Dash Cam video is 'jerky'

[Gourockian]

Hi,

I'm having an issue with playback of mp4 videos from the dashcam in my wife's car.  Using Avidemux 2.8.1, they play in 1 second bursts, giving a very jerky result.  However, they play perfectly smoothly using VLC Media Player. 

I've attached a copy of the Avidemux settings and the file properties of one of the videos which I need to edit for insurance purposes.

I'm not sure if it has anything to do with the H265 setting as videos from my other dash camera are set to H264 and play okay in Avidemux.

Can anyone suggest how I can get the videos to play smoothly?

Regards,

Al

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[eumagga0x2a]

Please provide a sample via WeTransfer (no email address required despite the website trying to suggest the opposite!), Mega, Dropbox or Google Drive (link share only, please).

[Gourockian]

Here's a link to a short video which I hope will indicate what's happening:

https://we.tl/t-8gXzRIr8ts

[eumagga0x2a]

Thank you for the sample, the issue should be fixed by commit [demuxers/Mp4] Do not fail on empty frames.

In this video each keyframe is followed by a zero-sized frame with almost zero duration, highly dubious. We were still trying to read from the file expecting a non-zero outcome, got nothing, considered this a failure and skipped to the next keyframe where the game started over.

Additionally, we missed the opportunity to decode the video in hardware because the code didn't accept an alias for yuv420 indicating full range color. This is now fixed for VDPAU (this is an older interface used by NVIDIA on Linux with their closed-source driver). I'll check other hw decoders later.

[Gourockian]

Thanks for taking the time to look at the sample.  However, I must confess that your explanation went right over my head, so to speak, as I'm not at all experienced in video editing (you probably can tell).

I only need to be able to edit a section of a video to show the relevant footage of a minor accident in which my wife was involved.  I've been able to do this before, using Avidemux but didn't have this issue regarding the frames.

I appreciate you planning to look at other hw decoders later and hope you will be able to suggest a fix for me.

Regards,

Al   

[eumagga0x2a]

The quintessence of my post was that future Avidemux nightlies will be able to handle the (presumably broken) videos produced by this dash cam. Regarding hw accelerated decoding, it is not critical for the task, and it looks like VDPAU was the only one needing a fix.

Of course, if you wish, you can compile Avidemux for Windows from source anytime, else you will have to wait until an official build is generated and uploaded to the server.

[Gourockian]

Thanks again for your reply suggesting that future nightlies will help with this issue. 

I'm not in the least doubting your expertise with Avidemux but I don't quite understand why, if the videos are "presumably broken", they play perfectly well using VLC media Player.

I've also since downloaded another 'free' video editor and again have no problem with their playback. Unfortunately, it does not allow exporting the edited file without leaving a watermark so I'm happy in the meantime to wait for the latest Avidemux upload.

I appreciate your work with this great program.

Regards,

Al

[eumagga0x2a]

Please try the latest nightly (r220605 or more recent) from https://avidemux.org/nightly/win64/