[MPlayer-users] What if different colorspace for codec and display output?

[boku]

Dear all,
    I have some questions about the video output and video filters (vf_vo.c).
1) Can a decoder decode input bit streams in different kinds of color
space format such as YUV420P, IYUV or UYVY422?
Or it only accepts one format such as YUV420? Also, where it can be defined?

2) Say if my specific mpeg decoder will decode YUV420P bit stream and
can only output one format of UYVY422 packed frame data,
how can I write my wrapper, vd_xxx.c in libmpcodecs to let video
output layer or the video filter change to the color space for the
output device?

3) For FFMPEG wrapper into mplayer, vd_ffmpeg.c, I checked out the
match mechanism in ::init() as folows:
	    lavc_codec = (AVCodec *)avcodec_find_decoder_by_name(sh->codec->dll);
it means mplayer uses "dll" field specified in codecs.conf to match
the decoder.
However, I checked the document and it seems "dll" field is not for
this definition or purpose. Am I misunderstanding?
Thank you!

BR,
boku