620 lines
19 KiB
C
Executable file
620 lines
19 KiB
C
Executable file
/*
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* MP3 demuxer
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* Copyright (c) 2003 Fabrice Bellard
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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 "libavutil/opt.h"
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#include "libavutil/avstring.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/crc.h"
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#include "libavutil/dict.h"
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#include "libavutil/mathematics.h"
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#include "avformat.h"
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#include "internal.h"
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#include "avio_internal.h"
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#include "id3v2.h"
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#include "id3v1.h"
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#include "replaygain.h"
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#include "libavcodec/avcodec.h"
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#include "libavcodec/mpegaudiodecheader.h"
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#define XING_FLAG_FRAMES 0x01
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#define XING_FLAG_SIZE 0x02
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#define XING_FLAG_TOC 0x04
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#define XING_FLAC_QSCALE 0x08
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#define XING_TOC_COUNT 100
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typedef struct {
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AVClass *class;
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int64_t filesize;
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int xing_toc;
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int start_pad;
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int end_pad;
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int usetoc;
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unsigned frames; /* Total number of frames in file */
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unsigned header_filesize; /* Total number of bytes in the stream */
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int is_cbr;
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} MP3DecContext;
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enum CheckRet {
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CHECK_WRONG_HEADER = -1,
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CHECK_SEEK_FAILED = -2,
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};
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static int check(AVIOContext *pb, int64_t pos, uint32_t *header);
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/* mp3 read */
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static int mp3_read_probe(const AVProbeData *p)
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{
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int max_frames, first_frames = 0;
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int whole_used = 0;
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int frames, ret;
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int framesizes, max_framesizes;
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uint32_t header;
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const uint8_t *buf, *buf0, *buf2, *buf3, *end;
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buf0 = p->buf;
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end = p->buf + p->buf_size - sizeof(uint32_t);
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while (buf0 < end && !*buf0)
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buf0++;
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max_frames = 0;
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max_framesizes = 0;
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buf = buf0;
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for (; buf < end; buf = buf2+1) {
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buf2 = buf;
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for (framesizes = frames = 0; buf2 < end; frames++) {
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MPADecodeHeader h;
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int header_emu = 0;
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int available;
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header = AV_RB32(buf2);
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ret = avpriv_mpegaudio_decode_header(&h, header);
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if (ret != 0)
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break;
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available = FFMIN(h.frame_size, end - buf2);
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for (buf3 = buf2 + 4; buf3 < buf2 + available; buf3++) {
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uint32_t next_sync = AV_RB32(buf3);
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header_emu += (next_sync & MP3_MASK) == (header & MP3_MASK);
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}
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if (header_emu > 2)
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break;
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framesizes += h.frame_size;
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if (available < h.frame_size) {
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frames++;
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break;
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}
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buf2 += h.frame_size;
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}
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max_frames = FFMAX(max_frames, frames);
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max_framesizes = FFMAX(max_framesizes, framesizes);
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if (buf == buf0) {
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first_frames= frames;
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if (buf2 == end + sizeof(uint32_t))
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whole_used = 1;
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}
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}
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// keep this in sync with ac3 probe, both need to avoid
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// issues with MPEG-files!
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if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1;
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else if (max_frames>200 && p->buf_size < 2*max_framesizes)return AVPROBE_SCORE_EXTENSION;
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else if (max_frames>=4 && p->buf_size < 2*max_framesizes) return AVPROBE_SCORE_EXTENSION / 2;
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else if (ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && 2*ff_id3v2_tag_len(buf0) >= p->buf_size)
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return p->buf_size < PROBE_BUF_MAX ? AVPROBE_SCORE_EXTENSION / 4 : AVPROBE_SCORE_EXTENSION - 2;
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else if (first_frames > 1 && whole_used) return 5;
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else if (max_frames>=1 && p->buf_size < 10*max_framesizes) return 1;
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else return 0;
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//mpegps_mp3_unrecognized_format.mpg has max_frames=3
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}
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static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
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{
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int i;
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MP3DecContext *mp3 = s->priv_data;
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int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
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int fill_index = (mp3->usetoc || fast_seek) && duration > 0;
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if (!filesize &&
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!(filesize = avio_size(s->pb))) {
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av_log(s, AV_LOG_WARNING, "Cannot determine file size, skipping TOC table.\n");
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fill_index = 0;
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}
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for (i = 0; i < XING_TOC_COUNT; i++) {
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uint8_t b = avio_r8(s->pb);
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if (fill_index)
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av_add_index_entry(s->streams[0],
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av_rescale(b, filesize, 256),
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av_rescale(i, duration, XING_TOC_COUNT),
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0, 0, AVINDEX_KEYFRAME);
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}
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if (fill_index)
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mp3->xing_toc = 1;
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}
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static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st,
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MPADecodeHeader *c, uint32_t spf)
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{
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#define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1))
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#define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m) + 1))
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uint16_t crc;
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uint32_t v;
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char version[10];
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uint32_t peak = 0;
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int32_t r_gain = INT32_MIN, a_gain = INT32_MIN;
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MP3DecContext *mp3 = s->priv_data;
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static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
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uint64_t fsize = avio_size(s->pb);
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fsize = fsize >= avio_tell(s->pb) ? fsize - avio_tell(s->pb) : 0;
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/* Check for Xing / Info tag */
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avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
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v = avio_rb32(s->pb);
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mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
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if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr)
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return;
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v = avio_rb32(s->pb);
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if (v & XING_FLAG_FRAMES)
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mp3->frames = avio_rb32(s->pb);
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if (v & XING_FLAG_SIZE)
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mp3->header_filesize = avio_rb32(s->pb);
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if (fsize && mp3->header_filesize) {
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uint64_t min, delta;
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min = FFMIN(fsize, mp3->header_filesize);
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delta = FFMAX(fsize, mp3->header_filesize) - min;
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if (fsize > mp3->header_filesize && delta > min >> 4) {
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mp3->frames = 0;
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av_log(s, AV_LOG_WARNING,
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"invalid concatenated file detected - using bitrate for duration\n");
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} else if (delta > min >> 4) {
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av_log(s, AV_LOG_WARNING,
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"filesize and duration do not match (growing file?)\n");
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}
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}
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if (v & XING_FLAG_TOC)
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read_xing_toc(s, mp3->header_filesize, av_rescale_q(mp3->frames,
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(AVRational){spf, c->sample_rate},
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st->time_base));
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/* VBR quality */
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if (v & XING_FLAC_QSCALE)
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avio_rb32(s->pb);
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/* Encoder short version string */
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memset(version, 0, sizeof(version));
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avio_read(s->pb, version, 9);
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/* Info Tag revision + VBR method */
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avio_r8(s->pb);
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/* Lowpass filter value */
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avio_r8(s->pb);
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/* ReplayGain peak */
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v = avio_rb32(s->pb);
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peak = av_rescale(v, 100000, 1 << 23);
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/* Radio ReplayGain */
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v = avio_rb16(s->pb);
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if (MIDDLE_BITS(v, 13, 15) == 1) {
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r_gain = MIDDLE_BITS(v, 0, 8) * 10000;
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if (v & (1 << 9))
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r_gain *= -1;
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}
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/* Audiophile ReplayGain */
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v = avio_rb16(s->pb);
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if (MIDDLE_BITS(v, 13, 15) == 2) {
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a_gain = MIDDLE_BITS(v, 0, 8) * 10000;
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if (v & (1 << 9))
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a_gain *= -1;
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}
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/* Encoding flags + ATH Type */
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avio_r8(s->pb);
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/* if ABR {specified bitrate} else {minimal bitrate} */
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avio_r8(s->pb);
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/* Encoder delays */
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v = avio_rb24(s->pb);
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if (AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E')
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|| AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')
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|| AV_RB32(version) == MKBETAG('L', 'a', 'v', 'c')
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) {
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mp3->start_pad = v>>12;
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mp3-> end_pad = v&4095;
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st->start_skip_samples = mp3->start_pad + 528 + 1;
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if (mp3->frames) {
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st->first_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf;
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st->last_discard_sample = mp3->frames * (int64_t)spf;
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}
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if (!st->start_time)
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st->start_time = av_rescale_q(st->start_skip_samples,
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(AVRational){1, c->sample_rate},
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st->time_base);
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av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad);
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}
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/* Misc */
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avio_r8(s->pb);
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/* MP3 gain */
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avio_r8(s->pb);
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/* Preset and surround info */
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avio_rb16(s->pb);
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/* Music length */
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avio_rb32(s->pb);
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/* Music CRC */
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avio_rb16(s->pb);
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/* Info Tag CRC */
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crc = ffio_get_checksum(s->pb);
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v = avio_rb16(s->pb);
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if (v == crc) {
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ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0);
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av_dict_set(&st->metadata, "encoder", version, 0);
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}
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}
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static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
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{
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uint32_t v;
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MP3DecContext *mp3 = s->priv_data;
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/* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
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avio_seek(s->pb, base + 4 + 32, SEEK_SET);
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v = avio_rb32(s->pb);
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if (v == MKBETAG('V', 'B', 'R', 'I')) {
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/* Check tag version */
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if (avio_rb16(s->pb) == 1) {
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/* skip delay and quality */
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avio_skip(s->pb, 4);
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mp3->header_filesize = avio_rb32(s->pb);
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mp3->frames = avio_rb32(s->pb);
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}
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}
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}
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/**
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* Try to find Xing/Info/VBRI tags and compute duration from info therein
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*/
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static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
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{
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uint32_t v, spf;
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MPADecodeHeader c;
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int vbrtag_size = 0;
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MP3DecContext *mp3 = s->priv_data;
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int ret;
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ffio_init_checksum(s->pb, ff_crcA001_update, 0);
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v = avio_rb32(s->pb);
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ret = avpriv_mpegaudio_decode_header(&c, v);
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if (ret < 0)
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return ret;
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else if (ret == 0)
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vbrtag_size = c.frame_size;
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if (c.layer != 3)
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return -1;
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spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
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mp3->frames = 0;
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mp3->header_filesize = 0;
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mp3_parse_info_tag(s, st, &c, spf);
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mp3_parse_vbri_tag(s, st, base);
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if (!mp3->frames && !mp3->header_filesize)
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return -1;
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/* Skip the vbr tag frame */
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avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
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if (mp3->frames)
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st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate},
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st->time_base);
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if (mp3->header_filesize && mp3->frames && !mp3->is_cbr)
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st->codecpar->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf);
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return 0;
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}
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static int mp3_read_header(AVFormatContext *s)
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{
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MP3DecContext *mp3 = s->priv_data;
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AVStream *st;
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int64_t off;
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int ret;
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int i;
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s->metadata = s->internal->id3v2_meta;
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s->internal->id3v2_meta = NULL;
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st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
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st->codecpar->codec_id = AV_CODEC_ID_MP3;
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st->need_parsing = AVSTREAM_PARSE_FULL_RAW;
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st->start_time = 0;
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// lcm of all mp3 sample rates
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avpriv_set_pts_info(st, 64, 1, 14112000);
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s->pb->maxsize = -1;
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off = avio_tell(s->pb);
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if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
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ff_id3v1_read(s);
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if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
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mp3->filesize = avio_size(s->pb);
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if (mp3_parse_vbr_tags(s, st, off) < 0)
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avio_seek(s->pb, off, SEEK_SET);
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ret = ff_replaygain_export(st, s->metadata);
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if (ret < 0)
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return ret;
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off = avio_tell(s->pb);
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for (i = 0; i < 64 * 1024; i++) {
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uint32_t header, header2;
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int frame_size;
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if (!(i&1023))
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ffio_ensure_seekback(s->pb, i + 1024 + 4);
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frame_size = check(s->pb, off + i, &header);
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if (frame_size > 0) {
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ret = avio_seek(s->pb, off, SEEK_SET);
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if (ret < 0)
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return ret;
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ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4);
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ret = check(s->pb, off + i + frame_size, &header2);
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if (ret >= 0 &&
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(header & MP3_MASK) == (header2 & MP3_MASK))
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{
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av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off);
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ret = avio_seek(s->pb, off + i, SEEK_SET);
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if (ret < 0)
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return ret;
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break;
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} else if (ret == CHECK_SEEK_FAILED) {
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av_log(s, AV_LOG_ERROR, "Invalid frame size (%d): Could not seek to %"PRId64".\n", frame_size, off + i + frame_size);
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return AVERROR(EINVAL);
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}
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} else if (frame_size == CHECK_SEEK_FAILED) {
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av_log(s, AV_LOG_ERROR, "Failed to read frame size: Could not seek to %"PRId64".\n", (int64_t) (i + 1024 + frame_size + 4));
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return AVERROR(EINVAL);
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}
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ret = avio_seek(s->pb, off, SEEK_SET);
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if (ret < 0)
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return ret;
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}
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// the seek index is relative to the end of the xing vbr headers
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for (i = 0; i < st->nb_index_entries; i++)
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st->index_entries[i].pos += avio_tell(s->pb);
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/* the parameters will be extracted from the compressed bitstream */
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return 0;
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}
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#define MP3_PACKET_SIZE 1024
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static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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MP3DecContext *mp3 = s->priv_data;
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int ret, size;
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int64_t pos;
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size = MP3_PACKET_SIZE;
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pos = avio_tell(s->pb);
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if (mp3->filesize > ID3v1_TAG_SIZE && pos < mp3->filesize)
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size= FFMIN(size, mp3->filesize - pos);
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ret = av_get_packet(s->pb, pkt, size);
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if (ret <= 0) {
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if(ret<0)
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return ret;
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return AVERROR_EOF;
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}
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pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
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pkt->stream_index = 0;
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return ret;
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}
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#define SEEK_WINDOW 4096
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static int check(AVIOContext *pb, int64_t pos, uint32_t *ret_header)
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{
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int64_t ret = avio_seek(pb, pos, SEEK_SET);
|
|
uint8_t header_buf[4];
|
|
unsigned header;
|
|
MPADecodeHeader sd;
|
|
if (ret < 0)
|
|
return CHECK_SEEK_FAILED;
|
|
|
|
ret = avio_read(pb, &header_buf[0], 4);
|
|
/* We should always find four bytes for a valid mpa header. */
|
|
if (ret < 4)
|
|
return CHECK_SEEK_FAILED;
|
|
|
|
header = AV_RB32(&header_buf[0]);
|
|
if (ff_mpa_check_header(header) < 0)
|
|
return CHECK_WRONG_HEADER;
|
|
if (avpriv_mpegaudio_decode_header(&sd, header) == 1)
|
|
return CHECK_WRONG_HEADER;
|
|
|
|
if (ret_header)
|
|
*ret_header = header;
|
|
return sd.frame_size;
|
|
}
|
|
|
|
static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
|
|
{
|
|
int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
|
|
int64_t best_pos;
|
|
int best_score, i, j;
|
|
int64_t ret;
|
|
|
|
avio_seek(s->pb, FFMAX(target_pos - SEEK_WINDOW, 0), SEEK_SET);
|
|
ret = avio_seek(s->pb, target_pos, SEEK_SET);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
#define MIN_VALID 3
|
|
best_pos = target_pos;
|
|
best_score = 999;
|
|
for (i = 0; i < SEEK_WINDOW; i++) {
|
|
int64_t pos = target_pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
|
|
int64_t candidate = -1;
|
|
int score = 999;
|
|
|
|
if (pos < 0)
|
|
continue;
|
|
|
|
for (j = 0; j < MIN_VALID; j++) {
|
|
ret = check(s->pb, pos, NULL);
|
|
if (ret < 0) {
|
|
if (ret == CHECK_WRONG_HEADER) {
|
|
break;
|
|
} else if (ret == CHECK_SEEK_FAILED) {
|
|
av_log(s, AV_LOG_ERROR, "Could not seek to %"PRId64".\n", pos);
|
|
return AVERROR(EINVAL);
|
|
}
|
|
}
|
|
if ((target_pos - pos)*dir <= 0 && FFABS(MIN_VALID/2-j) < score) {
|
|
candidate = pos;
|
|
score = FFABS(MIN_VALID/2-j);
|
|
}
|
|
pos += ret;
|
|
}
|
|
if (best_score > score && j == MIN_VALID) {
|
|
best_pos = candidate;
|
|
best_score = score;
|
|
if(score == 0)
|
|
break;
|
|
}
|
|
}
|
|
|
|
return avio_seek(s->pb, best_pos, SEEK_SET);
|
|
}
|
|
|
|
static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
|
|
int flags)
|
|
{
|
|
MP3DecContext *mp3 = s->priv_data;
|
|
AVIndexEntry *ie, ie1;
|
|
AVStream *st = s->streams[0];
|
|
int64_t best_pos;
|
|
int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
|
|
int64_t filesize = mp3->header_filesize;
|
|
|
|
if (filesize <= 0) {
|
|
int64_t size = avio_size(s->pb);
|
|
if (size > 0 && size > s->internal->data_offset)
|
|
filesize = size - s->internal->data_offset;
|
|
}
|
|
|
|
if (mp3->xing_toc && (mp3->usetoc || (fast_seek && !mp3->is_cbr))) {
|
|
int64_t ret = av_index_search_timestamp(st, timestamp, flags);
|
|
|
|
// NOTE: The MP3 TOC is not a precise lookup table. Accuracy is worse
|
|
// for bigger files.
|
|
av_log(s, AV_LOG_WARNING, "Using MP3 TOC to seek; may be imprecise.\n");
|
|
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
ie = &st->index_entries[ret];
|
|
} else if (fast_seek && st->duration > 0 && filesize > 0) {
|
|
if (!mp3->is_cbr)
|
|
av_log(s, AV_LOG_WARNING, "Using scaling to seek VBR MP3; may be imprecise.\n");
|
|
|
|
ie = &ie1;
|
|
timestamp = av_clip64(timestamp, 0, st->duration);
|
|
ie->timestamp = timestamp;
|
|
ie->pos = av_rescale(timestamp, filesize, st->duration) + s->internal->data_offset;
|
|
} else {
|
|
return -1; // generic index code
|
|
}
|
|
|
|
best_pos = mp3_sync(s, ie->pos, flags);
|
|
if (best_pos < 0)
|
|
return best_pos;
|
|
|
|
if (mp3->is_cbr && ie == &ie1 && mp3->frames) {
|
|
int frame_duration = av_rescale(st->duration, 1, mp3->frames);
|
|
ie1.timestamp = frame_duration * av_rescale(best_pos - s->internal->data_offset, mp3->frames, mp3->header_filesize);
|
|
}
|
|
|
|
ff_update_cur_dts(s, st, ie->timestamp);
|
|
return 0;
|
|
}
|
|
|
|
static const AVOption options[] = {
|
|
{ "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM},
|
|
{ NULL },
|
|
};
|
|
|
|
static const AVClass demuxer_class = {
|
|
.class_name = "mp3",
|
|
.item_name = av_default_item_name,
|
|
.option = options,
|
|
.version = LIBAVUTIL_VERSION_INT,
|
|
.category = AV_CLASS_CATEGORY_DEMUXER,
|
|
};
|
|
|
|
AVInputFormat ff_mp3_demuxer = {
|
|
.name = "mp3",
|
|
.long_name = NULL_IF_CONFIG_SMALL("MP2/3 (MPEG audio layer 2/3)"),
|
|
.read_probe = mp3_read_probe,
|
|
.read_header = mp3_read_header,
|
|
.read_packet = mp3_read_packet,
|
|
.read_seek = mp3_seek,
|
|
.priv_data_size = sizeof(MP3DecContext),
|
|
.flags = AVFMT_GENERIC_INDEX,
|
|
.extensions = "mp2,mp3,m2a,mpa", /* XXX: use probe */
|
|
.priv_class = &demuxer_class,
|
|
};
|