Author Topic: Audio out of sync while editing/previewing  (Read 220 times)

Sledgehog

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Audio out of sync while editing/previewing
« on: March 21, 2020, 02:47:43 AM »
My videos upon opening and playing in avidemux are fine. But once I make an edit such as a small cut, when I play and preview the video afterwards the audio goes way out of sync (audio actually gets ahead of the video somehow.) If I stop the video and start playing it again, it starts in sync then slowly goes out of sync again until i start and stop the video again.
Mind you when I save the file, both video and audio are fully in sync. This only happens while having the file open in avidemux and editing/previewing before saving.
This has happened with each version of 2.6 and 2.7 I've tried. Tonight alone I've tried the last 4 2.7 nightly builds including the newest one from march 18th. (avidemux_r200318_win64Qt5_90.zip)

I'm trying to edit MP4 videos from my action cam and pixel 2 phone if that makes any difference. But if I save them as an mkv and open them again, it still does the same thing.

Any ideas how to fix this?
« Last Edit: March 21, 2020, 03:10:22 AM by Sledgehog »

eumagga0x2a

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Re: Audio out of sync while editing/previewing
« Reply #1 on: March 21, 2020, 09:32:57 AM »
This happens when the hardware is not fast enough to decode and display the video with given Avidemux configuration in real time. Have you checked that both DXVA2 hw accelerated video decoding and DXVA2 video output are enabled in Avidemux Preferences?

The former won't help for codecs not supported for hw accelerated decoding, so as long as you provide neither information about codecs used by your action cam and the Pixel nor the admlog.txt file for information about supported codecs, it is impossible to tell whether this will help or not, but hw accelerated H.264 decoding should be almost universally supported. The latter (DXVA2 video output) is highly benefitial for reducing CPU load as other hw accelerated video outputs on Windows like OpenGL are far less efficient. I even don't mention the unaccelerated "Qt" / "RGB" video output which lets the CPU do all the work.

PS: please use the latest nightly for everything mp4 related.
« Last Edit: March 21, 2020, 09:34:36 AM by eumagga0x2a »

Sledgehog

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Re: Audio out of sync while editing/previewing
« Reply #2 on: March 23, 2020, 08:07:20 PM »
Checking the box for DVXA2 acceleration did the trick I think... so far so good. Thanks.