Bug Report Audio/Video out of sync

[Merlini]

Hi, I've been streaming live on TwitchTV for a couple of weeks and I get constant complaints that my audio/video are out of sync by a few seconds. I currently use 3 sources: Dota2 Software Capture Source, a Webcam, and a Cam Overlay (.png). I have tried enabling/disabling the "Use Video/Audio Sync Fix", as well as unchecking "Use Send Buffer" as well as setting "Send Buffer Size" to 8192 with the send buffer enabled. On top of this, I have tried the default settings. Everything works great except for the slight audio/video out of sync when I stream live.

Here is a copy paste of today's log. I am currently using the most recent version of OBS (0.43a)

http://pastebin.com/maQ3v5Lr

My stream link: http://www.twitch.tv/merlinidota

 

[Lain]

Is this specifically the webcam? or everything? Thank you very much for the log file, by the way.

 

[Merlini]

The webcam is out of sync with my microphone (webcam is delayed), and the game audio seems to be delayed a little bit when compared to the game video.

Apparently the problem gets worse the longer I stream - I have streamed for many hours at a time.

 

[Lain]

The sync fix should technically always work when it comes to the desktop audio/video. However, the web cam issues is unrelated to the sync fix -- some webcams send out their data later and it can be out of sync, this seems to be a limitation with some webcams that I find very annoying. I think what I need to do is implement a mic time adjustment option to compensate for this.

 

[Merlini]

I just noticed Dragon's thread and it turns out that I used two different sound devices as well. I assumed that this would have been noticeable from the log that I posted to pastebin, but it doesn't look like the log lists the output sound device - only the input sound device.

I have a realtek HD audio built in soundcard on my motherboard that I use for my output device. I also have a Sennheiser USB sound card that I use for my microphone. I do this so I can have music/game sounds on speakers while listening to voice chat / skype on my headset. I have NOT tested streaming with only one sound device for both sound input and output - I will probably try this later when I get home. Looks like we have a possible explanation here.

 

[Merlini]

Also, I am not sure if this is particularly relevant, but I have used FFSplit with the same sound device configuration (onboard sound card as ouput and usb soundcard as input) with no syncing issues.

Thank you for being so prompt in your responses.

 

[Saturn2888]

May not be related (definitely not for the webcam sync over time), but I changed my Global Audio Sync Offset and Scene Buffering Time under Settings > Advanced until they matched up. I used my dance game to help me ensure I was spot-on by using a keyboard, the game's audio, and the game's video to verify.

If your mic from the webcam is in-use also, you can go into there and also change the audio sync there as well. In my case, I was running mine through the 3.5mm jacks on the same board so there wasn't any noticeable lag between the mic and game audio; although, I know my USB mic has a lag of at most 10ms depending on what it's set to in its own configuration settings.