[x264-devel] x264: Field Handling in chroma channels at 4:2:0

[Sascha Werner]

Dear x264-team,

I very like the image quality of x264, but we often need to encode 
interlaced material and found some problems when using x264 for encoding 
a 1080i50 movie.

The used MBAFF algorithm does a good job for the luma channel, but not 
for the chromas. You will smile now and say: "Of course it doesn't, 
because it can't". I know that x264 "sees" the image as a whole and 
4:2:0 just means half the resolution in chroma channels resulting in 
heavily distorted chroma field informations.

Especially when encoding fast moving colored objects (i. e. a red bike 
passing by) you see that effect: The red bike drives smoothly in 50i - 
only its red color stutters like in a 25p movie.

As far as I know for example the MPEG2 algorithm encodes field 
information (including chroma channels) separately. Is there anything 
comparable for x264?

Thanks a lot and greetings  from germany,
S. Werner.

p. s. For Encoding we use the correct commandlines from 
http://www.x264bluray.com/ an a 4:2:2 Quicktimesource via Avisynth (YUY2 
colors).
-- 
sw-pro Film- und Fernsehproduktion Leipzig
Dipl.-Inf. Sascha Werner
Produktionsleitung