From 2f95bc3cb3c0d2e88e33b219409e5ca2719f0c73 Mon Sep 17 00:00:00 2001 From: Niklas Haas Date: Mon, 2 Dec 2024 13:08:52 +0100 Subject: [PATCH] swscale/utils: disable full_chr_h_input optimization for odd width The basic problem here is that the rgb*ToUV_half_* functions hard-code a bilinear downsample from src[i] + src[i+1], with no bounds check on the i+1 access. Due to the signature of the function, we cannot easily plumb the "true" width into the function body to perform a bounds check. Similarly, we cannot easily pre-pad the input because it is typically reading from the (const) input frame, which would require a full memcpy to pad. Either of these solutions are more trouble than the feature is worth, so just disable it on odd input sizes. Fixes: use of uninitialized value Fixes: ticket #11265 Signed-off-by: Niklas Haas Sponsored-by: Sovereign Tech Fund --- libswscale/utils.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libswscale/utils.c b/libswscale/utils.c index 26ea6062a0..32f90e366e 100644 --- a/libswscale/utils.c +++ b/libswscale/utils.c @@ -1535,7 +1535,7 @@ av_cold int ff_sws_init_single_context(SwsContext *sws, SwsFilter *srcFilter, /* drop every other pixel for chroma calculation unless user * wants full chroma */ - if (isAnyRGB(srcFormat) && !(flags & SWS_FULL_CHR_H_INP) && + if (isAnyRGB(srcFormat) && !(srcW & 1) && !(flags & SWS_FULL_CHR_H_INP) && srcFormat != AV_PIX_FMT_RGB8 && srcFormat != AV_PIX_FMT_BGR8 && srcFormat != AV_PIX_FMT_RGB4 && srcFormat != AV_PIX_FMT_BGR4 && srcFormat != AV_PIX_FMT_RGB4_BYTE && srcFormat != AV_PIX_FMT_BGR4_BYTE &&