Video playback choppy and stuttering in QuickTime, VLC

[DebD]

I have lots of videos from a Samsung camcorder in .mov that playback choppy and stuttering. I have tried converting to MP4 with same problem.
I don't know what the problem is so don't know how to fit them. Please use layman language in your response. My video knowledge is basic.

[jagabo]

Is this a laptop? An older laptop may have problems playing 4K video, for example. Can you upload a short sample? At least a MediaInfo report?

[DebD]

Cheers jagabo. It is an 18mth old MacBook Pro so not too old. MediaInfo report attached and a short movie example.

[poisondeathray]

Do the original files play the same way ?

Post the mediainfo report for one of the original files

[jagabo]

There's definitely a lot of frames out of sequence. An sample of the original (not reencoded) would be best.

[DebD]

Yes @poisondeathray, the originals play in the same way.

The movie files are saved on a cloud service, Amazon Drive, and automatically convert when I download them. The original is a .mov and you should be able to view it from the link below.

Take a look at the photos I shared from Amazon Photos: https://www.amazon.com.au/photos/share/YFmSGPzIbjm34VSwBF7IcloaejbwtOIcNKeLamgyQj3

[jagabo]

There's a download link on that page that gives a 42 MB mov file encoded with Apple Intermediate Codec. That's different than the "Converted" video which is encoded with Prores. But the sequence of the frames is exactly the same. I was able to analyze the clip and found that one frame out of every 6 was out of sequence. Unfortunately, the cadence changes several times. But here's an AviSynth script that puts them in the correct order:

src = LSmashVideoSource("C:\Users\John\Downloads\clip-2016-05-01 13;41;22.mov")

p1 = src.Trim(0,1)
p2 = src.Trim(2, 117).SelectEvery(6, 1,2,3,4,5,0).Trim(0,115)
p3 = src.Trim(118, 233).SelectEvery(6, 1,2,3,4,5,0).Trim(0,114)
p4 = src.Trim(234,349).SelectEvery(6, 1,2,3,4,5,0).Trim(0,116)
p5 = src.Trim(350,0).SelectEvery(6, 1,2,3,4,5,0).Trim(0,30)

p1++p2++p3++p4++p5

LSmashAudioSource() didn't work right for the audio so I muxed the original audio along with the new video.

[poisondeathray]

The movie files are saved on a cloud service, Amazon Drive, and automatically convert when I download them.

Do you have the original videos from the camcorder? No Samsung camcorder records in AIC or Prores

Or what files were saved to Amazon Drive? Can you download the originals, or only the converted versions ?

[jagabo]

Oh, there's another solution: discard all the odd numbered frames.

LSmashVideoSource("C:\Users\John\Downloads\clip-2016-05-01 13;41;22.mov")
SelectOdd()

That gives a 25 fps video. The original video is 50 fps but every frame has a duplicate. So you don't really lose anything by discarding half of them.

[DebD]

Thank you jagabo. It makes me really happy to know there is a solution. I have 236 movies like this. Can I use that AviSynth script and apply it to all of them at once? Or apply the second solution of deleting the odd numbered frames all at once, or will I have to go into each one and edit it? I haven't edited before. Which software is best to analyse them - and compatible to MacOS?

[DebD]

The movie files are saved on a cloud service, Amazon Drive, and automatically convert when I download them.

Do you have the original videos from the camcorder? No Samsung camcorder records in AIC or Prores

Or what files were saved to Amazon Drive? Can you download the originals, or only the converted versions ?

I think the files on Amazon Drive are the original .mov files. I don't know what AIC or Prores is? The files were downloaded to our Mac, saved to an external hard drive and to Amazon Drive. I've checked the hard drive and they are the same .mov.

[poisondeathray]

I think the files on Amazon Drive are the original .mov files. I don't know what AIC or Prores is? The files were downloaded to our Mac, saved to an external hard drive and to Amazon Drive. I've checked the hard drive and they are the same .mov.

AIC (Apple Intermediate Codec) and Prores are video formats and types of compression. Consumer level cameras typically do not record directly to those formats

When you have a camcorder, most Mac software like imovie does not ingest things like AVCHD natively; they convert to one of those intermediate formats for editing

So it's unlikely that the original camera files were like that - and it's probably an issue with the conversion somewhere

Also notice the resolution is 960x540 , again, unlikely that the camera recorded like that




To drop half the frames, one way is to use ffmpeg . It's command line driven and you would need to open a terminal . But that would make it possible to batch convert them . I don't know the syntax for ffmpeg batching on a mac.

I'm not sure if selur's hybrid can do it, it might be able to and runs crossplatform including osx
https://www.videohelp.com/software/Hybrid

This is what the ffmpeg command would look like for 1 file

ffmpeg -i "clip-2016-05-01 13;41;22 (Converted).mov" -map 0:0 -map 0:1 -map 0:2 -vf "select='mod(n, 2)',fps=25,format=yuv420p" -c:v libx264 -crf 20 -c:a copy output.mov

[jagabo]

I'm not sure keeping only odd frames will work for all the videos though. Some might need to keep only even frames. Some might require an adaptive algorithm. Poisondeathray's ffmpeg command line modified to keep even frames:

ffmpeg -i "clip-2016-05-01 13;41;22 (Converted).mov" -map 0:0 -map 0:1 -map 0:2 -vf "select='mod(n, 2)-1',fps=25,format=yuv420p" -c:v libx264 -crf 20 -c:a copy output.mov

[DebD]

Thank you. Taking a step back - how do I view my videos frame by frame to work out which frames are out of sync or the odds (or evens) are duplicate frames. I have tried looking on iMovie and can move frame by frame with an arrow key but I can’t see any info associated with each frame so can’t tell which is in the wrong order.

[poisondeathray]

Thank you. Taking a step back - how do I view my videos frame by frame to work out which frames are out of sync or the odds (or evens) are duplicate frames. I have tried looking on iMovie and can move frame by frame with an arrow key but I can’t see any info associated with each frame so can’t tell which is in the wrong order.

The old Quicktime Player 7 can display frame number, just click on the left bottom corner where the time is displayed and select "frame number"

https://support.apple.com/kb/DL923

[DebD]

I have QuickTime player 10.4 and can’t see the frame number or time of each frame. Does this version offer frame information?

[poisondeathray]

The old version 7 does - you can toggle the frame number display or time display;

I have the Windows version of QT player 7 and it does too

[poisondeathray]

Another way you can preview is to use ffplay to preview using one version of the filter.

ffplay -i "clip-2016-05-01 13;41;22 (Converted).mov" -vf "select='mod(n, 2)',fps=25,format=yuv420p"

or

ffplay -i "clip-2016-05-01 13;41;22 (Converted).mov" -vf "select='mod(n, 2)-1',fps=25,format=yuv420p"

But - if both are jerky with simple even or odd selection sets - then you probably have other problems with that video and would need to try other methods



There should be a way to make a droplet for ffplay or ffmpeg scripts for easier use, but I mainly use windows, not sure how to do it