diff options
| author | Andy Wu <tsunghung@chromium.org> | 2015-08-31 17:08:30 -0700 |
|---|---|---|
| committer | wm4 <nfxjfg@googlemail.com> | 2015-09-05 18:32:58 +0200 |
| commit | c43bd08f8b043df7e18110e5344283c37b8380c1 (patch) | |
| tree | 3aae7343d92bc2697b76e84dc3ab6174d2e0065d /libavformat/mp3dec.c | |
| parent | 237cf3786ef7dea60818fc3bc464f72ed4b4d833 (diff) | |
avformat/mp3dec: Make MP3 seek fast
When AVFMT_FLAG_FAST_SEEK is specified, make MP3 seek operation as
fast as possible.
When no "-usetoc" is specified, the default operation is using TOC
if available; otherwise, uses linear interpolation. This is useful
when seeking a large MP3 file with no TOC available. One example is
Podcast, many MP3 files are large, but no CBR/VBR tags. Most of
them are actually CBR. Even in VBR cases, this option sacrifices the
accuracy of playback time in exchange for responsiveness.
Diffstat (limited to 'libavformat/mp3dec.c')
| -rw-r--r-- | libavformat/mp3dec.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c index 007c6eaf8b..d3080d715c 100644 --- a/libavformat/mp3dec.c +++ b/libavformat/mp3dec.c @@ -342,7 +342,7 @@ static int mp3_read_header(AVFormatContext *s) int i; if (mp3->usetoc < 0) - mp3->usetoc = (s->flags & AVFMT_FLAG_FAST_SEEK) ? 0 : 2; + mp3->usetoc = (s->flags & AVFMT_FLAG_FAST_SEEK) ? 1 : 2; st = avformat_new_stream(s, NULL); if (!st) @@ -489,19 +489,26 @@ static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, AVStream *st = s->streams[0]; int64_t ret = av_index_search_timestamp(st, timestamp, flags); int64_t best_pos; + int fast_seek = (s->flags & AVFMT_FLAG_FAST_SEEK) ? 1 : 0; + int64_t filesize = mp3->header_filesize; if (mp3->usetoc == 2) return -1; // generic index code - if ( mp3->is_cbr + 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->is_cbr || fast_seek) && (mp3->usetoc == 0 || !mp3->xing_toc) && st->duration > 0 - && mp3->header_filesize > s->internal->data_offset - && mp3->frames) { + && filesize > 0) { ie = &ie1; timestamp = av_clip64(timestamp, 0, st->duration); ie->timestamp = timestamp; - ie->pos = av_rescale(timestamp, mp3->header_filesize, st->duration) + s->internal->data_offset; + ie->pos = av_rescale(timestamp, filesize, st->duration) + s->internal->data_offset; } else if (mp3->xing_toc) { if (ret < 0) return ret; @@ -515,7 +522,7 @@ static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, if (best_pos < 0) return best_pos; - if (mp3->is_cbr && ie == &ie1) { + 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); } |