parser.c
上传用户:jylinhe
上传日期:2022-07-11
资源大小:334k
文件大小:10k
- /*
- * Audio and Video frame extraction
- * Copyright (c) 2003 Fabrice Bellard.
- * Copyright (c) 2003 Michael Niedermayer.
- *
- * 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
- */
- #include "dsputil.h"
- //#include "internal.h"
- //#include "integer.h"
- #include "parser.h"
- static AVCodecParser *av_first_parser = NULL;
- AVCodecParser* av_parser_next(AVCodecParser *p){
- if(p) return p->next;
- else return av_first_parser;
- }
- void av_register_codec_parser(AVCodecParser *parser)
- {
- parser->next = av_first_parser;
- av_first_parser = parser;
- }
- AVCodecParserContext *av_parser_init(int codec_id)
- {
- AVCodecParserContext *s;
- AVCodecParser *parser;
- int ret;
- if(codec_id == CODEC_ID_NONE)
- return NULL;
- for(parser = av_first_parser; parser != NULL; parser = parser->next) {
- if (parser->codec_ids[0] == codec_id ||
- parser->codec_ids[1] == codec_id ||
- parser->codec_ids[2] == codec_id ||
- parser->codec_ids[3] == codec_id ||
- parser->codec_ids[4] == codec_id)
- goto found;
- }
- return NULL;
- found:
- s = av_mallocz(sizeof(AVCodecParserContext));
- if (!s)
- return NULL;
- s->parser = parser;
- s->priv_data = av_mallocz(parser->priv_data_size);
- if (!s->priv_data) {
- av_free(s);
- return NULL;
- }
- if (parser->parser_init) {
- ret = parser->parser_init(s);
- if (ret != 0) {
- av_free(s->priv_data);
- av_free(s);
- return NULL;
- }
- }
- s->fetch_timestamp=1;
- s->pict_type = FF_I_TYPE;
- return s;
- }
- void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
- int i;
- s->dts= s->pts= AV_NOPTS_VALUE;
- s->offset= 0;
- for(i = 0; i < AV_PARSER_PTS_NB; i++) {
- if ( s->next_frame_offset + off >= s->cur_frame_offset[i]
- &&(s-> frame_offset < s->cur_frame_offset[i] || !s->frame_offset)
- //check is disabled becausue mpeg-ts doesnt send complete PES packets
- && /*s->next_frame_offset + off <*/ s->cur_frame_end[i]){
- s->dts= s->cur_frame_dts[i];
- s->pts= s->cur_frame_pts[i];
- s->offset = s->next_frame_offset - s->cur_frame_offset[i];
- if(remove)
- s->cur_frame_offset[i]= INT64_MAX;
- }
- }
- }
- /**
- *
- * @param buf input
- * @param buf_size input length, to signal EOF, this should be 0 (so that the last frame can be output)
- * @param pts input presentation timestamp
- * @param dts input decoding timestamp
- * @param poutbuf will contain a pointer to the first byte of the output frame
- * @param poutbuf_size will contain the length of the output frame
- * @return the number of bytes of the input bitstream used
- *
- * Example:
- * @code
- * while(in_len){
- * len = av_parser_parse(myparser, AVCodecContext, &data, &size,
- * in_data, in_len,
- * pts, dts);
- * in_data += len;
- * in_len -= len;
- *
- * if(size)
- * decode_frame(data, size);
- * }
- * @endcode
- */
- int av_parser_parse(AVCodecParserContext *s,
- AVCodecContext *avctx,
- uint8_t **poutbuf, int *poutbuf_size,
- const uint8_t *buf, int buf_size,
- int64_t pts, int64_t dts)
- {
- int index, i;
- uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
- if (buf_size == 0) {
- /* padding is always necessary even if EOF, so we add it here */
- memset(dummy_buf, 0, sizeof(dummy_buf));
- buf = dummy_buf;
- } else {
- /* add a new packet descriptor */
- if(pts != AV_NOPTS_VALUE || dts != AV_NOPTS_VALUE){
- i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
- s->cur_frame_start_index = i;
- s->cur_frame_offset[i] = s->cur_offset;
- s->cur_frame_end[i] = s->cur_offset + buf_size;
- s->cur_frame_pts[i] = pts;
- s->cur_frame_dts[i] = dts;
- }
- }
- if (s->fetch_timestamp){
- s->fetch_timestamp=0;
- s->last_pts = s->pts;
- s->last_dts = s->dts;
- ff_fetch_timestamp(s, 0, 0);
- }
- /* WARNING: the returned index can be negative */
- index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
- //av_log(NULL, AV_LOG_DEBUG, "parser: in:%"PRId64", %"PRId64", out:%"PRId64", %"PRId64", in:%d out:%d id:%dn", pts, dts, s->last_pts, s->last_dts, buf_size, *poutbuf_size, avctx->codec_id);
- /* update the file pointer */
- if (*poutbuf_size) {
- /* fill the data for the current frame */
- s->frame_offset = s->next_frame_offset;
- /* offset of the next frame */
- s->next_frame_offset = s->cur_offset + index;
- s->fetch_timestamp=1;
- }
- if (index < 0)
- index = 0;
- s->cur_offset += index;
- return index;
- }
- /**
- *
- * @return 0 if the output buffer is a subset of the input, 1 if it is allocated and must be freed
- * @deprecated use AVBitstreamFilter
- */
- int av_parser_change(AVCodecParserContext *s,
- AVCodecContext *avctx,
- uint8_t **poutbuf, int *poutbuf_size,
- const uint8_t *buf, int buf_size, int keyframe){
- if(s && s->parser->split){
- if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
- int i= s->parser->split(avctx, buf, buf_size);
- buf += i;
- buf_size -= i;
- }
- }
- /* cast to avoid warning about discarding qualifiers */
- *poutbuf= (uint8_t *) buf;
- *poutbuf_size= buf_size;
- if(avctx->extradata){
- if( (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
- /*||(s->pict_type != FF_I_TYPE && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
- /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
- int size= buf_size + avctx->extradata_size;
- *poutbuf_size= size;
- *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
- memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
- memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
- return 1;
- }
- }
- return 0;
- }
- void av_parser_close(AVCodecParserContext *s)
- {
- if(s){
- if (s->parser->parser_close)
- s->parser->parser_close(s);
- av_free(s->priv_data);
- av_free(s);
- }
- }
- /*****************************************************/
- /**
- * combines the (truncated) bitstream to a complete frame
- * @returns -1 if no complete frame could be created, AVERROR(ENOMEM) if there was a memory allocation error
- */
- int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
- {
- #if 0
- if(pc->overread){
- printf("overread %d, state:%X next:%d index:%d o_index:%dn", pc->overread, pc->state, next, pc->index, pc->overread_index);
- printf("%X %X %X %Xn", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
- }
- #endif
- /* Copy overread bytes from last frame into buffer. */
- for(; pc->overread>0; pc->overread--){
- pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
- }
- /* flush remaining if EOF */
- if(!*buf_size && next == END_NOT_FOUND){
- next= 0;
- }
- pc->last_index= pc->index;
- /* copy into buffer end return */
- if(next == END_NOT_FOUND){
- void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
- if(!new_buffer)
- return AVERROR(ENOMEM);
- pc->buffer = new_buffer;
- memcpy(&pc->buffer[pc->index], *buf, *buf_size);
- pc->index += *buf_size;
- return -1;
- }
- *buf_size=
- pc->overread_index= pc->index + next;
- /* append to buffer */
- if(pc->index){
- void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
- if(!new_buffer)
- return AVERROR(ENOMEM);
- pc->buffer = new_buffer;
- memcpy(&pc->buffer[pc->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );
- pc->index = 0;
- *buf= pc->buffer;
- }
- /* store overread bytes */
- for(;next < 0; next++){
- pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
- pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
- pc->overread++;
- }
- #if 0
- if(pc->overread){
- printf("overread %d, state:%X next:%d index:%d o_index:%dn", pc->overread, pc->state, next, pc->index, pc->overread_index);
- printf("%X %X %X %Xn", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
- }
- #endif
- return 0;
- }
- void ff_parse_close(AVCodecParserContext *s)
- {
- ParseContext *pc = s->priv_data;
- av_freep(&pc->buffer);
- }
- void ff_parse1_close(AVCodecParserContext *s)
- {
- ParseContext1 *pc1 = s->priv_data;
- av_free(pc1->pc.buffer);
- av_free(pc1->enc);
- }
- /*************************/
- int ff_mpeg4video_split(AVCodecContext *avctx,
- const uint8_t *buf, int buf_size)
- {
- int i;
- uint32_t state= -1;
- for(i=0; i<buf_size; i++){
- state= (state<<8) | buf[i];
- if(state == 0x1B3 || state == 0x1B6)
- return i-3;
- }
- return 0;
- }