Bug Report Logitech HD Pro C920 Desync Issue

[Riptidepow]

Been having an issue with my camera and headset microphone desyncing. I have a Logitech HD Pro C920 webcam and I've searched everywhere on the forums and others have been told that there really is no fix. I've tried using my USB 3.0 port, lowering camera resolution, you name it but nothing fixes it. It's totally fine up to the 6-7 hour mark (I stream for a living so 7-8 hour days are normal). I also checked out the recent post that talked about desync fixes but it looks like it's only for the devices with audio, not my situation. I really love OBS but at this point it's getting so annoying that I'm reconsidering Xsplit regardless of CPU usage. Thank you for your time.

 

[dodgepong]

Have you tried the latest test version? A lot of work has been done on audio and it might be fixed in there.

 

[Lain]

With the C920, there are a few things. First, if you have a USB 3.0 port, use it. Secondly, set the output format to I420.

Another option is to try out the test build with the new "use buffering" option, and use the mic audio directly on the device rather than in audio settings, as that will force it to be in sync.

I have a C920 and I've never really had any problems with it personally. I think some intermediary directshow filters people install from codec packs seem to cause some issues as well.

 

[FerretBomb]

Just a note, I'm getting cam desync issues as well; I don't stream for nearly as long as Riptide though.
Issue started occurring when upgrading from v0.432a (64-bit) to v0.51b (64-bit). Older version was using the audio/video sync fix (desktop audio was lagging as well). New version is using the 'sync audio to video time' option, which fixes the desktop audio desync, but the mic audio is still skewed. Happening both with an analog mic connected to the on-board audio, or a USB condenser mic.

Logfile excerpt:

Spoiler

------------------------------------------
Open Broadcaster Software v0.51b - 64bit (　^ω^)
-------------------------------
CPU Name: Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz
CPU Speed: 2672MHz
Physical Memory: 49143MB Total, 37894MB Free
stepping id: 4, model 10, family 6, type 0, extmodel 0, extfamily 0, HTT 1, logical cores 8, total cores 4
monitor 1: pos={0, 0}, size={1920, 1080}
monitor 2: pos={-1920, 0}, size={1920, 1080}
monitor 3: pos={1920, 0}, size={1920, 1080}
Windows Version: 6.1 Build 7601 S
Aero is Disabled
------------------------------------------
Adapter 1
Video Adapter: AMD Radeon HD 6800 Series
Video Adapter Dedicated Video Memory: 1017868288
Video Adapter Shared System Memory: 4021872640
=====Stream Start: 2013-05-03, 18:22:09===============================================
Multithreaded optimizations: On
Base resolution: 1280x720
Output resolution: 1280x720
------------------------------------------
Loading up D3D10...
Playback device Default
------------------------------------------
Using desktop audio input: Speakers (SoundMAX Integrated Digital HD Audio)
------------------------------------------
Using auxilary audio input: Microphone (Producer USB)
------------------------------------------
Audio Encoding: AAC
bitrate: 128
Using Window Capture
------------------------------------------
Video Encoding: x264
fps: 60
width: 1280, height: 720
preset: veryfast
CBR: no
CFR: no
max bitrate: 3000
buffer size: 3000
quality: 8
------------------------------------------
Syncing audio to video time (WARNING: you should not be doing this if you are just having webcam desync, that's a separate issue)
Total frames rendered: 234, number of frames that lagged: 22 (9.40%) (it's okay for some frames to lag)

 

[dodgepong]

That doesn't look like the entire log...make sure OBS is closed when getting the log.

Have you tried plugging the webcam into a USB 3.0 port?

 

[FerretBomb]

I'd snipped it after I was done testing briefly; the full log is 4-5 tests with various settings. All still showed the sound lag issue on 0.51b, and none on 0.432a.
First-gen Core i7 means no USB 3.0 (I've had no reason to get an expansion card); still, dropping the cam to 320x240 should mean that port bandwidth shouldn't be an issue if that's the thought though. Have it connected to a mobo port where it's the only item on that hub, as well. Happens with MJPG or I420. Haven't tried with RGB24 yet.

 

[Torana]

Sorry could you explain this a little clearer, when you say go to video file do you mean click on a video file made by the C920.A route of how to get to the video file would be nice if that's ok please.

 

[Utorak007]

I too am having this very same issue. I use the exact same webcam, and when I add the source to my scene and check it, the audio of my mic stutters. I'm not using the webcam mic, and have disabled the webcam's audio. OBS is up to date, and it is not the latest build. I have done exactly what was said on this thread and still no fix. The thing I don't understand is that it works perfectly well with xsplit.

 

[Lain]

Also try the logitech drivers if you do not have them installed -- it's fixed problems for at least one other person out there

 

[sirsimon40]

I can't even get my video to show. Can someone please walk me through the steps?

 

[jahrein]

I got the same problem. I must insist that the problem is on the obs' end. Till now I had no problem with the web-cam mic sync. I tried everything you guys suggested above. none helped. Is there any way for me to download older versions so that i can go back to my happy streaming?

 

[dodgepong]

This is a fairly old thread, but I do know that the C920 has issues if you are running it in 1080p. Check the resolution inside the webcam source.

Also, you can try using Mic QPC timestamps, or the Mic Sync Fix hack. Just make sure your scene buffering time is set to at least 700.