mirror of https://git.ffmpeg.org/ffmpeg.git
278 lines
8.3 KiB
C
278 lines
8.3 KiB
C
/*
|
|
* H.26L/H.264/AVC/JVT/14496-10/... parser
|
|
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* 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/h264_parser.c
|
|
* H.264 / AVC / MPEG4 part10 parser.
|
|
* @author Michael Niedermayer <michaelni@gmx.at>
|
|
*/
|
|
|
|
#include "parser.h"
|
|
#include "h264_parser.h"
|
|
#include "h264data.h"
|
|
#include "golomb.h"
|
|
|
|
#include <assert.h>
|
|
|
|
|
|
int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
|
|
{
|
|
int i;
|
|
uint32_t state;
|
|
ParseContext *pc = &(h->s.parse_context);
|
|
//printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]);
|
|
// mb_addr= pc->mb_addr - 1;
|
|
state= pc->state;
|
|
if(state>13)
|
|
state= 7;
|
|
|
|
for(i=0; i<buf_size; i++){
|
|
if(state==7){
|
|
#if HAVE_FAST_UNALIGNED
|
|
/* we check i<buf_size instead of i+3/7 because its simpler
|
|
* and there should be FF_INPUT_BUFFER_PADDING_SIZE bytes at the end
|
|
*/
|
|
# if HAVE_FAST_64BIT
|
|
while(i<buf_size && !((~*(const uint64_t*)(buf+i) & (*(const uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
|
|
i+=8;
|
|
# else
|
|
while(i<buf_size && !((~*(const uint32_t*)(buf+i) & (*(const uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U))
|
|
i+=4;
|
|
# endif
|
|
#endif
|
|
for(; i<buf_size; i++){
|
|
if(!buf[i]){
|
|
state=2;
|
|
break;
|
|
}
|
|
}
|
|
}else if(state<=2){
|
|
if(buf[i]==1) state^= 5; //2->7, 1->4, 0->5
|
|
else if(buf[i]) state = 7;
|
|
else state>>=1; //2->1, 1->0, 0->0
|
|
}else if(state<=5){
|
|
int v= buf[i] & 0x1F;
|
|
if(v==7 || v==8 || v==9){
|
|
if(pc->frame_start_found){
|
|
i++;
|
|
goto found;
|
|
}
|
|
}else if(v==1 || v==2 || v==5){
|
|
if(pc->frame_start_found){
|
|
state+=8;
|
|
continue;
|
|
}else
|
|
pc->frame_start_found = 1;
|
|
}
|
|
state= 7;
|
|
}else{
|
|
if(buf[i] & 0x80)
|
|
goto found;
|
|
state= 7;
|
|
}
|
|
}
|
|
pc->state= state;
|
|
return END_NOT_FOUND;
|
|
|
|
found:
|
|
pc->state=7;
|
|
pc->frame_start_found= 0;
|
|
return i-(state&5);
|
|
}
|
|
|
|
/*!
|
|
* Parse NAL units of found picture and decode some basic information.
|
|
*
|
|
* @param s parser context.
|
|
* @param avctx codec context.
|
|
* @param buf buffer with field/frame data.
|
|
* @param buf_size size of the buffer.
|
|
*/
|
|
static inline int parse_nal_units(AVCodecParserContext *s,
|
|
AVCodecContext *avctx,
|
|
const uint8_t *buf, int buf_size)
|
|
{
|
|
H264Context *h = s->priv_data;
|
|
const uint8_t *buf_end = buf + buf_size;
|
|
unsigned int pps_id;
|
|
unsigned int slice_type;
|
|
int state;
|
|
const uint8_t *ptr;
|
|
|
|
/* set some sane default values */
|
|
s->pict_type = FF_I_TYPE;
|
|
s->key_frame = 0;
|
|
|
|
h->s.avctx= avctx;
|
|
h->sei_recovery_frame_cnt = -1;
|
|
|
|
for(;;) {
|
|
int src_length, dst_length, consumed;
|
|
buf = ff_find_start_code(buf, buf_end, &state);
|
|
if(buf >= buf_end)
|
|
break;
|
|
--buf;
|
|
src_length = buf_end - buf;
|
|
switch (state & 0x1f) {
|
|
case NAL_SLICE:
|
|
case NAL_IDR_SLICE:
|
|
// Do not walk the whole buffer just to decode slice header
|
|
if (src_length > 20)
|
|
src_length = 20;
|
|
break;
|
|
}
|
|
ptr= ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
|
|
if (ptr==NULL || dst_length < 0)
|
|
break;
|
|
|
|
init_get_bits(&h->s.gb, ptr, 8*dst_length);
|
|
switch(h->nal_unit_type) {
|
|
case NAL_SPS:
|
|
ff_h264_decode_seq_parameter_set(h);
|
|
break;
|
|
case NAL_PPS:
|
|
ff_h264_decode_picture_parameter_set(h, h->s.gb.size_in_bits);
|
|
break;
|
|
case NAL_SEI:
|
|
ff_h264_decode_sei(h);
|
|
break;
|
|
case NAL_IDR_SLICE:
|
|
s->key_frame = 1;
|
|
/* fall through */
|
|
case NAL_SLICE:
|
|
get_ue_golomb(&h->s.gb); // skip first_mb_in_slice
|
|
slice_type = get_ue_golomb_31(&h->s.gb);
|
|
s->pict_type = golomb_to_pict_type[slice_type % 5];
|
|
if (h->sei_recovery_frame_cnt >= 0) {
|
|
/* key frame, since recovery_frame_cnt is set */
|
|
s->key_frame = 1;
|
|
}
|
|
pps_id= get_ue_golomb(&h->s.gb);
|
|
if(pps_id>=MAX_PPS_COUNT) {
|
|
av_log(h->s.avctx, AV_LOG_ERROR, "pps_id out of range\n");
|
|
return -1;
|
|
}
|
|
if(!h->pps_buffers[pps_id]) {
|
|
av_log(h->s.avctx, AV_LOG_ERROR, "non-existing PPS referenced\n");
|
|
return -1;
|
|
}
|
|
h->pps= *h->pps_buffers[pps_id];
|
|
if(!h->sps_buffers[h->pps.sps_id]) {
|
|
av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS referenced\n");
|
|
return -1;
|
|
}
|
|
h->sps = *h->sps_buffers[h->pps.sps_id];
|
|
h->frame_num = get_bits(&h->s.gb, h->sps.log2_max_frame_num);
|
|
|
|
if(h->sps.frame_mbs_only_flag){
|
|
h->s.picture_structure= PICT_FRAME;
|
|
}else{
|
|
if(get_bits1(&h->s.gb)) { //field_pic_flag
|
|
h->s.picture_structure= PICT_TOP_FIELD + get_bits1(&h->s.gb); //bottom_field_flag
|
|
} else {
|
|
h->s.picture_structure= PICT_FRAME;
|
|
}
|
|
}
|
|
|
|
return 0; /* no need to evaluate the rest */
|
|
}
|
|
buf += consumed;
|
|
}
|
|
/* didn't find a picture! */
|
|
av_log(h->s.avctx, AV_LOG_ERROR, "missing picture in access unit\n");
|
|
return -1;
|
|
}
|
|
|
|
static int h264_parse(AVCodecParserContext *s,
|
|
AVCodecContext *avctx,
|
|
const uint8_t **poutbuf, int *poutbuf_size,
|
|
const uint8_t *buf, int buf_size)
|
|
{
|
|
H264Context *h = s->priv_data;
|
|
ParseContext *pc = &h->s.parse_context;
|
|
int next;
|
|
|
|
if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
|
|
next= buf_size;
|
|
}else{
|
|
next= ff_h264_find_frame_end(h, buf, buf_size);
|
|
|
|
if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
|
|
*poutbuf = NULL;
|
|
*poutbuf_size = 0;
|
|
return buf_size;
|
|
}
|
|
|
|
if(next<0 && next != END_NOT_FOUND){
|
|
assert(pc->last_index + next >= 0 );
|
|
ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
|
|
}
|
|
|
|
parse_nal_units(s, avctx, buf, buf_size);
|
|
}
|
|
|
|
*poutbuf = buf;
|
|
*poutbuf_size = buf_size;
|
|
return next;
|
|
}
|
|
|
|
static int h264_split(AVCodecContext *avctx,
|
|
const uint8_t *buf, int buf_size)
|
|
{
|
|
int i;
|
|
uint32_t state = -1;
|
|
int has_sps= 0;
|
|
|
|
for(i=0; i<=buf_size; i++){
|
|
if((state&0xFFFFFF1F) == 0x107)
|
|
has_sps=1;
|
|
/* if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){
|
|
}*/
|
|
if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){
|
|
if(has_sps){
|
|
while(i>4 && buf[i-5]==0) i--;
|
|
return i-4;
|
|
}
|
|
}
|
|
if (i<buf_size)
|
|
state= (state<<8) | buf[i];
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void close(AVCodecParserContext *s)
|
|
{
|
|
H264Context *h = s->priv_data;
|
|
ParseContext *pc = &h->s.parse_context;
|
|
|
|
av_free(pc->buffer);
|
|
}
|
|
|
|
|
|
AVCodecParser h264_parser = {
|
|
{ CODEC_ID_H264 },
|
|
sizeof(H264Context),
|
|
NULL,
|
|
h264_parse,
|
|
close,
|
|
h264_split,
|
|
};
|