Telestream Community Forum
Decrease font size
Increase font size
Topic Title: Audio Sync Issues with Skype and Virtual Audio Cable (VAC)
Topic Summary:
Created On: 6/16/2010 9:23 PM
Status Post and Reply
Linear : Threading : Single : Branch
Topic Tools Search Topic
Topic Tools Topic Tools
View topic in raw text format. Print this topic.
 6/16/2010 9:23 PM
User is offline View Users Profile Print this message

Author Icon
extremetour

Posts: 35
Joined: 6/16/2010

I am using Windows 7, and I'm piping the sound from a Skype video interview through Virtual Audio Cable and then finally into Wirecast.

The audio and video of the person I'm talking to on Skype are in sync.

However, my audio is delayed and out of sync with my video.

In VAC, I have the buffer as low as it will go without causing overflow issues, in order to minimize the delay.

Does anybody have suggestions on the best way to minimize audio delays with VAC? I find the VAC tutorial very hard to understand.

Or, if it isn't possible, is there another way I can get the sound into wirecast without a delay (ie - mixer, another audio card, etc.)?

Thanks for your help.

Best,
Michael
 6/17/2010 11:51 AM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

If Skype audio and video are in sync using VAC, there's no problem there. VAC is doing exactly what it should.
Unfortunately I don't know what "my video" is. Please explain the source of your other video and how you are inputing it into your computer.

-------------------------
CraigS
Telestream Desktop Forum Moderator
 6/17/2010 12:53 PM
User is offline View Users Profile Print this message

Author Icon
extremetour

Posts: 35
Joined: 6/16/2010

Hi Craig,

To capture the video and output it to multiple sources, I use ManyCam. The video from my webcam is going to ManyCam and then to Skype and to Wirecast.

To clarify what I said, when I'm in wirecast, on a shot of just me speaking, and I have the video set on ManyCam and the audio coming directly from the microphone, there is NO sync problem.

When I'm in wirecast and on a shot with me showing my skype conversation with side-by-side video, I run into problems. Below is how I have it setup:

1. Person I'm Interviewing Via Skype - Video Source: WebCamMax, Audio Source: Virtual Audio Cable (In Sync)
2. My Video/Audio = Video Source: ManyCam, Audio Source: Virtual Audio Cable (Out of Sync)

Does this clarify my challenge?

Best,
Michael

 6/17/2010 12:55 PM
User is offline View Users Profile Print this message

Author Icon
zimode

Posts: 317
Joined: 7/7/2009

Hmm.. I use DTP - Skype & VAC and it seems to me to work perfectly.. I just use the defaults -
Basically VAC1 is the Audio out from Skype & VAC1 is the Audio IN to Wirecast.. I do not use the Virtual Audio Cable on the microphone as it's not necessary, the mic is just shared via Skype & Wirecast.. works fine..

what's your CPU usage is there something going on at that end?

-------------------------
ATI Radeon HD 4650 1Gb
i7 860 2.8 GHz 8Gb ram
WIn7 64bit
 6/17/2010 1:12 PM
User is offline View Users Profile Print this message

Author Icon
extremetour

Posts: 35
Joined: 6/16/2010

Zimode,

Thank you very much for our advice. Interesting. I am going to look into testing what you've done.

Below is the setup I have for each of the repeaters and relevant software programs, which was recommended in the VAC Resources:

VAC REPEATER 1 - Take audio from Microphone and turns into a VAC
Wave In: Microphone
Wave Out: Line 1 (Virtual Audio Cable)

VAC REPEATER 2 - Takes audio from the skype conversation (only the person I'm talking to) and outputs into my headphones so I can listen
Wave In: Line 2 (Virtual Audio Cable)
Wave Out: Headphones

VAC REPEATER 3 - Puts my Microphone VAC into the Skype VAC so that I can use one VAC as the source in Wirecast. This VAC has my voice and the person I'm talking to on Skype's voice.
Wave In: Line 1 (Virtual Audio Cable)
Wave Out: Line 2 (Virtual Audio Cable)

SKYPE
Microphone: Line 1 (Virtual Audio Cable)
Speakers: Line 2 (Virtual Audio Cable)

Wirecast Shot Where Challenge Happens
Audio Source: Line 2 (Virtual Audio Cable)


QUESTION: Instead of REPEATER 3, could I have Line 1 go directly into Wirecast? In other words, can I have Line 1 & Line 2 (Virtual Audio Cable) go directly into one shot in wirecast? In other words, is it possible to have two audio sources for one shot in wirecast?
 6/17/2010 3:14 PM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

Why not Mic into Skype (VAC not needed) and Skype into Wirecast (use VAC). Both you and your guest are now in Wirecast. Whether you use video 2 shot, video just guest, video just you, audio is always following the same path.
You can send Skype audio to headphones as well.

Interesting thing in zimode's post that I have not looked into is that he says mic input into Skype is shared with Wirecast. If so I need to test that. It depends on what you mean be "shared" (which is why I try to avoid words that can be misinterpreted). If he means mic to Skype to VAC to Wirecast and he use (shares?) the audio with all shot variations, that's what I'm playing with.

-------------------------
CraigS
Telestream Desktop Forum Moderator
 6/17/2010 3:41 PM
User is offline View Users Profile Print this message

Author Icon
zimode

Posts: 317
Joined: 7/7/2009

A quick clarification.. In Skype I select my mic "Blue Mic Snowball".. In wirecast under Audio I select "Blue Mic Snowball" as my audio layer and use it for the appropriate shots.. I never use VAC for the mic.. (that's what I meant by shared.. I just select the Mic in both applications WC & Skype) It's the output audio from Skype that needs to re-directed into WC..

-------------------------
ATI Radeon HD 4650 1Gb
i7 860 2.8 GHz 8Gb ram
WIn7 64bit
 6/17/2010 3:54 PM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

How are you monitoring Skype audio? If you monitor from Wirecast to headphones you might get a slight delay when speaking and hearing your own voice.

-------------------------
CraigS
Telestream Desktop Forum Moderator
 6/17/2010 4:10 PM
User is offline View Users Profile Print this message

Author Icon
zimode

Posts: 317
Joined: 7/7/2009

You're right I do monitor with one headphone (not both) as I do get a slight delay in my voice and it can be a tad distracting, but one headphone seems to be right.. Since my format is interview the delay doesn't affect the flow of the conversation at all. I used to use my Alexis USB mixer but I wanted to be mobile with my laptop so I adopted the 1 headphone & just got used to it. I now use my 860 PC but just kept the headphone thing.. I try to keep things very simple, as I have a very small brain!

-------------------------
ATI Radeon HD 4650 1Gb
i7 860 2.8 GHz 8Gb ram
WIn7 64bit
 6/17/2010 4:29 PM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

Why not send Skype to headphone? Then there's no delay.
If you cut to you solo on the Blue Mic you obviously don't hear whats going on in Wirecast but you can watch the meters so you know the audio is happening.
For me the main thing is to hear and talk to my guest and not hear me in my headphone a fraction of a second later.

-------------------------
CraigS
Telestream Desktop Forum Moderator
 6/17/2010 4:37 PM
User is offline View Users Profile Print this message

Author Icon
zimode

Posts: 317
Joined: 7/7/2009

Yep.. you're right what I could do it is use VAC repeater (input headphone) to VAC1 => WC Audio Layer.. My partner in crime monitors the stream in our Website (with our chat room) so I know if there's any kind of problem..

I have another show next Wednesday and will switch it up a tad and see how I like it..

-------------------------
ATI Radeon HD 4650 1Gb
i7 860 2.8 GHz 8Gb ram
WIn7 64bit
 6/17/2010 4:46 PM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

Let me know how it goes.

-------------------------
CraigS
Telestream Desktop Forum Moderator
 6/27/2010 2:06 PM
User is offline View Users Profile Print this message

Author Icon
extremetour

Posts: 35
Joined: 6/16/2010

Thanks for your posts! I'm a little confused on the exact configuration that is being recommended. It's not working for me. Here's why:

1. From my experience, I can only use a microphone once as an input at the same time. So, if I use the microphone as an input for Skype, then I can't use it as an input into Wirecast at the same time.

2. From my experience, the skype output only captures my guest's audio. It doesn't capture my microphone.

3. From my understanding, I can only have one audio source into Wirecast at one time. Therefore, I couldn't have a mic and a VAC as sources. I'd have to run the mic through a VAC and then feed one source into wirecast.


Am I seeing something wrong? Can you be more specific on the configuration you have for vac and wirecast?

Thanks so much for your help!

Best,
Michael
 6/27/2010 8:16 PM
User is offline View Users Profile Print this message

Author Icon
zimode

Posts: 317
Joined: 7/7/2009

Extremetour:

I use WC for 3 different Websites.. The scenario below is the one that I use when we're live and taking questions from an audience (via Chat)..

Here's an example of my setup w/VAC - this works for me, but again what the heck do I know.. It's the simplest and I get decent results..

1) Audio Layer in WC - Blue Snowball Mic

2) Mic in Skype - Blue Snowball mic

3) Background layer in WC - VAC1

4) output in Skype - VAC1

5) Headphones jack with WC stream output ON (meaning I can listen to what is being streamed out )

6) DTP capturing screen from Skype -


I'm using a 2 shot deal..me & Skype (via DTP) very basic - but it gets the job done.

I also record it & put it up on the forum when I'm done. Here's the last show so you can see what it looks & sounds like:

http://escapeforum.org/index.php?topic=1196.0

-------------------------
ATI Radeon HD 4650 1Gb
i7 860 2.8 GHz 8Gb ram
WIn7 64bit
 6/28/2010 1:22 AM
User is offline View Users Profile Print this message

Author Icon
extremetour

Posts: 35
Joined: 6/16/2010

Wow! Thanks. I didn't know you could use the background layer in Wirecast as an audio layer. Very cool!!!

Now the only thing to figure out is using the same microphone in two places - Skype and Wirecast. When, I try to use the same Microphone, it doesn't allow it. Do you have two separate microphones connected to your computer or some other method that allows you to use one microphone in two programs at once?
 6/28/2010 11:28 AM
User is offline View Users Profile Print this message

Author Icon
zimode

Posts: 317
Joined: 7/7/2009

Extremetour-

Hmm.. my USB Blue Snowball Mic works in both apps at the same time (WC & Skype) so I never questioned why.. In my other shows I use a 2 Mic set-up, both USB and have no problem..so I would imagine use a 2 mic (1 for Skype & 1 for WC) keep it simple, heck a lapel mic for Skype as the quality isn't an issue for the skype call (going out). VAC will work as well for Mic, but I think it just adds another layer of complexity as it's just another thing that can go wrong.. In a Live set-up the simpler the better, especially if you can't control the quality on the other end (your Skype caller) who may or may not have any computer skills at all. So when something goes wrong (LIVE) you're frantically trying to figure out what the problem is. That why a lot of the other Skype call in shows use a capture card or audio Mixer & DTP to bring in both Video & Audio from another PC (Dedicated to Skype)..

But I must stress that I use the one headphone & listen to conversation/stream via the WC output, but again I'm used to it and want to keep things extremely easy.. I do have a audio mixer (as I used to do Podcasting - switched to video), but since I'm trying to get proficient in "low-tech - small footprint" approach, as I want to eventually use my laptop for remote on-location streaming and hoping the the 4.0 version of WC fits that perfectly.

-------------------------
ATI Radeon HD 4650 1Gb
i7 860 2.8 GHz 8Gb ram
WIn7 64bit
 6/28/2010 4:48 PM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

Wirecast is very flexible when it comes to handling audio.
First, Layers aren't limited to what their names are. You can put audio in Background Layer.
Both the Shot Editor and the Main Window have audio layers.

Here's what I did on a recent stream on the Mac side so I use SoundFlower instead of VAC but it's the same idea.

USB mic going to Skype

Skype going to SoundFlower

Create two shot in Wirecast in which A is my camera and B is Skype in Desktop Presenter.

In Shot Editor SoundFlower is audio source in Audio Layer bringing in guest on Skype.

In Main Window USB Mic is audio source in Audio Layer bringing in my audio (note USB Mic feeding both Skype and Wirecast. Also note Shot Editor Audio Layer and Main Window Audio Layer are both being used. This also gives me separate audio fader control for guest)

Speaker icon (monitor) is off in Wirecast. SoundFlowerBed (patches audio to output) sends SoundFlower (which is Skype) to my headphones so I can hear guest without me being delayed and heard in my headset.

Once you wrap your head (or ears?) around VAC (or SoundFlower on Mac) you can see how powerful Wirecast's audio features are. Admittedly not obviously intuitive but flexible. It's one way Wirecast excells compared to other utilities that only allow a single input source and require you to buy a mixing board.

BTW if you do have an issue with Mic working in two places (Skype and Wirecast) you can always have one feeding into Skype and use Camera mic selected in another layer.


-------------------------
CraigS
Telestream Desktop Forum Moderator
 7/20/2010 10:46 AM
User is offline View Users Profile Print this message

Author Icon
extremetour

Posts: 35
Joined: 6/16/2010

Thanks so much for your help. I'm getting closer to a solution.

I'm now using two audio layers in my shots.

My main problem seems to be the overflow on VAC where I'm converting the Microphone to the VAC1.

The overflow increases overtime and causes the audio not to sync with the video.

I've increased the total buffer to 300 and the buffers to 15. If I increase these any more, then the audio sync issue will actually get worse.

Is there anything else I can do to reduce overflow issues?

Is it being caused by using the Microphone in two places (Wirecast and VAC) at the same time?

Would it help if I just purchased another Microphone and used it on the same computer or is it impossible to have two microphones going into one sound card?
 7/20/2010 12:14 PM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

I need more details.
Wirecast would have two audio sources. One from VAC from Skype and the other from Mic direct. Are you saying it's the VAC from Skype that is not in sync?
Are you saying it's drifting out of sync over time?
Are you following zimode's setup?
Your post on 6/17 has a very different setup and zimode's is one that I'd recommend.

-------------------------
CraigS
Telestream Desktop Forum Moderator
 7/21/2010 3:14 PM
User is offline View Users Profile Print this message

Author Icon
extremetour

Posts: 35
Joined: 6/16/2010

Below is the setup I used:

VAC REPEATER 1 - Take audio from Microphone and turns into a VAC
Wave In: Microphone
Wave Out: Line 1 (Virtual Audio Cable)

VAC REPEATER 2 - Takes audio from the skype conversation (only the person I'm talking to) and outputs into my headphones so I can listen
Wave In: Line 2 (Virtual Audio Cable)
Wave Out: Headphones

SKYPE
Microphone: Line 1 (Virtual Audio Cable)
Speakers: Line 2 (Virtual Audio Cable)

WIRECAST
Background Layer - Audio Source: Line 1 (Virtual Audio Cable)
Audio Source Layer: Line 2 (Virtual Audio Cable)


After rereading zimode's post, I modified my setup to the following, and the microphone seems to be working in both places!!! Awesome.:

VAC REPEATER 2 - Takes audio from the skype conversation (only the person I'm talking to) and outputs into my headphones so I can listen
Wave In: Line 2 (Virtual Audio Cable)
Wave Out: Headphones

SKYPE
Microphone: Microphone
Speakers: Line 2 (Virtual Audio Cable)

WIRECAST
Background Layer - Microphone
Audio Source Layer: Line 2 (Virtual Audio Cable)

Thank you!
 7/21/2010 3:17 PM
User is offline View Users Profile Print this message

Author Icon
extremetour

Posts: 35
Joined: 6/16/2010

When I just rewatched some of the footage, I see that the individual coming in through skype has his audio and video out of sync.

Is the only way that I can correct that via changing the number and size of the buffer on VAC?

Is there anything else I can do?
 7/22/2010 12:43 PM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

I've often found Skype is actually the issue. I've recently had situations where Skype Audio was as much as 30 seconds out of sync with the video. So many people use VAC with Skype that I'd doubt that there's a major change in the buffer you'd have to do with VAC. Sometimes I'll recommend someone call back and it fixes the issue. You have do some testing to ensure that it's Skype at issue. One thing I do is use two Skype accounts and call myself from another room while Wirecast records a few seconds. It's a bit of running back and forth but generally it verifies that Skype can often be the cause of the issue. Maybe zimode will talk about his experiences as well.

-------------------------
CraigS
Telestream Desktop Forum Moderator
 7/22/2010 1:11 PM
User is offline View Users Profile Print this message

Author Icon
extremetour

Posts: 35
Joined: 6/16/2010

Thanks for the reply. I will now know to test out the Skype connection.

I'm assuming that the main cause for this would be connection speed, not the CPU/RAM of my guest's computer? Is that right?

At home, I currently have an upgraded version of Comcast Cable for my Internet connection. What would be the next level of upgrade on connection speed?
 7/22/2010 2:29 PM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

It could be connection speed but I've tested at my own location, making both the sending and receiving Skype over my ISP with a tested speed of 32Mbps down and 5Mbps up and found that every few calls, one would be way out of sync.

-------------------------
CraigS
Telestream Desktop Forum Moderator
 7/22/2010 3:56 PM
User is offline View Users Profile Print this message

Author Icon
zimode

Posts: 317
Joined: 7/7/2009

My understanding is Skype will throttle down & up based on the perceived connection and CPU usage.. that's why sometimes you see things slow down/out-of-sync in Skype. My last show (yesterday) had bouts of slow-downs & once the camera froze..I just roll with it and have the interviewee stop & start their video and it seems to correct itself. I would say that it's basically 1 out of 5-7 chance that Skype will have an issue, never catastrophic, at least for me anyway. But part of the problem is that I can't vouch for the other persons connection, they are usually remote on some sort of public WiFi.. My calls with my buddies (that are IT professionals ) are usually rock solid..BTW I'm running the Beta 5.0x Skype.. I also DO NOT have firefox running as sometimes I find that just goes nuts on the CPU for some unknown reason.. So when I do a show I just have those apps running that are essential to producing the show and highly suggest that both sides of the Skype call just run whats needed for the call, as you don't want something "kicking in" in the middle of a show..

-------------------------
ATI Radeon HD 4650 1Gb
i7 860 2.8 GHz 8Gb ram
WIn7 64bit
 7/23/2010 1:17 PM
User is offline View Users Profile Print this message

Author Icon
CraigS

Posts: 45143
Joined: 4/4/2007

Your frequency of Skype issues matches mine for the most part.

As an aside, given that Apple is open sourcing the technology behind FaceTime (which some see as a potential improvement over Skype's technology) I wonder where things might be in a year from now. Some say that FaceTime's interaction with servers has the potential to be better.


-------------------------
CraigS
Telestream Desktop Forum Moderator

FuseTalk Basic Edition v3.0 - © 1999-2014 FuseTalk Inc. All rights reserved.