[FFmpeg-user] h264 looks bad in Flash Player

[wtfux]

Hey!
I got a problem with x264 and Flash Player. I need to convert video
clips for embedding (progressive download) using Flash Player. It
works fine but Flash shows the video in a quite bad quality (wrong
colors and pixelated). The same file played back with VLC looks much
better.
I searched for known problems with Flash Player but didn't find any.
Is there a way to increase the quality in Flash Player?
I tried different players, VideoJS and jwplayer -> same result except
on Chrome where VideoJS uses HTML5 embedding (the video looks right).
I also tried using different x264 profiles/levels but everything from
baseline3.1 to high4.1 got the same problems.
ReFrames is quite high (due to the video being a 2d animation), but
setting refs=3 doesn't solve this either.

Example image: http://i.imgur.com/IRJdu.png (top: flash player (latest
version), bottom: VLC 2.0)

Command: ffmpeg -i file.mp4 -codec:a libfaac -b:a 150k -codec:v
libx264 -preset slow -profile:v high -tune:v animation -level:v 4.1
-refs:v 9 -crf:v 21 -threads 8 -f mp4 ~/test.mp4
MediaInfo: http://pastebin.com/rRxtrQ5z

Anyone got an idea? Thanks!