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https://github.com/FFmpeg/FFmpeg.git
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df9b956751
It's got_frame, not data size
656 lines
18 KiB
C
656 lines
18 KiB
C
/*
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* H261 decoder
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* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
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* Copyright (c) 2004 Maarten Daniels
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* H.261 decoder.
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*/
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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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#include "h263.h"
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#include "h261.h"
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#include "h261data.h"
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#define H261_MBA_VLC_BITS 9
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#define H261_MTYPE_VLC_BITS 6
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#define H261_MV_VLC_BITS 7
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#define H261_CBP_VLC_BITS 9
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#define TCOEFF_VLC_BITS 9
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#define MBA_STUFFING 33
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#define MBA_STARTCODE 34
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extern uint8_t ff_h261_rl_table_store[2][2*MAX_RUN + MAX_LEVEL + 3];
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static VLC h261_mba_vlc;
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static VLC h261_mtype_vlc;
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static VLC h261_mv_vlc;
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static VLC h261_cbp_vlc;
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static int h261_decode_block(H261Context * h, DCTELEM * block, int n, int coded);
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static av_cold void h261_decode_init_vlc(H261Context *h){
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static int done = 0;
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if(!done){
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done = 1;
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INIT_VLC_STATIC(&h261_mba_vlc, H261_MBA_VLC_BITS, 35,
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h261_mba_bits, 1, 1,
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h261_mba_code, 1, 1, 662);
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INIT_VLC_STATIC(&h261_mtype_vlc, H261_MTYPE_VLC_BITS, 10,
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h261_mtype_bits, 1, 1,
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h261_mtype_code, 1, 1, 80);
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INIT_VLC_STATIC(&h261_mv_vlc, H261_MV_VLC_BITS, 17,
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&h261_mv_tab[0][1], 2, 1,
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&h261_mv_tab[0][0], 2, 1, 144);
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INIT_VLC_STATIC(&h261_cbp_vlc, H261_CBP_VLC_BITS, 63,
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&h261_cbp_tab[0][1], 2, 1,
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&h261_cbp_tab[0][0], 2, 1, 512);
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ff_init_rl(&h261_rl_tcoeff, ff_h261_rl_table_store);
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INIT_VLC_RL(h261_rl_tcoeff, 552);
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}
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}
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static av_cold int h261_decode_init(AVCodecContext *avctx){
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H261Context *h= avctx->priv_data;
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MpegEncContext * const s = &h->s;
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// set defaults
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ff_MPV_decode_defaults(s);
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s->avctx = avctx;
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s->width = s->avctx->coded_width;
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s->height = s->avctx->coded_height;
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s->codec_id = s->avctx->codec->id;
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s->out_format = FMT_H261;
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s->low_delay= 1;
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avctx->pix_fmt= AV_PIX_FMT_YUV420P;
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s->codec_id= avctx->codec->id;
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h261_decode_init_vlc(h);
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h->gob_start_code_skipped = 0;
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return 0;
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}
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/**
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* Decode the group of blocks header or slice header.
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* @return <0 if an error occurred
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*/
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static int h261_decode_gob_header(H261Context *h){
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unsigned int val;
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MpegEncContext * const s = &h->s;
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if ( !h->gob_start_code_skipped ){
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/* Check for GOB Start Code */
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val = show_bits(&s->gb, 15);
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if(val)
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return -1;
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/* We have a GBSC */
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skip_bits(&s->gb, 16);
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}
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h->gob_start_code_skipped = 0;
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h->gob_number = get_bits(&s->gb, 4); /* GN */
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s->qscale = get_bits(&s->gb, 5); /* GQUANT */
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/* Check if gob_number is valid */
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if (s->mb_height==18){ //cif
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if ((h->gob_number<=0) || (h->gob_number>12))
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return -1;
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}
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else{ //qcif
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if ((h->gob_number!=1) && (h->gob_number!=3) && (h->gob_number!=5))
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return -1;
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}
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/* GEI */
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while (get_bits1(&s->gb) != 0) {
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skip_bits(&s->gb, 8);
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}
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if(s->qscale==0) {
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av_log(s->avctx, AV_LOG_ERROR, "qscale has forbidden 0 value\n");
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if (s->avctx->err_recognition & AV_EF_BITSTREAM)
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return -1;
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}
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// For the first transmitted macroblock in a GOB, MBA is the absolute address. For
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// subsequent macroblocks, MBA is the difference between the absolute addresses of
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// the macroblock and the last transmitted macroblock.
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h->current_mba = 0;
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h->mba_diff = 0;
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return 0;
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}
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/**
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* Decode the group of blocks / video packet header.
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* @return <0 if no resync found
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*/
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static int ff_h261_resync(H261Context *h){
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MpegEncContext * const s = &h->s;
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int left, ret;
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if ( h->gob_start_code_skipped ){
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ret= h261_decode_gob_header(h);
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if(ret>=0)
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return 0;
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}
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else{
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if(show_bits(&s->gb, 15)==0){
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ret= h261_decode_gob_header(h);
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if(ret>=0)
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return 0;
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}
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//OK, it is not where it is supposed to be ...
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s->gb= s->last_resync_gb;
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align_get_bits(&s->gb);
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left= get_bits_left(&s->gb);
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for(;left>15+1+4+5; left-=8){
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if(show_bits(&s->gb, 15)==0){
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GetBitContext bak= s->gb;
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ret= h261_decode_gob_header(h);
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if(ret>=0)
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return 0;
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s->gb= bak;
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}
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skip_bits(&s->gb, 8);
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}
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}
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return -1;
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}
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/**
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* Decode skipped macroblocks.
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* @return 0
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*/
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static int h261_decode_mb_skipped(H261Context *h, int mba1, int mba2 )
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{
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MpegEncContext * const s = &h->s;
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int i;
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s->mb_intra = 0;
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for(i=mba1; i<mba2; i++){
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int j, xy;
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s->mb_x= ((h->gob_number-1) % 2) * 11 + i % 11;
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s->mb_y= ((h->gob_number-1) / 2) * 3 + i / 11;
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xy = s->mb_x + s->mb_y * s->mb_stride;
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ff_init_block_index(s);
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ff_update_block_index(s);
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for(j=0;j<6;j++)
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s->block_last_index[j] = -1;
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s->mv_dir = MV_DIR_FORWARD;
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s->mv_type = MV_TYPE_16X16;
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s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
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s->mv[0][0][0] = 0;
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s->mv[0][0][1] = 0;
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s->mb_skipped = 1;
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h->mtype &= ~MB_TYPE_H261_FIL;
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ff_MPV_decode_mb(s, s->block);
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}
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return 0;
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}
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static int decode_mv_component(GetBitContext *gb, int v){
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int mv_diff = get_vlc2(gb, h261_mv_vlc.table, H261_MV_VLC_BITS, 2);
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/* check if mv_diff is valid */
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if ( mv_diff < 0 )
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return v;
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mv_diff = mvmap[mv_diff];
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if(mv_diff && !get_bits1(gb))
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mv_diff= -mv_diff;
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v += mv_diff;
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if (v <=-16) v+= 32;
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else if(v >= 16) v-= 32;
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return v;
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}
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static int h261_decode_mb(H261Context *h){
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MpegEncContext * const s = &h->s;
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int i, cbp, xy;
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cbp = 63;
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// Read mba
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do{
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h->mba_diff = get_vlc2(&s->gb, h261_mba_vlc.table, H261_MBA_VLC_BITS, 2);
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/* Check for slice end */
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/* NOTE: GOB can be empty (no MB data) or exist only of MBA_stuffing */
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if (h->mba_diff == MBA_STARTCODE){ // start code
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h->gob_start_code_skipped = 1;
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return SLICE_END;
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}
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}
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while( h->mba_diff == MBA_STUFFING ); // stuffing
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if ( h->mba_diff < 0 ){
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if (get_bits_left(&s->gb) <= 7)
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return SLICE_END;
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av_log(s->avctx, AV_LOG_ERROR, "illegal mba at %d %d\n", s->mb_x, s->mb_y);
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return SLICE_ERROR;
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}
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h->mba_diff += 1;
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h->current_mba += h->mba_diff;
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if ( h->current_mba > MBA_STUFFING )
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return SLICE_ERROR;
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s->mb_x= ((h->gob_number-1) % 2) * 11 + ((h->current_mba-1) % 11);
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s->mb_y= ((h->gob_number-1) / 2) * 3 + ((h->current_mba-1) / 11);
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xy = s->mb_x + s->mb_y * s->mb_stride;
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ff_init_block_index(s);
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ff_update_block_index(s);
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// Read mtype
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h->mtype = get_vlc2(&s->gb, h261_mtype_vlc.table, H261_MTYPE_VLC_BITS, 2);
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h->mtype = h261_mtype_map[h->mtype];
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// Read mquant
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if ( IS_QUANT ( h->mtype ) ){
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ff_set_qscale(s, get_bits(&s->gb, 5));
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}
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s->mb_intra = IS_INTRA4x4(h->mtype);
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// Read mv
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if ( IS_16X16 ( h->mtype ) ){
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// Motion vector data is included for all MC macroblocks. MVD is obtained from the macroblock vector by subtracting the
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// vector of the preceding macroblock. For this calculation the vector of the preceding macroblock is regarded as zero in the
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// following three situations:
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// 1) evaluating MVD for macroblocks 1, 12 and 23;
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// 2) evaluating MVD for macroblocks in which MBA does not represent a difference of 1;
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// 3) MTYPE of the previous macroblock was not MC.
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if ( ( h->current_mba == 1 ) || ( h->current_mba == 12 ) || ( h->current_mba == 23 ) ||
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( h->mba_diff != 1))
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{
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h->current_mv_x = 0;
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h->current_mv_y = 0;
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}
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h->current_mv_x= decode_mv_component(&s->gb, h->current_mv_x);
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h->current_mv_y= decode_mv_component(&s->gb, h->current_mv_y);
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}else{
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h->current_mv_x = 0;
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h->current_mv_y = 0;
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}
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// Read cbp
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if ( HAS_CBP( h->mtype ) ){
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cbp = get_vlc2(&s->gb, h261_cbp_vlc.table, H261_CBP_VLC_BITS, 2) + 1;
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}
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if(s->mb_intra){
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s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
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goto intra;
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}
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//set motion vectors
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s->mv_dir = MV_DIR_FORWARD;
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s->mv_type = MV_TYPE_16X16;
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s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
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s->mv[0][0][0] = h->current_mv_x * 2;//gets divided by 2 in motion compensation
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s->mv[0][0][1] = h->current_mv_y * 2;
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intra:
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/* decode each block */
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if(s->mb_intra || HAS_CBP(h->mtype)){
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s->dsp.clear_blocks(s->block[0]);
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for (i = 0; i < 6; i++) {
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if (h261_decode_block(h, s->block[i], i, cbp&32) < 0){
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return SLICE_ERROR;
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}
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cbp+=cbp;
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}
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}else{
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for (i = 0; i < 6; i++)
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s->block_last_index[i]= -1;
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}
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ff_MPV_decode_mb(s, s->block);
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return SLICE_OK;
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}
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/**
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* Decode a macroblock.
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* @return <0 if an error occurred
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*/
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static int h261_decode_block(H261Context * h, DCTELEM * block,
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int n, int coded)
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{
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MpegEncContext * const s = &h->s;
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int code, level, i, j, run;
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RLTable *rl = &h261_rl_tcoeff;
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const uint8_t *scan_table;
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// For the variable length encoding there are two code tables, one being used for
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// the first transmitted LEVEL in INTER, INTER+MC and INTER+MC+FIL blocks, the second
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// for all other LEVELs except the first one in INTRA blocks which is fixed length
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// coded with 8 bits.
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// NOTE: the two code tables only differ in one VLC so we handle that manually.
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scan_table = s->intra_scantable.permutated;
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if (s->mb_intra){
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/* DC coef */
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level = get_bits(&s->gb, 8);
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// 0 (00000000b) and -128 (10000000b) are FORBIDDEN
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if((level&0x7F) == 0){
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av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
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return -1;
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}
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// The code 1000 0000 is not used, the reconstruction level of 1024 being coded as 1111 1111.
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if (level == 255)
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level = 128;
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block[0] = level;
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i = 1;
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}else if(coded){
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// Run Level Code
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// EOB Not possible for first level when cbp is available (that's why the table is different)
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// 0 1 1s
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// * * 0*
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int check = show_bits(&s->gb, 2);
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i = 0;
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if ( check & 0x2 ){
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skip_bits(&s->gb, 2);
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block[0] = ( check & 0x1 ) ? -1 : 1;
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i = 1;
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}
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}else{
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i = 0;
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}
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if(!coded){
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s->block_last_index[n] = i - 1;
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return 0;
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}
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for(;;){
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code = get_vlc2(&s->gb, rl->vlc.table, TCOEFF_VLC_BITS, 2);
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if (code < 0){
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av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
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return -1;
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}
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if (code == rl->n) {
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/* escape */
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// The remaining combinations of (run, level) are encoded with a 20-bit word consisting of 6 bits escape, 6 bits run and 8 bits level.
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run = get_bits(&s->gb, 6);
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level = get_sbits(&s->gb, 8);
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}else if(code == 0){
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break;
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}else{
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run = rl->table_run[code];
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level = rl->table_level[code];
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if (get_bits1(&s->gb))
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level = -level;
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}
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i += run;
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if (i >= 64){
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av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d\n", s->mb_x, s->mb_y);
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return -1;
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}
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j = scan_table[i];
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block[j] = level;
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i++;
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}
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s->block_last_index[n] = i-1;
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return 0;
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}
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/**
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* Decode the H.261 picture header.
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* @return <0 if no startcode found
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*/
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static int h261_decode_picture_header(H261Context *h){
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MpegEncContext * const s = &h->s;
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int format, i;
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uint32_t startcode= 0;
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for(i= get_bits_left(&s->gb); i>24; i-=1){
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startcode = ((startcode << 1) | get_bits(&s->gb, 1)) & 0x000FFFFF;
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if(startcode == 0x10)
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break;
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}
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if (startcode != 0x10){
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av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
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return -1;
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}
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/* temporal reference */
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i= get_bits(&s->gb, 5); /* picture timestamp */
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if(i < (s->picture_number&31))
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i += 32;
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s->picture_number = (s->picture_number&~31) + i;
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s->avctx->time_base= (AVRational){1001, 30000};
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s->current_picture.f.pts = s->picture_number;
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/* PTYPE starts here */
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skip_bits1(&s->gb); /* split screen off */
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skip_bits1(&s->gb); /* camera off */
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skip_bits1(&s->gb); /* freeze picture release off */
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format = get_bits1(&s->gb);
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//only 2 formats possible
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if (format == 0){//QCIF
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s->width = 176;
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s->height = 144;
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s->mb_width = 11;
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s->mb_height = 9;
|
|
}else{//CIF
|
|
s->width = 352;
|
|
s->height = 288;
|
|
s->mb_width = 22;
|
|
s->mb_height = 18;
|
|
}
|
|
|
|
s->mb_num = s->mb_width * s->mb_height;
|
|
|
|
skip_bits1(&s->gb); /* still image mode off */
|
|
skip_bits1(&s->gb); /* Reserved */
|
|
|
|
/* PEI */
|
|
while (get_bits1(&s->gb) != 0){
|
|
skip_bits(&s->gb, 8);
|
|
}
|
|
|
|
// h261 has no I-FRAMES, but if we pass AV_PICTURE_TYPE_I for the first frame, the codec crashes if it does
|
|
// not contain all I-blocks (e.g. when a packet is lost)
|
|
s->pict_type = AV_PICTURE_TYPE_P;
|
|
|
|
h->gob_number = 0;
|
|
return 0;
|
|
}
|
|
|
|
static int h261_decode_gob(H261Context *h){
|
|
MpegEncContext * const s = &h->s;
|
|
|
|
ff_set_qscale(s, s->qscale);
|
|
|
|
/* decode mb's */
|
|
while(h->current_mba <= MBA_STUFFING)
|
|
{
|
|
int ret;
|
|
/* DCT & quantize */
|
|
ret= h261_decode_mb(h);
|
|
if(ret<0){
|
|
if(ret==SLICE_END){
|
|
h261_decode_mb_skipped(h, h->current_mba, 33);
|
|
return 0;
|
|
}
|
|
av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", s->mb_x + s->mb_y*s->mb_stride);
|
|
return -1;
|
|
}
|
|
|
|
h261_decode_mb_skipped(h, h->current_mba-h->mba_diff, h->current_mba-1);
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* returns the number of bytes consumed for building the current frame
|
|
*/
|
|
static int get_consumed_bytes(MpegEncContext *s, int buf_size){
|
|
int pos= get_bits_count(&s->gb)>>3;
|
|
if(pos==0) pos=1; //avoid infinite loops (i doubt that is needed but ...)
|
|
if(pos+10>buf_size) pos=buf_size; // oops ;)
|
|
|
|
return pos;
|
|
}
|
|
|
|
static int h261_decode_frame(AVCodecContext *avctx,
|
|
void *data, int *got_frame,
|
|
AVPacket *avpkt)
|
|
{
|
|
const uint8_t *buf = avpkt->data;
|
|
int buf_size = avpkt->size;
|
|
H261Context *h= avctx->priv_data;
|
|
MpegEncContext *s = &h->s;
|
|
int ret;
|
|
AVFrame *pict = data;
|
|
|
|
av_dlog(avctx, "*****frame %d size=%d\n", avctx->frame_number, buf_size);
|
|
av_dlog(avctx, "bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
|
|
s->flags= avctx->flags;
|
|
s->flags2= avctx->flags2;
|
|
|
|
h->gob_start_code_skipped=0;
|
|
|
|
retry:
|
|
|
|
init_get_bits(&s->gb, buf, buf_size*8);
|
|
|
|
if(!s->context_initialized){
|
|
if (ff_MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
|
|
return -1;
|
|
}
|
|
|
|
//we need to set current_picture_ptr before reading the header, otherwise we cannot store anyting im there
|
|
if (s->current_picture_ptr == NULL || s->current_picture_ptr->f.data[0]) {
|
|
int i= ff_find_unused_picture(s, 0);
|
|
if (i < 0)
|
|
return i;
|
|
s->current_picture_ptr= &s->picture[i];
|
|
}
|
|
|
|
ret = h261_decode_picture_header(h);
|
|
|
|
/* skip if the header was thrashed */
|
|
if (ret < 0){
|
|
av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
|
|
return -1;
|
|
}
|
|
|
|
if (s->width != avctx->coded_width || s->height != avctx->coded_height){
|
|
ParseContext pc= s->parse_context; //FIXME move this demuxing hack to libavformat
|
|
s->parse_context.buffer=0;
|
|
ff_MPV_common_end(s);
|
|
s->parse_context= pc;
|
|
}
|
|
if (!s->context_initialized) {
|
|
avcodec_set_dimensions(avctx, s->width, s->height);
|
|
|
|
goto retry;
|
|
}
|
|
|
|
// for skipping the frame
|
|
s->current_picture.f.pict_type = s->pict_type;
|
|
s->current_picture.f.key_frame = s->pict_type == AV_PICTURE_TYPE_I;
|
|
|
|
if( (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==AV_PICTURE_TYPE_B)
|
|
||(avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=AV_PICTURE_TYPE_I)
|
|
|| avctx->skip_frame >= AVDISCARD_ALL)
|
|
return get_consumed_bytes(s, buf_size);
|
|
|
|
if(ff_MPV_frame_start(s, avctx) < 0)
|
|
return -1;
|
|
|
|
ff_er_frame_start(s);
|
|
|
|
/* decode each macroblock */
|
|
s->mb_x=0;
|
|
s->mb_y=0;
|
|
|
|
while(h->gob_number < (s->mb_height==18 ? 12 : 5)){
|
|
if(ff_h261_resync(h)<0)
|
|
break;
|
|
h261_decode_gob(h);
|
|
}
|
|
ff_MPV_frame_end(s);
|
|
|
|
assert(s->current_picture.f.pict_type == s->current_picture_ptr->f.pict_type);
|
|
assert(s->current_picture.f.pict_type == s->pict_type);
|
|
|
|
*pict = s->current_picture_ptr->f;
|
|
ff_print_debug_info(s, pict);
|
|
|
|
*got_frame = 1;
|
|
|
|
return get_consumed_bytes(s, buf_size);
|
|
}
|
|
|
|
static av_cold int h261_decode_end(AVCodecContext *avctx)
|
|
{
|
|
H261Context *h= avctx->priv_data;
|
|
MpegEncContext *s = &h->s;
|
|
|
|
ff_MPV_common_end(s);
|
|
return 0;
|
|
}
|
|
|
|
AVCodec ff_h261_decoder = {
|
|
.name = "h261",
|
|
.type = AVMEDIA_TYPE_VIDEO,
|
|
.id = AV_CODEC_ID_H261,
|
|
.priv_data_size = sizeof(H261Context),
|
|
.init = h261_decode_init,
|
|
.close = h261_decode_end,
|
|
.decode = h261_decode_frame,
|
|
.capabilities = CODEC_CAP_DR1,
|
|
.long_name = NULL_IF_CONFIG_SMALL("H.261"),
|
|
};
|