HD Multiclip editing in FCP7

[Simon Green]

Hi Shane

I am back doing another edit on XDCAM HD. I have 9 steams which I have converted to Pro Res Proxies so the data rate is about 5.8mbs. The streams play ok in the viewer, However as soon as I click on another stream to make an edit point on the timeline, I get the “Warning – dropped frames” message. Everything is set to what it should be (dynamic playback, closed other seqs & projects) and so I tried to lower the data rate in the proxy setting in Compressor and create new proxy files. But I can’t seem to adjust the data rate in the Pro Res proxy setting, even after I have duplicated the setting.. HAve you had this problem? Is there a compressor setting I could try? Does Pro Res proxy even work?

I am on a 2×2.93 Quad Intel with 8GB DDR3 RAM running from an xserve with 32TB Sonnet drives on a fibre connection so the system speed should not be an issue.

Cheers

Si

[Jared Jordan]

I’ve had similar issues with FCP for that last several months. LOTS of crashes. Oddly enough, when working with my MacPro, 32 GB 1066 MHz DDR3, 2 x 2.93 GHz Quard-Core Intel Xeon, Kona 3, Apple XRaid, I’m having these issues. When putting a project on a firewire hard drive and editing from home on my iMac, it doesn’t crash. I’ve tried uninstalling the Kona 3 software, but that didn’t make a difference. I’m also editing everything using Apple ProRes codecs… from proxy to HQ, but still have the issues. Every time there is a software update from Apple or AJA I cross my fingers and hope the problems will be solved. Has anyone figured out these issues?

[Christer Molander]

Just to sum up. On a project that we mastered out before summer and was aired a week ago. 4 streams of ProRes HQ. It´s not about anything else than the discs seeking time.
We divided the material evenly over two RAID groups on the same DX800RAID and voliá – everything worked like a charm.
So my saying is; it´s not the CPUs, It´s not the throughput, it´s the discs seeking time. And that´s why AVID is working. They know about this from ProTools were you can work with many tens of streams that are cached up before playing out.
Well that´s my guess anyway.

[Chris Cameron]

I’m seeing this yet again on very large project. We have transcoded to Proxy and it made it better but still performance issues. Unfortunately we don’t have the luxiary of splitting into two RAID groups and considering one of these experiences entailed media on an XSAN I’d say this a real bug. When you say seek time, do you think that simply having a folder structure like Avid where all media is contained in one folder and has database files would make all the difference? why apple never integrated that function into the FCP universe is beyond me. Does anyone have any other suggestions for tweaks that might help ease the pain? Tried just about everything i can think of.

[Christer Molander]

Seek time – I mean the discs seeking time. The hardware. But now this has taken a new turn. After two loong conversations with Sonnettech support (they really try, and knows a lot, but not all about this) we now get a troughput of 8 ProResHQ 720p50 and 8 streams if 24/48 audio. Pretty impressive.

We found out that trying to bypass the cards caching will let the discs use it´s internal caching.
So what we did was setting up the ATTO R380 card like this. Everything as recommended in the manual except;

SpeedRead = adaptive (SpeedRead specifies the cache policy to be used during read operations. Once a read command is given, the ExpressSAS RAID storage controller retrieves the next set of sequential data from the RAID group and caches it in internal memory. If you select Never, read caching is never performed. If you select Always, read caching is always performed. If you select Adaptive, the default, SpeedRead is enabled or disabled depending on the sequential patterns detected in I/O requests.)

Prefetch = 0. (Prefetch specifies the number of stripes that are read when SpeedRead is enabled or adaptive. The valid values for Prefetch are 0, 1, 2, 3, 4, 5 and 6, and the default value is 1. This property can only be changed after the RAID group is created. To access this property, select the RAID group and view its properties.)

Hope this help
/Christer