diff options
author | Anton Khirnov <anton@khirnov.net> | 2012-09-02 17:36:18 +0400 |
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committer | Anton Khirnov <anton@khirnov.net> | 2012-09-19 22:59:45 +0400 |
commit | 50d1f4437be88a4b7e412e90d71153cae68017cc (patch) | |
tree | 955e05ed96de2135c9f8c4c81e25db7c0255fc6d /libavformat/mp3dec.c | |
parent | 2d1a1a7f62623ff153184dc75dd9559d93b76619 (diff) |
mp3dec: read Xing frame TOC index
Diffstat (limited to 'libavformat/mp3dec.c')
-rw-r--r-- | libavformat/mp3dec.c | 58 |
1 files changed, 57 insertions, 1 deletions
diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c index ffc1c35a60..7d0c2fb6ed 100644 --- a/libavformat/mp3dec.c +++ b/libavformat/mp3dec.c @@ -31,6 +31,9 @@ #define XING_FLAG_FRAMES 0x01 #define XING_FLAG_SIZE 0x02 +#define XING_FLAG_TOC 0x04 + +#define XING_TOC_COUNT 100 /* mp3 read */ @@ -94,6 +97,26 @@ static int mp3_read_probe(AVProbeData *p) //mpegps_mp3_unrecognized_format.mpg has max_frames=3 } +static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration) +{ + int i; + + if (!filesize && + !(filesize = avio_size(s->pb))) { + av_log(s, AV_LOG_WARNING, "Cannot determine file size, skipping TOC table.\n"); + return; + } + + for (i = 0; i < XING_TOC_COUNT; i++) { + uint8_t b = avio_r8(s->pb); + + av_add_index_entry(s->streams[0], + av_rescale(b, filesize, 256), + av_rescale(i, duration, XING_TOC_COUNT), + 0, 0, AVINDEX_KEYFRAME); + } +} + /** * Try to find Xing/Info/VBRI tags and compute duration from info therein */ @@ -115,6 +138,8 @@ static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base) if(c.layer != 3) return -1; + spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */ + /* Check for Xing / Info tag */ avio_skip(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1]); v = avio_rb32(s->pb); @@ -124,6 +149,9 @@ static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base) frames = avio_rb32(s->pb); if(v & XING_FLAG_SIZE) size = avio_rb32(s->pb); + if (v & XING_FLAG_TOC && frames) + read_xing_toc(s, size, av_rescale_q(frames, (AVRational){spf, c.sample_rate}, + st->time_base)); } /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */ @@ -145,7 +173,6 @@ static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base) /* Skip the vbr tag frame */ avio_seek(s->pb, base + vbrtag_size, SEEK_SET); - spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */ if(frames) st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate}, st->time_base); @@ -206,12 +233,41 @@ static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt) return ret; } +static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, + int flags) +{ + AVIndexEntry *ie; + AVStream *st = s->streams[0]; + int64_t ret = av_index_search_timestamp(st, timestamp, flags); + uint32_t header = 0; + + if (ret < 0) + return ret; + + ie = &st->index_entries[ret]; + ret = avio_seek(s->pb, ie->pos, SEEK_SET); + if (ret < 0) + return ret; + + while (!s->pb->eof_reached) { + header = (header << 8) + avio_r8(s->pb); + if (ff_mpa_check_header(header) >= 0) { + ff_update_cur_dts(s, st, ie->timestamp); + ret = avio_seek(s->pb, -4, SEEK_CUR); + return (ret >= 0) ? 0 : ret; + } + } + + return AVERROR_EOF; +} + 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, .flags = AVFMT_GENERIC_INDEX, .extensions = "mp2,mp3,m2a", /* XXX: use probe */ }; |