Video/Audio Desync Issue (2.4.0)

[Mah0uPh0x]

While using the newest version of Attract-Mode for about a week, I started to realize that my video snaps would desync with its audio as it plays.

https://www.youtube.com/watch?v=Cw1mGMmrGdU

As you can see from the video I posted, when Ryu shoots his hadouken, the sound effect and voice do not match up with his action around halfway through the video snap. After this, I replay the video snap in VLC, and its perfectly in sync.

I've also been having problems with certain video snaps stuttering and skipping as well. I've been using the software decoder since the other video decoders (d3d11 and dxva2) do not work.

https://www.youtube.com/watch?v=js1HZSQ4EDA

And this video shows the problems with the hardware video decoders. Some video snaps work, but most of them do not.

FFmpeg: get_buffer() failed FFmpeg: thread_get_buffer() failed FFmpeg: decode_slice_header error FFmpeg: no frame! Error decoding video Error initializing video thread

This is what showed up in my last_run.log file from when I used the hardware decoders.

[mickelson]

Do you know if the audio and video were synced before in earlier versions? (2.3)? I'm wondering if something has broken or if this has always been a problem...

[Mah0uPh0x]

I do not know. I started with version 2.4. Its the first version I've ever used. Maybe if the hardware video encoder issue gets fixed, it might fix the rest of these desync issues.

[va-lemon]

I have the same issue with snap videos losing sync with audio in version 2.4 running a Pi 3B+. I can confirm that these videos worked fine under version 2.3. I still have it running on an older Pi 3B. Hardware decoding is enabled with the MMAL option selected. The videos appears to be running slower than the 30fps at which they're encoded. Audio ends but video keeps playing until the end is reached.
As far as I can tell, videos encoded in H264 (640x480 or lower) exhibit this issue. Some system snap videos encoded in XVID seem to play fine.

[eulogy37]

I created an account just for this comment. I had this issue in 2.4.0 and all versions beyond on my Pi 3B+. I checked out commit 23264ee and the issue was gone. Working my way forward in commits, the last commit which everything was fine was 793c2f8. Hope this helps.

[Mah0uPh0x]

I've tried the latest nightly build of AttractMode, the stuttering and skipping problems are gone, but the videos still desync on my end.

[eulogy37]

Try an earlier build as outlined here
http://forum.attractmode.org/index.php?topic=2786.0

[Mah0uPh0x]

I'm using Windows, not a raspberry pi or linux, I can't get this to work.

[oomek]

I finally found the sourceof the a/v sync issues. It's caused by insufficient resolution of the sf::Time type. The video you posted has a time base of 1/60000 which is 16.666667 microseconds. By converting it to sf::Time we get 16 microseconds, so each frame is rendered 0.66667 microseconds ahead.

Fix in on the way.

[Mah0uPh0x]

Thank you so much! I'm looking forward to testing out the fix.

[oomek]

Fix for a/v sync issues #549