89a420b71b
Ideally this should be discarded by the demuxer but this is not possible without fully parsing which would be then very similar to this. The current ID3v1 discard code in the demuxer does not work and will be removed in a subsequent commit The discard code could be adjusted if needed to also discard tags at other locations than the end or to limit this possibly to input from the mp3 demuxer or even to move the discarding to the decoder. Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
135 lines
4.4 KiB
C
135 lines
4.4 KiB
C
/*
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* MPEG Audio parser
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* Copyright (c) 2003 Fabrice Bellard
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* Copyright (c) 2003 Michael Niedermayer
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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#include "parser.h"
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#include "mpegaudiodecheader.h"
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#include "libavutil/common.h"
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#include "libavformat/id3v1.h" // for ID3v1_TAG_SIZE
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typedef struct MpegAudioParseContext {
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ParseContext pc;
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int frame_size;
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uint32_t header;
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int header_count;
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int no_bitrate;
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} MpegAudioParseContext;
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#define MPA_HEADER_SIZE 4
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/* header + layer + bitrate + freq + lsf/mpeg25 */
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#define SAME_HEADER_MASK \
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(0xffe00000 | (3 << 17) | (3 << 10) | (3 << 19))
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static int mpegaudio_parse(AVCodecParserContext *s1,
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AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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MpegAudioParseContext *s = s1->priv_data;
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ParseContext *pc = &s->pc;
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uint32_t state= pc->state;
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int i;
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int next= END_NOT_FOUND;
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int flush = !buf_size;
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for(i=0; i<buf_size; ){
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if(s->frame_size){
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int inc= FFMIN(buf_size - i, s->frame_size);
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i += inc;
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s->frame_size -= inc;
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state = 0;
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if(!s->frame_size){
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next= i;
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break;
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}
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}else{
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while(i<buf_size){
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int ret, sr, channels, bit_rate, frame_size;
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enum AVCodecID codec_id = avctx->codec_id;
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state= (state<<8) + buf[i++];
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ret = avpriv_mpa_decode_header2(state, &sr, &channels, &frame_size, &bit_rate, &codec_id);
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if (ret < 4) {
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if (i > 4)
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s->header_count = -2;
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} else {
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int header_threshold = avctx->codec_id != AV_CODEC_ID_NONE && avctx->codec_id != codec_id;
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if((state&SAME_HEADER_MASK) != (s->header&SAME_HEADER_MASK) && s->header)
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s->header_count= -3;
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s->header= state;
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s->header_count++;
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s->frame_size = ret-4;
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if (s->header_count > header_threshold) {
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avctx->sample_rate= sr;
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avctx->channels = channels;
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s1->duration = frame_size;
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avctx->codec_id = codec_id;
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if (s->no_bitrate || !avctx->bit_rate) {
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s->no_bitrate = 1;
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avctx->bit_rate += (bit_rate - avctx->bit_rate) / (s->header_count - header_threshold);
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}
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}
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if (s1->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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s->frame_size = 0;
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next = buf_size;
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} else if (codec_id == AV_CODEC_ID_MP3ADU) {
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avpriv_report_missing_feature(avctx,
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"MP3ADU full parser");
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return AVERROR_PATCHWELCOME;
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}
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break;
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}
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}
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}
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}
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pc->state= state;
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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if (flush && buf_size >= ID3v1_TAG_SIZE && memcmp(buf, "TAG", 3) == 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return next;
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}
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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AVCodecParser ff_mpegaudio_parser = {
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.codec_ids = { AV_CODEC_ID_MP1, AV_CODEC_ID_MP2, AV_CODEC_ID_MP3, AV_CODEC_ID_MP3ADU },
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.priv_data_size = sizeof(MpegAudioParseContext),
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.parser_parse = mpegaudio_parse,
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.parser_close = ff_parse_close,
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};
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