fftheora and 4:4:4 chroma subsampling

[Reimar.Doeffinger at gmx.de (Reimar Döffinger)]

On Sun, Jun 06, 2010 at 01:22:23PM +0200, Reimar D?ffinger wrote:
> On Sun, Jun 06, 2010 at 12:51:52PM +0200, Giorgio wrote:
> > I have a file with 4:4:4 chroma subsampling that doesn't decode
> > correctly with -vc fftheora. As you can see from the picture [2] the
> > colored rectangles in the top part of the picture aren't horizontal.
> > It's worth noting that ffplay displays the video perfectly.
> 
> I think ffplay does not support slices.
> It works fine with -noslices, I guess the slice code was not updated
> properly for 4:4:4

This seems to fix it:
Index: libavcodec/vp3.c
===================================================================
--- libavcodec/vp3.c    (revision 23501)
+++ libavcodec/vp3.c    (working copy)
@@ -1329,7 +1329,9 @@
         y = s->height - y - h;
     }
 
-    cy = y >> 1;
+    cy = y;
+    if (s->avctx->pix_fmt == PIX_FMT_YUV420P)
+        cy >>= 1;
     offset[0] = s->current_frame.linesize[0]*y;
     offset[1] = s->current_frame.linesize[1]*cy;
     offset[2] = s->current_frame.linesize[2]*cy;