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+--- Thread: Audio Sync problem after re-encoding (/thread-1450.html)
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Audio Sync problem after re-encoding - jweaver - 12.07.2020
I have found 100s of overly large "TV" shows on my NAS which i am in the process of renecoding to make them smaller.
I have encountered a pair of files (2 halfs of the same show), that after reencoding the audio "slips" out of sync through the lenght of the show. at the beginning its in sync and by the end its several seconds out.
There is clearly something wrong with the files, rather than Hybrid as I have encoded many 100s of other files with no issue.
I have tried my normal techniques to get around this:
1. Passthrough Video, encode Audio
2. Encode Video, Passthough Audio
3. Passthrough Video, Encode audio without any encoding.
etc
No matter what I do, every time or method of encoding, the resulting file has bad audio sync... I am tempted to just give up on this one.. But before I do.. I just wondered if there were any tools, switches or feauture that I might not be aware of which would help in situations like this..
I know that there is little help that can be offered here and I am not expecting anything.. But just wondered if I was overlooking something obvious.
Jon
RE: Audio Sync problem after re-encoding - Selur - 12.07.2020
Might be decoding problems, might be stretched streams might be a bug in the time codes might be a glitch one of the streams,...
No details -> no clue
RE: Audio Sync problem after re-encoding - jweaver - 12.07.2020
(12.07.2020, 14:39)Selur Wrote: Might be decoding problems, might be stretched streams might be a bug in the time codes might be a glitch one of the streams,...
No details -> no clue
Cheers.. I didn't really expect anything really.. Just wondered if there were any "magic" switches which might help in cases like this.
Its not even worth your time trying to debug this (unless you want too) as I have only seen it with THIS pair of files.
If you wanted to take a look, I will gladly grab some debug.. its easy to reproduce....
RE: Audio Sync problem after re-encoding - Selur - 12.07.2020
Without knowing anything about the files or whether there are any filters applied I can't really recommend any specific option.
Cu Selur
RE: Audio Sync problem after re-encoding - jweaver - 12.07.2020
(12.07.2020, 16:06)Selur Wrote: Without knowing anything about the files or whether there are any filters applied I can't really recommend any specific option.
Cu Selur
So do you want to see a debug? Are you interested in looking at this? As I said, I don't mind if you don't as I am sure its a couple of bad files.. But if you want to take a look, I am more than happy.
RE: Audio Sync problem after re-encoding - Selur - 12.07.2020
If you assume the file is broken, I won't look at it. Not worth the effort.
If you can reproduce the problem and create a debug output that should be enough for me to see whether there is a bug in Hybrid or not.
Cu Selur
RE: Audio Sync problem after re-encoding - jweaver - 12.07.2020
(12.07.2020, 18:48)Selur Wrote: If you assume the file is broken, I won't look at it. Not worth the effort.
If you can reproduce the problem and create a debug output that should be enough for me to see whether there is a bug in Hybrid or not.
Cu Selur
Will do.. No evidence that the file is "broken"... 2 do exactly the same thing.. But its the only files I have encountered with this isssue, out of 100s if not 1000s.
I just did a test with Audio AND Video to Passthrough and changing the container.. And the audio still comes out broken.
So I am intreaged, so will send you the debug later just so you can give an opinion...
RE: Audio Sync problem after re-encoding - jweaver - 13.07.2020
Just sent you a debug file by email.. Dont' spent any time on this, but sent in just incase you wanted to see if there was anything obvious.
RE: Audio Sync problem after re-encoding - Selur - 13.07.2020
I looked through the debug output,... sadly there's no error or warning anywhere.
Since the input is a .mkv file, try whether it changes anything if you enable "Config->Automation->On Load->Always extract timecodes form input" before loading the source.
Cu Selur
RE: Audio Sync problem after re-encoding - jweaver - 17.07.2020
Sorry to take so long to get back to you.. I have been re-encoding my entire collection of "MythBusters" which has taken days...
During my Mythbusters marathon, I found a few of those files whihc had the same issue (i.e the audio "slips" out of sync)..
I tried your suggestion of using "Always extract timecodes form input" and it didn't help
So I turned to my no2 backup encoder (AVIDemux) which I often use on the odd files that Hybrid struggles with it.. And to my surprise it encoded it without issue.. The Audio is perfectly in sync on all of them.
I can live with this soluition to be honest... But if there is something you want to look at, say the word... I can suply you with the affected files if you are interested.
I have found with Hybrid, that if I take one of these files and simply re-encode with passthrough for Audio and Video (just chaning the containter) I get the audio problem, so its not even an "encoding" thing.
Jon