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avformat/matroskadec: Make cluster parsing level compatible 

Before this commit, the parsing of clusters mixed EBML levels by
allowing elements from different levels in a EbmlSyntax (namely
matroska_cluster_parsing). This has been changed. And the level
is now explicitly used to determine how to parse.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2019-05-17 00:30:08 +02:00 committed by James Almer
parent b31c9b72e5
commit 865c537007
1 changed files with 47 additions and 59 deletions
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106
libavformat/matroskadec.c
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@ -722,15 +722,10 @@ static const EbmlSyntax matroska_cluster_parsing[] = {
{ MATROSKA_ID_SIMPLEBLOCK, EBML_BIN, 0, offsetof(MatroskaBlock, bin) },
{ MATROSKA_ID_CLUSTERPOSITION, EBML_NONE },
{ MATROSKA_ID_CLUSTERPREVSIZE, EBML_NONE },
{ MATROSKA_ID_INFO, EBML_NONE },
{ MATROSKA_ID_CUES, EBML_NONE },
{ MATROSKA_ID_TAGS, EBML_NONE },
{ MATROSKA_ID_SEEKHEAD, EBML_NONE },
{ MATROSKA_ID_CLUSTER, EBML_STOP },
{ 0 } /* We don't want to go back to level 0, so don't add the parent. */
CHILD_OF(matroska_segment)
};
static const EbmlSyntax matroska_cluster[] = {
static const EbmlSyntax matroska_cluster_initial[] = {
{ MATROSKA_ID_CLUSTERTIMECODE, EBML_UINT, 0, offsetof(MatroskaCluster, timecode) },
{ MATROSKA_ID_BLOCKGROUP, EBML_STOP },
{ MATROSKA_ID_SIMPLEBLOCK, EBML_STOP },
@ -739,12 +734,20 @@ static const EbmlSyntax matroska_cluster[] = {
CHILD_OF(matroska_segment)
};
static const EbmlSyntax matroska_cluster_enter[] = {
{ MATROSKA_ID_CLUSTER, EBML_NEST, 0, 0, { .n = matroska_cluster_initial } },
{ 0 }
};
static const EbmlSyntax matroska_clusters[] = {
{ MATROSKA_ID_CLUSTER, EBML_NEST, 0, 0, { .n = matroska_cluster } },
{ MATROSKA_ID_INFO, EBML_NONE },
{ MATROSKA_ID_CUES, EBML_NONE },
{ MATROSKA_ID_TAGS, EBML_NONE },
{ MATROSKA_ID_SEEKHEAD, EBML_NONE },
{ MATROSKA_ID_CLUSTER, EBML_STOP },
{ MATROSKA_ID_CUES, EBML_NONE },
{ MATROSKA_ID_TAGS, EBML_NONE },
{ MATROSKA_ID_INFO, EBML_NONE },
{ MATROSKA_ID_TRACKS, EBML_NONE },
{ MATROSKA_ID_ATTACHMENTS, EBML_NONE },
{ MATROSKA_ID_CHAPTERS, EBML_NONE },
{ MATROSKA_ID_SEEKHEAD, EBML_NONE },
{ 0 } /* We don't want to go back to level 0, so don't add the parent. */
};
#undef CHILD_OF
@ -814,24 +817,6 @@ static int matroska_resync(MatroskaDemuxContext *matroska, int64_t last_pos)
return pb->error ? pb->error : AVERROR_EOF;
}
/*
* Return: Whether we reached the end of a level in the hierarchy or not.
*/
static int ebml_level_end(MatroskaDemuxContext *matroska)
{
AVIOContext *pb = matroska->ctx->pb;
int64_t pos = avio_tell(pb);
if (matroska->num_levels > 0) {
MatroskaLevel *level = &matroska->levels[matroska->num_levels - 1];
if (pos - level->start >= level->length || matroska->current_id) {
matroska->num_levels--;
return 1;
}
}
return (matroska->is_live && matroska->ctx->pb->eof_reached) ? 1 : 0;
}
/*
* Read: an "EBML number", which is defined as a variable-length
* array of bytes. The first byte indicates the length by giving a
@ -3604,43 +3589,39 @@ static int matroska_parse_cluster(MatroskaDemuxContext *matroska)
MatroskaCluster *cluster = &matroska->current_cluster;
MatroskaBlock *block = &cluster->block;
int res;
res = ebml_parse(matroska,
matroska_cluster_parsing,
cluster);
if (res == 1) {
/* New Cluster */
if (cluster->pos)
ebml_level_end(matroska);
cluster->pos = avio_tell(matroska->ctx->pb);
/* sizeof the ID which was already read */
if (matroska->current_id)
cluster->pos -= 4;
res = ebml_parse(matroska,
matroska_clusters,
cluster);
/* Try parsing the block again. */
if (res == 1)
res = ebml_parse(matroska,
matroska_cluster_parsing,
cluster);
else
cluster->pos = 0;
av_assert0(matroska->num_levels <= 2);
if (matroska->num_levels == 1) {
res = ebml_parse(matroska, matroska_clusters, NULL);
if (res == 1) {
/* Found a cluster: subtract the size of the ID already read. */
cluster->pos = avio_tell(matroska->ctx->pb) - 4;
res = ebml_parse(matroska, matroska_cluster_enter, cluster);
if (res < 0)
return res;
}
}
if (res >= 0 && block->bin.size > 0) {
if (matroska->num_levels == 2) {
int err = 0;
/* We are inside a cluster. */
res = ebml_parse(matroska, matroska_cluster_parsing, cluster);
if (res >= 0 && block->bin.size > 0) {
int is_keyframe = block->non_simple ? block->reference == INT64_MIN : -1;
uint8_t* additional = block->additional.size > 0 ?
block->additional.data : NULL;
res = matroska_parse_block(matroska, block->bin.buf, block->bin.data,
err = matroska_parse_block(matroska, block->bin.buf, block->bin.data,
block->bin.size, block->bin.pos,
matroska->current_cluster.timecode,
block->duration, is_keyframe,
additional, block->additional_id,
block->additional.size,
cluster->pos,
cluster->timecode, block->duration,
is_keyframe, additional, block->additional_id,
block->additional.size, cluster->pos,
block->discard_padding);
}
}
if (res == LEVEL_ENDED)
cluster->pos = 0;
@ -3648,6 +3629,13 @@ static int matroska_parse_cluster(MatroskaDemuxContext *matroska)
ebml_free(matroska_blockgroup, block);
memset(block, 0, sizeof(*block));
if (err < 0)
return err;
} else if (!matroska->num_levels) {
matroska->done = 1;
return AVERROR_EOF;
}
return res;
}