Audio out of sync during Avidemux playback

[johnr283]

I'm trying to edit an MP4 but the video is out of sync during Avidemux playback. It's only in Avidemux. The video plays fine in VLC and MPC. I re-encoded it and it's the same thing.

[eumagga0x2a]

If audio is progressively ahead of video, this means you experience a performance limitation. Please make sure you have selected a hardware accelerated video output (on Windows: DXVA2 or OpenGL) and either enabled hardware accelerated video decoding (on Windows: DXVA2) if the MP4 the video track is encoded using a codec supported by the available hardware decoder or enabled multithreaded software decoding in Avidemux Preferences.

If video is progressively ahead of audio or the A/V offset remains strictly constant, please provide admlog.txt from loading this particular MP4 file. The Avidemux log file is located in %localappdata%\avidemux. The textual output of MediaInfo would be also useful.

[johnr283]

You cannot view this attachment.

[johnr283]

The video is ahead of the audio.

[johnr283]

I can open the file in MediaInfo. How do I save the info?

[eumagga0x2a]

Code Select Expand

[simpleRender] 20:00:38-502 creating simple render
Please select the DXVA2 or the OpenGL renderer.

The video is ahead of the audio.

Are you absolutely sure? A ubiquitous stereo AC3 audio track should not pose any problems. On the other hand, using an unaccelerated renderer (i.e. letting the CPU do all the heavy color conversion and scaling work) may easily result in video playback not reaching the necessary refresh rate.

Please retry with the DXVA2 renderer. If the problem persists, I'd probably need a sample.

[johnr283]

You cannot view this attachment.

[johnr283]

How do I upload a sample here?

[szlldm]

use wetransfer, and insert link her, or send via PM to eumagga0x2a

[eumagga0x2a]

Code Select Expand

[init] 00:36:40-319 Dxva (D3D) init successful, dxva render. w=1920, h=1080, zoom=0.2639, displayWidth=506, displayHeight=285
[spawnRenderer] 00:36:40-329 Dxva2 init ok
Hw accelerated renderer enabled and working, good. If the problem persists and you are going to provide the necessary sample, do you experience the A/V desync problem with a short MKV video created from this one by saving a part of it in copy mode? I prefer to keep samples rather small :-)

use wetransfer, and insert link her, or send via PM to eumagga0x2a

I'd like to add that WeTransfer doesn't require an email address despite suggesting otherwise. If you don't like WeTransfer for whatever reason, you could use Meta, Dropbox or Google Drive, which are also good options for providing samples.

[johnr283]

I tried to upload the wetransfer link but get this error:
CleanTalk: *** Forbidden. Please enable JavaScript. Message seems to be spam. ***

[eumagga0x2a]

If you have uploaded the sample to WeTransfer and CleanTalk interferes with posting the link, please send me the link via PM.

[eumagga0x2a]

Thanks, got the sample, 18 seconds in duration. When I play it in Avidemux (my own local build off the latest git master), A/V sync is flawless as is in mpv. What do you observe when playing it?

[johnr283]

Thanks, got the sample, 18 seconds in duration. When I play it in Avidemux (my own local build off the latest git master), A/V sync is flawless as is in mpv. What do you observe when playing it?

When I play it in Avidemux, the audio is a few seconds behind the video.

[johnr283]

By behind the video, I mean the audio happens after the action has occurred.