Slow down a video 10 times

[Maukr]

Hi.

I have a few 240fps videos that I want to slow down to 24fps. Virtualdub doesn't open these mp4 files. I've tried Avidemux but it only goes up to 200fps, and I can't seem to slow it down, maybe it's just me doing it the wrong way.
I also have Freemake Video Converter but I haven't found a way to slow it down there.

Do you think Avidemux can do it? Or should I try something else?

Thank you in advance!

[poisondeathray]

you can do it with vdub

vdub can open mp4 files with the proper import plugins and x264vfw if you have h.264 video

[jagabo]

Try remuxing and marking the video track as 24 fps. That way there will be no loss of quality. The audio will be out of sync though.

[Maukr]

Try remuxing and marking the video track as 24 fps. That way there will be no loss of quality. The audio will be out of sync though.

What do I use to remux? Thanks

you can do it with vdub

vdub can open mp4 files with the proper import plugins and x264vfw if you have h.264 video

Thanks I might try that again, I was trying to do this a while back but I couldn't find the right plugins to import these specific mp4 files.

[theewizard]

where did these videos come from ?

i had/still-have an LG phone that will record at 120 Fps

but the files automatically play back at 30fps, its for high speed capture -slow mode play

never had to 'reduce speed' on them, even when i moved them to the PC

[Maukr]

They come from a GoPro camera. When playing them on my pc using VLC I can slow them down and watch them in slow motion but when I transfer them to my phone for example they are played at normal speed. So that's why I want to slow them down.

[jagabo]

What do I use to remux?

MP4Muxer or YAMB.

[poisondeathray]

You can use mymp4boxgui to demux and remux and set the fps as jagabo suggested. It works for gopro hero3 240fps videos for pc playback, but I don't know if it will work ok for your phone or other devices. It's worth a shot since it's a lot faster than re-encoding, and no quality loss

[Selur]

btw. does someone know a place where to download non-edited 240fps material of the gopro hero3? (I googled a bit but stumbled only over reencoded material)

[poisondeathray]

btw. does someone know a place where to download non-edited 240fps material of the gopro hero3? (I googled a bit but stumbled only over reencoded material)

https://www.dropbox.com/sh/82pbbc9zsjnbu1q/NCoAXX-B8j?lst

[Selur]

Nice! Thanks

[jagabo]

Thanks from here too. I keep a collection of odds-and-ends videos so I downloaded the 240 fps video. Remuxing with the frame rate marked as 24 fps slowed the video down as expected. Remuxing to MKV worked as well.