avcodec: add LSCR decoder

Fixes #4711.

libavcodec/codec_desc.c

@@ -1712,6 +1712,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("Amuse Graphics Movie"),
         .props     = AV_CODEC_PROP_LOSSY,
     },
+    {
+        .id        = AV_CODEC_ID_LSCR,
+        .type      = AVMEDIA_TYPE_VIDEO,
+        .name      = "lscr",
+        .long_name = NULL_IF_CONFIG_SMALL("LEAD Screen Capture"),
+        .props     = AV_CODEC_PROP_LOSSY,
+    },
 
     /* various PCM "codecs" */
     {