Bug Report Potential Stream Crash Fix & Webcam/USB Mic Lag/De-sync

I am no tech guru, I simply hope to help others based on my experiences.

First of all, I love the program. Wow I get so much better performance with it than with Xsplit, and I am able to stream at 60 fps without even noticing a CPU hit while streaming. It's amazing.

With that said I did have some problems that I briefly tried to search solutions for on the forum and did not find. They may be there but I'm not patient enough to look so I'm sorry if this is has already been resolved.

1. Random stream crashes/'red zones' for 5 - 10 seconds every time I streamed dropping thousands of frames or just taking me offline completely for a minute. This would occur after a couple hours of streaming and I had no idea why as I was streaming at 2200 bitrate with a 4k upload bandwidth which never gave me problems with xsplit.

Check the setting "Send Buffer" under the advanced tab. I had mine initially set to 32768 because it said recommended when you hovered over the "use send buffer" check box. Well I dropped it down to 8192 and I have successfully streamed for more than 30 hours since then without the issue reoccurring. I can't say that will work for everyone nor why it worked for me, but hopefully it helps someone else.

2. Webcam/mic lag using a USB mic. For some reason the audio from a usb mic (im using the Samson c01u) and my webcam (Logitech HD C525) would be out of sync. No idea why but if you patch your mic's audio through Virtual Audio Cable (it's an application) to virtual audio cable 1, then use virtual audio cable 1 as your Mic instead, the problem seems to be fixed for me.

I certainly hope this helps, if anyone has any more questions my contact info is at http://www.twitch.tv/epicbaddie & I'll do what I can.

Thanks to the Devs of OBS, I am really enjoying the performance increase from switching to it.

-EpicBaddie

Hey there, apologies for any troubles. Yea, the old send buffer size recommendation was 32k, but it was quite high and turned out to be far less optimal than I expected, and in later versions it was changed to a multiple of the default maximum segment size, with the higher values removed. (It was a learning experience)

Could you tell me which specifically is delayed, your webcam, or your audio? Is the delay only by a certain amount or does it increase with time? These things would be most helpful to me if you could tell me more.

Thanks for the feedback.

I know for me, my mic tends to lag behind my webcam. And it falls further behind the longer I stream. Using a USB mic and Logitech webcam.

So to verify -- it -is- the mic then? I just need to be absolutely sure. If possible as well, could you specify exactly what mic and webcam you are using?

For me, I'm using a Logitech C310 webcam and a Logitech G35 headset as mic. Yes, for me, my mic audio seems to lag behind the webcam. I can see myself talk, then 3-5 seconds later I'll here it. The delay is greater the longer I stream.

I seem to have the opposite issue. My mic is getting ahead of my webcam. I'm using a Logitech C920 webcam and Astro A40s through optical out.

I have an example video here: http://www.twitch.tv/talutha/b/341461893
I'm not quite sure how long Twitch will hold onto that so the earler you view it the better.

At 16 minutes in, you can see it is perfectly in sync.
56 minutes you can see it slightly out of sync with the mic before the webcam.
1 hour 50 minutes you can see it is so out of sync I had to just turn the webcam off completely.

In the webcam settings I had it manually set to I420 as the other two options are completely out of sync from the get go. I also run at a 1280x720, 30fps on the camera.

I've also ran into the issue where the game audio was behind my mic as well. I would describe something happening before it happened. This gets worse the longer I stream but over a much longer period.

If you need any more information from me, please let me know, thanks!

I'm sorry, I had it backwards. It is my Mic audio getting ahead of my webcam. I had it totally backward. In this VOD, at about the 1:08:00 mark, you can really see the lag. http://www.twitch.tv/scxerouz/b/342016752 It starts before hand, but It is a massive difference. A whole 2-3 seconds of audio coming through before the video.

Update: After looking at the VOD a little bit more, it was hard when a lot of talking is going on in the video, but at the 1:10:00 mark or so, you can see me cough in the video, then 2-3 seconds later you hear it. It's later in the video that you can definitely tell my Mic audio is lagging behind my Webcam video.

Okay, just to be sure, it is the audio data that comes in later, not the webcam data, right? For example, using the desktop to base your synchronization on? Because the desktop is always on time.

In my VOD I posted, I actually forgot to switch scenes, which helps in this case. I have my game and webcam at the same size side by side. The audio is coming in later than the webcam video. The desktop and audio is in perfect sync.

Well, I think I may have finally figured out the issue then. This problem has been around forever and it's annoyed me to no end. I think I can get this fixed by the next major update.

Yeah was about to post something about this but I think my issue kinda fits in with this, but the longer i stream, the further away the game sounds are to what im actually saying/showing from my mic/webcam. I can link a video of what i mean http://www.twitch.tv/bilehazard/b/343535421 if you skip between parts of the video, youll see the sounds arent insync with whats actually going on in the game.

Have you used the sync fixed in advanced? If you get desktop video/audio desync, that usually requires the sync fix. I am currently looking to potentially make a computer that currently has the motherboard/cpu sync issue so I can investigate that particular sync problem more directly, but I know what's causing the mic one now at least.

Yeah im using that option in Advanced Tab, still doesnt fix anything.

Looks like I may have to buy computer equipment that causes the motherboard/cpu sync problems to more easily debug that particular sync problem. If you are using sync fix, make sure that your maximum set FPS is at or lower than the capture FPS you get (which is reported to you in the main window while you stream) , or you could have issues with it.

Yeah i've always streamed with 30fps, and nothing higher. Ill try to mess around with some more settings and see what happens.

Well if I have the Sync fix unchecked, the video/sound from the game is alright, but then the Camera/mic is out of sync. I've also disabled Multithread opt and still no fix. Let me try some different fps settings.

Could you use pastebin.com and post me a dxdiag log, bilehazard? would be helpful for me.

For the mic desync - could you guys try out the latest test build in the daily build thread? It should produce some useful log information if there is indeed something weird going on with the audio subsystem.

Here is the DxDiag info you wanted
http://pastebin.com/hfQdrTjg

Tested out v.499a and the Sync Fix still doesnt work, ill test it again without the sync fix when i get back from work later tonight. What is CBR under the Advanced Tab by the way?

Alright so i tested a few things out, and it seems the syncing issues may be caused by the Audio Bitrate being too high, since i had 320 selected, i dropped it down to 192 and the syncing was gone. This was with Sync Fix unchecked.