Linux > JRiver Media Center 33 for Linux
Video and Audio Desync on Seeking (Relevant to New Video Presentation Mode)
mwillems:
So I have a longstanding issue with video playback on Linux where if I seek multiple times forward or backward (i.e. by pressing the right or left arrow keys) the video and audio will become visibly desynced or the audio will drop out entirely. These issues will stick around as long as the current playback session is ongoing, but stopping and restarting playback will restart at the same part of the video with the video and audio perfectly synced. I don't do much seeking except when watching recorded TV, so I've just been using the seek/stop/start as a workaround. I thought I reported the issue a few years back, but I can't find any threads so maybe I just forgot to report it?
With the "old" JRVR renderer the issue usually isn't a problem for the first few seeks, but if I seek more than a few times it gets farther and farther out of sync, and sometimes the audio drops out completely. I was hoping the issue might be resolved when using the new presentation/rendering queue, but if anything the issue seems worse. Seeking is kind of rough with the presentation queue and even two or three seeks now seems like enough get the audio visibly out of sync with the video.
Reproduction steps:
1) Start video playback and seek forward maybe five or ten times in quick succession by pressing the right arrow key (i.e. seeking forward 3:00 to 5:00 minutes with default settings).
2) Look for a scene with dialog and the audio from the dialog will be notably out of lipsync with the characters speaking on screen (in my testing the audio always lags behind the video, not vice versa).
3) If you press stop and then play again, playback will resume almost instantly at the same spot with perfect lipsync.
I can reproduce this on Debian Bookworm running XFCE4 or Gnome, and also on other Linux systems. The issue doesn't seem to care about whether the files are on a local drive or accessed via CIFS (although it seems easier to get the audio to drop completely on remote files). I'm mostly testing with DVD or Blu Ray rips to mkv, with a few mp4s thrown in, but the issue also affects TV programs recorded by JRiver in .ts format. I haven't tested whether it's an issue with live TV playback or not.
Let me know if I can provide logs or any additional info.
drmimosa:
I see this behavior as well, when I'm seeking MKV movies and concert videos the video and audio go out of sync.
Stopping and Starting playback resolves the sync.
Hendrik:
Does this only happen if you seek rapidly in quick succession? If you seek once eg. by clicking on the seek bar its fine?
Is the file from local, or network?
mwillems:
--- Quote from: Hendrik on August 26, 2024, 04:07:01 am ---Does this only happen if you seek rapidly in quick succession? If you seek once eg. by clicking on the seek bar its fine?
--- End quote ---
I think one seek causes mild desync. The desync seems cumulative so it's a little hard to tell with one seek. For example, in one playback session, if I sync four or five time the sync will be visibly off. If I then wait and sync four more times during the same playback session the sync seems even more off than it was, and if I keep syncing I'll sometimes lose the audio entirely. It doesn't seem to make a difference whether I seek using the scrubber bar or using the keyboard/remote controls, if I seek on the scrubber bar multiple times I definitely get desync. So that said, I think that I see mild desync after one seek, but it's hard to tell as there's only a little desync after one seek. The problem becomes much more obvious after a few seeks.
--- Quote ---Is the file from local, or network?
--- End quote ---
I can reproduce the issue with either local or networked files. I think (and this is a vibe) that the problem is slightly worse with networked files, but that may just be because seeking is generally more responsive with local files. That is, I feel like it might take a few more seeks to reproduce the issue with a local file, but I don't have a good way to measure, so it might just be a false impression. To be clear I definitely still see the desync when seeking in local files.
Hendrik:
I can't seem to reproduce this on Windows using the cross-platform playback engine, the only difference then being the audio output itself, which makes me wonder if thats related to that part.
Next going to update one of my NUCs for some real hardware linux testing.
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