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DSLR, DHxHD and all that – chosing new HD setup.
As a result of other posts I am thinking of getting new HDs but wanted to check this was needed, and if is have I come up with is OK.
Currently my HD delivers around 85MB/s, which I gather is not enough for native DSLR. Still not got a good pragmatic answer for what would be. My first question is would this be enough for DHxHD, ime guessing no as I believe the number is the DHxHD flavor indicates MB/second so only DHxHD 36 would be usable, or have I misread something. In my initial experiments the drive seems to be able to play DHxHD 120 smoothly but I have not used this in anger.
OK, so if the DHxHD format name tells me the MB/s I need. That seems fairly straightforward, although as with most things I ma guessing it is not;). DHxHD ‘1080p/25 120 8 bit’ seems the minimum sensible format I would want to use for DSLR (although 10 bit is obviously preferable). Is this correct?
One thing I was wondering was is is possible to use the 36 DHxHD 36 format and then conform to the original DSLR files. How would I do this, can I simply copy the DSLR files over the DHxHD ones at the end of the edit?
I am thinking of doing RAID0 with Seagate Barracudas but cant find a benchmark for the likely read throughput. Anyone know where I can find this/what it would be?
Regards,
Ben—
Ben Edwards – Freelance Picture Editor
https://www.funkytwig.comi5 550, Windows 7 / Mac Lion, Nvida 550 Ti, 8GB Mem
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25 Replies
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Ben,
I’m assuming you mean DNxHD (not DHxHD)…Avid’s codec. If so, then when you transcode from h.264 DSLR footage you’ll likely go with DNxHD 145 (as there is no 120). DNxHD 36 is meant for offline editing….though in some cases this may be sufficient. Depends on the footage, the client, the budget, and the post-prodution process.DNxHD 145 will do great with compositing or color correction needed. Remember you’re footage is only ever as good as the original capture format. In your case, a DSLR shooting to the h.264 codec. Currently that is only an 8-bit codec. So even if you transcode to DNxHD 220, you’re not going to be adding data or picture quality to your image.
If you setup a RAID0 with 2 or more disks you should be fine on playback with DNxHD. It is a pretty efficient codec (similar to Apple ProRes).
Ryan Holmes
http://www.ryanholmes.me
vimeo.com/ryanholmes -
Thanks for that, Yes it is the Avid Codec. I am currently playing with the 36 version for offline editing and will replace the files with 145 for final finishing.
Ben
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Ben Edwards – Freelance Picture Editor
https://www.funkytwig.comi5 550, Windows 7 / Mac Lion, Nvida 550 Ti, 8GB Mem
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Ben– FYI, the AVID codecs are specified in bits (not bytes) per second.
-Jeff
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Jeff – Very good point. Sorry I missed that.
Quick conversion for you:
36 Mbps = 4.50 MB/s
145 Mbps = 18.13 MB/s
220 Mbps = 27.50 MB/sIf you had a codec running at 85 MB/s (megabytes) then that’s equivalent to 680 Mbps (megabits). Bits and bytes matter! 😉
Ryan Holmes
http://www.ryanholmes.me
vimeo.com/ryanholmes -
OK, I have not transcended everything to DNxHD 36 and it does not play smoothly. I have a i5 3550 and 8GB of memory. The disk delivers around 85 MB/s. Do I need to separate disks for this? Odd as I was using Avid on a lower spec box and did not have any problem (cant remember which Avid codec I was using but it was way above 36).
Any idea what is going on?
Ben
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Ben Edwards – Freelance Picture Editor
https://www.funkytwig.comi5 550, Windows 7 / Mac Lion, Nvida 550 Ti, 8GB Mem
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Sorry, I mean I have ‘NOW transcended everything’, not ‘not transcended everything’
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Ben Edwards – Freelance Picture Editor
https://www.funkytwig.comi5 550, Windows 7 / Mac Lion, Nvida 550 Ti, 8GB Mem
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Are you using an internal hard disk? Or an external one?
If internal – is it the primary drive (which houses applications, operating system, etc.)? How full is it?
If external – what type of drive? How is connected (Firewire, USB, eSATA)? How full is it?
It’s a bad idea to edit video off the internal boot drive of the computer. That disk is already spinning for operating system related tasks. Asking it to read video files as well is a large challenge task, and it will often come up short.
If whatever drive you have the media on is even half full you’ll start to notice a degradation in performance. This is just the nature of spinning drives. If you can clear off space on your hard drive that may help.
If it’s an external drive – connect it by firewire or eSATA. USB is a poor connection for video editing needs. It works better to transfer data, but not to edit video from (even a compressed format like DNxHD 36).
Ryan Holmes
http://www.ryanholmes.me
vimeo.com/ryanholmes -
I am using a eSATA Seagate Barracuda 72000 3TG which is around 80% full. Personally I would avoid fire-wire as compared to eSATA (and probably USB3) it is very slow. The Blackmagic Disk Test shows 85MB/s Read.
DHxHD 36 is around 4.5 MB/s and is a proper editing format so I am very surprised I am having a problem. Maybe I need more that 8GB (Adobe say PP works with 4 and 8 is recommended).
I am bending over backwards to help Premiere (i.e. attempting to transcode into something PP likes).
I am beginning to feel I should of gone the avid route.
Ben
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Ben Edwards – Freelance Picture Editor
https://www.funkytwig.comi5 550, Windows 7 / Mac Lion, Nvida 550 Ti, 8GB Mem
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Ben, any system I have used professionally has always had an external esata or similar type PCIE driven raid. Providing the Mercury Playback Engines what it needs to excell in performance (fast CPU/GPU/lots of ram amd fast raid system) is crucial to being happy with its performance.
With Avid you can get away with a lot less power since it is optimized to use DNxHD.
FYI, DNxHD plays nicely on my system. But I purchased it with the idea that it could handle whatever was thrown at it.
Sorry you are not having a good experience 🙁
Tom Daigon
PrP / After Effects Editor
http://www.hdshotsandcuts.com
https://www.youtube.com/watch?v=XRIg6h-LIm0
HP Z820 Dual 2687
64GB ram
Dulce DQg2 16TB raid -
Hi Ben,
An i5 processor is kind of weak for HD editing, a Core i7 being preferred. Have you hacked your 550 display card to enable the Mercury Playback Engine? That should help a lot. And RAM is cheap right now, upgrading from 8GB to 16GB may be beneficial.
I really didn’t see your full system specs in the thread. You said your drive was 80% full – is that a dedicated video drive, or C: drive? In any case, performance is on the decline when that full, and hopefully it is defragged?
Thanks
Jeff Pulera
Safe Harbor
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