@RogerS

I'm not sure how to interpret that. Is there a secret handshake required to render a Vegas Pro timeline? Please elucidate.

Hi John, sync appears to vary based how Vegas decodes the original files. The author of Voukoder stated:

It is absolutely not right to encode a file wrongly so a broken decoder can import it the right way. Remember: The issue is with the broken decoder, not the encoder. If I play the generated file with MPC_HC it is perfectly in sync. If I import this in Premiere it is in sync too...

So with the latest 0.7.1 connector the audio is beeing adjusted by 44.4ms. This is in sync when checking it with MPC-HC, Premiere and VEGAS 15+.

With VEGAS <= 14 (or if you disable so4compoundplug) it is one frame off.

This was the thread in question and I haven't spent much time with it as it isn't a problem I'm having so my motivation to dive into it is limited:

https://www.voukoder.org/forum/thread/635-audio-drift-when-using-the-voukoder-encoder-in-vegas-pro/?pageNo=1

Hope that's of some help.

@john_dennis

The sync of the audio rendered in Voukoder and others external encoders depends on the encoder used by VEGAS: 

so4compoundplug = Audio a little out of sync 
Compoundplug = Normal Audio Sync  

Vegas Pro 14 uses the encoder "compoundplug" by default. Vegas Pro 15 or higher uses the encoder "so4compundplug" by default.  

I talked to the Voukoder developer about this a couple of years ago. He is aware of this. Unfortunately it's a problem with VEGAS' new so4compoundplug encoder that hasn't been fixed yet, and I honestly don't have hopes that it will ever be fixed.

This also happens on HOS, and talking to Wayne he informed me the same thing as the Voukoder developer.

Here's some more comparisons

Top line is original file, 2 and 3 Voukoder, 4,5 Magix. Showing the difference between playback with SO4 and Legacy decoder

The same files in Davinci Resolve

That seems to be a bug with the Vegas' decoder. 😶

John, I believe it's the same legacy issue with PCM audio source and libx264. I filed a ticket on github about 2012 iirc and it never was resolved; still occurs in Handbrake and ffmpeg to my knowledge.

Test with properly synced aac source and see if you get different results. Unfortunately, audio delay settings are not exposed in Voukoder.

@RogerS

Thank you for the background. I'll admit that I had a Post-it note on my desk for a long time reminding me to install Voukoder and enshrine it in my system image because of this very issue.

@Former user

"The sync of the audio rendered in Voukoder and others external encoders depends on the encoder used by VEGAS:"

I checked Enable Legacy AVC Decoder in Vegas 19-550 on my laptop and the audio sync was as expected.

I created this project without outside video to avoid decode issues. That didn't get me very far down the road.

I'm aware of Wayne's intervention when using HOS.

@Former user

Thanks.

@lan-mLMC

I'm going to revisit this thread, perhaps we need an audio offset knob.

https://www.vegascreativesoftware.info/us/forum/prores-audio-video-sync-offset-by-2-or-3-frames--134408/?page=1#ca839537

I've added the encoded files from Davinci Resolve, and Voukoder via Davinci Resolve. It's concerning to see that all files encoded by Vegas are not in sync with Voukoder via Vegas the worst.

@Musicvid

I replaced the WAV audio with AAC from Sound Forge 15 and the audio lead was only affected by the Enable Legacy AVC Decoder switch as Joelson Forte suggested earlier.

I'll summarize what I learned from this experience.

• The file generated by Vegas Pro to Voukoder is in sync with the Vegas timeline that generated to file whether compoundplug or so4compoundplug is active at render time.
• If one places the Vegas Pro-Voukoder generated file back on a Vegas Pro timeline, the sync of the audio is controlled by which decoder is used. Compoundplug will display the file in sync, so4compoundplug will cause the audio to lead the video by a fixed amount (22ms).

I used Vegas Pro 12 as a neutral arbiter and placed the Vegas Pro-Voukoder files rendered with so4compoundplug active back on the timeline and the audio was in sync.

When placing the same file back on a Vegas Pro 19-550 timeline, the audio sync was affected by the state of the Enable Legacy AVC Decoder switch.

Thanks for the analysis. It seems unrelated to the legacy PCM/libx264 issue I brought up.

This is looking at the same tracks as I showed before but in premiere.

This time the Vegas and Voukoder via Vegas files are at the top, and they sync with each other, the tracks that are advanced are the Resolve and Resolve via Voukoder, with bottom tracking being original. A different result again.

Very strange. I wonder about the qualities of the Voukoder (via Vegas) encoded files that make SO4 and Resolve advance the audio, but Premiere and Legacy decoder not advance the audio.And then you have the mystery of why the Voukoder(via Resolve) files don't advance, not even in Vegas

@Former user

"Very strange. I wonder about the qualities of the Voukoder (via Vegas) encoded files that make SO4 and Resolve advance the audio, but Premiere and Legacy decoder not advance the audio."

Perhaps, the answer lies in this description of how the alignment decision is made.

Since (for me at least) a Voukoder x264/x265 render (from Vegas or Resolve) is a final and delivery render. I don't experience any out of sync issues when viewing those renders at PC or UHDTV, or do you? So I actually don't care about how Vegas interprets those renders on its timeline, because I never re-import a Voukoder render for further editing.