Resending as it's own message per contribution rules. I've also attached the patch in case the formatting gets trashed.
When sidx box support is enabled, the code will skip reading all trun boxes (each containing ctts entries for samples inthat box). If seeks are attempted before all ctts values are known, the old code would dump ctts entries into the wrong location. These are then used to compute pts values which leads to out of order and incorrectly timestamped packets. This patch fixes ctts processing by always using the index returned by av_add_index_entry() as the ctts_data index. When the index gains new entries old values are reshuffled as appropriate. This approach makes sense since the mov demuxer is already relying on the mapping of AVIndex entries to samples for correct demuxing. Notes for future improvement: Probably there are other boxes (stts, stsc, etc) that are impacted by this issue... this patch only attempts to fix ctts since it completely breaks packet timestamping. This patch continues using an array for the ctts data, which is not the most ideal given the rearrangement that needs to happen (via memmove as new entries are read in). Ideally AVIndex and the ctts data would be set-type structures so addition is always worst case O(lg(n)) instead of the O(n^2) that exists now; this slowdown is noticeable during seeks. Additionally since ctts samples from trun boxes always have a count of 1, there's probably an opportunity to avoid the post-seek fixup that iterates O(n) over all samples with an O(1) when no non-1 count samples are present. Signed-off-by: Dale Curtis <dalecur...@chromium.org> --- libavformat/isom.h | 1 + libavformat/mov.c | 46 +++++++++++++++++++++++++++++++--------------- 2 files changed, 32 insertions(+), 15 deletions(-) diff --git a/libavformat/isom.h b/libavformat/isom.h index ff009b0896..fdd98c28f5 100644 --- a/libavformat/isom.h +++ b/libavformat/isom.h @@ -137,6 +137,7 @@ typedef struct MOVStreamContext { unsigned int stts_count; MOVStts *stts_data; unsigned int ctts_count; + unsigned int ctts_allocated_size; MOVStts *ctts_data; unsigned int stsc_count; MOVStsc *stsc_data; diff --git a/libavformat/mov.c b/libavformat/mov.c index 63f84be782..412290b435 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -4297,11 +4297,6 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom) } if ((uint64_t)entries+sc->ctts_count >= UINT_MAX/sizeof(*sc->ctts_ data)) return AVERROR_INVALIDDATA; - if ((err = av_reallocp_array(&sc->ctts_data, entries + sc->ctts_count, - sizeof(*sc->ctts_data))) < 0) { - sc->ctts_count = 0; - return err; - } if (flags & MOV_TRUN_DATA_OFFSET) data_offset = avio_rb32(pb); if (flags & MOV_TRUN_FIRST_SAMPLE_FLAGS) first_sample_flags = avio_rb32(pb); dts = sc->track_end - sc->time_offset; @@ -4312,26 +4307,28 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom) unsigned sample_size = frag->size; int sample_flags = i ? frag->flags : first_sample_flags; unsigned sample_duration = frag->duration; + unsigned ctts_duration = 0; int keyframe = 0; + int ctts_index = 0; + int old_nb_index_entries = st->nb_index_entries; 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; - mov_update_dts_shift(sc, sc->ctts_data[sc->ctts_count].duration); + if (flags & MOV_TRUN_SAMPLE_CTS) ctts_duration = avio_rb32(pb); + + mov_update_dts_shift(sc, ctts_duration); if (frag->time != AV_NOPTS_VALUE) { if (c->use_mfra_for == FF_MOV_FLAG_MFRA_PTS) { int64_t pts = frag->time; av_log(c->fc, AV_LOG_DEBUG, "found frag time %"PRId64 " sc->dts_shift %d ctts.duration %d" " sc->time_offset %"PRId64" flags & MOV_TRUN_SAMPLE_CTS %d\n", pts, - sc->dts_shift, sc->ctts_data[sc->ctts_count]. duration, + sc->dts_shift, ctts_duration, sc->time_offset, flags & MOV_TRUN_SAMPLE_CTS); dts = pts - sc->dts_shift; if (flags & MOV_TRUN_SAMPLE_CTS) { - dts -= sc->ctts_data[sc->ctts_count].duration; + dts -= ctts_duration; } else { dts -= sc->time_offset; } @@ -4343,7 +4340,7 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom) } frag->time = AV_NOPTS_VALUE; } - sc->ctts_count++; + if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) keyframe = 1; else @@ -4352,11 +4349,30 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom) MOV_FRAG_SAMPLE_FLAG_DEPENDS_YES)); if (keyframe) distance = 0; - err = av_add_index_entry(st, offset, dts, sample_size, distance, - keyframe ? AVINDEX_KEYFRAME : 0); - if (err < 0) { + ctts_index = av_add_index_entry(st, offset, dts, sample_size, distance, + keyframe ? AVINDEX_KEYFRAME : 0); + if (ctts_index >= 0 && old_nb_index_entries < st->nb_index_entries) { + unsigned int size_needed = st->nb_index_entries * sizeof(*sc->ctts_data); + unsigned int request_size = size_needed > sc->ctts_allocated_size ? + FFMAX(size_needed, 2 * sc->ctts_allocated_size) : size_needed; + sc->ctts_data = av_fast_realloc(sc->ctts_data, &sc->ctts_allocated_size, request_size); + if (!sc->ctts_data) { + sc->ctts_count = 0; + return AVERROR(ENOMEM); + } + + if (ctts_index != old_nb_index_entries) { + memmove(sc->ctts_data + ctts_index + 1, sc->ctts_data + ctts_index, + sizeof(*sc->ctts_data) * (sc->ctts_count - ctts_index)); + } + + sc->ctts_data[ctts_index].count = 1; + sc->ctts_data[ctts_index].duration = ctts_duration; + sc->ctts_count++; + } else { av_log(c->fc, AV_LOG_ERROR, "Failed to add index entry\n"); } + av_log(c->fc, AV_LOG_TRACE, "AVIndex stream %d, sample %u, offset %"PRIx64", dts %"PRId64", " "size %u, distance %d, keyframe %d\n", st->index, sc->sample_count+i, offset, dts, sample_size, distance, keyframe); -- 2.13.2.932.g7449e964c-goog
0001-Fix-trampling-of-ctts-during-seeks-when-sidx-support.patch
Description: Binary data
_______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel