From 31ad14c21e0735387ba8082c6e3436241f7ccfc8 Mon Sep 17 00:00:00 2001 From: Aaron Colwell Date: Sat, 9 Jul 2011 07:48:43 +0200 Subject: [PATCH] matroskadec: defer parsing of cues element until we seek. This decreases startup latency. Signed-off-by: Ronald S. Bultje Signed-off-by: Anton Khirnov --- libavformat/matroskadec.c | 131 +++++++++++++++++++++++++------------- 1 file changed, 86 insertions(+), 45 deletions(-) diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index a1e827f093..37ce3342b1 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -244,6 +244,9 @@ typedef struct { /* What to skip before effectively reading a packet. */ int skip_to_keyframe; uint64_t skip_to_timecode; + + /* File has a CUES element, but we defer parsing until it is needed. */ + int cues_parsing_deferred; } MatroskaDemuxContext; typedef struct { @@ -1110,7 +1113,7 @@ static void matroska_convert_tags(AVFormatContext *s) } } -static void matroska_execute_seekhead(MatroskaDemuxContext *matroska) +static int matroska_parse_seekhead_entry(MatroskaDemuxContext *matroska, int idx) { EbmlList *seekhead_list = &matroska->seekhead; MatroskaSeekhead *seekhead = seekhead_list->elem; @@ -1118,34 +1121,25 @@ static void matroska_execute_seekhead(MatroskaDemuxContext *matroska) int64_t before_pos = avio_tell(matroska->ctx->pb); uint32_t saved_id = matroska->current_id; MatroskaLevel level; - int i; + int64_t offset; + int ret = 0; - // we should not do any seeking in the streaming case - if (!matroska->ctx->pb->seekable || - (matroska->ctx->flags & AVFMT_FLAG_IGNIDX)) - return; - - for (i=0; inb_elem; i++) { - int64_t offset = seekhead[i].pos + matroska->segment_start; - - if (seekhead[i].pos <= before_pos - || seekhead[i].id == MATROSKA_ID_SEEKHEAD - || seekhead[i].id == MATROSKA_ID_CLUSTER) - continue; + if (idx >= seekhead_list->nb_elem + || seekhead[idx].id == MATROSKA_ID_SEEKHEAD + || seekhead[idx].id == MATROSKA_ID_CLUSTER) + return 0; /* seek */ - if (avio_seek(matroska->ctx->pb, offset, SEEK_SET) != offset) - continue; - + offset = seekhead[idx].pos + matroska->segment_start; + if (avio_seek(matroska->ctx->pb, offset, SEEK_SET) == offset) { /* We don't want to lose our seekhead level, so we add * a dummy. This is a crude hack. */ if (matroska->num_levels == EBML_MAX_DEPTH) { av_log(matroska->ctx, AV_LOG_INFO, "Max EBML element depth (%d) reached, " "cannot parse further.\n", EBML_MAX_DEPTH); - break; - } - + ret = AVERROR_INVALIDDATA; + } else { level.start = 0; level.length = (uint64_t)-1; matroska->levels[matroska->num_levels] = level; @@ -1161,11 +1155,76 @@ static void matroska_execute_seekhead(MatroskaDemuxContext *matroska) break; } } - + } /* seek back */ avio_seek(matroska->ctx->pb, before_pos, SEEK_SET); matroska->level_up = level_up; matroska->current_id = saved_id; + + return ret; +} + +static void matroska_execute_seekhead(MatroskaDemuxContext *matroska) +{ + EbmlList *seekhead_list = &matroska->seekhead; + MatroskaSeekhead *seekhead = seekhead_list->elem; + int64_t before_pos = avio_tell(matroska->ctx->pb); + int i; + + // we should not do any seeking in the streaming case + if (!matroska->ctx->pb->seekable || + (matroska->ctx->flags & AVFMT_FLAG_IGNIDX)) + return; + + for (i = 0; i < seekhead_list->nb_elem; i++) { + if (seekhead[i].pos <= before_pos) + continue; + + // defer cues parsing until we actually need cue data. + if (seekhead[i].id == MATROSKA_ID_CUES) { + matroska->cues_parsing_deferred = 1; + continue; + } + + if (matroska_parse_seekhead_entry(matroska, i) < 0) + break; + } +} + +static void matroska_parse_cues(MatroskaDemuxContext *matroska) { + EbmlList *seekhead_list = &matroska->seekhead; + MatroskaSeekhead *seekhead = seekhead_list->elem; + EbmlList *index_list; + MatroskaIndex *index; + int index_scale = 1; + int i, j; + + for (i = 0; i < seekhead_list->nb_elem; i++) + if (seekhead[i].id != MATROSKA_ID_CUES) + break; + assert(i <= seekhead_list->nb_elem); + + matroska_parse_seekhead_entry(matroska, i); + + index_list = &matroska->index; + index = index_list->elem; + if (index_list->nb_elem + && index[0].time > 1E14/matroska->time_scale) { + av_log(matroska->ctx, AV_LOG_WARNING, "Working around broken index.\n"); + index_scale = matroska->time_scale; + } + for (i = 0; i < index_list->nb_elem; i++) { + EbmlList *pos_list = &index[i].pos; + MatroskaIndexPos *pos = pos_list->elem; + for (j = 0; j < pos_list->nb_elem; j++) { + MatroskaTrack *track = matroska_find_track_by_num(matroska, pos[j].track); + if (track && track->stream) + av_add_index_entry(track->stream, + pos[j].pos + matroska->segment_start, + index[i].time/index_scale, 0, 0, + AVINDEX_KEYFRAME); + } + } } static int matroska_aac_profile(char *codec_id) @@ -1197,9 +1256,6 @@ static int matroska_read_header(AVFormatContext *s, AVFormatParameters *ap) EbmlList *chapters_list = &matroska->chapters; MatroskaChapter *chapters; MatroskaTrack *tracks; - EbmlList *index_list; - MatroskaIndex *index; - int index_scale = 1; uint64_t max_start = 0; Ebml ebml = { 0 }; AVStream *st; @@ -1529,27 +1585,6 @@ static int matroska_read_header(AVFormatContext *s, AVFormatParameters *ap) max_start = chapters[i].start; } - index_list = &matroska->index; - index = index_list->elem; - if (index_list->nb_elem - && index[0].time > 100000000000000/matroska->time_scale) { - av_log(matroska->ctx, AV_LOG_WARNING, "Working around broken index.\n"); - index_scale = matroska->time_scale; - } - for (i=0; inb_elem; i++) { - EbmlList *pos_list = &index[i].pos; - MatroskaIndexPos *pos = pos_list->elem; - for (j=0; jnb_elem; j++) { - MatroskaTrack *track = matroska_find_track_by_num(matroska, - pos[j].track); - if (track && track->stream) - av_add_index_entry(track->stream, - pos[j].pos + matroska->segment_start, - index[i].time/index_scale, 0, 0, - AVINDEX_KEYFRAME); - } - } - matroska_convert_tags(s); return 0; @@ -1898,6 +1933,12 @@ static int matroska_read_seek(AVFormatContext *s, int stream_index, AVStream *st = s->streams[stream_index]; int i, index, index_sub, index_min; + /* Parse the CUES now since we need the index data to seek. */ + if (matroska->cues_parsing_deferred) { + matroska_parse_cues(matroska); + matroska->cues_parsing_deferred = 0; + } + if (!st->nb_index_entries) return 0; timestamp = FFMAX(timestamp, st->index_entries[0].timestamp);