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Newly added Tracks not trimmed with video

Started by grayscale, December 31, 2021, 12:35:57 AM

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grayscale

When adding an additional audio track to a video (first thing), and then cutting the video, the new audio track(s) are left as-is instead of being cut identical to the video.
So when adding (back) the (externally denoised) audio and cutting off the first few seconds (and probably parts in the middle) of a recording the audio and video are no longer in sync.

This can be easily seen when keeping the native audio track and then importing the resulting video-file into Audacity.


Workaround is to add the audio, A/V stream copy to new file, then cut the newly generated file.


It does not matter if it's set to A/V stream copy (cutting on keyframes), audio re-encode or full A/V re-encode. The Track ID does not matter either, only the native track is cut.

So maybe this is working as intended after all, and just an uncommon usecase on my side? (current behavior would be correct for adding background music)

Tested versions:
* 2.6.8
* 2.8.0
* 2.8.0 nightly (30 Dec 21)



Windows 10 x64
MKV Muxer output

eumagga0x2a

Quote from: grayscale on December 31, 2021, 12:35:57 AMWorkaround is to add the audio, A/V stream copy to new file, then cut the newly generated file.

Yes, this is how external audio tracks are supposed to be handled. External tracks are not segmented like internal ones.

Imagine deleting an inner part of a video, then adding an external audio track, then undoing the deletion. What should happen then? A hole in the audio stream? The duration of an external audio track can also be much shorter than the duration of the video while seek accuracy can be worse compared to streams packaged in a container. There are multiple possible difficulties which IMHO justify the limitation imposed onto external audio tracks by the creators of Avidemux.