From 19ccc06d8b617ba48c3122decf59b9e3376b415b Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 7 Sep 2014 21:44:19 +0200 Subject: [PATCH] avformat/mp3dec: Improve seeking frame sync code Fixes Ticket3884 Signed-off-by: Michael Niedermayer (cherry picked from commit 1b5ccae0f2045ac86bc9e1257cec1b3fba81315f) --- libavformat/mp3dec.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c index 8335388409..8936854621 100644 --- a/libavformat/mp3dec.c +++ b/libavformat/mp3dec.c @@ -398,6 +398,8 @@ static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int64_t ret = av_index_search_timestamp(st, timestamp, flags); int i, j; int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1; + int64_t best_pos; + int best_score; if (mp3->is_cbr && st->duration > 0 && mp3->header_filesize > s->data_offset) { int64_t filesize = avio_size(s->pb); @@ -421,28 +423,37 @@ static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, return -1; } - if (dir < 0) - avio_seek(s->pb, FFMAX(ie->pos - 4096, 0), SEEK_SET); + avio_seek(s->pb, FFMAX(ie->pos - 4096, 0), SEEK_SET); ret = avio_seek(s->pb, ie->pos, SEEK_SET); if (ret < 0) return ret; #define MIN_VALID 3 + best_pos = ie->pos; + best_score = 999; for(i=0; i<4096; i++) { - int64_t pos = ie->pos + i*dir; + int64_t pos = ie->pos + (dir > 0 ? i - 1024 : -i); + int64_t candidate = -1; + int score = 999; for(j=0; jpos - pos)*dir <= 0 && abs(MIN_VALID/2-j) < score) { + candidate = pos; + score = abs(MIN_VALID/2-j); + } pos += ret; } - if(j==MIN_VALID) - break; + if (best_score > score && j == MIN_VALID) { + best_pos = candidate; + best_score = score; + if(score == 0) + break; + } } - if(j!=MIN_VALID) - i=0; - ret = avio_seek(s->pb, ie->pos + i*dir, SEEK_SET); + ret = avio_seek(s->pb, best_pos, SEEK_SET); if (ret < 0) return ret; ff_update_cur_dts(s, st, ie->timestamp);