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.
Unified · Split
| @@ -1535,7 +1535,7 @@ av_cold int ff_sws_init_single_context(SwsContext *sws, SwsFilter *srcFilter, · 1534 unmodified lines | ||
| 1535 | 1535 | |
| 1536 | 1536 | /* drop every other pixel for chroma calculation unless user |
| 1537 | 1537 | * wants full chroma */ |
| 1538 | − if (isAnyRGB(srcFormat) && !(flags & SWS_FULL_CHR_H_INP) && | |
| 1538 | + if (isAnyRGB(srcFormat) && !(srcW & 1) && !(flags & SWS_FULL_CHR_H_INP) && | |
| 1539 | 1539 | srcFormat != AV_PIX_FMT_RGB8 && srcFormat != AV_PIX_FMT_BGR8 && |
| 1540 | 1540 | srcFormat != AV_PIX_FMT_RGB4 && srcFormat != AV_PIX_FMT_BGR4 && |
| 1541 | 1541 | srcFormat != AV_PIX_FMT_RGB4_BYTE && srcFormat != AV_PIX_FMT_BGR4_BYTE && |