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What is the reclocking latency in Milliseconds?

Posted by CaptainCapitalism 
What is the reclocking latency in Milliseconds?
February 06, 2017 09:09PM
I just ordered an HDMI video delay system (1st pic below; Roland vc-1-dl) and would like to add the Vanity's latency time (on top of the Trinnov's latency's time I have downstream.)

As per the attached pics, the Trinnov's + speaker distance latency time is 40 ms. Very cool that Trinnov is upfront and tells you the exact latency in real time. The latency changes with 96khz.

Since the Roland only delays by (1/2) frame rates (they call fields) and I most of the time watch 1080p60, I am 2.26 frames behind with just the Trinnov as per the 30fps screen shot below.

If the Vanity latency is 10ms I would be able to "dial" in 2.5 frames.

If you look at the 2nd pic, the Trinnov 24fps, the delay is .91 frame. If the Vanity is a mere 4 ms delay, I would be able to dial in 1 frame. Even.

I know nothing about syncing A/V, but I would not round frames. I would not want to be ahead a pic/frame. So if the Vanity has no delay I would have dialed in .5 frame. But if the Vanity delay is 4ms I can do a frame.

Yes, I would have to manually dial in the delay when I switch 24fps vs 60fps. But I am manuallly putting in BD anyway...
Just hope I remember to put it back smiling smiley. BD frame rates are more than double the ms time of 60fps.


30fps delay

24fps delay:

Edited 1 time(s). Last edit at 02/06/2017 11:25PM by CaptainCapitalism.
Re: What is the reclocking latency in Milliseconds?
February 08, 2017 12:39PM
Hi Captain,
The latency of the digital reclocking is mainly the latency of the FIFO buffer. The buffer is 32 samples long and under ideal conditions the FIFO utilization is kept at 50% (in the middle), thus 16 audio samples. For PCM material there is only additional IO delay of about 4 samples. Therefore the time delay depends on the sampling frequency and is approximately (assuming 20 samples delay) 0.4ms for 48kHz and 0.1ms for 192kHz.

For DSD (SACD playback) there is additional delay introduced by DSD to PCM conversion, which is roughly 10 samples, so the total delay for SACD playback is ~30samples at 176.4kHz (0.2ms).

I personally think such delays are negligible and nothing to worry about, but you may have a different opinion smiling smiley
Unfortunately there is nothing we can do about A/V synchronization on the Vanity board itself.

Re: What is the reclocking latency in Milliseconds?
February 10, 2017 10:19PM
You have achieved an amazing first in playback history. More on that later.

Not only do I agree, scientifically it is negligible.
There is 16ms in a pic. 40ms when 24fps. Logically, When the original engineers embed the audio, they have a 40ms leeway. Same pic the entire duration. Probably why the Roland delays by frame

Anyway, I can now, to the 1/10 of a millisecond sync the A/V. No playback system has ever achieved this.

No PrePro can come close to that. Engineers don't have to bother.
Anyway, after speaking with professionals, we only have the science to test a/v sync to 2 ms at listening point.

Based on your info:
I can add a delay in trinnov to the 1/10 ms to match an even frame by adding an (additional) delay. Funny, both A/V is buffered. I now have a complete memory a/v playback.

I will have one of, if not the first, to the 1/10 ms a/v synced playback at the listening point system in the history of the world. Not possible without the Vanity. This is exactly why the Vanity should exist.

I'll report back once working.

Re: What is the reclocking latency in Milliseconds?
February 18, 2017 08:17PM
Hi Captain,
Thanks for your appreciation. smiling smiley
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