From 3ede6cc0f18c3da842d18153b860d911bdbfbde9 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Sat, 30 Sep 2023 18:07:58 +0200 Subject: [PATCH] avcodec/mpegvideo_dec: Check for existence of planes before accesses Fixes segfaults with -debug +nomc -flags +gray (presuming a build with --enable-gray). Signed-off-by: Andreas Rheinhardt --- libavcodec/mpegvideo_dec.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/libavcodec/mpegvideo_dec.c b/libavcodec/mpegvideo_dec.c index aab2a4655a..c5e42e8ab6 100644 --- a/libavcodec/mpegvideo_dec.c +++ b/libavcodec/mpegvideo_dec.c @@ -249,10 +249,12 @@ static void gray_frame(AVFrame *frame) { int h_chroma_shift, v_chroma_shift; - av_pix_fmt_get_chroma_sub_sample(frame->format, &h_chroma_shift, &v_chroma_shift); - for (int i = 0; i < frame->height; i++) memset(frame->data[0] + frame->linesize[0] * i, 0x80, frame->width); + + if (!frame->data[1]) + return; + av_pix_fmt_get_chroma_sub_sample(frame->format, &h_chroma_shift, &v_chroma_shift); for (int i = 0; i < AV_CEIL_RSHIFT(frame->height, v_chroma_shift); i++) { memset(frame->data[1] + frame->linesize[1] * i, 0x80, AV_CEIL_RSHIFT(frame->width, h_chroma_shift));