mirror of
https://git.videolan.org/git/ffmpeg.git
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206 lines
4.9 KiB
C
206 lines
4.9 KiB
C
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/*
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* H263 decoder
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* Copyright (c) 2001 Gerard Lantau.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include "dsputil.h"
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#include "avcodec.h"
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#include "mpegvideo.h"
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//#define DEBUG
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static int h263_decode_init(AVCodecContext *avctx)
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{
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MpegEncContext *s = avctx->priv_data;
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s->out_format = FMT_H263;
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s->width = avctx->width;
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s->height = avctx->height;
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/* select sub codec */
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switch(avctx->codec->id) {
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case CODEC_ID_H263:
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break;
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case CODEC_ID_OPENDIVX:
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s->time_increment_bits = 4; /* default value for broken headers */
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s->h263_pred = 1;
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break;
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case CODEC_ID_MSMPEG4:
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s->h263_msmpeg4 = 1;
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s->h263_pred = 1;
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break;
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case CODEC_ID_H263I:
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s->h263_intel = 1;
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break;
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default:
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return -1;
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}
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/* for h263, we allocate the images after having read the header */
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if (MPV_common_init(s) < 0)
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return -1;
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if (s->h263_msmpeg4)
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msmpeg4_decode_init_vlc(s);
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else
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h263_decode_init_vlc(s);
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return 0;
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}
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static int h263_decode_end(AVCodecContext *avctx)
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{
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MpegEncContext *s = avctx->priv_data;
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MPV_common_end(s);
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return 0;
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}
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static int h263_decode_frame(AVCodecContext *avctx,
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void *data, int *data_size,
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UINT8 *buf, int buf_size)
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{
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MpegEncContext *s = avctx->priv_data;
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int ret;
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DCTELEM block[6][64];
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AVPicture *pict = data;
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#ifdef DEBUG
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printf("*****frame %d size=%d\n", avctx->frame_number, buf_size);
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printf("bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
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#endif
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/* no supplementary picture */
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if (buf_size == 0) {
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*data_size = 0;
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return 0;
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}
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init_get_bits(&s->gb, buf, buf_size);
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/* let's go :-) */
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if (s->h263_msmpeg4) {
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ret = msmpeg4_decode_picture_header(s);
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} else if (s->h263_pred) {
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ret = mpeg4_decode_picture_header(s);
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} else if (s->h263_intel) {
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ret = intel_h263_decode_picture_header(s);
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} else {
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ret = h263_decode_picture_header(s);
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}
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if (ret < 0)
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return -1;
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MPV_frame_start(s);
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#ifdef DEBUG
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printf("qscale=%d\n", s->qscale);
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#endif
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/* decode each macroblock */
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for(s->mb_y=0; s->mb_y < s->mb_height; s->mb_y++) {
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for(s->mb_x=0; s->mb_x < s->mb_width; s->mb_x++) {
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#ifdef DEBUG
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printf("**mb x=%d y=%d\n", s->mb_x, s->mb_y);
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#endif
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/* DCT & quantize */
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if (s->h263_msmpeg4) {
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msmpeg4_dc_scale(s);
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} else if (s->h263_pred) {
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h263_dc_scale(s);
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} else {
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/* default quantization values */
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s->y_dc_scale = 8;
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s->c_dc_scale = 8;
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}
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memset(block, 0, sizeof(block));
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s->mv_dir = MV_DIR_FORWARD;
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s->mv_type = MV_TYPE_16X16;
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if (s->h263_msmpeg4) {
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if (msmpeg4_decode_mb(s, block) < 0)
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return -1;
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} else {
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if (h263_decode_mb(s, block) < 0)
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return -1;
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}
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MPV_decode_mb(s, block);
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}
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}
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MPV_frame_end(s);
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pict->data[0] = s->current_picture[0];
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pict->data[1] = s->current_picture[1];
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pict->data[2] = s->current_picture[2];
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pict->linesize[0] = s->linesize;
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pict->linesize[1] = s->linesize / 2;
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pict->linesize[2] = s->linesize / 2;
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avctx->quality = s->qscale;
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*data_size = sizeof(AVPicture);
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return buf_size;
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}
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AVCodec opendivx_decoder = {
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"opendivx",
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CODEC_TYPE_VIDEO,
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CODEC_ID_OPENDIVX,
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sizeof(MpegEncContext),
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h263_decode_init,
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NULL,
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h263_decode_end,
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h263_decode_frame,
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};
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AVCodec h263_decoder = {
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"h263",
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CODEC_TYPE_VIDEO,
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CODEC_ID_H263,
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sizeof(MpegEncContext),
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h263_decode_init,
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NULL,
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h263_decode_end,
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h263_decode_frame,
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};
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AVCodec msmpeg4_decoder = {
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"msmpeg4",
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CODEC_TYPE_VIDEO,
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CODEC_ID_MSMPEG4,
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sizeof(MpegEncContext),
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h263_decode_init,
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NULL,
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h263_decode_end,
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h263_decode_frame,
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};
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AVCodec h263i_decoder = {
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"h263i",
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CODEC_TYPE_VIDEO,
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CODEC_ID_H263I,
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sizeof(MpegEncContext),
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h263_decode_init,
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NULL,
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h263_decode_end,
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h263_decode_frame,
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};
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