[FFmpeg-user] Unexpected additional frames while stream copy

Ulf Zibis Ulf.Zibis at CoSoCo.de
Mon Oct 2 02:39:25 EEST 2023

Am 01.10.23 um 23:25 schrieb Ferdi Scholten:
> On 01-10-2023 19:28, Ulf Zibis wrote:
>> Hi,
>> I have a video, grabbed from screen with "-c:v libx264rgb -crf 0 -preset ultrafast".
>> When I re-encode a small scene out of it, it counts 576 frames. (Same number of images, when I extract all frames as JPEG.)
>> But when I just do a stream copy, I get 761 frames, even when I use "-fps_mode:v passthrough", which should be superfluous.
>> Can one explain this miracle?
> Stream copying can only cut on key-frames as far as I know. That might be your difference?
Thanks, interesting.

But are there so few key frames? The difference is 185 frames.


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