avcodec: add ClearVideo decoder

Only I-frames are decoded for now.

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavcodec/codec_desc.c

@@ -1367,6 +1367,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("ScreenPressor"),
         .props     = AV_CODEC_PROP_LOSSLESS | AV_CODEC_PROP_LOSSY,
     },
+    {
+        .id        = AV_CODEC_ID_CLEARVIDEO,
+        .type      = AVMEDIA_TYPE_VIDEO,
+        .name      = "clearvideo",
+        .long_name = NULL_IF_CONFIG_SMALL("Iterated Systems ClearVideo"),
+        .props     = AV_CODEC_PROP_LOSSY,
+    },
 
     /* image codecs */
     {