[FFmpeg-user] How to dynamically drop frames as required to keep transcoding real time?

Mark Filipak (ffmpeg) markfilipak at bog.us
Thu Apr 8 05:54:21 EEST 2021

On 2021-04-07 22:33, Adrian Cable wrote:
> Mark – yes – you’re understanding exactly right! I was thinking specifically of the encoder ‘throttle’ being a frame rate control, but other forms of quality control that could be self-adjusted by the encoder to keep up with the input would also work for me.
> I did look through the history here but couldn’t find anything quite applicable. I do appreciate you taking the time to understand my issue! Hopefully someone who has direct experience of how to achieve this will read this as a result and be able to help.

Then you should restart this topic with a subject line that doesn't say "drop frames".

This is dropping frames, and it's exactly what the 'fps' filter does.
[A]  [B]  [C]  [D] [E] [F] [G] [H] [I] [J] ...input
[A]  [B]  [C]  [D]  [E]  [F]  [G]  [I]  [H] ...output CFR ([H] dropped)

This is repeating frames, and it's also exactly what the 'fps' filter does.
[A]  [B]  [C]  [D]   [E]   [F]  [G]  [H]  [I] ...input
[A]  [B]  [C]  [D]  [D]  [E]  [F]  [G]  [H] ...output CFR ([D] repeated)

CFR: constant frame rate.

Of course, the pictures will judder when frames are either dropped or repeated.

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