Back in July I tested the AJA T-Tap with Pro Tools to see if a small simple diminutive box could meet the needs of audio professionals needing to work to picture.
Conventional wisdom was that if you wanted accurate sync between picture and audio, your Pro Tools must be clocked to the same video reference (via the Sync peripheral) as your video I/O interface (Mojo or Blackmagic). This practice would reduce two important things:
- The randomness between audio starting and video starting (as audio would be timed to start on the frame edge boundaries) between each play pass.
- Any drift or meandering during a single play pass (like desktop video in Pro Tools 10) as the audio and video are both resolved to frame pulses.
This is good basic engineering practice and is still the perceived wisdom of the day.
The AVE in Pro Tools 11
When Pro Tools 11 arrived, the new AVE promised to do serval exciting new things:
- To release the dependancy upon Avid media (MXF) for accurate sync - as the QT engine was no longer in use.
- To release the need to transcode media - any media was playable.
- Have more accurate desktop playback.
- Playback on desktop AS WELL AS out the video peripheral.
You can see the tests and results for the AJA T-Tap in my Review & Test: AJA T-TAP - Professional Thunderbolt Portable Video Monitoring. Today we are going to look at the Blackmagic UltraStudio Mini Monitor and see how that performs.
I have been loaned a Blackmagic UltraStudio Mini Monitor (thunderbolt to SDI/HDMI) portable video monitor by friend of PTE, David Yorath to undertake these tests.
The Ultrastudio Mini Monitor (USMM) has a Thunderbolt connector on one end and a BNC SDI and a mini HDMI at the other end. Simples. It's a very similar diminutive size similar to the T-Tap and just like the AJA T-Tap, no video references are required. I also wanted to test the BM Mini Monitor on both the Windows and Mac platforms to see if there is any difference. All measurement duties (to 1/100 of a PAL video frame) were taken care of by my Harkwood Services Sync-One2 as with the T-Tap tests.
Testing The Blackmagic Mini Monitor On Windows
For the Windows test I went over to 8dB Sound, run by fellow PTE team member Alan Sallabank, to his new post production surround studio in leafy Chingford, North East London.
Alan runs a custom PC with an i7 5700 6 core processor, 16GB DDR4 ram, NVidia GTX 660Ti Gfx. He runs Pro Tools HD 11.3.2 on Windows 7 Pro (SP1) and runs PT HD on non-Avid hardware - a RME Fireface 802, connected via USB (as recommended by RME when using with Windows) and Alan's Blackmagic Mini Monitor is the pci-e DeckLink version.
Alan runs all his media runs off SSDs, and so doesn't use the RAM cache. For video duties he runs an Epson LCD HD projector and HD LED screen. We had his DeckLink Mini Monitor running with a 6qf of Pro Tools video delay compensation to compensate for latency on the projector. We also measured the LED HD monitor for completeness.
Results Of The Blackmagic Mini Monitor On Windows
We noticed that the Blackmagic Mini Monitor slews into sync on this particular set up. By the third of the flash/blips it was solid, with only the occasional wiggle or perturbation of around a few 1/100's of a frame.
The steady state playback was very solid and similar to the AJA T-Tap. However we noticed that each play pass had a higher variation in latency than the T-Tap with the variance between half a frame or so behind to a quarter of a frame ahead. Sadly we were having so much fun we forgot to video the test results, so you will have to take our word for how well it did.
Testing The Blackmagic Mini Monitor On Mac OSX
Back at my own Twickenham post production surround studio, Mikerophonics, I re-ran the tests with the following set up:
Pro Tools PC - 3.5 Ghz Quad i7 (8 core) with 32GB DDR3 RAM, running in Mackintosh mode with OSX 10.10.3 with Pro Tools HDX 11.3.2 and the latest BM desktop video 10.5 software.
Results Of The Blackmagic Mini Monitor On Mac OS X
On the Mac OS, the Blackmagic UltraStudio Mini Monitor was very flickery and jittery playing 1080i50 video with the output mode set in Pro Tools to full 10 bit video mode, with obvious double flashes.
However the playback was much more stable in draft mode.
Finally here is a video of one play pass....
The sync was all over the place compared to Windows performance, with drift and perturbations during a play pass giving a span of over 306 ms - i.e. 7.6 PAL frames!
Whereas the AJA T-Tap on the same system had only an 8 ms average difference (less than 1/4 of a frame) or about 27cm extra distance from the speakers in terms of time of arrival difference!