[FFmpeg-user] Generating v210 uncompressed AVIs from v210 individual files in 720p and 1080i formats

[Mark Himsley]

On 05/09/11 10:38, Thomas Worth wrote:
>> Looking at the source, the mp tinterlace filter accepts these mplayer
>> formats only: IMGFMT_YV12, IMGFMT_IYUV, IMGFMT_I420.
>>
>> And in the shim between FFmpeg and mplayer filter all three equate to
>> FFmpeg's YUV420P.
>>
>> Therefore the FFmpeg filter chain has done the conversion to the only
>> available format in the tinterlace filter.
>>
>> Stefano's new tinterlace filter will do all these - so, not the 10 bit
>> you're after, but better than 420.
>>
>>   PIX_FMT_YUV420P,  PIX_FMT_YUV422P,  PIX_FMT_YUV444P,
>>   PIX_FMT_YUV444P,  PIX_FMT_YUV410P,  PIX_FMT_YUVA420P,
>>   PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ444P,
>>   PIX_FMT_YUVJ440P, PIX_FMT_GRAY8
>
> Since v210 is still 4:2:2, is it possible that the filter will just
> reduce precision to 8 bit? Or does it fail completely since it can't
> match the pixel format exactly?

Yes. FFmpeg's filter chain logic adds format conversion when it's needed 
- although I haven't looked into how it chooses the best quality format 
to convert to. Maybe Stefano could describe that?

Personally I would format the filter line to force the conversion to the 
format I want, using a scale filter followed by a format filter (format 
conversion is done in the scale filter). I add the scale filter myself, 
instead of letting the filter chain add a scale filter for me because, 
by default, non-interlaced aware scale filters are added, which *can* 
wreck the chroma of format conversions.

-- 
Mark