Hardware for Multiclip playback

I'm starting to use Multiclip but it keeps dropping frames when playing 4 videos in my Viewer. All the clips are the same codec and frame rate. I've tried reducing the Timeline Playback to Low Quality and Half Frame rate but frames are still dropped. All video is coming from a second internal 7200 RPM hard drive.

What kind of hardware upgrade do people suggest (at a modest budget) to get Multiclip to play without dropping frames?

-- Jeff

Final Cut Pro 6.2
Mac OS X 10.6.2
Mac Pro 2 x 3 GHz Quad-Core Intel
5 GB 677 MHz DDR2 FB-DIMM RAM
ATI Radeon X1900 w/ 512 MB RAM

You didn't tell us what format you're cutting, so of course we can't make a recommendation.

But the math is real easy. Just take the data rate of one stream and multiply it by the number of streams. If one stream is 20 MB/s, then you need 80 MB/s to be able to play back four streams. Like that.

Of course I would forget a big piece of info. Sorry about that.

The format I'm editing in is Apple ProRes 422. I checked the Data Rate of the clips and they are approx. 15 MB/s. Totally that up with 4 videos thats about 60 MB/s. Checking the specs on my hard drive my thru-put is 70 MB/s. Am I too close to the limit of my hard drive?

-- Jeff

I am not sure if this is for everyone, however with my MBP if I only have a single track of audio that is unmuted when I am cutting the 4-6 angles of video I don't get dropped frames. (with SD)
(I do edit with a CalDigital VR via Sata) its ONLY when I have the 6 channels or 8 channels of audio associated with the different angles do I get dropped frames.

I have cut a 4 cam multi SD shoots over firewire 800 and used the same process without any dropped frames.

The big test will be tomorrow when I have to do 4 tracks of 720p, in prores.

Quote

Am I too close to the limit of my hard drive?

Yup. My personal rule of thumb has always been two-to-one. If you need to play back 60 frames a second, make sure your system can do 120. If you need 120, spec for 240. That's probably too conservative, but that's just how I've always done it.

>Checking the specs on my hard drive my thru-put is 70 MB/s.

Did you run a system test on it? 70 MB/s seems a little bit high for a solitary hard drive. Ideally you should RAID/stripe the drives to handle multiple streams of video.



www.strypesinpost.com

Wait a minute-- Mac Pro internal SATA's are supposed to support 3 GIGABITS per second, the SATA II standard, are they not? That's like around 375 MegaBYTES/second-- over 5 times the need described. Even with drive filling or fragmentation why is it coming out 70 MB/s?

Is the drive full?

Is Snow Leopard 10.6.2 compatible with FCP 6.x?

- Loren

Today's FCP keytip:
Invoke your Opacity/Audio Levels Adjust dialog with
Command-Option-L !

Your Final Cut Studio KeyGuide? Power Pack.
Now available at KeyGuide Central.
www.neotrondesign.com

>Mac Pro internal SATA's are supposed to support 3 GIGABITS per second

Yes. But the bottleneck is not in the interface. It's in the fact that the OP is (probably) running solitary drives, and the drive itself isn't spinning fast enough to read/write 3 Gb/s, unless you stripe them in a RAID. Server class drives are faster at 10k RPM, and SSD drives faster still (but much more expensive).



www.strypesinpost.com

Thanks Gerard for the info. Yes the specs are correct, at least according to our company tech guy. But he did suggested I setup a RAID. So currently as I'm typing this a RAID is be setup right now for me.

Thanks for everyone's comments.

-- Jeff

>Yes the specs are correct, at least according to our company tech guy.

Why don't you do a test yourself? Run the AJA system test. This graph will show you both sustained data rates as well as peak and average data rates you can expect off your drive.

[www.aja.com]



www.strypesinpost.com

Thanks for the app, Gerard. It will come in handy.

I did do a test and you were right. My estimate was a little high. My Write speed was 38.1 MB/s and my Read speed was 64.3 MB/s.

My tech guy is setting up a RAID for me today.

-- Jeff

Yea, the read/write off a solitary 3.5" 7200 RPM drive is somewhere between 35-60 MB/s. And those are averages. For video, you need sustained data rates, in other words, the graph at any point cannot dip below the threshold required for the single or combined video streams.

The alternate way to get multi clip playback on the cheap, is to allocate the different angles to different drives. That way, the load is split up.



www.strypesinpost.com