How fast does an SDHC card need to be for 1080p?

Discussion in 'Digital Video' started by badlydrawnboy, Dec 4, 2010.

  1. badlydrawnboy macrumors 65816

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    Oct 20, 2003
    #1
    I'm looking to buy a 16 GB SDHC card for my Kodak Zi8. It shoots 1080p HD video. How fast do I need the card to be? I see several options. Is 15 GB/s enough, or do I need the "Extreme" 30 GB/s version?
     
  2. jwheeler macrumors regular

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    Jan 14, 2010
    #2
    I have two class 6 16gb sd cards for my Zi8

    It works fine

    In fact i will still use them when i get my Canon 60D.
     
  3. xStep macrumors 68000

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    #3
    Well, I see that information isn't found at Kodak where one might expect, like the user guide for instance. My search came up with this Kodak article that should be helpful.
     
  4. Cabbit macrumors 68020

    Cabbit

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    #4
    My Canon 550 uses class 6 cards (20 MB/s Sandisk Extreme) though i believe full HD is 25 MB/s though i have not noticed any slowdown or stuttering.

    One thing i get told all the time is not to scrimp on the memory card get a good brand like Sandisk and get faster than you need if you can.
     
  5. badlydrawnboy thread starter macrumors 65816

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    #5
    That's good to know. I was considering an 15 GB/s card, and it sounds like that might not be enough. I'll go for the 20 GB/s, or maybe even the 30 GB/s.
     
  6. KeithPratt macrumors 6502a

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    #6
    The numbers in this thread are all over the place...

    First find out the data rate of the video the Zi8 produces. If it's in Mb/s (megabits per second), divide it by 8 to give you MB/s (megabytes per second). SD card classes are named after their minimum guaranteed write MB/s. For example, a class 4 card will always write at 4MB/s (32Mb/s) or higher.
     
  7. badlydrawnboy thread starter macrumors 65816

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    #7
    Thanks for the clarification. Obviously I don't know much about video. I did a bit of research and found the following about the Zi8:

    That doesn't really make sense though using your numbers. 13 Mb/s / 8 = 1.65 MB/s. Would that mean I only need a class 2 card?
     
  8. Cabbit macrumors 68020

    Cabbit

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    #8
    Get a class 6 card. 20 MB/s will be plenty and there is very little difference in price.

    A 720 30fps video i shot earlier today was 48 Mb/s or 6MB/s to give you some idea of what your looking at, also the better cards have the added benefit of being able to copy there files over to your Mac quicker than a slower card.
     
  9. mulo macrumors 68020

    mulo

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    #9
    Apples default movie compression method, compresses 1080p to 10MB/s, 720p to 5MB/s, so obviously lossless is larger.
     
  10. hchung macrumors 6502a

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    Oct 2, 2008
    #10
    That is correct.
    You can get a class 2 card and you won't have any problems recording.

    My camcorder, a Panasonic 3MOS SD600's bitrate is 28Mbit/sec so I just need a Class 4.

    There's nothing wrong with buying a higher class. It just that it's not necessary. With that said, most of mine are class 6 because that happened to be the best deal when I was buying them. But yeah, I do have some class 4s as well that work perfectly.
     
  11. nateo200 macrumors 68030

    nateo200

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    #11
    I use Class 6 Sandisk Extreme HD's 20MB/s and have noticed no issues with shooting even long cuts. The 1080p files usually come out at 45mbps which is quite large so I wouldn't drop below class 6 or else your shots are going to be really short, your buffer is going to fly up fast, or you won't even be able to do video/RAW. I used a Class 2 16GB card once from my old Droid...by God it worked and pretty damn well I don't know how because it was pretty slow withe everything else..Brand name is actually something to look for..I have a Class 10 PNY 8GB SDHC card that buffers out more than my 4GB Sandisk class 6...its sort of annoying, especially when your trying to do something serious for once and it buffers out...I say get at least ONE SDHC card you know will be 99% reliable then you can hop on amazon and grab some cheapo Class 6's+

    EDIT: To OP and anyone else...make sure you have your numbers right...15GB/s and we wouldn't even need a thread let alone SD card classes for cameras...
     
  12. xStep macrumors 68000

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    #12
    I'm at a loss to understand what this has to do with OP. What Apple default are you referring to? In software, hardware?

    The iPod touch I have uses 10Mbps when creating video from the back camera which generates 720p video.
     
  13. nateo200 macrumors 68030

    nateo200

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    #13
    That's great but that has nothing to do with my DSLR's bit rate.
     

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