From 4abfa387b8234736f6e0e541951e3d5eb60eb843 Mon Sep 17 00:00:00 2001 From: Yusuke Nakamura Date: Tue, 27 Jan 2015 19:15:37 +0900 Subject: [PATCH] mov: Change DTS-based seek into CTS-based seek. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit CTS-based seek is reasonable since player requests frames in output order not coded order. This change fixes seek to a keyframe within consecutive keyframes. Let's say P[0|-1] and P[1|0], here x and y inside [x|y] are PTS and DTS respectively, and both two frames are a keyframe. If you try to seek on PTS=0, i.e. P[0|-1], you'll get P[1|0] if the demuxer is DTS based. This is obviously undesirable. Signed-off-by: Martin Storsjö --- libavformat/mov.c | 44 +++++++++++++++++++++++++++++--------------- 1 file changed, 29 insertions(+), 15 deletions(-) diff --git a/libavformat/mov.c b/libavformat/mov.c index df7357f30e..fb756c4718 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -2099,6 +2099,7 @@ static void mov_build_index(MOVContext *mov, AVStream *st) int64_t current_offset; int64_t current_dts = 0; unsigned int stts_index = 0; + unsigned int ctts_index = 0; unsigned int stsc_index = 0; unsigned int stss_index = 0; unsigned int stps_index = 0; @@ -2124,6 +2125,7 @@ static void mov_build_index(MOVContext *mov, AVStream *st) sc->stts_count == 1 && sc->stts_data[0].duration == 1)) { unsigned int current_sample = 0; unsigned int stts_sample = 0; + unsigned int ctts_sample = 0; unsigned int sample_size; unsigned int distance = 0; unsigned int rap_group_index = 0; @@ -2131,8 +2133,6 @@ static void mov_build_index(MOVContext *mov, AVStream *st) int rap_group_present = sc->rap_group_count && sc->rap_group; int key_off = (sc->keyframes && sc->keyframes[0] > 0) || (sc->stps_data && sc->stps_data[0] > 0); - current_dts -= sc->dts_shift; - if (!sc->sample_count) return; if (sc->sample_count >= UINT_MAX / sizeof(*st->index_entries) - st->nb_index_entries) @@ -2180,14 +2180,15 @@ static void mov_build_index(MOVContext *mov, AVStream *st) if (sc->pseudo_stream_id == -1 || sc->stsc_data[stsc_index].id - 1 == sc->pseudo_stream_id) { AVIndexEntry *e = &st->index_entries[st->nb_index_entries++]; + int64_t current_cts = current_dts + (sc->ctts_data ? sc->ctts_data[ctts_index].duration : 0); e->pos = current_offset; - e->timestamp = current_dts; + e->timestamp = current_cts; e->size = sample_size; e->min_distance = distance; e->flags = keyframe ? AVINDEX_KEYFRAME : 0; - av_dlog(mov->fc, "AVIndex stream %d, sample %d, offset %"PRIx64", dts %"PRId64", " + av_dlog(mov->fc, "AVIndex stream %d, sample %d, offset %"PRIx64", cts %"PRId64", " "size %d, distance %d, keyframe %d\n", st->index, current_sample, - current_offset, current_dts, sample_size, distance, keyframe); + current_offset, current_cts, sample_size, distance, keyframe); } current_offset += sample_size; @@ -2195,11 +2196,16 @@ static void mov_build_index(MOVContext *mov, AVStream *st) current_dts += sc->stts_data[stts_index].duration; distance++; stts_sample++; + ctts_sample++; current_sample++; if (stts_index + 1 < sc->stts_count && stts_sample == sc->stts_data[stts_index].count) { stts_sample = 0; stts_index++; } + if (ctts_index + 1 < sc->ctts_count && ctts_sample == sc->ctts_data[ctts_index].count) { + ctts_sample = 0; + ctts_index++; + } } } if (st->duration > 0) @@ -2789,13 +2795,16 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom) int sample_flags = i ? frag->flags : first_sample_flags; unsigned sample_duration = frag->duration; int keyframe = 0; + int sample_cts = 0; + int64_t cts; if (flags & MOV_TRUN_SAMPLE_DURATION) sample_duration = avio_rb32(pb); if (flags & MOV_TRUN_SAMPLE_SIZE) sample_size = avio_rb32(pb); if (flags & MOV_TRUN_SAMPLE_FLAGS) sample_flags = avio_rb32(pb); - sc->ctts_data[sc->ctts_count].count = 1; - sc->ctts_data[sc->ctts_count].duration = (flags & MOV_TRUN_SAMPLE_CTS) ? - avio_rb32(pb) : 0; + if (flags & MOV_TRUN_SAMPLE_CTS) sample_cts = avio_rb32(pb); + sc->ctts_data[sc->ctts_count].count = 1; + sc->ctts_data[sc->ctts_count].duration = sample_cts; + cts = dts + sample_cts; sc->ctts_count++; if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) keyframe = 1; @@ -2805,11 +2814,11 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom) MOV_FRAG_SAMPLE_FLAG_DEPENDS_YES)); if (keyframe) distance = 0; - av_add_index_entry(st, offset, dts, sample_size, distance, + av_add_index_entry(st, offset, cts, sample_size, distance, keyframe ? AVINDEX_KEYFRAME : 0); - av_dlog(c->fc, "AVIndex stream %d, sample %d, offset %"PRIx64", dts %"PRId64", " + av_dlog(c->fc, "AVIndex stream %d, sample %d, offset %"PRIx64", cts %"PRId64", " "size %d, distance %d, keyframe %d\n", st->index, sc->sample_count+i, - offset, dts, sample_size, distance, keyframe); + offset, cts, sample_size, distance, keyframe); distance++; dts += sample_duration; offset += sample_size; @@ -3335,7 +3344,12 @@ static AVIndexEntry *mov_find_next_sample(AVFormatContext *s, AVStream **st) MOVStreamContext *msc = avst->priv_data; if (msc->pb && msc->current_sample < avst->nb_index_entries) { AVIndexEntry *current_sample = &avst->index_entries[msc->current_sample]; - int64_t dts = av_rescale(current_sample->timestamp, AV_TIME_BASE, msc->time_scale); + int64_t dts; + if (msc->ctts_data) + dts = av_rescale(current_sample->timestamp - msc->dts_shift - msc->ctts_data[msc->ctts_index].duration, + AV_TIME_BASE, msc->time_scale); + else + dts = av_rescale(current_sample->timestamp, AV_TIME_BASE, msc->time_scale); av_dlog(s, "stream %d, sample %d, dts %"PRId64"\n", i, msc->current_sample, dts); if (!sample || (!s->pb->seekable && current_sample->pos < sample->pos) || (s->pb->seekable && @@ -3409,9 +3423,9 @@ static int mov_read_packet(AVFormatContext *s, AVPacket *pkt) } pkt->stream_index = sc->ffindex; - pkt->dts = sample->timestamp; + pkt->pts = sample->timestamp; if (sc->ctts_data && sc->ctts_index < sc->ctts_count) { - pkt->pts = pkt->dts + sc->dts_shift + sc->ctts_data[sc->ctts_index].duration; + pkt->dts = pkt->pts - sc->dts_shift - sc->ctts_data[sc->ctts_index].duration; /* update ctts context */ sc->ctts_sample++; if (sc->ctts_index < sc->ctts_count && @@ -3424,8 +3438,8 @@ static int mov_read_packet(AVFormatContext *s, AVPacket *pkt) } else { int64_t next_dts = (sc->current_sample < st->nb_index_entries) ? st->index_entries[sc->current_sample].timestamp : st->duration; + pkt->dts = pkt->pts; pkt->duration = next_dts - pkt->dts; - pkt->pts = pkt->dts; } if (st->discard == AVDISCARD_ALL) goto retry;