[MEncoder-users] order in filter chain for eq2 and scale

[Christian Ebert]

* RC on Monday, March 30, 2009 at 19:59:25 -0700
> On Mon, 30 Mar 2009 10:41:14 +0200
> Christian Ebert <blacktrash at gmx.net> wrote:
>> What's the canonical order of the eq2 and scale filters?
>> 
>> So far I do eq2=<params>,scale. Is this correct or should it be
>> the other way round?
> 
> The answer is VERY complex, as scale does the colorspace conversion.
> 
> eq2 works with the following formats:
> 
>    YVU9:
>    IF09:
>    YV12:
>    I420:
>    IYUV:
>    Y800:
>    Y8:
>    444P:
>    422P:
>    411P:

I must admit I am confused by them ;-)

> If the decoder you're using isn't able to output one of those, the scale
> filter IS going to be inserted before it, automatically by mplayer if
> you don't do so yourself.  

An example of mencoder output:

Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
Opening video filter: [harddup]
Opening video filter: [scale]
Opening video filter: [eq2=0.9:1.01:-0.01:1.03::0.7]
Opening video filter: [softskip]
Opening video filter: [framestep=2]
Opening video filter: [mcdeint=1:1:10]
Opening video filter: [yadif=3]
==========================================================================
Trying to force video codec driver family ffmpeg...
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Unsupported PixelFormat -1
Selected video codec: [ffdv] vfm: ffmpeg (FFmpeg DV)
==========================================================================
VDec: vo config request - 720 x 576 (preferred colorspace: Planar YV12)
VDec: using Planar YV12 as output csp (no 2)
Movie-Aspect is 1.37:1 - prescaling to correct movie aspect.
[swscaler @ 0x3c77000]using unscaled yuv420p -> yuv420p special converter

Does this look ok?

I also wonder why yuv420p or 420P or something is not mentioned
as format anywhere (I looked).

> If the encoder, or VO method you are using is also NOT able to use one
> of those, then you ALSO need to have scale AFTER the filter(s) that need
> the different color space.
> 
> This results in convoluted and seemingly nonsensical filter chains like:
> 
>  -vf format=yv12,scale,eq2,scale,format=bgr15

I wonder whether I could use something along those lines to avoid
the bleached colors when deinterlacing from interlaced dvvideo to
progressive.

c
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