Transcode AVCHD for FCP

D

dsmpls

Member
I work with FCP and usually shoot with a Sony EX3 and HMC150. I just spent a week transcoding 16 hours of AVCHD footage, so I decided to do some simple tests to see what I could speed up.

First, I currently use a 17" MBP 2.16 core duo with 2 GM DDR2. My scratch discs are a mirrored Firewire 800 drive and an eSATA drive using the Firmtek Express 34 card.

First, I used Log and Transfer within FCP to transcode a 5 minute test clip shot 1080/60i to Apple Pro Res 422. Then I tried using Toast Titanium 10 to transcode the same raw clip to Apple Pro Res 422, DVCPRO HD, and XDCAM.

Here are the results:

Log and Transfer to Pro Res
Time: 14:05
File Size: 5.14 GB
Duration: 5:00.25

Toast to Pro Res
Time: 15:32
File Size: 4.98 GB
Duration: 4:59.29

Toast to DVCPRO HD
Time: 12:21
File Size: 4.07 GB
Duration 4:59.29

Toast to XDCAM
Time 46:05
File Size: 1.27 GB
Duration: 4:59.29


So the DVCPRO HD was marginally faster, and the file was about 20% smaller than Pro Res. The XDCAM made a relatively small file size, but took almost 3-4 times as long.

Also, not during this test, but while I was transcoding long clips during the weekend, the Log and Transfer method several times gave me only partially completed files with no warning or error messages (durations of 35:00, say, instead of 48:00 of the original).

SO, this brings up several questions:

I'll be upgrading to a new MacPro soon -- what options will give me the best performance boost in transcode times? Faster processors? More RAM? Internal drives? External devices (AJA, Blackmagic, Matrox)?

Is the difference in duration because of how the pulldown is handled?

Anyone else have Log and Transfer complete only partial clips?

Any other settings or workflows that are better?

Thanks!
 
I'm afraid I don't have an answer for you, though I would assume processing speed will really turn the tide when it comes to transcoding time.
I just bought an HMC 150 and should be getting it shortly. I have a MacPro (early 08, octo-core), so I'll be happy to post my render times for you once I take some test shots.

Since, DVCPRO HD transcode size seems to be shorter and produces smaller file size, what exactly is the benefit of transcoding to Pro Res via log and transfer? I mean, considering that DVCPRO HD is pretty reliable codec that seems to play well with a lot of NLEs, would there be any disadvantage to using that vs ProRes to edit in Final Cut Pro?
 
Processors, processors, processors...

And an internal hard drive might help a little, and provide some more stability and security. External hard drives can be finnickey sometimes
 
It's pretty much all CPU for now. More cores first, then speed. So if you're deciding between a faster 4-core or a slower 8-core, definitely go with the 8-core. Watch the Activity Monitor while rendering and you'll see that FCP does a pretty good job distributing across all cores, though never really fully maximizing each CPU. When Snow Leopard/Grand Central comes out, this might be optimized even more.

What will be interesting to see is if they build OpenCL optimizations to Final Cut Studio 3.
Then your GPU might also come into play.
 
I believe that your bottleneck is your MBP. WHen you get to the macpro all will be right in the world. Right now, I use a friends macpro and the transcode times with his 4 core mac pro are really great.. takes about as long as the DVCPRO did on my G5 when I had an HVX. I personally can't transcode the 150 footage through FCP on this G5, and Toast and Voltaic are painfully slow.

On his Mac Pro, the footage takes about 40 percent of the runtime to transcode so it's not that bad at all. On my macbook dual 2.0, it takes about 3x the runtime or more. Really really slow.


Cheers and on an 8 core macpro, I'm sure you'll be in the .30 times or so, and if FCP3 is native editing well then we'll all be good on that.
 
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