id	summary	reporter	owner	description	type	status	priority	component	version	resolution	keywords	cc	blockedby	blocking	reproduced	analyzed
694	Speed-up/Slow-down a video	burek		"The problem: Video is recorded at 10 fps, but always plays at 30 fps (erroneously encoded somehow). How to correct such a video to play with the correct speed?

I'm not sure if there is an easy way to do this, but afaik there is no simple way to do this, because FFmpeg does not do any kind of buffering of frames it reads from the input, it just drops/duplicates the frames.

We had few people on irc channel, trying to fix their videos, using FFmpeg, that's why I'm posting this. We resolved this issue by writting raw video to a tmp file (to loose the timestamps) and then we read the tmp file with a slower frame rate, like this:

> ffmpeg -i input.264 -f rawvideo -r 30 tmpfile
> ffmpeg -s 1280x720 -r 10 -f rawvideo -i tmpfile output.mp4

The video in input.264 would play nice at 10 fps, but somehow timestamps are saved just like it's 30 fps video, so it was always played back too fast.

The suggestion is to create an enhancement to rearrange timestamps on the fly, to avoid the need for the tmp file, to be able to speed up/slow down a video stream (also if possible even without re-encoding it)."	enhancement	closed	wish	undetermined	unspecified	fixed					0	1