Audio drift when using the Voukoder encoder in Vegas Pro

Zitat von Hannibal_Lecter

In my view the audio rendered in voukoder is 1 frame AFTER the original audio, just see that the peak of the audio signal is on the right, when compared to the original audio. This happens in mine and in your screenshot.

Sure. But previously you said 'ahead', not 'after'. I said 'behind' == 'after'.

Yes, I also have the new so4 decoder disabled in internal preferences as it does not work correctly with my AC3 5.1 audio streams.

I'm confirming that when the so4 option is in default value (TRUE), the audio in mp4 file rendered with voukoder connector 0.7.1 is in sync with original audio.

When the option is in non-default value (FALSE), the audio in rendered mp4 file is 1 frame behind.

You do not need to re-render, just change the option, restart VP, put original an rendered on timeline & compare.

I've experimented a bit and tried to fix the offset in mp4 rendered with connector 0.5.1 using itsoffset ffmpeg option:

ffmpeg.exe -i voukoder.mp4 -itsoffset 0.044 -i voukoder.mp4 -map 0:0 -map 1:1 -acodec copy -vcodec copy synced.mp4

ffprobe synced.mp4:

start_pts=1056
start_time=0.022000

However, the synced.mp4 file behaves in VP exactly like file rendered using connector 0.7.1: if so4 disabled (default in up to VP14) -- the audio stream shifted one frame behind comparing to when so4 is enabled (default in VP15+).

So looks like the VP's decoders decode audio streams differently depend on the start_time stream information.

I suspect that Happy Otter Scripts is also affected.

As a result, you cannot actually fix this using the offset and the only way to fix it properly for VP is to add silence at the beginning or trim audio.

In any case, current implementation looks better as audio shift is smaller.

If I'm understanding correctly, Vegas 17 works fine with Voukoder as is if so4 is enabled (default), but not if it is disabled. If that's the case, can Voukoder have a checkbox in the rendering window- if you manually disabled it, check the box and it can then apply a fix?

Did you report this issue to the Vegas programming team fifonik? I hope we can get it resolved in 18.

I'm confused- so if a video is exported with Voukoder than it works perfectly in MPC or other players. However upon bringing it back into Vegas Pro, the decoders (so4 and non-so4?) make it appear to be out of sync?

Thanks for clarifying (and for fixing it!) Vegas works in mysterious ways.

Dumb question- do some types of footage not use SO4 even in Vegas 15+?

Zitat von rsmith02

Thanks for clarifying (and for fixing it!) Vegas works in mysterious ways.

Dumb question- do some types of footage not use SO4 even in Vegas 15+?

So4 only decodes AVC media. I've never seen any AVC get decoded by compoundplug.dll if so4compoundplug.dll is enabled.

Zitat von Nick Hope

So4 only decodes AVC media. I've never seen any AVC get decoded by compoundplug.dll if so4compoundplug.dll is enabled.

Does that mean that this fix depends on the file format used?

I do not really understand what fix you are talking about.