HD Editing in FCP with MBP ?

Hello Everyone,

I am hoping you can all help. My manager has bought a Mac Book Pro and a fairly comprehensive editing system, and asked me to help him set it up. We have, however, hit upon a few problems - and have received wildly varying responses from the various professionals we have asked. Hopefully someone on here will have had experience with these kind of issues.

So here goes, and apologies for my first post being a long one .....

Specs:

- Computer is a Mac Book Pro. 2.5GHz Intel Core 2 Duo processor, 4GB Ram. Running OSX v10.5.7.

- Software is Final Cut Pro v7 (I believe he actually has the full Final Cut Studio package).

- Interface Hardware is an AJA IOHD box.

- External HDD is a 4TB G-Raid.


Scenario:

- As MBP only has 1x FW800 port built-in, an Express Card with 2x additional FW800 sockets was bought (a "Sonnet" something-or-other, if memory serves correctly). HOWEVER, this didn't work. A little googling found that this particular Express Card did not work with the G-Raid.

- Next thought was to get an Express Card with an eSata port, as the G-Raid has an eSata connection too. eSata is faster than FW800, right ? As I understand it the limit here is down to the speed of the physical drive rather than the eSata connection ?

- 1x Express Card with eSata port purchased. Testing the water here, he bought what I would describe as an "el-cheapo" card at approx £20. The mindset here being that at that price it was worth a go, and if it didn't work we would only be out 20 quid.


So, with this little lot all connected up I started trying a few things. First thing to notice was that trying to launch FCP with the AJA IOHD box connected to the FW800 port caused FCP to "unexpectedly quit" right after opening. Open FCP with the AJA IOHD disconnected, then connect it afterwards and all is well with the world. Whether the Express Card was connected or not made zero difference. Something seems not quite right there, and it may be a clue to problems experienced later, but for the moment I let that particular oddity slide as we could work around it ....

Now that we could get FCP up and running (albeit with a bit of a bodge to get it started), we tried to capture some footage. The footage is on HDCam (HD DigiBeta) at 1080i, so we want to capture at the best possible resolution - we chose 1080i25 10bit uncompressed.

Using "Log & Capture" I get a lot of glitches on the footage as it is being captured (and also when the captured clip is played back from the timeline as well). No reports of dropped frames or anything during log & capture, however.

I accept that 1080i25 uncompressed is a lot of data to be throwing around, so I tried capturing at all manner of lower settings (Apple Pro Res, etc). Nothing captured and played back cleanly until I got down as far as capturing at SD (625i25 10bit uncompressed).

Thinking that it may be an issue with the eSata Express Card, I disconnected this and restarted everything, then set the FCP scratch drive to the internal MBP drive. As expected, this did not work. Lots of glitches, but also a "dropped frames" warning after about 1.5 seconds of capture.


So, armed with all this info, I called a few FCP experts. So far I have been told :

- "It should be possible, I've done it plenty of times."
- "It should be possible, but best to limit yourself to 720p rather than 1080i" (this one confused me as I thought the data rate would be similar).
- "Can't be done as the Express Card slot is on the same bus as the onboard FW800 port".


I guess what we really want to know is, are we being caught out by the el-cheapo eSata Express Card or is what we are trying to do just not possible ? If we go and spend big bucks on a "known and trusted" Express Card will we get a working solution, or will we be wasting our money ?


Thanks everyone for reading this long-winded ramble, and thanks for any advice or help you can offer.

Jon Mitchell

HD Editing in FCP with MBP

Hi Everyone,

No-one got any thoughts on this one ? Even if it's "you can't do that", at least we'll know.

Thanks,

Jon

not sure if this helps or not.

But I use a Macbook, just entry level, std 600.00 one.
and Western Digital 1.5TB USB 2.0 MyBook Studio External Hard Drive with FireWire 800, and a Hauppague HD-PVR.

I can record in 1080, and dump direct onto the hard drive.

I don't have anyproblems.

BigRob: Big difference. capture from Hauppague is a VERY low bitrate compared to 1080i25 uncompressed - the Hauppague tops out at about 17Megabits/s (maybe 24, but most capture software I've used with my HDPVR has a top setting of 17).

jonmitch: It looks like you're *most likely* problem is your overall throughput. This is a guess as I don't have and have never worked with HD DigiBeta - but looking at some numbers on the container you plan to store the data in (1080i25 10bit uncompressed) it would require a record rate capability of:

10 bit @ 1920 x 1080 @ 25fps = 132 MB per/sec, or 463 GB per/hr. (numbers from: Blackmagic Design: Support Detail )

and according to Apples FCP 7 manual (see: Final Cut Pro 7 User Manual )

Uncompressed 10-bit 1080 29.97i HD video 166 MB/sec. (figure maybe a bit less at 25 rather then 29.97)

You would need a dedicated drive array that can reach/maintain that transfer rate - 132~166 MegaBytes / sec - this is above FW800 capability (maxing out at about 100MBytes/s)

The internal drive obviously won't work.

you'll need an express card esata adapter to make it work - and one that is compatible with OSX (and the drive ) I honestly don't know what card that is, but I'm sure asking other owners you'd be able to find one.

HD Editing in FCP with MBP

Hi,

Thanks for the responses so far.

Nethfel - the AJA IOHD box takes the HD-SDI signal in from the HDCam deck and connects to the MBP via FW800. Assuming that FW800 does actually max out at about 100 MB/s, then how am I recording in 1080i25 10-bit uncompressed ? I'm not in any way doubting your figures, it just seems that it might not add up - and maybe that's where my problem lies ?

Still, I would expect it to work at ProRes in HD as that should compress down below 100MB/s - right ?

And, does anyone have a definitive answer on whether the Express Card port is on the same bus as the built-in FW800 port ? I've heard contradicting answers to that question - and if they are on the same bus I suspect that may be my bottle-neck.

Thanks again,

Jon

Because the actual data stream I'm sure is compressed and using less bandwidth and can fit within the bandwidth limitations of firewire.

1080i25 10bit uncompressed is what the output file is (considering the input is from the AJA IOHD) - in terms of loosing frames it's probably happening because the output storage device can't keep up in terms of how much data it needs to store with uncompressed video, so data is getting queued and more data is coming in before all of the existing data is written out - eventually that buffer fills up and the only thing left to do until the system catches up is to drop frames.

ProRES has some compression, but it is not heavily compressed - here's the line from Apples manual on it:

1920x1080 25fps, 4:4:4 - 275MBits/s; 4:2:2 HQ - 184MBits/s; 4:2:2 122MBits/s, etc. - as you can see, ProRES is rated in BITS / second rather then uncompressed rated in BYTES / sec (for anyone reading this not sure of the ratio, 8 bits = 1 byte) - so it requires SIGNIFICANTLY less bandwidth to the output drives then uncompressed video.

In terms of if they (the express card and the FW port) are on the same bus, honestly, I don't know. Of course, also if you're using an express card with an esata chipset that isn't really fully compatible with OSX that can cause some serious grief as well.

HD Editing in FCP with MBP

Hi,

Thanks again for the response, it's quite a learning curve .... I thought the software would be the difficult bit.

Anyway, I may have left out one bit of info originally (or not stressed it enough). I originally said that ...

Using "Log & Capture" I get a lot of glitches on the footage as it is being captured (and also when the captured clip is played back from the timeline as well).


However, when I opened the "Log & Capture" window the glitches were immediately present on the pictures - even before I had pressed the "capture now" button. Unless FCP is doing something clever in the background, then I don't think it would be writing to the external HDD at this point ? Am I right there ? To me this suggests that the problem may be unconnected to the HDD and/or the eSATA card ?

Thanks again for the responses. It is rather a minefield this, but so far it sounds like what we are trying should be possible (albeit using slightly less than 1080i25 10-bit uncompressed). It would be good to have confirmation from someone who has successfully done this though, before spending too much time/money on a fruitless exercise.

Regards,

Jon

If you're just previewing and not actually capturing, I wouldn't think it would skip - I know while capturing sometimes it can appear to skip but it really isn't dropping frames.

Have you tried throwing iStat on the system and having it display the CPU status and seeing if something is hogging CPU time? Have you tried this on another similar Mac or higher end Mac to compare results? Does he have anything else running?

In all honesty, I only use AVCHD footage atm, and I've logged and transferred footage to firewire drives as well as drives hooked up via USB, but the process is different then Log and Capture w/ firewire (dropped frames becomes irrelevant during the capture process as there technically is no capture process, it's converting the footage from AVCHD into AIC or ProRES and it can go as slow or fast as it needs to do that). There are some other users on here that do use high end gear capture via firewire, and they may be able to answer better, I was just hopping that I might be able to find a simple solution until they came around