[FFmpeg-user] Syncing stereo videos - what method?

[Jesper Taxbøl]

Hi Guys,

I am trying to sync two videos recorded simultaniously from a stereo setup.

I am extracting their audio (mono) and find their offset, which I can
easily find in Audacity. With the offset in hand I cut off the start of
 the earliest video, so they start at the same time. I use the -ss flag for
this.

 ffmpeg -ss 0.75 -i A.mp4 -acodec copy -vcodec copy cut_A.mp4


Hereafter I assemble them side by side into one video using a complex
filter.

I am however having trouble with their syncronization in the end product.

I am therefore wondering if the -ss flag is the right way to do this or if
I can achieve syncronization between the videos a different way?

I suspect the -ss method is affected by where there are keyframes in the
video as I constantly get it wrong more than a second.

All ideas are welcome.

Kind regards

Jesper