difficult syncing videos, add hotkey to increment right frame only

[Zero834]

in order to sync videos which are offset slightly requires a ton of trial and error using the -t flag. first guessing a value, then observing the offset then closing the program, trying another value then closing the program, etc.

propose adding a feature where a hotkey will increment or decrement the right frame only.

[jonfryd]

This is the formal feature request for what we discussed in #12, I guess. I'm open to PRs.

[Shuunen]

As I mentioned in #12 I'm not a C++ developer so I'm willing to pay someone to dev this feature

maybe we could use a bounty like https://app.bountysource.com/issues/110752435-difficult-syncing-videos-add-hotkey-to-increment-right-frame-only or another platform like issue hunt

[jonfryd]

Hi @Zero834 and @Shuunen,

So I have implemented key bindings for fine-tuning the right video's time shift today by pressing + and - (1 frame for every keystroke).

Let me know if it works OK.

[Shuunen]

Hi @jonfryd

I tried these 2 sample files, at first I can seek with the mouse, but then when I press +/- I got an error displaying that it can't timeshift, and I cannot seek anymore

https://user-images.githubusercontent.com/439158/190002006-d49b3eb9-fbdb-4736-ba68-890974a57402.mp4 numbered-medium-crf24-grain.mkv.log

I had to add the .log extension to the 2nd file to be able to upload it here

PS : first video file found here : https://forum.videohelp.com/threads/391581-Looking-for-Test-MP4-File-With-Numbered-Frames second file : a conversion I did of the first file to a x265 mkv using ffmpeg

[jonfryd]

OK, thanks for providing sample files and a description of how to reproduce the issue. It makes debugging a lot simpler for me!

So it seems there is a particular challenge with one of the files (AVFrame's coded picture number remains zero) which causes my frame delta determination logic to fail.

I'll look into a robust solution later today and give you an update.

[jonfryd]

@Shuunen,

I have addressed the issue and published a new release just now (20220914).

BTW, please note that your mkv video file only contains a single keyframe at time 00:00.00 which means seeking past the beginning won't work. Time-shifting still works fine, though.

Cheers!