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MC 6 External Monitor latency issues/solutions (?)

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Ray Chung
MC 6 External Monitor latency issues/solutions (?)
on Jan 28, 2012 at 8:54:53 pm

Much of this has been discussed and documented elsewhere, more notably in Avid user forums, but I was wondering if anyone here had some new things to share. Forgive the length of the post, but I think it's ultimately useful to cover a lot of specifics when it comes to this....

In switching back to Media Composer from FCP, it's nice that MC 6 allows you to use non-AVID i/o cards and systems. Mine is a Blackmagic Multibridge Pro. In discussions regarding external LCD monitor issues, many have noted that LCD's usually have some inherent latency of a frame or two...maybe even more depending on what sort of picture processing you're asking it to do. The results being that your desktop project playback is ahead of your monitor playback by a few frames at least. My monitor is a JVC DT-20L1U, for which I use the BM's HDMI out to the JVC's DVI in via adaptor.

As many FCP users know, you can manually compensate for this in the FCP system settings by adding frames of delay etc, then check by playing your timeline on both your desktop and the monitor and watch the sync...and the audio follows suit and stays in sync with whatever offset you choose. And the amount of offset can vary between resolutions and codecs, but you can almost always get it spot-on.

With MC6, no such adjustment exists. There is a 'desktop delay' setting, but that only delays the actual picture on the timeline from the sound playback...probably meant to compensate for audio delays through various sound processors or what have you.....it doesn't do anything to the video monitor out. At, for example, a 1080p timeline...with ProRes or DnxHD, there is a set latency of about 2 frames from desktop to monitor, no matter what you set the 'desktop delay' to. As mentioned before, it could be the actual monitor doing that delay, because when I play a 720p timeline/project in MC, there is no delay. The monitor itself is downsizing a 1080 to fit on its slightly smaller native-res 20" panel, whereas a 720p is upsized or perhaps treated as more 'native'....so perhaps the monitor is taking more time to process a 1080p than a 720p. But again in FCP you had an adjustment for that, in MC6 you don't.

Discussions in places like the Avid users group note some solutions of using an audio delay device between the system's chosen audio out and mixer/preamp/speakers to at least have the monitor be in sync with audio upon ultimate playback...but the discrepancy between desktop/project and monitor still remains and can be very annoying for some, whereas in FCP, it could be taken care of in-program. I am looking to upgrade to a 24" 1080-native monitor anyway (probably another JVC) and hope that with it being native 1080, it will not have the latency issues like it does on the 20". But then, I'm also wondering if it's the MC6-to-Blackmagic that's having the issue with 1080 and not 720. I have yet to try the BM's component out to anything, or a CRT monitor or the SDI direct as comparison to see if it's specific to the HDMI.

From looking around, there's apparently something to be found in an Avid-made program called "Video Satellite" which seems to allow using Avid-edited video from one computer while using ProTools on another...which I don't need. If you look here...

http://avid.custkb.com/avid/app/selfservice/search.jsp?DocId=367331

...it talks of entering commands in MC6's console...but from what I can tell, it only works if you have Video Satellite...i.e. it's not a command that has any function in MC6's console without Video Satellite.

So basically...are we truly stuck with this issue of always having a delay between system and monitor, or has anyone out there figured a way to compensate for it internally like you can in FCP? Also, have those using AJA, Matrox, etc. cards/boxes noticed the same thing consistently, and/or have Mojo Nitris/Dx users not had it? Thanks in advance for people's patience and understanding.



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John Pale
Re: MC 6 External Monitor latency issues/solutions (?)
on Jan 28, 2012 at 10:22:34 pm

I have the 17 inch model from the same series as your 20 inch. It has a low latency setting that solves any issues for me. Does the 20 inch model have this?

BTW, the delay setting in FCP is primarily for situations where you are using a Firewire device to monitor video. Firewire introduces a significant delay, usually 4 frames or more. The delay setting affects the desktop display to make it match the output via firewire. If you are using a capture card, the setting is supposed to be changed to zero, as there is no delay.

The delay setting in MC does the same thing.


In most edit rooms that I freelance in (with avid dx hardware), there are audio delays installed to bring the audio in sync with the video monitor. I don't have them in my home system, as the JVC low latency setting does the job for me.


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Ray Chung
Re: MC 6 External Monitor latency issues/solutions (?)
on Jan 28, 2012 at 11:51:38 pm

Thanks for replying, John. I'm not aware of a latency setting on my monitor...is it in the menu? Can't seem to find it in the settings or any mention of it in the manual, so maybe just your version has it.

I hear what you're saying about the delay setting in FCP originally meant for firwire, but it doesn't seem to work the same way in MC6. When it delays in FCP, the audio stays in sync with the video through the BM. With the MC6 one the audio stays in its original sync with the video playing however many frames later that's indicated. At least that's what's been happening with mine. On my FCP system, I set the 'frame offset' from 4 to 5 with a 1080p sequence, to 2 for a 720.

Again, it's understandable that there may be some unavoidable delay in the external hardware used in conjunction...and that can be compensated for on the tail end with audio delays et al. But this really should be a function in MC6 like it is in FCP to take care of it beforehand.

I guess it also has to do with the 'video out' in FCP, like firewire, being something that's indicated specifically...whereas in MC6 you can choose HD or two other things, but the video out via whatever PCI-E you use is a constant setting with just an on/off toggle....hence the desktop delay not having the same effect on it.


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Ray Chung
Re: MC 6 External Monitor latency issues/solutions (?)
on Jan 29, 2012 at 4:38:32 am

Also, when I use the Blackmagic Media Express to just play back 1080p material from a drive as if I was going to tape, there is no noticeable delay on the monitor. So it seems to be more of a case of the Blackmagic somehow having some delay coming out of FCP and Avid.



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Lee Warner
Re: MC 6 External Monitor latency issues/solutions (?)
on Jan 30, 2012 at 11:00:12 pm

I have a JVC 24 inch reference monitor in one suite and a FSI 17 inch in another. In both instances I take the audio from the monitor which strips the embedded audio from the SDI stream and sends it out from an analog jack. Any delay issues are compensated for with the monitor electronics.

Lee

SAMDOG Digital Post
Calgary, Alberta
Mac Pro 2.66 12-core 16gb ram • FSI LM1760W Monitor • Matrox MX02 • Caldigit HD One 8tb Raid • Avid Artist Transport • Media Composer 5.5 • Final Cut Studio 3 • Premiere Pro CS5

• Living my life one frame at a time •


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Ray Chung
Re: MC 6 External Monitor latency issues/solutions (?)
on Jan 31, 2012 at 11:40:35 am

Thanks Lee. Yeah, embedded audio can come from the monitor or even an adapter. It'd be a little less of a pain when I was using a mixer for my audio as I could just put it on another channel and keep it open. These days, I use a JVC MSC-1, so you can only choose one channel at a time. As mentioned before, I'd attribute the latency mostly to the monitor itself...but it doesn't show any latency when I play a 1080 clip through the Blackmagic Media Express app...so it seems to be happening with FCP and MC. And...the audio is set to always come from the balanced audio outs on my Multibridge (or out of the Intensity Pro on my other computer)...and that's always in sync with the edit in the app/desktop. So something with FCP and MC is causing a delay in the (in my case) HDMI out, apparently irrespective of the monitor....on both the Multibridge and an Intensity Pro...when neither experience a delay with Media Express.

Again, easy enough to work around with FCP's frame delay, but not so on MC's. Does anyone out there that uses or used a Kona or other PCI-e interface with FCP set their frame offset to zero?



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John Pale
Re: MC 6 External Monitor latency issues/solutions (?)
on Jan 31, 2012 at 9:58:29 pm

[Ray Chung] "Does anyone out there that uses or used a Kona or other PCI-e interface with FCP set their frame offset to zero?"

Yes. Thats what you are supposed to do. If you don't, you are really out of sync.


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Ray Chung
Re: MC 6 External Monitor latency issues/solutions (?)
on Jan 31, 2012 at 10:29:49 pm

Thanks John. Yeah, I have read through a couple of discussions with AJA users and it seems to vary....some work with a 0 offset, some with other numbers. With FCP and the Blackmagic Multibridge, it was the same on two different computers, 5...and there was no latency when playing video on Media Express.



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