/* * MPEG Audio parser * 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 "parser.h" #include "mpegaudiodecheader.h" #include "libavutil/common.h" #include "libavformat/apetag.h" // for APE tag. #include "libavformat/id3v1.h" // for ID3v1_TAG_SIZE typedef struct MpegAudioParseContext { ParseContext pc; int frame_size; uint32_t header; int header_count; int no_bitrate; } MpegAudioParseContext; #define MPA_HEADER_SIZE 4 /* header + layer + freq + lsf/mpeg25 */ #define SAME_HEADER_MASK \ (0xffe00000 | (3 << 17) | (3 << 10) | (3 << 19)) static int mpegaudio_parse(AVCodecParserContext *s1, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size) { MpegAudioParseContext *s = s1->priv_data; ParseContext *pc = &s->pc; uint32_t state= pc->state; int i; int next= END_NOT_FOUND; int flush = !buf_size; for(i=0; i<buf_size; ){ if(s->frame_size){ int inc= FFMIN(buf_size - i, s->frame_size); i += inc; s->frame_size -= inc; state = 0; if(!s->frame_size){ next= i; break; } }else{ while(i<buf_size){ int ret, sr, channels, bit_rate, frame_size; enum AVCodecID codec_id = avctx->codec_id; state= (state<<8) + buf[i++]; ret = ff_mpa_decode_header(state, &sr, &channels, &frame_size, &bit_rate, &codec_id); if (ret < 4) { if (i > 4) s->header_count = -2; } else { int header_threshold = avctx->codec_id != AV_CODEC_ID_NONE && avctx->codec_id != codec_id; if((state&SAME_HEADER_MASK) != (s->header&SAME_HEADER_MASK) && s->header) s->header_count= -3; s->header= state; s->header_count++; s->frame_size = ret-4; if (s->header_count > header_threshold) { avctx->sample_rate= sr; avctx->channels = channels; s1->duration = frame_size; avctx->codec_id = codec_id; if (s->no_bitrate || !avctx->bit_rate) { s->no_bitrate = 1; avctx->bit_rate += (bit_rate - avctx->bit_rate) / (s->header_count - header_threshold); } } if (s1->flags & PARSER_FLAG_COMPLETE_FRAMES) { s->frame_size = 0; next = buf_size; } else if (codec_id == AV_CODEC_ID_MP3ADU) { avpriv_report_missing_feature(avctx, "MP3ADU full parser"); *poutbuf = NULL; *poutbuf_size = 0; return buf_size; /* parsers must not return error codes */ } break; } } } } pc->state= state; if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { *poutbuf = NULL; *poutbuf_size = 0; return buf_size; } if (flush && buf_size >= ID3v1_TAG_SIZE && memcmp(buf, "TAG", 3) == 0) { *poutbuf = NULL; *poutbuf_size = 0; return next; } if (flush && buf_size >= APE_TAG_FOOTER_BYTES && memcmp(buf, APE_TAG_PREAMBLE, 8) == 0) { *poutbuf = NULL; *poutbuf_size = 0; return next; } *poutbuf = buf; *poutbuf_size = buf_size; return next; } AVCodecParser ff_mpegaudio_parser = { .codec_ids = { AV_CODEC_ID_MP1, AV_CODEC_ID_MP2, AV_CODEC_ID_MP3, AV_CODEC_ID_MP3ADU }, .priv_data_size = sizeof(MpegAudioParseContext), .parser_parse = mpegaudio_parse, .parser_close = ff_parse_close, };