lavu: make sure av_pix_fmt_desc_next returns a valid pix fmt.

This is required because there are some "holes" in the list for
compatibility with the fork.

The commit also removes the now unecessary check from cmdutils.

Found-by: wm4

1 files changed, 5 insertions, 2 deletions

diff --git a/libavutil/pixdesc.c b/libavutil/pixdesc.c
index 1f2aa58a42..362edfa07f 100644
--- a/libavutil/pixdesc.c
+++ b/libavutil/pixdesc.c
@@ -1757,8 +1757,11 @@ const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)
 {
     if (!prev)
         return &av_pix_fmt_descriptors[0];
-    if (prev - av_pix_fmt_descriptors < FF_ARRAY_ELEMS(av_pix_fmt_descriptors) - 1)
-        return prev + 1;
+    while (prev - av_pix_fmt_descriptors < FF_ARRAY_ELEMS(av_pix_fmt_descriptors) - 1) {
+        prev++;
+        if (prev->name)
+            return prev;
+    }
     return NULL;
 }