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FFmpeg/libavcodec/cavsdec.c
Stefan Gehrer cd3356ff73 check for a stuffing byte at the end of a slice 
Originally committed as revision 17559 to svn://svn.ffmpeg.org/ffmpeg/trunk
2009-02-24 15:56:53 +00:00

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/*
* Chinese AVS video (AVS1-P2, JiZhun profile) decoder.
* Copyright (c) 2006 Stefan Gehrer <stefan.gehrer@gmx.de>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file libavcodec/cavsdec.c
* Chinese AVS video (AVS1-P2, JiZhun profile) decoder
* @author Stefan Gehrer <stefan.gehrer@gmx.de>
*/
#include "avcodec.h"
#include "bitstream.h"
#include "golomb.h"
#include "cavs.h"
static const uint8_t mv_scan[4] = {
MV_FWD_X0,MV_FWD_X1,
MV_FWD_X2,MV_FWD_X3
};
static const uint8_t cbp_tab[64][2] = {
{63, 0},{15,15},{31,63},{47,31},{ 0,16},{14,32},{13,47},{11,13},
{ 7,14},{ 5,11},{10,12},{ 8, 5},{12,10},{61, 7},{ 4,48},{55, 3},
{ 1, 2},{ 2, 8},{59, 4},{ 3, 1},{62,61},{ 9,55},{ 6,59},{29,62},
{45,29},{51,27},{23,23},{39,19},{27,30},{46,28},{53, 9},{30, 6},
{43,60},{37,21},{60,44},{16,26},{21,51},{28,35},{19,18},{35,20},
{42,24},{26,53},{44,17},{32,37},{58,39},{24,45},{20,58},{17,43},
{18,42},{48,46},{22,36},{33,33},{25,34},{49,40},{40,52},{36,49},
{34,50},{50,56},{52,25},{54,22},{41,54},{56,57},{38,41},{57,38}
};
/*****************************************************************************
*
* motion vector prediction
*
****************************************************************************/
static inline void store_mvs(AVSContext *h) {
h->col_mv[h->mbidx*4 + 0] = h->mv[MV_FWD_X0];
h->col_mv[h->mbidx*4 + 1] = h->mv[MV_FWD_X1];
h->col_mv[h->mbidx*4 + 2] = h->mv[MV_FWD_X2];
h->col_mv[h->mbidx*4 + 3] = h->mv[MV_FWD_X3];
}
static inline void mv_pred_direct(AVSContext *h, cavs_vector *pmv_fw,
cavs_vector *col_mv) {
cavs_vector *pmv_bw = pmv_fw + MV_BWD_OFFS;
int den = h->direct_den[col_mv->ref];
int m = col_mv->x >> 31;
pmv_fw->dist = h->dist[1];
pmv_bw->dist = h->dist[0];
pmv_fw->ref = 1;
pmv_bw->ref = 0;
/* scale the co-located motion vector according to its temporal span */
pmv_fw->x = (((den+(den*col_mv->x*pmv_fw->dist^m)-m-1)>>14)^m)-m;
pmv_bw->x = m-(((den+(den*col_mv->x*pmv_bw->dist^m)-m-1)>>14)^m);
m = col_mv->y >> 31;
pmv_fw->y = (((den+(den*col_mv->y*pmv_fw->dist^m)-m-1)>>14)^m)-m;
pmv_bw->y = m-(((den+(den*col_mv->y*pmv_bw->dist^m)-m-1)>>14)^m);
}
static inline void mv_pred_sym(AVSContext *h, cavs_vector *src, enum cavs_block size) {
cavs_vector *dst = src + MV_BWD_OFFS;
/* backward mv is the scaled and negated forward mv */
dst->x = -((src->x * h->sym_factor + 256) >> 9);
dst->y = -((src->y * h->sym_factor + 256) >> 9);
dst->ref = 0;
dst->dist = h->dist[0];
set_mvs(dst, size);
}
/*****************************************************************************
*
* residual data decoding
*
****************************************************************************/
/** kth-order exponential golomb code */
static inline int get_ue_code(GetBitContext *gb, int order) {
if(order) {
int ret = get_ue_golomb(gb) << order;
return ret + get_bits(gb,order);
}
return get_ue_golomb(gb);
}
/**
* decode coefficients from one 8x8 block, dequantize, inverse transform
* and add them to sample block
* @param r pointer to 2D VLC table
* @param esc_golomb_order escape codes are k-golomb with this order k
* @param qp quantizer
* @param dst location of sample block
* @param stride line stride in frame buffer
*/
static int decode_residual_block(AVSContext *h, GetBitContext *gb,
const struct dec_2dvlc *r, int esc_golomb_order,
int qp, uint8_t *dst, int stride) {
int i, level_code, esc_code, level, run, mask;
DCTELEM level_buf[65];
uint8_t run_buf[65];
DCTELEM *block = h->block;
for(i=0;i<65;i++) {
level_code = get_ue_code(gb,r->golomb_order);
if(level_code >= ESCAPE_CODE) {
run = ((level_code - ESCAPE_CODE) >> 1) + 1;
esc_code = get_ue_code(gb,esc_golomb_order);
level = esc_code + (run > r->max_run ? 1 : r->level_add[run]);
while(level > r->inc_limit)
r++;
mask = -(level_code & 1);
level = (level^mask) - mask;
} else {
level = r->rltab[level_code][0];
if(!level) //end of block signal
break;
run = r->rltab[level_code][1];
r += r->rltab[level_code][2];
}
level_buf[i] = level;
run_buf[i] = run;
}
if(dequant(h,level_buf, run_buf, block, ff_cavs_dequant_mul[qp],
ff_cavs_dequant_shift[qp], i))
return -1;
h->s.dsp.cavs_idct8_add(dst,block,stride);
h->s.dsp.clear_block(block);
return 0;
}
static inline void decode_residual_chroma(AVSContext *h) {
if(h->cbp & (1<<4))
decode_residual_block(h,&h->s.gb,ff_cavs_chroma_dec,0,
ff_cavs_chroma_qp[h->qp],h->cu,h->c_stride);
if(h->cbp & (1<<5))
decode_residual_block(h,&h->s.gb,ff_cavs_chroma_dec,0,
ff_cavs_chroma_qp[h->qp],h->cv,h->c_stride);
}
static inline int decode_residual_inter(AVSContext *h) {
int block;
/* get coded block pattern */
int cbp= get_ue_golomb(&h->s.gb);
if(cbp > 63){
av_log(h->s.avctx, AV_LOG_ERROR, "illegal inter cbp\n");
return -1;
}
h->cbp = cbp_tab[cbp][1];
/* get quantizer */
if(h->cbp && !h->qp_fixed)
h->qp = (h->qp + get_se_golomb(&h->s.gb)) & 63;
for(block=0;block<4;block++)
if(h->cbp & (1<<block))
decode_residual_block(h,&h->s.gb,ff_cavs_inter_dec,0,h->qp,
h->cy + h->luma_scan[block], h->l_stride);
decode_residual_chroma(h);
return 0;
}
/*****************************************************************************
*
* macroblock level
*
****************************************************************************/
static int decode_mb_i(AVSContext *h, int cbp_code) {
GetBitContext *gb = &h->s.gb;
int block, pred_mode_uv;
uint8_t top[18];
uint8_t *left = NULL;
uint8_t *d;
ff_cavs_init_mb(h);
/* get intra prediction modes from stream */
for(block=0;block<4;block++) {
int nA,nB,predpred;
int pos = ff_cavs_scan3x3[block];
nA = h->pred_mode_Y[pos-1];
nB = h->pred_mode_Y[pos-3];
predpred = FFMIN(nA,nB);
if(predpred == NOT_AVAIL) // if either is not available
predpred = INTRA_L_LP;
if(!get_bits1(gb)){
int rem_mode= get_bits(gb, 2);
predpred = rem_mode + (rem_mode >= predpred);
}
h->pred_mode_Y[pos] = predpred;
}
pred_mode_uv = get_ue_golomb(gb);
if(pred_mode_uv > 6) {
av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra chroma pred mode\n");
return -1;
}
ff_cavs_modify_mb_i(h, &pred_mode_uv);
/* get coded block pattern */
if(h->pic_type == FF_I_TYPE)
cbp_code = get_ue_golomb(gb);
if(cbp_code > 63){
av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra cbp\n");
return -1;
}
h->cbp = cbp_tab[cbp_code][0];
if(h->cbp && !h->qp_fixed)
h->qp = (h->qp + get_se_golomb(gb)) & 63; //qp_delta
/* luma intra prediction interleaved with residual decode/transform/add */
for(block=0;block<4;block++) {
d = h->cy + h->luma_scan[block];
ff_cavs_load_intra_pred_luma(h, top, &left, block);
h->intra_pred_l[h->pred_mode_Y[ff_cavs_scan3x3[block]]]
(d, top, left, h->l_stride);
if(h->cbp & (1<<block))
decode_residual_block(h,gb,ff_cavs_intra_dec,1,h->qp,d,h->l_stride);
}
/* chroma intra prediction */
ff_cavs_load_intra_pred_chroma(h);
h->intra_pred_c[pred_mode_uv](h->cu, &h->top_border_u[h->mbx*10],
h->left_border_u, h->c_stride);
h->intra_pred_c[pred_mode_uv](h->cv, &h->top_border_v[h->mbx*10],
h->left_border_v, h->c_stride);
decode_residual_chroma(h);
ff_cavs_filter(h,I_8X8);
set_mv_intra(h);
return 0;
}
static void decode_mb_p(AVSContext *h, enum cavs_mb mb_type) {
GetBitContext *gb = &h->s.gb;
int ref[4];
ff_cavs_init_mb(h);
switch(mb_type) {
case P_SKIP:
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_PSKIP, BLK_16X16, 0);
break;
case P_16X16:
ref[0] = h->ref_flag ? 0 : get_bits1(gb);
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16,ref[0]);
break;
case P_16X8:
ref[0] = h->ref_flag ? 0 : get_bits1(gb);
ref[2] = h->ref_flag ? 0 : get_bits1(gb);
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_TOP, BLK_16X8, ref[0]);
ff_cavs_mv(h, MV_FWD_X2, MV_FWD_A1, MV_PRED_LEFT, BLK_16X8, ref[2]);
break;
case P_8X16:
ref[0] = h->ref_flag ? 0 : get_bits1(gb);
ref[1] = h->ref_flag ? 0 : get_bits1(gb);
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_LEFT, BLK_8X16, ref[0]);
ff_cavs_mv(h, MV_FWD_X1, MV_FWD_C2, MV_PRED_TOPRIGHT,BLK_8X16, ref[1]);
break;
case P_8X8:
ref[0] = h->ref_flag ? 0 : get_bits1(gb);
ref[1] = h->ref_flag ? 0 : get_bits1(gb);
ref[2] = h->ref_flag ? 0 : get_bits1(gb);
ref[3] = h->ref_flag ? 0 : get_bits1(gb);
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_MEDIAN, BLK_8X8, ref[0]);
ff_cavs_mv(h, MV_FWD_X1, MV_FWD_C2, MV_PRED_MEDIAN, BLK_8X8, ref[1]);
ff_cavs_mv(h, MV_FWD_X2, MV_FWD_X1, MV_PRED_MEDIAN, BLK_8X8, ref[2]);
ff_cavs_mv(h, MV_FWD_X3, MV_FWD_X0, MV_PRED_MEDIAN, BLK_8X8, ref[3]);
}
ff_cavs_inter(h, mb_type);
set_intra_mode_default(h);
store_mvs(h);
if(mb_type != P_SKIP)
decode_residual_inter(h);
ff_cavs_filter(h,mb_type);
h->col_type_base[h->mbidx] = mb_type;
}
static void decode_mb_b(AVSContext *h, enum cavs_mb mb_type) {
int block;
enum cavs_sub_mb sub_type[4];
int flags;
ff_cavs_init_mb(h);
/* reset all MVs */
h->mv[MV_FWD_X0] = ff_cavs_dir_mv;
set_mvs(&h->mv[MV_FWD_X0], BLK_16X16);
h->mv[MV_BWD_X0] = ff_cavs_dir_mv;
set_mvs(&h->mv[MV_BWD_X0], BLK_16X16);
switch(mb_type) {
case B_SKIP:
case B_DIRECT:
if(!h->col_type_base[h->mbidx]) {
/* intra MB at co-location, do in-plane prediction */
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_BSKIP, BLK_16X16, 1);
ff_cavs_mv(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_BSKIP, BLK_16X16, 0);
} else
/* direct prediction from co-located P MB, block-wise */
for(block=0;block<4;block++)
mv_pred_direct(h,&h->mv[mv_scan[block]],
&h->col_mv[h->mbidx*4 + block]);
break;
case B_FWD_16X16:
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16, 1);
break;
case B_SYM_16X16:
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16, 1);
mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X16);
break;
case B_BWD_16X16:
ff_cavs_mv(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_MEDIAN, BLK_16X16, 0);
break;
case B_8X8:
for(block=0;block<4;block++)
sub_type[block] = get_bits(&h->s.gb,2);
for(block=0;block<4;block++) {
switch(sub_type[block]) {
case B_SUB_DIRECT:
if(!h->col_type_base[h->mbidx]) {
/* intra MB at co-location, do in-plane prediction */
ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3,
MV_PRED_BSKIP, BLK_8X8, 1);
ff_cavs_mv(h, mv_scan[block]+MV_BWD_OFFS,
mv_scan[block]-3+MV_BWD_OFFS,
MV_PRED_BSKIP, BLK_8X8, 0);
} else
mv_pred_direct(h,&h->mv[mv_scan[block]],
&h->col_mv[h->mbidx*4 + block]);
break;
case B_SUB_FWD:
ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3,
MV_PRED_MEDIAN, BLK_8X8, 1);
break;
case B_SUB_SYM:
ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3,
MV_PRED_MEDIAN, BLK_8X8, 1);
mv_pred_sym(h, &h->mv[mv_scan[block]], BLK_8X8);
break;
}
}
for(block=0;block<4;block++) {
if(sub_type[block] == B_SUB_BWD)
ff_cavs_mv(h, mv_scan[block]+MV_BWD_OFFS,
mv_scan[block]+MV_BWD_OFFS-3,
MV_PRED_MEDIAN, BLK_8X8, 0);
}
break;
default:
assert((mb_type > B_SYM_16X16) && (mb_type < B_8X8));
flags = ff_cavs_partition_flags[mb_type];
if(mb_type & 1) { /* 16x8 macroblock types */
if(flags & FWD0)
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_TOP, BLK_16X8, 1);
if(flags & SYM0)
mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X8);
if(flags & FWD1)
ff_cavs_mv(h, MV_FWD_X2, MV_FWD_A1, MV_PRED_LEFT, BLK_16X8, 1);
if(flags & SYM1)
mv_pred_sym(h, &h->mv[MV_FWD_X2], BLK_16X8);
if(flags & BWD0)
ff_cavs_mv(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_TOP, BLK_16X8, 0);
if(flags & BWD1)
ff_cavs_mv(h, MV_BWD_X2, MV_BWD_A1, MV_PRED_LEFT, BLK_16X8, 0);
} else { /* 8x16 macroblock types */
if(flags & FWD0)
ff_cavs_mv(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_LEFT, BLK_8X16, 1);
if(flags & SYM0)
mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_8X16);
if(flags & FWD1)
ff_cavs_mv(h,MV_FWD_X1,MV_FWD_C2,MV_PRED_TOPRIGHT,BLK_8X16,1);
if(flags & SYM1)
mv_pred_sym(h, &h->mv[MV_FWD_X1], BLK_8X16);
if(flags & BWD0)
ff_cavs_mv(h, MV_BWD_X0, MV_BWD_B3, MV_PRED_LEFT, BLK_8X16, 0);
if(flags & BWD1)
ff_cavs_mv(h,MV_BWD_X1,MV_BWD_C2,MV_PRED_TOPRIGHT,BLK_8X16,0);
}
}
ff_cavs_inter(h, mb_type);
set_intra_mode_default(h);
if(mb_type != B_SKIP)
decode_residual_inter(h);
ff_cavs_filter(h,mb_type);
}
/*****************************************************************************
*
* slice level
*
****************************************************************************/
static inline int decode_slice_header(AVSContext *h, GetBitContext *gb) {
if(h->stc > 0xAF)
av_log(h->s.avctx, AV_LOG_ERROR, "unexpected start code 0x%02x\n", h->stc);
h->mby = h->stc;
h->mbidx = h->mby*h->mb_width;
/* mark top macroblocks as unavailable */
h->flags &= ~(B_AVAIL|C_AVAIL);
if((h->mby == 0) && (!h->qp_fixed)){
h->qp_fixed = get_bits1(gb);
h->qp = get_bits(gb,6);
}
/* inter frame or second slice can have weighting params */
if((h->pic_type != FF_I_TYPE) || (!h->pic_structure && h->mby >= h->mb_width/2))
if(get_bits1(gb)) { //slice_weighting_flag
av_log(h->s.avctx, AV_LOG_ERROR,
"weighted prediction not yet supported\n");
}
return 0;
}
static inline int check_for_slice(AVSContext *h) {
GetBitContext *gb = &h->s.gb;
int align;
if(h->mbx)
return 0;
align = (-get_bits_count(gb)) & 7;
/* check for stuffing byte */
if(!align && (show_bits(gb,8) == 0x80))
get_bits(gb,8);
if((show_bits_long(gb,24+align) & 0xFFFFFF) == 0x000001) {
skip_bits_long(gb,24+align);
h->stc = get_bits(gb,8);
decode_slice_header(h,gb);
return 1;
}
return 0;
}
/*****************************************************************************
*
* frame level
*
****************************************************************************/
static int decode_pic(AVSContext *h) {
MpegEncContext *s = &h->s;
int skip_count = -1;
enum cavs_mb mb_type;
if (!s->context_initialized) {
s->avctx->idct_algo = FF_IDCT_CAVS;
if (MPV_common_init(s) < 0)
return -1;
ff_init_scantable(s->dsp.idct_permutation,&h->scantable,ff_zigzag_direct);
}
skip_bits(&s->gb,16);//bbv_dwlay
if(h->stc == PIC_PB_START_CODE) {
h->pic_type = get_bits(&s->gb,2) + FF_I_TYPE;
if(h->pic_type > FF_B_TYPE) {
av_log(s->avctx, AV_LOG_ERROR, "illegal picture type\n");
return -1;
}
/* make sure we have the reference frames we need */
if(!h->DPB[0].data[0] ||
(!h->DPB[1].data[0] && h->pic_type == FF_B_TYPE))
return -1;
} else {
h->pic_type = FF_I_TYPE;
if(get_bits1(&s->gb))
skip_bits(&s->gb,24);//time_code
}
/* release last B frame */
if(h->picture.data[0])
s->avctx->release_buffer(s->avctx, (AVFrame *)&h->picture);
s->avctx->get_buffer(s->avctx, (AVFrame *)&h->picture);
ff_cavs_init_pic(h);
h->picture.poc = get_bits(&s->gb,8)*2;
/* get temporal distances and MV scaling factors */
if(h->pic_type != FF_B_TYPE) {
h->dist[0] = (h->picture.poc - h->DPB[0].poc + 512) % 512;
} else {
h->dist[0] = (h->DPB[0].poc - h->picture.poc + 512) % 512;
}
h->dist[1] = (h->picture.poc - h->DPB[1].poc + 512) % 512;
h->scale_den[0] = h->dist[0] ? 512/h->dist[0] : 0;
h->scale_den[1] = h->dist[1] ? 512/h->dist[1] : 0;
if(h->pic_type == FF_B_TYPE) {
h->sym_factor = h->dist[0]*h->scale_den[1];
} else {
h->direct_den[0] = h->dist[0] ? 16384/h->dist[0] : 0;
h->direct_den[1] = h->dist[1] ? 16384/h->dist[1] : 0;
}
if(s->low_delay)
get_ue_golomb(&s->gb); //bbv_check_times
h->progressive = get_bits1(&s->gb);
h->pic_structure = 1;
if(!h->progressive)
h->pic_structure = get_bits1(&s->gb);
if(!h->pic_structure && h->stc == PIC_PB_START_CODE)
skip_bits1(&s->gb); //advanced_pred_mode_disable
skip_bits1(&s->gb); //top_field_first
skip_bits1(&s->gb); //repeat_first_field
h->qp_fixed = get_bits1(&s->gb);
h->qp = get_bits(&s->gb,6);
if(h->pic_type == FF_I_TYPE) {
if(!h->progressive && !h->pic_structure)
skip_bits1(&s->gb);//what is this?
skip_bits(&s->gb,4); //reserved bits
} else {
if(!(h->pic_type == FF_B_TYPE && h->pic_structure == 1))
h->ref_flag = get_bits1(&s->gb);
skip_bits(&s->gb,4); //reserved bits
h->skip_mode_flag = get_bits1(&s->gb);
}
h->loop_filter_disable = get_bits1(&s->gb);
if(!h->loop_filter_disable && get_bits1(&s->gb)) {
h->alpha_offset = get_se_golomb(&s->gb);
h->beta_offset = get_se_golomb(&s->gb);
} else {
h->alpha_offset = h->beta_offset = 0;
}
if(h->pic_type == FF_I_TYPE) {
do {
check_for_slice(h);
decode_mb_i(h, 0);
} while(ff_cavs_next_mb(h));
} else if(h->pic_type == FF_P_TYPE) {
do {
if(check_for_slice(h))
skip_count = -1;
if(h->skip_mode_flag && (skip_count < 0))
skip_count = get_ue_golomb(&s->gb);
if(h->skip_mode_flag && skip_count--) {
decode_mb_p(h,P_SKIP);
} else {
mb_type = get_ue_golomb(&s->gb) + P_SKIP + h->skip_mode_flag;
if(mb_type > P_8X8)
decode_mb_i(h, mb_type - P_8X8 - 1);
else
decode_mb_p(h,mb_type);
}
} while(ff_cavs_next_mb(h));
} else { /* FF_B_TYPE */
do {
if(check_for_slice(h))
skip_count = -1;
if(h->skip_mode_flag && (skip_count < 0))
skip_count = get_ue_golomb(&s->gb);
if(h->skip_mode_flag && skip_count--) {
decode_mb_b(h,B_SKIP);
} else {
mb_type = get_ue_golomb(&s->gb) + B_SKIP + h->skip_mode_flag;
if(mb_type > B_8X8)
decode_mb_i(h, mb_type - B_8X8 - 1);
else
decode_mb_b(h,mb_type);
}
} while(ff_cavs_next_mb(h));
}
if(h->pic_type != FF_B_TYPE) {
if(h->DPB[1].data[0])
s->avctx->release_buffer(s->avctx, (AVFrame *)&h->DPB[1]);
h->DPB[1] = h->DPB[0];
h->DPB[0] = h->picture;
memset(&h->picture,0,sizeof(Picture));
}
return 0;
}
/*****************************************************************************
*
* headers and interface
*
****************************************************************************/
static int decode_seq_header(AVSContext *h) {
MpegEncContext *s = &h->s;
int frame_rate_code;
h->profile = get_bits(&s->gb,8);
h->level = get_bits(&s->gb,8);
skip_bits1(&s->gb); //progressive sequence
s->width = get_bits(&s->gb,14);
s->height = get_bits(&s->gb,14);
skip_bits(&s->gb,2); //chroma format
skip_bits(&s->gb,3); //sample_precision
h->aspect_ratio = get_bits(&s->gb,4);
frame_rate_code = get_bits(&s->gb,4);
skip_bits(&s->gb,18);//bit_rate_lower
skip_bits1(&s->gb); //marker_bit
skip_bits(&s->gb,12);//bit_rate_upper
s->low_delay = get_bits1(&s->gb);
h->mb_width = (s->width + 15) >> 4;
h->mb_height = (s->height + 15) >> 4;
h->s.avctx->time_base.den = ff_frame_rate_tab[frame_rate_code].num;
h->s.avctx->time_base.num = ff_frame_rate_tab[frame_rate_code].den;
h->s.avctx->width = s->width;
h->s.avctx->height = s->height;
if(!h->top_qp)
ff_cavs_init_top_lines(h);
return 0;
}
static void cavs_flush(AVCodecContext * avctx) {
AVSContext *h = avctx->priv_data;
h->got_keyframe = 0;
}
static int cavs_decode_frame(AVCodecContext * avctx,void *data, int *data_size,
const uint8_t * buf, int buf_size) {
AVSContext *h = avctx->priv_data;
MpegEncContext *s = &h->s;
int input_size;
const uint8_t *buf_end;
const uint8_t *buf_ptr;
AVFrame *picture = data;
uint32_t stc = -1;
s->avctx = avctx;
if (buf_size == 0) {
if(!s->low_delay && h->DPB[0].data[0]) {
*data_size = sizeof(AVPicture);
*picture = *(AVFrame *) &h->DPB[0];
}
return 0;
}
buf_ptr = buf;
buf_end = buf + buf_size;
for(;;) {
buf_ptr = ff_find_start_code(buf_ptr,buf_end, &stc);
if(stc & 0xFFFFFE00)
return FFMAX(0, buf_ptr - buf - s->parse_context.last_index);
input_size = (buf_end - buf_ptr)*8;
switch(stc) {
case CAVS_START_CODE:
init_get_bits(&s->gb, buf_ptr, input_size);
decode_seq_header(h);
break;
case PIC_I_START_CODE:
if(!h->got_keyframe) {
if(h->DPB[0].data[0])
avctx->release_buffer(avctx, (AVFrame *)&h->DPB[0]);
if(h->DPB[1].data[0])
avctx->release_buffer(avctx, (AVFrame *)&h->DPB[1]);
h->got_keyframe = 1;
}
case PIC_PB_START_CODE:
*data_size = 0;
if(!h->got_keyframe)
break;
init_get_bits(&s->gb, buf_ptr, input_size);
h->stc = stc;
if(decode_pic(h))
break;
*data_size = sizeof(AVPicture);
if(h->pic_type != FF_B_TYPE) {
if(h->DPB[1].data[0]) {
*picture = *(AVFrame *) &h->DPB[1];
} else {
*data_size = 0;
}
} else
*picture = *(AVFrame *) &h->picture;
break;
case EXT_START_CODE:
//mpeg_decode_extension(avctx,buf_ptr, input_size);
break;
case USER_START_CODE:
//mpeg_decode_user_data(avctx,buf_ptr, input_size);
break;
default:
if (stc <= SLICE_MAX_START_CODE) {
init_get_bits(&s->gb, buf_ptr, input_size);
decode_slice_header(h, &s->gb);
}
break;
}
}
}
AVCodec cavs_decoder = {
"cavs",
CODEC_TYPE_VIDEO,
CODEC_ID_CAVS,
sizeof(AVSContext),
ff_cavs_init,
NULL,
ff_cavs_end,
cavs_decode_frame,
CODEC_CAP_DR1 | CODEC_CAP_DELAY,
.flush= cavs_flush,
.long_name= NULL_IF_CONFIG_SMALL("Chinese AVS video (AVS1-P2, JiZhun profile)"),
};
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