[FFmpeg-cvslog] swscale/unscaled: correctly copy semiplanar formats

[Niklas Haas]

ffmpeg | branch: master | Niklas Haas <git at haasn.dev> | Thu Dec 19 14:41:34 2024 +0100| [77db7f9b87811aa588e6ab6a7256f7cd8267265d] | committer: Niklas Haas

swscale/unscaled: correctly copy semiplanar formats

This fixes multiple bugs with semiplanar formats like NV12. Not only do these
false positive the grayscale format checks (because dst[2] in NULL), but they
also copied an incorrect number of pixels.

Fixes conversions such as nv12 -> nv12, gray8 -> nv12, nv20le -> nv20be, etc.

Fixes: #11239
Signed-off-by: Niklas Haas <git at haasn.dev>
Sponsored-by: Sovereign Tech Fund

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=77db7f9b87811aa588e6ab6a7256f7cd8267265d
---

 libswscale/swscale_unscaled.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libswscale/swscale_unscaled.c b/libswscale/swscale_unscaled.c
index f0fe8304f5..a4d18bf63e 100644
--- a/libswscale/swscale_unscaled.c
+++ b/libswscale/swscale_unscaled.c
@@ -2148,10 +2148,12 @@ static int planarCopyWrapper(SwsInternal *c, const uint8_t *const src[],
         const uint8_t *srcPtr = src[plane];
         uint8_t *dstPtr = dst[plane] + dstStride[plane] * y;
         int shiftonly = plane == 1 || plane == 2 || (!c->opts.src_range && plane == 0);
+        if (plane == 1 && isSemiPlanarYUV(c->opts.dst_format))
+            length *= 2;
 
         // ignore palette for GRAY8
-        if (plane == 1 && !dst[2]) continue;
-        if (!src[plane] || (plane == 1 && !src[2])) {
+        if (plane == 1 && desc_dst->nb_components < 3) continue;
+        if (!src[plane] || (plane == 1 && desc_src->nb_components < 3)) {
             if (is16BPS(c->opts.dst_format) || isNBPS(c->opts.dst_format)) {
                 fillPlane16(dst[plane], dstStride[plane], length, height, y,
                         plane == 3, desc_dst->comp[plane].depth,