Start a new topic

video sync offset. 3 frame delay on renderer.

Have you attempted to send a 2-pop to the renderer and to the output bus at the same time?  Im getting a 3 frame delay on the renderer.  This is not fixed with video sync offset It makes it worse. 


I've confirmed the same with another persons system. 


*Ive recorded the pops with my sony d50 and can confirm the delay is about 2.75 frames  

WAV
(2.81 MB)

avid confirms video sync offset works on internal video. 

ive aso used video sync offset in sessions for over a decade. 

while im waiting on hold for avid to give me a definitive Ive added 24qf to a different session and can clearly see the video is delayed.  So Im 100% certain that video sync offset affects internal video. 

I've also confirmed the issue on another persons system. 

its out by 3 frames. Confirmed by eye and then by catchin sync. 


I believe video sync offset does affect internal video.  I just posed the question to avid directly. We will have that answer shorty.


Regardless, When I set the video sync offset to 11qf catchin sync reports even greater latency. 5 frames or so. 

If you are using a quicktime locally i.e. without video hardware. does it look in sync? 

If not is it by 3 frames?


Video sync offset has no effect on internal video playback so just trying to track down where this issue is occurring


How can you do initial track lay if you are 3 frames out of sync? 


video sync offset isnt compensating for the delay of the renderer. 

Delay compensation and Video Sync are two different processes. 


1/ Delay compensation is not automatic with the Production Suite which is why it is advised not to do Mastering with the tools but rather initial track lay and final qc of Mastered content. 


2/ Video Sync offset should be functioning just fine. 

do my pops test.  Send pops direct to the speakers and a set of pops thru the renderer.  If delay is being compensated they will arrive at the same time. 

yes this is hdx2.  I am using the dsp versions of the plug ins.  Thanks.


I dont think the returns are reporting the correct latency of the renderer or protools isnt doing the correct delay compensation. Im seeing 6146 samples at 48khz. 


I believe that is 128ms?


3 frames is around 120ms.


So maybe the returns ARE reporting the correct latency but protools isnt doing the delay compensation? 


I am running 12.8.2

Hi Jeff.   Is this an HDX system?    If so please make sure to use the multi-mono DSP versions of the Renderer Send and Return instead of the Native versions as this can affect the latency of the renderer.   

Thanks.

sent.  Thanks. 

email it to vrcontent@dolby.com


Thanks

I cant change the frame rate as its tied to the video.  If you give me a email I can send a ptx file.  But the issue is within protools/the renderer not doing the expected thing with the video sync offset. 

Right, i'm just trying to understand why you are sending to the renderer and the output bus at the same time?


Does the issue change at different frame rates i.e. if you set 11qf at 30 fps does it behave differently than at 23.976 for example?


Could you share your test session for someone to take a look at?

Login to post a comment