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matroskadec: on the fly index construction for index-less files

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each cluster that is read and that contains a video key frame is added
to the index

Originally committed as revision 14957 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Aurelien Jacobs 2008-08-25 00:09:08 +00:00
parent dfbbbdc0bf
commit 8bc98ba92b
1 changed files with 16 additions and 4 deletions
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20
libavformat/matroskadec.c
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@ -204,6 +204,7 @@ typedef struct {
AVPacket **packets; AVPacket **packets;
int num_packets; int num_packets;
AVStream *vstream;
int done; int done;
int has_cluster_id; int has_cluster_id;
@ -1270,6 +1271,7 @@ static int matroska_read_header(AVFormatContext *s, AVFormatParameters *ap)
} }
if (track->type == MATROSKA_TRACK_TYPE_VIDEO) { if (track->type == MATROSKA_TRACK_TYPE_VIDEO) {
if (!matroska->vstream) matroska->vstream = st;
st->codec->codec_type = CODEC_TYPE_VIDEO; st->codec->codec_type = CODEC_TYPE_VIDEO;
st->codec->codec_tag = track->video.fourcc; st->codec->codec_tag = track->video.fourcc;
st->codec->width = track->video.pixel_width; st->codec->width = track->video.pixel_width;
@ -1390,7 +1392,7 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data,
uint64_t duration, int is_keyframe) uint64_t duration, int is_keyframe)
{ {
MatroskaTrack *track; MatroskaTrack *track;
int res = 0; int is_video_key_frame = is_keyframe, res = 0;
AVStream *st; AVStream *st;
AVPacket *pkt; AVPacket *pkt;
int16_t block_time; int16_t block_time;
@ -1430,6 +1432,8 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data,
matroska->skip_to_keyframe = 0; matroska->skip_to_keyframe = 0;
} }
is_video_key_frame &= st == matroska->vstream;
switch ((flags & 0x06) >> 1) { switch ((flags & 0x06) >> 1) {
case 0x0: /* no lacing */ case 0x0: /* no lacing */
laces = 1; laces = 1;
@ -1592,7 +1596,7 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data,
} }
av_free(lace_size); av_free(lace_size);
return res; return res < 0 ? res : is_video_key_frame;
} }
static int matroska_parse_cluster(MatroskaDemuxContext *matroska) static int matroska_parse_cluster(MatroskaDemuxContext *matroska)
@ -1600,23 +1604,31 @@ static int matroska_parse_cluster(MatroskaDemuxContext *matroska)
MatroskaCluster cluster = { 0 }; MatroskaCluster cluster = { 0 };
EbmlList *blocks_list; EbmlList *blocks_list;
MatroskaBlock *blocks; MatroskaBlock *blocks;
int i, res; int i, res, key_frame = 0;
offset_t pos = url_ftell(matroska->ctx->pb);
if (matroska->has_cluster_id){ if (matroska->has_cluster_id){
/* For the first cluster we parse, its ID was already read as /* For the first cluster we parse, its ID was already read as
part of matroska_read_header(), so don't read it again */ part of matroska_read_header(), so don't read it again */
res = ebml_parse_id(matroska, matroska_clusters, res = ebml_parse_id(matroska, matroska_clusters,
MATROSKA_ID_CLUSTER, &cluster); MATROSKA_ID_CLUSTER, &cluster);
pos -= 4; /* sizeof the ID which was already read */
matroska->has_cluster_id = 0; matroska->has_cluster_id = 0;
} else } else
res = ebml_parse(matroska, matroska_clusters, &cluster); res = ebml_parse(matroska, matroska_clusters, &cluster);
blocks_list = &cluster.blocks; blocks_list = &cluster.blocks;
blocks = blocks_list->elem; blocks = blocks_list->elem;
for (i=0; i<blocks_list->nb_elem; i++) for (i=0; i<blocks_list->nb_elem; i++)
if (blocks[i].bin.size > 0) if (blocks[i].bin.size > 0) {
res=matroska_parse_block(matroska, res=matroska_parse_block(matroska,
blocks[i].bin.data, blocks[i].bin.size, blocks[i].bin.data, blocks[i].bin.size,
blocks[i].bin.pos, cluster.timecode, blocks[i].bin.pos, cluster.timecode,
blocks[i].duration, !blocks[i].reference); blocks[i].duration, !blocks[i].reference);
key_frame |= res > 0;
}
if (key_frame)
av_add_index_entry(matroska->vstream, pos,
cluster.timecode*matroska->time_scale/AV_TIME_BASE,
0, 0, AVINDEX_KEYFRAME);
ebml_free(matroska_cluster, &cluster); ebml_free(matroska_cluster, &cluster);
if (res < 0) matroska->done = 1; if (res < 0) matroska->done = 1;
return res; return res;