Change duration of a video

[BobMoor]

I downloaded an older movie and it seems to have been shortened / it's speed has changed ??!!.
As said it looks as if the speed has been changed as everything looks a bit faster.
Normal duration of the movie is almost 1 hour, now it is somewhere around 52 minutes
There are no cuttings in it as far as I notice.

Is there a way to change the speed back to normal (calculation and try and error).
I calculated that it needs played to be about 15% slower.

If this can be done, which video program can I use.

Thanks, Bob

[ProWo]

Post a mediainfo of this movie here

[BobMoor]

Thanks for the tip about Mediainfo, because the one I had was very old.
That one was from 2018.

Is this what you mean (see below)?
But it is another movie with the same problem.
The movie is much shorter in time as was told to me and slowing down using VLC gives a much better view.
As I want to make subtitles with Subtitle Edit, the time/length must be ok.

The one I mentioned appeared to have corrupted data in it, but both have the same strange problem.
Maybe because the upload to Youtube was to big.
The actual movie I heard is almost 2 hours

Algemeen
Complete name : C:\Users\Bob\Documents\YouTubeDownloads\Testritten .avi
Format : AVI
Format/Info : Audio Video Interleave
Format profile : OpenDML
File size : 2,30 GiB
Duration : 1 h 22 min
Overall bit rate mode : Variabel
Overall bit rate : 3 973 kb/s
Writing application : Lavf57.66.101

Video
ID : 0
Format : MPEG-4 Visual
Format profile : Simple@L1
Format settings, BVOP : Nee
Format settings, QPel : Nee
Format settings, GMC : Geen warppoints
Format settings, Matrix : Default (H.263)
Codec ID : FMP4
Duration : 1 h 22 min
Bit rate : 3 776 kb/s
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate : 30,000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressief
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.137
Stream size : 2,19 GiB (95%)
Writing library : Lavc57.75.100

Audio
ID : 1
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Format settings : Joint stereo / MS Stereo
Codec ID : 55
Codec ID/Hint : MP3
Duration : 1 h 22 min
Bit rate mode : Variabel
Bit rate : 184 kb/s
Channel(s) : 2 kanalen
Sampling rate : 44,1 kHz
Compression mode : Lossy
Stream size : 109 MiB (5%)
Alignment : Uitgelijnd op interleaves
Interleave, duration : 26 ms (0,78 videoframes)

[davexnet]

Provide a Youtube link to one of these sped up movies

[aedipuss]

lol. there's no way any movie was just "sped" up and lost over 30 minutes of a 2 hour show.

[BobMoor]

Ok, I got it.
Just forget it
I will try to contact the uploader and ask what has been done.
Thanks for giving advise and trying to help.

[Alwyn]

The question I'd ask is if the audio sounds sped-up as well. If the sound isn't sped up, then you have a problem. If it is sped up, the file could be slowed down.

Some video editing apps can slow down or speed up video.

[abolibibelot]

A question is : if the source is YouTube, why did you re-compress it straight away to AVI / FMP4 (whatever that is) instead of downloading the streams as-is, to MP4 or WEBM container ? How did you download these videos ? YouTube compression is already very agressive, so if you add another compression it can not look pretty, especially if it's an old movie with film artifacts and whatnot... If you manage to get in touch with the uploader (but these days don't touch too much or your lungs could turn into mush !), try to ask a copy of the source file, before it got uploaded to YouTube. (Problem is, it would seem like it's no longer possible to exchange private messages on YT, apparently those progressive fascists at Google headquarters deemed this feature expendable.) Or perhaps the source file can be locateds somewhere else.

As for the duration discrepancy : is it also present when watching both videos from YouTube, or only on the downloaded (and re-compressed) videos ? If they're fine on YT, then something went wrong during at the (unnecessary) re-compression step.

[BobMoor]

Yes Alwyn, the whole movie including the sound has been sped-up.
One hardly notices but you can notice it.
The time difference is not as much as I expected, so not half an hour, but that is not important.

Not a real big problem, but I see it as a challenge to fix it.
Also because I want to learn to work better with video and so before I start working with my own family recordings.
And I want to start again with making subtitles to have my English speaking family to understand what we say and to have our (grand)children understand what the English speaking part of my family says.
If you are retired you want to have something to do.
And now in corona time.... even more.

[BobMoor]

As for the last question.
Yes also the movie on Youtube appears to be shorter than the movie.
I hope to get the original movie via another way to see if I can find what has been done, but that is not certain.
The guy likes to tease me sometimes, so I never know.
If so I will tell it here.

[ProWo]

For the beginning you could try

ffmpeg -r 25 -i "full path\yourmovie.avi" -c:v libx264 -crf 21 -preset veryfast - na "output.mkv"

This should slowdown your movie from 30fps to 25fps.
The movie duration will be longer, no audio.
See also
https://trac.ffmpeg.org/wiki/How%20to%20speed%20up%20/%20slow%20down%20a%20video