[FFmpeg-user] Set MPEG-2 interlace flag without re-encoding

[Nicolas Gaullier]

>Envoyé : vendredi 6 mai 2022 20:20
>À : ffmpeg-user at ffmpeg.org
>Objet : [FFmpeg-user] Set MPEG-2 interlace flag without re-encoding
>
>I have an MPEG-2 video which is progressive but marked as interlaced, so video players try to deinterlace it and ruin the quality. Is there a way to fix the interlace flag without re-encoding the video and causing quality loss?
>
>Thanks,
>Alex

In a general manner, I would say no.
In case your content is exclusively frame-encoded, you might try to set the progressive_frame flag (currently, there is no bsf filter for that in ffmpeg) and hope your player take it into account: this is not absolutely impossible but far from obvious.
Note that if you reencode, you might consider processing the chroma in between (convert to 4:2:2 back and forth) since the vertical sampling filtering is affected.

Nicolas