[FFmpeg-cvslog] sws: move the early return for zero-sized slices higher up

[Anton Khirnov]

ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Fri May 21 12:06:52 2021 +0200| [e1889855983094ca74c494d29b33e482b1bba865] | committer: Anton Khirnov

sws: move the early return for zero-sized slices higher up

Place it right after the input parameter validation. There is no point
in performing any setup if the sws_scale() call won't do anything.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e1889855983094ca74c494d29b33e482b1bba865
---

 libswscale/swscale.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libswscale/swscale.c b/libswscale/swscale.c
index 05544ea9fb..8471f112ac 100644
--- a/libswscale/swscale.c
+++ b/libswscale/swscale.c
@@ -897,6 +897,10 @@ int attribute_align_arg sws_scale(struct SwsContext *c,
         return AVERROR(EINVAL);
     }
 
+    // do not mess up sliceDir if we have a "trailing" 0-size slice
+    if (srcSliceH == 0)
+        return 0;
+
     if (c->gamma_flag && c->cascaded_context[0])
         return scale_gamma(c, srcSlice, srcStride, srcSliceY, srcSliceH, dst, dstStride);
 
@@ -908,10 +912,6 @@ int attribute_align_arg sws_scale(struct SwsContext *c,
     memcpy(srcStride2, srcStride, sizeof(srcStride2));
     memcpy(dstStride2, dstStride, sizeof(dstStride2));
 
-    // do not mess up sliceDir if we have a "trailing" 0-size slice
-    if (srcSliceH == 0)
-        return 0;
-
     if (frame_start) {
         if (srcSliceY != 0 && srcSliceY + srcSliceH != c->srcH) {
             av_log(c, AV_LOG_ERROR, "Slices start in the middle!\n");