From 741565a1e69c45ce4848f01e45be5e66a68efa2f Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 22 Mar 2020 16:38:24 +0100 Subject: [PATCH] avcodec/cbs_h264_syntax_template: fix off by 1 error with slice_group_change_cycle Fixes: assertion failure Fixes: 20390/clusterfuzz-testcase-minimized-ffmpeg_BSF_H264_REDUNDANT_PPS_fuzzer-5683400772157440 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/cbs_h264_syntax_template.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/cbs_h264_syntax_template.c b/libavcodec/cbs_h264_syntax_template.c index 878d348b94..b65460996b 100644 --- a/libavcodec/cbs_h264_syntax_template.c +++ b/libavcodec/cbs_h264_syntax_template.c @@ -1366,7 +1366,7 @@ static int FUNC(slice_header)(CodedBitstreamContext *ctx, RWContext *rw, (sps->pic_height_in_map_units_minus1 + 1); max = (pic_size + pps->slice_group_change_rate_minus1) / (pps->slice_group_change_rate_minus1 + 1); - bits = av_log2(2 * max - 1); + bits = av_ceil_log2(max + 1); u(bits, slice_group_change_cycle, 0, max); }