Question about Raid 0/multiclip work flow

Discussion in 'Digital Video' started by HunterGather, May 6, 2011.

  1. HunterGather macrumors member

    Joined:
    Oct 18, 2008
    #1
    I'm going to take advantage of my schools fully equipped Mac Pros for personal projects, and obviously school related ones as well.

    I know what Raid is, but i have a question about work flow.

    I want an external bus powered Raid 0 drive (found one that suits my needs on OWC) for portability.

    My question is, is this the best work flow for someone who is working on projects on a school computer? (or in general, i suppose too).
    (Capturing footage isn't an issue. I already have the footage to begin with).

    -Do I throw all the footage I'm going to edit with on the Raid 0 drive(s), or put the footage on a separate fast drive, and then use the raid 0 as the drive for rendering/scratch drive?

    If it helps to know, I'm going to be messing with 4 to 6 HD steams/multicam editing (most likely 720p only).

    Also, I'm eyeing the OWC Elite-AL Pro DUal Mini 7200rpm drive
    http://eshop.macsales.com/shop/firewire/EliteALmini/RAID/eSATA_FW800_FW400_USB
     
  2. shorafix, May 7, 2011
    Last edited: May 7, 2011

    shorafix macrumors member

    Joined:
    May 15, 2008
    Location:
    Frankfurt, Germany
    #2
    That doesn't help much. 720p is just a category of HDTV video modes and doesn't tell anything about the compression and thus Bitrate of your clips.

    For example AVCHD - commonly used in many consumer cameras - uses data rates up to 24 Mbit/s while Apples Prores 422 is from 73 up to 110 Mb/s. So if you have AVCHD and you edit on Premiere CS5, CPU and GPU performance of your Mac Pro would rather be an issue than datarates. If you are going to edit on Final Cut Pro instead, data rates maybe an issue.

    However, I have never experienced any problems with Prores 422 and 2-3 Multicam with 1.920 x 1.080 @ 50fps on my MacPro's internal Softraid 0. There was never a need to separate capture scratch from rendering on my equipment.

    Speedtest Softraid 0 on MacPro 5.1 (12 Core):

    [​IMG]

    Speedtest SSD on MacPro 5.1 (12 Core):

    [​IMG]
     
  3. HunterGather thread starter macrumors member

    Joined:
    Oct 18, 2008
    #3
    Thanks for the reply! And benchmarks.
    Hmm, not exactly sure at this second which one I'll be using.

    For one of my projects, it's a concert movie and the source footage is various HD videos taken from various cameras by audience members. I'm going to have to convert them all to one single editable format to make things simple (i'm talking Flip video, iphone 4 videos, digital camera video, and so on).
    Off hand, maybe AIC or ProRes?

    In any case, so for something like this, I should just load up the Raid 0 drive(s) with all the footage I'm going to use, and take it to school and thats it?
    Would it be best to have a separate Raid 0 drive to render to? (or at least a single 7200rpm drive?)
    (even though you say it may be fine to just use the single raid to hold footage, edit multiple HD streams, and render to).


    ALSO, while I have someones attention, does this apply when I'm working on something big in After Effects or Motion? Should I have the working drive with videos (if any) on the Raid 0? Or if its simply just using a bunch of plug ins and such, just let it work on the schools hard drive?

    I thought I knew a lot, but I still have a lot to learn. Thanks for!
     
  4. shorafix macrumors member

    Joined:
    May 15, 2008
    Location:
    Frankfurt, Germany
    #4
    Take my advice: You better use your time getting yourself comfortable with your editing suite. Do you already know how to do multicam in Premiere Pro or CS5? Do you know hot to perform J and L cuts? That's all much more important. Don't waste your time with theoretical hardware issues. Everything will be fine. Both Premiere CS5 as well as FCP can handle different video resources such as AVCHD, HDV and even DV in the very same sequence. Believe me: it is more important to learn your editing software than anything else.

    One more thing: always keep your project files separate from your resources and backup! In case your RAID 0 crashes (2x probability of crash over a single HD), you can still log your clips again from the original storage (such as SD-cards, HD etc.). However, if you loose your project files, you are doomed.

    Andreas
    non-linear video editing since 1995
     
  5. Transporteur macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #5
    The question whether to use RAID or not for external storage is quite simple; which interface will you be using?

    The advertised 300MB/s sustained reads are only possible via eSATA (even then I doubt the 300MB/s as there are no 2.5" mechanical drives that can deliver 150MB/s. 100MB/s is the maximum I've seen for an empty drive, so the realistic throughput over eSATA would be 200MB/s).

    Now if the machines you'll be using have only FW, the whole point of using a RAID0 for an external drive (which is doubling the sustained reads/writes) is moot as FW provides only up to 80MB/s, which can be saturated by a single hard drive (both 5400 and 7200RPM depending on the size).
     
  6. HunterGather thread starter macrumors member

    Joined:
    Oct 18, 2008
    #6
    Yes, i do. But I've only messed with DV footage before. I was just wondering about technical work flows for HD video in general, i suppose.

    I'm 99% sure that the Mac Pros at school don't have eSata connections. So Firewire 800 for me.
    So it's pointless to get a Raid 0 in this scenario? I'd just be better off with a SSD or 7200rpm external FW800 drive?

    And for future reference, is an external Raid 0 SSD set up the best way to go for a project like this, so long as its eSata (or a single internal SSD drive)?

    Thanks!
     
  7. Transporteur macrumors 68030

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    Nov 30, 2008
    Location:
    UK
    #7
    Yes, totally pointless. And forget about SSDs as well for FW800. Although you'd still get faster access times and faster random reads/writes, video applications benefit from sequential speeds, which would still be limited by the 80MB/s cap of FW.
     
  8. shorafix macrumors member

    Joined:
    May 15, 2008
    Location:
    Frankfurt, Germany
    #8
    That's absolutely right, while in practice even less than 80 MB/s may be achieved. Example of FW800 HD (external case):

    [​IMG]

    However, from what the TS wrote above we learn that the clips are probably consumer based AVCHD @ 720p. So working with Premiere Pro CS5 with AVCHD natively and data rates between 16 and 24 MBs, any FW800 HD should be good enough for the job even for Multicam up to 2-3 cams at the same time.
     
  9. KeithPratt macrumors 6502a

    Joined:
    Mar 6, 2007
    #9
    This is getting a bit messy. I don't know how we've got this far without establishing what software you're using...

    To work with up to 6 streams, your typical options would be a beefy RAID or an offline workflow. An online workflow would require at least a two-disk RAID0 and eSATA connectivity. If your Mac Pros don't have eSATA, it's an offline workflow for you.

    (And to be pedantic, Firewire 800's theoretical bandwidth is 100MB/s, and AVCHD 24Mb/s is 3MB/s.)
     
  10. shorafix macrumors member

    Joined:
    May 15, 2008
    Location:
    Frankfurt, Germany
    #10
    I absolutely agree!


    I disagree. With Premiere Pro CS5 you can handle at least 4 Cams even from a single internal SATA HD. Datarates of AVCHD - and this is presumable what we are taking about (see above) - are just up to 24 Mb/s (3MB/s). Premiere is handling AVCHD without transcoding in an intermediate format such as Prores 422 etc. and from my own experience I can confirm, that this will work. Example (from a single internal HD with approx. 78 MB/s read and write):

    [​IMG]

    100 MB/s (or 800 Megabit per second) is only theory - practice is less than 80 MB/s (see above). However, even 60 MB/s is fine for several AVCHD streams
     
  11. KeithPratt macrumors 6502a

    Joined:
    Mar 6, 2007
    #11
    We don't know it's AVCHD and we don't know it's Premiere. From this...

    ... I'd assume it's FCP. Even if it's Premiere or Media Composer, with those different formats I'd transcode.

    But this is all speculation until the OP furnishes us with the pertinent info.
     

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