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Author Topic: maximum delay of corrrection for audio to video  (Read 1525 times)

RC23

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maximum delay of corrrection for audio to video
« on: August 28, 2013, 01:31:07 pm »

JRiver delivers the opportunity for lipsync if convolution and active network produces a time delay of audio to video. I will build a 5.2 setup with 4-way speakers as satellites. Acourate delivers the FIR filters for convolution and active network.

What is the maximum of time delay which JR is able to handle?

I suppose that every additional channel increases the CPU load and not the time delay. Is this right?

Ruediger
 
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Matt

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Re: maximum delay of corrrection for audio to video
« Reply #1 on: August 29, 2013, 10:40:19 am »

There's no hard limit.

DVD playback won't work with more than a few hundred milliseconds of latency.  Audio and most other video formats work with any amount of latency.
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Matt Ashland, JRiver Media Center

RC23

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Re: maximum delay of corrrection for audio to video
« Reply #2 on: August 30, 2013, 07:30:53 am »

The latency comes by Acourate a software for room correction and digital frequency crossovers. http://www.audiovero.de/en/

Here an estimation downward for online convolution: With 65536 taps for example you get a latency of 743ms. Acourate works easy with higher number of taps such as 262144 which produce a latency of 2972ms. And this value is to high for JRiver which is only applicable for maximum 2500ms.



The latency [ms] will be calculated by dividing half of filter length by sample rate.

The value 2500 I have found in a posting of Bob Katz who had initially a problem with to high latency. http://yabb.jriver.com/interact/index.php?topic=76969.msg553500#msg553500

More latency comes by ASIO buffer size up a maximum of 2048 samples. I will use an 8-channel Focusrite Saffire 40 Firewire interface for a 4-way active loudspeaker.

It would be fine if you increase the maximum latency from 2500s to 5000ms. This value delivers a future-proof solution for further steps with Acourate.

Ruediger
  
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