Bug Report Audio sync issues

[Palom]

I'm having problems where the audio of my local recordings is out of sync with the video. The audio is played ahead of the video, anywhere from 10 to 45 frames (in a 60 fps recording). I have no idea this is happening until after the fact when I review my video files, and it doesn't happen all the time. For example, my recordings from October 5 were all fine (log file: http://pastebin.com/eJEgFt9h), but my recordings from October 6 had sync issues (log file: http://pastebin.com/esSAvHSM).

In my October 6th session, I recorded nine videos. First video is off by about 12 frames. Second by about 23 frames. Third by 33 frames. Four, Five, and Six by 44 frames. Seventh, eighth, and ninth videos were not out of sync.

I have tried messing with various settings, without much success. Changing my CPU preset to ultrafast did not help. Changing processor priority to Above Normal or High did not help. The zerolatency tuning setting didn't seem to help. I tried different combinations of CBR, VBR, and CRF recordings without any change. While recording, I have no other programs running, aside from OBS and a simple text editor. The program shows about 15%-20% CPU usage while recording, and my overall system-wide CPU usage doesn't get much higher than 30%.

Going back and reviewing my stream archive, it appears my stream suffers from the same audio sync issue (I use NVENC for stream and x264 for local recording), so I guess it's something that progressively gets worse, and then corrects itself.

Other pertinent information if necessary: Windows 10 64-bit, i5-4670k at 4.2GHz, 8GB RAM, recording with a Startech USB3HDCAP video capture device from external sources (in this case, PS2 with a 480p signal). I started noticing the problem since the 0.14.x releases. I thought it might have been related to a particular version, and I recall reverting to 0.14.1 a few times, but I can't be certain because the audio sync issue doesn't occur consistently.

Hoping someone can help me remedy this situation, as it's causing me all kinds of hassles in video editing. I'll try going back to 0.14.1 again for now, and see if the issue doesn't pop up. Edit: Never mind. I have some recordings with sync issues today after switching back to 0.14.1.

 

[Palom]

I was editing one of my recordings today and was having trouble getting the audio aligned properly. I tried aligning it based on a section near the beginning of the video, then the end was off. If the end was aligned properly, the beginning was off. I noticed a section in the video (in the middle of speech, so it was easy to identify) where the audio is paused for 37 frames while the video continues. It seems that everything after this point was synced properly, but everything prior was off by 37 frames. Once I deleted that blank audio gap and moved up the earlier audio segment, everything was synced properly.

I have attached the log file from when this happened, and the problem is found in the recording that started at 22:27:44.973 in the timeline. Based on where the audio gap shows up in the video, it occurred at about 23:15:09.150 in the timeline, although there is nothing in the log at that moment. It can be seen at 5:15:45 in the Twitch archive at https://www.twitch.tv/sieffreplays/v/94784883 If you go to an earlier point (e.g. 4:35:00), you can see how far out of sync it got, but then after that point (like at 5:34:00), it's in sync.

Could this be related to recording at 59.94 fps? It's almost like one of the audio or video tracks is being recorded at 59.94, but the other is at 60, so they eventually lose sync, and then I get the blank audio gap and they resynchronize until it gets out of sync again. I'm recording from a console source, which is sending the standard NTSC 59.94 fps signal.