mirror of https://git.ffmpeg.org/ffmpeg.git
1080 lines
30 KiB
C
1080 lines
30 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 library 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 of the License, or (at your option) any later version.
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*
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* This library 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 this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/**
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* @file h261.c
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* h261codec.
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*/
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#include "common.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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#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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#define IS_FIL(a) ((a)&MB_TYPE_H261_FIL)
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/**
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* H261Context
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*/
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typedef struct H261Context{
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MpegEncContext s;
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int current_mba;
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int previous_mba;
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int mba_diff;
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int mtype;
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int current_mv_x;
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int current_mv_y;
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int gob_number;
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int bits_left; //8 - nr of bits left of the following frame in the last byte in this frame
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int last_bits; //bits left of the following frame in the last byte in this frame
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int gob_start_code_skipped; // 1 if gob start code is already read before gob header is read
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}H261Context;
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void ff_h261_loop_filter(MpegEncContext *s){
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H261Context * h= (H261Context*)s;
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const int linesize = s->linesize;
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const int uvlinesize= s->uvlinesize;
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uint8_t *dest_y = s->dest[0];
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uint8_t *dest_cb= s->dest[1];
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uint8_t *dest_cr= s->dest[2];
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if(!(IS_FIL (h->mtype)))
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return;
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s->dsp.h261_loop_filter(dest_y , linesize);
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s->dsp.h261_loop_filter(dest_y + 8, linesize);
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s->dsp.h261_loop_filter(dest_y + 8 * linesize , linesize);
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s->dsp.h261_loop_filter(dest_y + 8 * linesize + 8, linesize);
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s->dsp.h261_loop_filter(dest_cb, uvlinesize);
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s->dsp.h261_loop_filter(dest_cr, uvlinesize);
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}
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static int ff_h261_get_picture_format(int width, int height){
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// QCIF
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if (width == 176 && height == 144)
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return 0;
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// CIF
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else if (width == 352 && height == 288)
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return 1;
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// ERROR
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else
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return -1;
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}
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static void h261_encode_block(H261Context * h, DCTELEM * block,
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int n);
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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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void ff_h261_encode_picture_header(MpegEncContext * s, int picture_number){
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H261Context * h = (H261Context *) s;
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int format, temp_ref;
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align_put_bits(&s->pb);
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/* Update the pointer to last GOB */
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s->ptr_lastgob = pbBufPtr(&s->pb);
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put_bits(&s->pb, 20, 0x10); /* PSC */
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temp_ref= s->picture_number * (int64_t)30000 * s->avctx->frame_rate_base /
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(1001 * (int64_t)s->avctx->frame_rate);
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put_bits(&s->pb, 5, temp_ref & 0x1f); /* TemporalReference */
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put_bits(&s->pb, 1, 0); /* split screen off */
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put_bits(&s->pb, 1, 0); /* camera off */
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put_bits(&s->pb, 1, 0); /* freeze picture release off */
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format = ff_h261_get_picture_format(s->width, s->height);
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put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */
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put_bits(&s->pb, 1, 0); /* still image mode */
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put_bits(&s->pb, 1, 0); /* reserved */
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put_bits(&s->pb, 1, 0); /* no PEI */
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if(format == 0)
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h->gob_number = -1;
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else
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h->gob_number = 0;
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h->current_mba = 0;
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}
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/**
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* Encodes a group of blocks header.
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*/
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static void h261_encode_gob_header(MpegEncContext * s, int mb_line){
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H261Context * h = (H261Context *)s;
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if(ff_h261_get_picture_format(s->width, s->height) == 0){
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h->gob_number+=2; // QCIF
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}
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else{
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h->gob_number++; // CIF
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}
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put_bits(&s->pb, 16, 1); /* GBSC */
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put_bits(&s->pb, 4, h->gob_number); /* GN */
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put_bits(&s->pb, 5, s->qscale); /* GQUANT */
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put_bits(&s->pb, 1, 0); /* no GEI */
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h->current_mba = 0;
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h->previous_mba = 0;
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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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void ff_h261_reorder_mb_index(MpegEncContext* s){
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int index= s->mb_x + s->mb_y*s->mb_width;
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if(index % 33 == 0)
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h261_encode_gob_header(s,0);
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/* for CIF the GOB's are fragmented in the middle of a scanline
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that's why we need to adjust the x and y index of the macroblocks */
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if(ff_h261_get_picture_format(s->width,s->height) == 1){ // CIF
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s->mb_x = index % 11 ; index /= 11;
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s->mb_y = index % 3 ; index /= 3;
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s->mb_x+= 11*(index % 2); index /= 2;
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s->mb_y+= 3*index;
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ff_init_block_index(s);
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ff_update_block_index(s);
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}
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}
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static void h261_encode_motion(H261Context * h, int val){
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MpegEncContext * const s = &h->s;
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int sign, code;
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if(val==0){
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code = 0;
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put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]);
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}
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else{
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if(val > 16)
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val -=32;
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if(val < -16)
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val+=32;
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sign = val < 0;
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code = sign ? -val : val;
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put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]);
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put_bits(&s->pb,1,sign);
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}
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}
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static inline int get_cbp(MpegEncContext * s,
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DCTELEM block[6][64])
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{
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int i, cbp;
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cbp= 0;
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for (i = 0; i < 6; i++) {
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if (s->block_last_index[i] >= 0)
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cbp |= 1 << (5 - i);
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}
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return cbp;
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}
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void ff_h261_encode_mb(MpegEncContext * s,
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DCTELEM block[6][64],
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int motion_x, int motion_y)
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{
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H261Context * h = (H261Context *)s;
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int mvd, mv_diff_x, mv_diff_y, i, cbp;
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cbp = 63; // avoid warning
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mvd = 0;
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h->current_mba++;
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h->mtype = 0;
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if (!s->mb_intra){
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/* compute cbp */
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cbp= get_cbp(s, block);
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/* mvd indicates if this block is motion compensated */
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mvd = motion_x | motion_y;
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if((cbp | mvd | s->dquant ) == 0) {
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/* skip macroblock */
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s->skip_count++;
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h->current_mv_x=0;
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h->current_mv_y=0;
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return;
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}
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}
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/* MB is not skipped, encode MBA */
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put_bits(&s->pb, h261_mba_bits[(h->current_mba-h->previous_mba)-1], h261_mba_code[(h->current_mba-h->previous_mba)-1]);
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/* calculate MTYPE */
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if(!s->mb_intra){
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h->mtype++;
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if(mvd || s->loop_filter)
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h->mtype+=3;
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if(s->loop_filter)
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h->mtype+=3;
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if(cbp || s->dquant)
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h->mtype++;
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assert(h->mtype > 1);
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}
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if(s->dquant)
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h->mtype++;
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put_bits(&s->pb, h261_mtype_bits[h->mtype], h261_mtype_code[h->mtype]);
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h->mtype = h261_mtype_map[h->mtype];
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if(IS_QUANT(h->mtype)){
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ff_set_qscale(s,s->qscale+s->dquant);
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put_bits(&s->pb, 5, s->qscale);
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}
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if(IS_16X16(h->mtype)){
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mv_diff_x = (motion_x >> 1) - h->current_mv_x;
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mv_diff_y = (motion_y >> 1) - h->current_mv_y;
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h->current_mv_x = (motion_x >> 1);
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h->current_mv_y = (motion_y >> 1);
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h261_encode_motion(h,mv_diff_x);
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h261_encode_motion(h,mv_diff_y);
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}
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h->previous_mba = h->current_mba;
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if(HAS_CBP(h->mtype)){
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put_bits(&s->pb,h261_cbp_tab[cbp-1][1],h261_cbp_tab[cbp-1][0]);
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}
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for(i=0; i<6; i++) {
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/* encode each block */
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h261_encode_block(h, block[i], i);
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}
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if ( ( h->current_mba == 11 ) || ( h->current_mba == 22 ) || ( h->current_mba == 33 ) || ( !IS_16X16 ( h->mtype ) )){
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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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}
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void ff_h261_encode_init(MpegEncContext *s){
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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_rl(&h261_rl_tcoeff);
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}
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s->min_qcoeff= -127;
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s->max_qcoeff= 127;
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s->y_dc_scale_table=
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s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
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}
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/**
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* encodes a 8x8 block.
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* @param block the 8x8 block
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* @param n block index (0-3 are luma, 4-5 are chroma)
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*/
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static void h261_encode_block(H261Context * h, DCTELEM * block, int n){
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MpegEncContext * const s = &h->s;
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int level, run, last, i, j, last_index, last_non_zero, sign, slevel, code;
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RLTable *rl;
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rl = &h261_rl_tcoeff;
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if (s->mb_intra) {
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/* DC coef */
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level = block[0];
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/* 255 cannot be represented, so we clamp */
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if (level > 254) {
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level = 254;
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block[0] = 254;
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}
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/* 0 cannot be represented also */
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else if (level < 1) {
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level = 1;
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block[0] = 1;
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}
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if (level == 128)
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put_bits(&s->pb, 8, 0xff);
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else
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put_bits(&s->pb, 8, level);
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i = 1;
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} else if((block[0]==1 || block[0] == -1) && (s->block_last_index[n] > -1)){
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//special case
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put_bits(&s->pb,2,block[0]>0 ? 2 : 3 );
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i = 1;
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} else {
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i = 0;
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}
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/* AC coefs */
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last_index = s->block_last_index[n];
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last_non_zero = i - 1;
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for (; i <= last_index; i++) {
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j = s->intra_scantable.permutated[i];
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level = block[j];
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if (level) {
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run = i - last_non_zero - 1;
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last = (i == last_index);
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sign = 0;
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slevel = level;
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if (level < 0) {
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sign = 1;
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level = -level;
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}
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code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/, run, level);
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if(run==0 && level < 16)
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code+=1;
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put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
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if (code == rl->n) {
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put_bits(&s->pb, 6, run);
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assert(slevel != 0);
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assert(level <= 127);
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put_bits(&s->pb, 8, slevel & 0xff);
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} else {
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put_bits(&s->pb, 1, sign);
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}
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last_non_zero = i;
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}
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}
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if(last_index > -1){
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put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]);// END OF BLOCK
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}
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}
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/***********************************************/
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/* decoding */
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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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void init_vlc_rl(RLTable *rl);
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static 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(&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);
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init_vlc(&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);
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init_vlc(&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);
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init_vlc(&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);
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init_rl(&h261_rl_tcoeff);
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init_vlc_rl(&h261_rl_tcoeff);
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}
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}
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static 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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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= 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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* decodes the group of blocks header or slice header.
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* @return <0 if an error occured
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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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return -1;
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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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* decodes 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, its not where its supposed to be ...
|
|
s->gb= s->last_resync_gb;
|
|
align_get_bits(&s->gb);
|
|
left= s->gb.size_in_bits - get_bits_count(&s->gb);
|
|
|
|
for(;left>15+1+4+5; left-=8){
|
|
if(show_bits(&s->gb, 15)==0){
|
|
GetBitContext bak= s->gb;
|
|
|
|
ret= h261_decode_gob_header(h);
|
|
if(ret>=0)
|
|
return 0;
|
|
|
|
s->gb= bak;
|
|
}
|
|
skip_bits(&s->gb, 8);
|
|
}
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* decodes skipped macroblocks
|
|
* @return 0
|
|
*/
|
|
static int h261_decode_mb_skipped(H261Context *h, int mba1, int mba2 )
|
|
{
|
|
MpegEncContext * const s = &h->s;
|
|
int i;
|
|
|
|
s->mb_intra = 0;
|
|
|
|
for(i=mba1; i<mba2; i++){
|
|
int j, xy;
|
|
|
|
s->mb_x= ((h->gob_number-1) % 2) * 11 + i % 11;
|
|
s->mb_y= ((h->gob_number-1) / 2) * 3 + i / 11;
|
|
xy = s->mb_x + s->mb_y * s->mb_stride;
|
|
ff_init_block_index(s);
|
|
ff_update_block_index(s);
|
|
s->dsp.clear_blocks(s->block[0]);
|
|
|
|
for(j=0;j<6;j++)
|
|
s->block_last_index[j] = -1;
|
|
|
|
s->mv_dir = MV_DIR_FORWARD;
|
|
s->mv_type = MV_TYPE_16X16;
|
|
s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
|
|
s->mv[0][0][0] = 0;
|
|
s->mv[0][0][1] = 0;
|
|
s->mb_skiped = 1;
|
|
h->mtype &= ~MB_TYPE_H261_FIL;
|
|
|
|
MPV_decode_mb(s, s->block);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int decode_mv_component(GetBitContext *gb, int v){
|
|
int mv_diff = get_vlc2(gb, h261_mv_vlc.table, H261_MV_VLC_BITS, 2);
|
|
|
|
/* check if mv_diff is valid */
|
|
if ( mv_diff < 0 )
|
|
return v;
|
|
|
|
mv_diff = mvmap[mv_diff];
|
|
|
|
if(mv_diff && !get_bits1(gb))
|
|
mv_diff= -mv_diff;
|
|
|
|
v += mv_diff;
|
|
if (v <=-16) v+= 32;
|
|
else if(v >= 16) v-= 32;
|
|
|
|
return v;
|
|
}
|
|
|
|
static int h261_decode_mb(H261Context *h){
|
|
MpegEncContext * const s = &h->s;
|
|
int i, cbp, xy;
|
|
|
|
cbp = 63;
|
|
// Read mba
|
|
do{
|
|
h->mba_diff = get_vlc2(&s->gb, h261_mba_vlc.table, H261_MBA_VLC_BITS, 2);
|
|
|
|
/* Check for slice end */
|
|
/* NOTE: GOB can be empty (no MB data) or exist only of MBA_stuffing */
|
|
if (h->mba_diff == MBA_STARTCODE){ // start code
|
|
h->gob_start_code_skipped = 1;
|
|
return SLICE_END;
|
|
}
|
|
}
|
|
while( h->mba_diff == MBA_STUFFING ); // stuffing
|
|
|
|
if ( h->mba_diff < 0 ){
|
|
if ( get_bits_count(&s->gb) + 7 >= s->gb.size_in_bits )
|
|
return SLICE_END;
|
|
|
|
av_log(s->avctx, AV_LOG_ERROR, "illegal mba at %d %d\n", s->mb_x, s->mb_y);
|
|
return SLICE_ERROR;
|
|
}
|
|
|
|
h->mba_diff += 1;
|
|
h->current_mba += h->mba_diff;
|
|
|
|
if ( h->current_mba > MBA_STUFFING )
|
|
return SLICE_ERROR;
|
|
|
|
s->mb_x= ((h->gob_number-1) % 2) * 11 + ((h->current_mba-1) % 11);
|
|
s->mb_y= ((h->gob_number-1) / 2) * 3 + ((h->current_mba-1) / 11);
|
|
xy = s->mb_x + s->mb_y * s->mb_stride;
|
|
ff_init_block_index(s);
|
|
ff_update_block_index(s);
|
|
s->dsp.clear_blocks(s->block[0]);
|
|
|
|
// Read mtype
|
|
h->mtype = get_vlc2(&s->gb, h261_mtype_vlc.table, H261_MTYPE_VLC_BITS, 2);
|
|
h->mtype = h261_mtype_map[h->mtype];
|
|
|
|
// Read mquant
|
|
if ( IS_QUANT ( h->mtype ) ){
|
|
ff_set_qscale(s, get_bits(&s->gb, 5));
|
|
}
|
|
|
|
s->mb_intra = IS_INTRA4x4(h->mtype);
|
|
|
|
// Read mv
|
|
if ( IS_16X16 ( h->mtype ) ){
|
|
// Motion vector data is included for all MC macroblocks. MVD is obtained from the macroblock vector by subtracting the
|
|
// vector of the preceding macroblock. For this calculation the vector of the preceding macroblock is regarded as zero in the
|
|
// following three situations:
|
|
// 1) evaluating MVD for macroblocks 1, 12 and 23;
|
|
// 2) evaluating MVD for macroblocks in which MBA does not represent a difference of 1;
|
|
// 3) MTYPE of the previous macroblock was not MC.
|
|
if ( ( h->current_mba == 1 ) || ( h->current_mba == 12 ) || ( h->current_mba == 23 ) ||
|
|
( h->mba_diff != 1))
|
|
{
|
|
h->current_mv_x = 0;
|
|
h->current_mv_y = 0;
|
|
}
|
|
|
|
h->current_mv_x= decode_mv_component(&s->gb, h->current_mv_x);
|
|
h->current_mv_y= decode_mv_component(&s->gb, h->current_mv_y);
|
|
}else{
|
|
h->current_mv_x = 0;
|
|
h->current_mv_y = 0;
|
|
}
|
|
|
|
// Read cbp
|
|
if ( HAS_CBP( h->mtype ) ){
|
|
cbp = get_vlc2(&s->gb, h261_cbp_vlc.table, H261_CBP_VLC_BITS, 2) + 1;
|
|
}
|
|
|
|
if(s->mb_intra){
|
|
s->current_picture.mb_type[xy]= MB_TYPE_INTRA;
|
|
goto intra;
|
|
}
|
|
|
|
//set motion vectors
|
|
s->mv_dir = MV_DIR_FORWARD;
|
|
s->mv_type = MV_TYPE_16X16;
|
|
s->current_picture.mb_type[xy]= MB_TYPE_16x16 | MB_TYPE_L0;
|
|
s->mv[0][0][0] = h->current_mv_x * 2;//gets divided by 2 in motion compensation
|
|
s->mv[0][0][1] = h->current_mv_y * 2;
|
|
|
|
intra:
|
|
/* decode each block */
|
|
if(s->mb_intra || HAS_CBP(h->mtype)){
|
|
for (i = 0; i < 6; i++) {
|
|
if (h261_decode_block(h, s->block[i], i, cbp&32) < 0){
|
|
return SLICE_ERROR;
|
|
}
|
|
cbp+=cbp;
|
|
}
|
|
}
|
|
|
|
MPV_decode_mb(s, s->block);
|
|
|
|
return SLICE_OK;
|
|
}
|
|
|
|
/**
|
|
* decodes a macroblock
|
|
* @return <0 if an error occured
|
|
*/
|
|
static int h261_decode_block(H261Context * h, DCTELEM * block,
|
|
int n, int coded)
|
|
{
|
|
MpegEncContext * const s = &h->s;
|
|
int code, level, i, j, run;
|
|
RLTable *rl = &h261_rl_tcoeff;
|
|
const uint8_t *scan_table;
|
|
|
|
// For the variable length encoding there are two code tables, one being used for
|
|
// the first transmitted LEVEL in INTER, INTER+MC and INTER+MC+FIL blocks, the second
|
|
// for all other LEVELs except the first one in INTRA blocks which is fixed length
|
|
// coded with 8 bits.
|
|
// NOTE: the two code tables only differ in one VLC so we handle that manually.
|
|
scan_table = s->intra_scantable.permutated;
|
|
if (s->mb_intra){
|
|
/* DC coef */
|
|
level = get_bits(&s->gb, 8);
|
|
// 0 (00000000b) and -128 (10000000b) are FORBIDDEN
|
|
if((level&0x7F) == 0){
|
|
av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
|
|
return -1;
|
|
}
|
|
// The code 1000 0000 is not used, the reconstruction level of 1024 being coded as 1111 1111.
|
|
if (level == 255)
|
|
level = 128;
|
|
block[0] = level;
|
|
i = 1;
|
|
}else if(coded){
|
|
// Run Level Code
|
|
// EOB Not possible for first level when cbp is available (that's why the table is different)
|
|
// 0 1 1s
|
|
// * * 0*
|
|
int check = show_bits(&s->gb, 2);
|
|
i = 0;
|
|
if ( check & 0x2 ){
|
|
skip_bits(&s->gb, 2);
|
|
block[0] = ( check & 0x1 ) ? -1 : 1;
|
|
i = 1;
|
|
}
|
|
}else{
|
|
i = 0;
|
|
}
|
|
if(!coded){
|
|
s->block_last_index[n] = i - 1;
|
|
return 0;
|
|
}
|
|
for(;;){
|
|
code = get_vlc2(&s->gb, rl->vlc.table, TCOEFF_VLC_BITS, 2);
|
|
if (code < 0){
|
|
av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
|
|
return -1;
|
|
}
|
|
if (code == rl->n) {
|
|
/* escape */
|
|
// 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.
|
|
run = get_bits(&s->gb, 6);
|
|
level = get_sbits(&s->gb, 8);
|
|
}else if(code == 0){
|
|
break;
|
|
}else{
|
|
run = rl->table_run[code];
|
|
level = rl->table_level[code];
|
|
if (get_bits1(&s->gb))
|
|
level = -level;
|
|
}
|
|
i += run;
|
|
if (i >= 64){
|
|
av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d\n", s->mb_x, s->mb_y);
|
|
return -1;
|
|
}
|
|
j = scan_table[i];
|
|
block[j] = level;
|
|
i++;
|
|
}
|
|
s->block_last_index[n] = i-1;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* decodes the H261 picture header.
|
|
* @return <0 if no startcode found
|
|
*/
|
|
int h261_decode_picture_header(H261Context *h){
|
|
MpegEncContext * const s = &h->s;
|
|
int format, i;
|
|
uint32_t startcode= 0;
|
|
|
|
for(i= s->gb.size_in_bits - get_bits_count(&s->gb); i>24; i-=1){
|
|
startcode = ((startcode << 1) | get_bits(&s->gb, 1)) & 0x000FFFFF;
|
|
|
|
if(startcode == 0x10)
|
|
break;
|
|
}
|
|
|
|
if (startcode != 0x10){
|
|
av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
|
|
return -1;
|
|
}
|
|
|
|
/* temporal reference */
|
|
s->picture_number = get_bits(&s->gb, 5); /* picture timestamp */
|
|
|
|
/* PTYPE starts here */
|
|
skip_bits1(&s->gb); /* split screen off */
|
|
skip_bits1(&s->gb); /* camera off */
|
|
skip_bits1(&s->gb); /* freeze picture release off */
|
|
|
|
format = get_bits1(&s->gb);
|
|
|
|
//only 2 formats possible
|
|
if (format == 0){//QCIF
|
|
s->width = 176;
|
|
s->height = 144;
|
|
s->mb_width = 11;
|
|
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 I_TYPE 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 = P_TYPE;
|
|
|
|
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;
|
|
}
|
|
|
|
static int h261_find_frame_end(ParseContext *pc, AVCodecContext* avctx, const uint8_t *buf, int buf_size){
|
|
int vop_found, i, j, bits_left, last_bits;
|
|
uint32_t state;
|
|
|
|
H261Context *h = avctx->priv_data;
|
|
|
|
if(h){
|
|
bits_left = h->bits_left;
|
|
last_bits = h->last_bits;
|
|
}
|
|
else{
|
|
bits_left = 0;
|
|
last_bits = 0;
|
|
}
|
|
|
|
vop_found= pc->frame_start_found;
|
|
state= pc->state;
|
|
if(bits_left!=0 && !vop_found)
|
|
state = state << (8-bits_left) | last_bits;
|
|
i=0;
|
|
if(!vop_found){
|
|
for(i=0; i<buf_size; i++){
|
|
state= (state<<8) | buf[i];
|
|
for(j=0; j<8; j++){
|
|
if(( ( (state<<j) | (buf[i]>>(8-j)) )>>(32-20) == 0x10 )&&(((state >> (17-j)) & 0x4000) == 0x0)){
|
|
i++;
|
|
vop_found=1;
|
|
break;
|
|
}
|
|
}
|
|
if(vop_found)
|
|
break;
|
|
}
|
|
}
|
|
if(vop_found){
|
|
for(; i<buf_size; i++){
|
|
if(avctx->flags & CODEC_FLAG_TRUNCATED)//XXX ffplay workaround, someone a better solution?
|
|
state= (state<<8) | buf[i];
|
|
for(j=0; j<8; j++){
|
|
if(( ( (state<<j) | (buf[i]>>(8-j)) )>>(32-20) == 0x10 )&&(((state >> (17-j)) & 0x4000) == 0x0)){
|
|
pc->frame_start_found=0;
|
|
pc->state=-1;
|
|
return i-3;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pc->frame_start_found= vop_found;
|
|
pc->state= state;
|
|
return END_NOT_FOUND;
|
|
}
|
|
|
|
static int h261_parse(AVCodecParserContext *s,
|
|
AVCodecContext *avctx,
|
|
uint8_t **poutbuf, int *poutbuf_size,
|
|
const uint8_t *buf, int buf_size)
|
|
{
|
|
ParseContext *pc = s->priv_data;
|
|
int next;
|
|
|
|
next= h261_find_frame_end(pc,avctx, buf, buf_size);
|
|
if (ff_combine_frame(pc, next, (uint8_t **)&buf, &buf_size) < 0) {
|
|
*poutbuf = NULL;
|
|
*poutbuf_size = 0;
|
|
return buf_size;
|
|
}
|
|
*poutbuf = (uint8_t *)buf;
|
|
*poutbuf_size = buf_size;
|
|
return next;
|
|
}
|
|
|
|
/**
|
|
* returns the number of bytes consumed for building the current frame
|
|
*/
|
|
static int get_consumed_bytes(MpegEncContext *s, int buf_size){
|
|
if(s->flags&CODEC_FLAG_TRUNCATED){
|
|
int pos= (get_bits_count(&s->gb)+7)>>3;
|
|
pos -= s->parse_context.last_index;
|
|
if(pos<0) pos=0;// padding is not really read so this might be -1
|
|
return pos;
|
|
}else{
|
|
int pos= get_bits_count(&s->gb)>>3;
|
|
if(pos==0) pos=1; //avoid infinite loops (i doubt thats needed but ...)
|
|
if(pos+10>buf_size) pos=buf_size; // oops ;)
|
|
|
|
return pos;
|
|
}
|
|
}
|
|
|
|
static int h261_decode_frame(AVCodecContext *avctx,
|
|
void *data, int *data_size,
|
|
uint8_t *buf, int buf_size)
|
|
{
|
|
H261Context *h= avctx->priv_data;
|
|
MpegEncContext *s = &h->s;
|
|
int ret;
|
|
AVFrame *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
|
|
s->flags= avctx->flags;
|
|
s->flags2= avctx->flags2;
|
|
|
|
/* no supplementary picture */
|
|
if (buf_size == 0) {
|
|
return 0;
|
|
}
|
|
|
|
if(s->flags&CODEC_FLAG_TRUNCATED){
|
|
int next;
|
|
|
|
next= h261_find_frame_end(&s->parse_context,avctx, buf, buf_size);
|
|
|
|
if( ff_combine_frame(&s->parse_context, next, &buf, &buf_size) < 0 )
|
|
return buf_size;
|
|
}
|
|
|
|
|
|
retry:
|
|
|
|
init_get_bits(&s->gb, buf, buf_size*8);
|
|
|
|
if(!s->context_initialized){
|
|
if (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 cant store anyting im there
|
|
if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){
|
|
int i= ff_find_unused_picture(s, 0);
|
|
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 these demuxng hack to avformat
|
|
s->parse_context.buffer=0;
|
|
MPV_common_end(s);
|
|
s->parse_context= pc;
|
|
}
|
|
if (!s->context_initialized) {
|
|
avcodec_set_dimensions(avctx, s->width, s->height);
|
|
|
|
goto retry;
|
|
}
|
|
|
|
// for hurry_up==5
|
|
s->current_picture.pict_type= s->pict_type;
|
|
s->current_picture.key_frame= s->pict_type == I_TYPE;
|
|
|
|
/* skip everything if we are in a hurry>=5 */
|
|
if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
|
|
|
|
if(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);
|
|
}
|
|
MPV_frame_end(s);
|
|
|
|
assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
|
|
assert(s->current_picture.pict_type == s->pict_type);
|
|
*pict= *(AVFrame*)&s->current_picture;
|
|
ff_print_debug_info(s, pict);
|
|
|
|
/* Return the Picture timestamp as the frame number */
|
|
/* we substract 1 because it is added on utils.c */
|
|
avctx->frame_number = s->picture_number - 1;
|
|
|
|
*data_size = sizeof(AVFrame);
|
|
|
|
return get_consumed_bytes(s, buf_size);
|
|
}
|
|
|
|
static int h261_decode_end(AVCodecContext *avctx)
|
|
{
|
|
H261Context *h= avctx->priv_data;
|
|
MpegEncContext *s = &h->s;
|
|
|
|
MPV_common_end(s);
|
|
return 0;
|
|
}
|
|
|
|
AVCodec h261_encoder = {
|
|
"h261",
|
|
CODEC_TYPE_VIDEO,
|
|
CODEC_ID_H261,
|
|
sizeof(H261Context),
|
|
MPV_encode_init,
|
|
MPV_encode_picture,
|
|
MPV_encode_end,
|
|
};
|
|
|
|
AVCodec h261_decoder = {
|
|
"h261",
|
|
CODEC_TYPE_VIDEO,
|
|
CODEC_ID_H261,
|
|
sizeof(H261Context),
|
|
h261_decode_init,
|
|
NULL,
|
|
h261_decode_end,
|
|
h261_decode_frame,
|
|
CODEC_CAP_TRUNCATED,
|
|
};
|
|
|
|
AVCodecParser h261_parser = {
|
|
{ CODEC_ID_H261 },
|
|
sizeof(ParseContext),
|
|
NULL,
|
|
h261_parse,
|
|
ff_parse_close,
|
|
};
|