Has no one noticed yet that the Voukoder soundtrack is slightly shifted?
Pictures below:
File 1: Original MTS from the camera
File 2: Voukoder rendered file
File 3: Mediaconcept AVC rendered file
You can see that the audio in file 2 is sped up by 1.5 frames (i.e. about 0.02s = 2ms)
This is, of course, an unnoticeable glitch, but a bit of an annoying.
This was an issue when Voukoder was first launched. A similar issue can be found when using Handbrake for transcoding since they both use FFmpeg libraries. Having said that, I thought the problem had been fixed in later builds.
Because of this issue and differences in formats, I have included an option in most HOS rendering tools to adjust audio offset as shown in this example.
I also thought the Voukoder author concluded that the issue was when the files are brought back in to Vegas so there wasn't going to be a fix on that end.
Maybe we'll get a manual audio offset option in Vegas for such files.
My past analysis.
I turned on the "AVC legacy decoder" and the problem is actually gone https://imgur.com/a/gKzGWjb
BUT
I decided to check the files in DaVinci Resolve as well. And here is the real surprise (look @ attachment)
1. You can't see it in the picture, but both paths are synchronized perfectly.
2. But the first 20 seconds of audio from the Voukoder file are "missing"!
a) but only the graph is missing - the sound is actually playing!
b) but it isn't played from the beginning - less than the first second is missing (it is exactly played from frame 58 - from the red line in the picture)
(Summarizing: frames 0-57 - no graph and no audio, frame 58 to ~20s - only the graph is missing, sound is playing, from 20s - everything is ok)
There may be a problem with the new decoder in Vegas, but it looks like the encoder in Voukoder is just causing some problems for other programs.
(Edit: I corrected the wrong attachment)
As I use Voukoder only for final renders, which play absolutely in-sync on my TV, I really don't care how Vegas or other NLE's interpret those renders when re-imported on their timelines. To my opinion and experience, don't trust blindly how Vegas interprets those re-imports.
I might be side-stepping the issue by relying primarily on externally recorded audio. Has anyone tested Voukoder audio alignment with externally recorded wav tracks or camera clips with pcm audio?
It's a bug that has been around as long as ffmpeg / libavcodec. I documented and tested and submitted thorough bug reports in 2012, never was acted on, it's even worse with PCM audio source.
Just tested it with some mov/pcm footage and can confirm the bug's still there in ffmpeg4, ffmpeg5, and Voukoder 11.
Also noticed Voukoder 11 lost its Intel/qsv hardware support... even the one that's marked Intel Arc beta. That's an ffmpeg5 bug. Probably going to back-pedal Voukoder on my systems to the one built on the last ffmpeg4, which I think is v4.4.1. UPDATE!!!: There's a trick to making qsv available in Voukoder... gotta go into Windows, Graphics, Advanced and set Vegas to use an Intel igpu or Arc board... then the Vegas plugin sees it and menu items appear. Similar trick works for ffmpeg v5 decoding... just point ffmpeg to an Intel gpu in Windows and use "-hwaccel auto".
Just found the original test I did a few years ago showing a 44msec delay.
As I recall, you can render your aac audio using Sony AVC (audio only) and then remux with the video to eliminate the audio sync problem.