Inverse telecine: Frame #20 at 1.23394 is still interlaced

[camjac251]

I am getting that error mentioned in the readme for The reverse telecine command

ffmpeg does a pretty good job of IVTC via the filterchain -vf "fieldmatch,yadif,decimate", but results also depend on the encoding speed, the qualities of the source, etc.
In particular, at high encoding speeds it's reasonably common for some frames not to be successfully deinterlaced.
⤷ In this case, ffmpeg prints a message like [Parsed_fieldmatch_0 @ 0x34d63e0] Frame #20 at 1.23394 is still interlaced.

Is there possibly a way to correct the speed of the encode to allow it to accurately deinterlace all of the frames?

[kfrn]

Hi there! Sorry for the belated response, I was on holiday.

What encoding settings are you using? Assuming you're encoding to H.264, you can change the value of the preset flag to the slowest available, veryslow. e.g.:

ffmpeg -i input.mov \
       -c:v libx264 \
       -vf "fieldmatch,yadif,decimate" \
       -preset veryslow \
       -crf 18 \
       output.mp4

Maybe you already tried it, but if not, let me know if that makes a difference.

[kfrn]

Notes to self - things to look at:

• fieldmatch docs
• mailing list discussion on fieldmatch, decimate and framerate
• source code

[camjac251]

I am trying a different source now and it seems to not give the error anymore, but I do get audio that is out of sync with the video for some reason. I haven't been able to figure out how to fix it.

[kfrn]

Ah - I don't think I've encountered that myself, but I can imagine how sync issues could occur. How out of sync is your output file?