Module: libav
Branch: master
Commit: 50d1f4437be88a4b7e412e90d71153cae68017cc
Author: Anton Khirnov <an...@khirnov.net>
Committer: Anton Khirnov <an...@khirnov.net>
Date: Sun Sep 2 15:36:18 2012 +0200
mp3dec: read Xing frame TOC index
---
libavformat/mp3dec.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 57 insertions(+), 1 deletions(-)
diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c
index ffc1c35..7d0c2fb 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 */
};
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