LiveTV deinterlacing behavior with possible format changes mid-stream

[spatula]

Digging into this a little bit more, I noticed from the logs that despite having deinterlacing configured in the transcode interface, no filters are actually selected to perform deinterlacing in the ffmpeg command that gets generated for streaming either live TV content or recorded TV content. This holds true whether hardware acceleration is enabled or not. The -vf argument just looks like this:

-vf "setparams=color_primaries=bt709:color_trc=bt709:colorspace=bt709,bwdif=10,scale=trunc(min(max(iw\,ih*a)\,min(704\,480*a))/2)*2:trunc(min(max(iw/a\,ih)\,min(704/a\,480))/2)*2,format=yuv420p"

(in this case the content I was streaming was 480i, but 1080i is similar)