From 806ac7da6927c1a9db2d6bc7af272733078964a0 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Fri, 17 May 2019 00:30:21 +0200 Subject: avformat/matroskadec: Improve check for level 1 duplicates If a file uses unknown-length level 1 elements besides clusters and such elements are after the first cluster, then these elements will usually be parsed twice: Once during parsing of the file header and once when reading the file reaches the position where these elements are located. The second time the element is parsed leads to a "Duplicate element" error message. Known-length elements are not affected by this as they are skipped except during parsing the header. This commit fixes this by explicitly adding a check for whether the position of the element to be parsed is the same as the position of the already known level 1 element. Signed-off-by: Andreas Rheinhardt --- libavformat/matroskadec.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'libavformat/matroskadec.c') diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index 3abdf01374..b97189e674 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -1390,7 +1390,10 @@ static int ebml_parse(MatroskaDemuxContext *matroska, matroska->cues_parsing_deferred = 0; if (syntax->type == EBML_LEVEL1 && (level1_elem = matroska_find_level1_elem(matroska, syntax->id))) { - if (level1_elem->parsed) + if (!level1_elem->pos) { + // Zero is not a valid position for a level 1 element. + level1_elem->pos = pos; + } else if (level1_elem->pos != pos) av_log(matroska->ctx, AV_LOG_ERROR, "Duplicate element\n"); level1_elem->parsed = 1; } -- cgit v1.2.3