale = 8;
s->c_dc_scale = 8;
}
memset(s->block, 0, sizeof(s->block));
s->mv_dir = MV_DIR_FORWARD;
s->mv_type = MV_TYPE_16X16;
if (s->h263_msmpeg4) {
if (msmpeg4_decode_mb(s, s->block) < 0)
return -1;
} else {
if (h263_decode_mb(s, s->block) < 0) {
fprintf(stderr,"\nError at MB: %d\n", (s->mb_y * s->mb_width) + s->mb_x);
return -1;
}
}
MPV_decode_mb(s, s->block);
}
if (avctx->draw_horiz_band) {
UINT8 *src_ptr[3];
int y, h, offset;
y = s->mb_y * 16;
h = s->height - y;
if (h > 16)
h = 16;
offset = y * s->linesize;
src_ptr[0] = s->current_picture[0] + offset;
src_ptr[1] = s->current_picture[1] + (offset >> 2);
src_ptr[2] = s->current_picture[2] + (offset >> 2);
avctx->draw_horiz_band(avctx, src_ptr, s->linesize,
y, s->width, h);
}
}
MPV_frame_end(s);
pict->data[0] = s->current_picture[0];
pict->data[1] = s->current_picture[1];
pict->data[2] = s->current_picture[2];
pict->linesize[0] = s->linesize;
pict->linesize[1] = s->linesize / 2;
pict->linesize[2] = s->linesize / 2;
avctx->quality = s->qscale;
*data_size = sizeof(AVPicture);
return buf_size;
}
AVCodec mpeg4_decoder = {
"mpeg4",
CODEC_TYPE_VIDEO,
CODEC_ID_MPEG4,
sizeof(MpegEncContext),
h263_decode_init,
NULL,
h263_decode_end,
h263_decode_frame,
CODEC_CAP_DRAW_HORIZ_BAND,
};
AVCodec h263_decoder = {
"h263",
CODEC_TYPE_VIDEO,
CODEC_ID_H263,
sizeof(MpegEncContext),
h263_decode_init,
NULL,
h263_decode_end,
h263_decode_frame,
CODEC_CAP_DRAW_HORIZ_BAND,
};
AVCodec msmpeg4_decoder = {
"msmpeg4",
CODEC_TYPE_VIDEO,
CODEC_ID_MSMPEG4,
sizeof(MpegEncContext),
h263_decode_init,
NULL,
h263_decode_end,
h263_decode_frame,
CODEC_CAP_DRAW_HORIZ_BAND,
};
AVCodec h263i_decoder = {
"h263i",
CODEC_TYPE_VIDEO,
CODEC_ID_H263I,
sizeof(MpegEncContext),
h263_decode_init,
NULL,
h263_decode_end,
h263_decode_frame,
CODEC_CAP_DRAW_HORIZ_BAND,
};