[MEncoder-users] MEncoder outputs "could not find matching colorspace"

[Cristian Manea]

When I start to encode a DVD title to H.264 using MEncoder SVN-r33953 and
x264 (on Debian Testing, from Debian Multimedia repository), MEncoder
outputs the following:

Could not find matching colorspace - retrying with -vf scale...
> Opening video filter: [scale]
> The selected video_out device is incompatible with this codec.
> Try appending the scale filter to your filter list,
> e.g. -vf spp,scale instead of -vf spp.
>

but it continues to encode without any problem and the encoded stream seems
properly encoded.

These are the parameters I use in MEncoder:

mencoder vobfile.vob -vf crop=704:464:12:8,yadif,hqdn3d -nosound -ovc x264
> -x264encopts
> crf=18.0:preset=slower:tune=film:profile=high:level_idc=30:threads=auto -of
> rawvideo -o encodedstream.264
>


But even if I append the scale filter to the above parameters, like MEncoder
tells me:

mencoder vobfile.vob -vf crop=704:464:12:8,yadif,hqdn3d,scale -nosound -ovc
> x264 -x264encopts
> crf=18.0:preset=slower:tune=film:profile=high:level_idc=30:threads=auto -of
> rawvideo -o encodedstream.264
>

then MEncoder still outputs the same message as it does when I don't append
the scale filter to the filter list:

Could not find matching colorspace - retrying with -vf scale...
> Opening video filter: [scale]
> The selected video_out device is incompatible with this codec.
> Try appending the scale filter to your filter list,
> e.g. -vf spp,scale instead of -vf spp.
>

In MPlayer manual it says that the scale filter "Scales the image with the
software scaler (slow) and performs a YUV<->RGB colorspace conversion". From
this, I understand that it converts the source frames to RBG before sending
them to x264, but I don't know if this conversion is necessary, therefore, I
don't know if the scale filter is needed, but even if I add it, mencoder
tells me to add it.