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Topic Title: Video Lag/Audio Sync issues
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Created On: 4/4/2012 5:00 PM
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 4/4/2012 5:00 PM
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smswise

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Joined: 4/4/2012

Just bought Wirecast Saturday, love the program but a few issues maybe someone can assist with. Here's my setup:

OS: Mac OS X 10.4.3
Computer and CPU (PPC, Intel): 3.2 GHz Intel Core i3
Input source of the video/audio: Audio: Built-in audio from sound board, Video: DV-VCR
complete hardware setup used for streaming: Camera directly to computer via firewire, audio plugged into mic-jack directly from auxiliary out on sound board
All software versions including drivers: Using Wirecast 4.1.3
Server and/or CDN: Flash Media Server
Wirecast preference settings (be complete):
Encoder: H.264, Width: 760, Height: 480, FPS: 30, ABR: 768kb/s, Profile: Baseline, Key frame: 90 frames, Timecode: off, AAC: Stero, 128kb/s, 44.1kHz

Here's my issues/questions:

1) The quality of the video is outstanding, but the video is getting about a two-second delay from the camera to the computer. Considering we use the computer screen as our preview to pan the camera left to right with a remote, this has presented a considerable problem because our panning is about two seconds (approx.) behind the speaker. Is there a setting I need to change or perhaps a cable problem?

2) The audio feed, via built-in input from our sound board, is on a one-second delay (approx.) So not only is it delayed, but it is not matching the speakers voice and causing for degraded quality for our live-stream audience.

3) My camera is an HD camera, and the camera is saying it currently has an HDV output. Why, then, is the camera registered as a DV camera in the program?

Any thoughts and assistance is most appreciated.

Thanks!

SMSWise
 4/4/2012 5:45 PM
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CraigS

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Joined: 4/4/2007

OS 10.4.3? Might you mean 10.7.3?
HDV will lag because of the time it takes to decode the codec. Make sure your camera is in DV mode.
Audio will tend to be ahead of the video from HDV camera due to the aforementioned lag.
Also check Wirecast Output Statistics CPU% while streaming.

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CraigS
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 4/4/2012 5:47 PM
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smswise

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Joined: 4/4/2012

Sorry, long day. Did mean 10.7.3. When camera is in DV mode, Wirecast does not show video, only a blue screen. The interesting part is that, although the audio is ahead of the video in the program, in the actual stream the video is ahead of the audio. CPU is steady between 35-40%.
 4/4/2012 6:01 PM
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smswise

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Update: I found a setting on camera hadn't seen before. Dropped it down to DV, and the lag has stopped and audio is matched. I guess we're stuck with a lower quality for now, until we can get a computer with a faster processor?
 4/4/2012 7:51 PM
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CraigS

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HDV lag is inherent to the codec being decoded compared to audio. With Wirecast Pro if you bring in the audio separately, you can delay the audio to match the video. HDV itself does take more CPU resources to decode. Newer cameras with HDMI out (or HD-SDI on the high end) avoid that issue as they send out uncompressed video. On Thunderbolt Macs you'd be able to use various Thunderbolt boxes from Blackmagic or Matrox to bring it in. On MBPs with Express ports the Matrox box would work. There's no lag in that.

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CraigS
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 4/19/2012 6:48 PM
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sconway

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I'm using Wirecast 4.1.3 and having an audio sync problem My video is delayed when I play a Quicktime. I'm using Mac OS 10.7.3 on an iMac (3.06 GHZ Core 2 Duo). Will I experience the same delay on live SD camera feeds and will the sync delay on Wirecast Pro fix the audio sync?
Here's the quicktime info:

Size: 704x480
Codecs: H264 & AAC
Duration 4:29
Total bit rate: 1,583
Encoding software: MacOS X 10.7.2
 4/19/2012 9:27 PM
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CraigS

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I'm not sure I understand your issue. Quicktime is .mov but could be any number of codecs.
Can you tell me the codec?
Can you tell me how it plays in Quicktime 10.1?
Can you tell me how you are monitoring playback?
There are no audio sync issues with most camera inputs except HDV and that's due to the nature of the GOP based codec being decoded.
Wirecast Pro allows you to adjust sync on separate live input sources since signal processing based on different signal paths can result in audio being delayed against some video sources.
For playing back files I find Apple Intermediate Code Quicktime works best.

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CraigS
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 4/19/2012 11:57 PM
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joedemax

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The other option is to run the audio into the inputs on the camera, then it will all be synced in HDV mode, as the latency is the same.

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Joe de Max - @joedemax on Twitter
 4/20/2012 11:31 AM
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CraigS

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Often times, HDV muxed with audio is not in sync. It takes some miliseconds longer to decode the HDV video than the audio. Many people can see/hear this. I can. I've tested my Sony EX1 which can send HDV out of firewire or send uncompressed out of SDI. SDI is in sync. HDV audio leads video. Since it's muxed (not separate) Wirecast can handle the audio separately to adjust the sync. Bring in the audio another way and you can adjust it. Use HDMI or SDI and there's generally no issue.

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CraigS
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 4/20/2012 5:57 PM
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sconway

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I'm using SD and experiencing audio lag both during record to disk monitoring on an external display and when I play back the recorded quicktime file on my computer I'm using a MBP iCore 5 with 8 meg RAM. Again, here's the codec info:
Size: 704x480
Codecs: H264 & AAC
Duration 4:29
Total bit rate: 1,583
Encoding software: MacOS X 10.7.2
I'm also experiencing intermittent crackling on the audio. It not recorded interference. It is a playback issue. Sometimes it occurs when I switch to a shot, goes away when a switch again and may or may not happen again when I switch back to that same shot or some other.
 4/23/2012 11:59 AM
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CraigS

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I'd like to help but there's not enough information. Please read READ BEFORE POSTING near the top of this forum.
I need to know your input devices and sources attached to them. I need to know what you're hearing in Wirecast Layout/Master Audio.

Generally please don't add to a thread in progress unless you're certain you have the same issue. Similar symptoms have different causes. This thread points to HDV. If that's your case then the thread indicates the solution. HDV has an inherent delay due to the codec.

Also update to Wirecast 4.1.3.

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CraigS
Telestream Desktop Forum Moderator

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