flv: Workaround for buggy Omnia A/XE encoder

The Omnia A/XE encoder writes the explicit extra data incorrectly
and wrongly disables parametric stereo. Truncating the extra data
by setting the size to 2 works around this. The AAC extra data
parser will then only parse the correct parts.

Bug-id: 599
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  flv: Workaround for buggy Omnia A/XE encoder

Conflicts:
	libavformat/flvdec.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mjpegenc: pass chroma quantization matrix through as well, not just luma

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpegvideo_enc: init chroma matrix for mjpeg

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mjpegenc: use a seperate chroma matrix when luma and chroma differ

drop hardcoded TWOMATRIX code

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>