HD vs SD file size

Discussion in 'Digital Video' started by macuser154, Feb 16, 2009.

  1. macuser154 macrumors 6502

    Joined:
    Jan 17, 2009
    Location:
    UK
    #1
    I have a Sony HDR-CX7EK video camera. I am wondering how much more space HD video takes as opposed to SD video.
     
  2. ftaok macrumors 601

    ftaok

    Joined:
    Jan 23, 2002
    Location:
    East Coast
    #2
    It depends on which format/codec you're using. I'm assuming that you're using a Mac and probably iMovie or Final Cut.

    For Standard Def material, you're looking at either a miniDV or MPEG-2/4 camcorder. DV footage clocks in at 25 Mbps (or 11 GB/hr). MPEG-2/4 varies greatly, but I'll assume that it tops out at 9 Mbps (4 GB/hr). There's also some overhead for audio.

    For HD, since it all gets transcoded to AIC, the various formats don't matter too much. I think AIC is about 100 Mbps or 44 GB/hr. Until Apple allows for direct editing of HDV or AVCHD, you're going to be using AIC.

    ft
     
  3. macuser154 thread starter macrumors 6502

    Joined:
    Jan 17, 2009
    Location:
    UK
    #3
    Thankyou for your quick response. I just checked, and it will be shooting at 1080P at 15MBPS.
     
  4. Courtaj macrumors 6502a

    Courtaj

    Joined:
    Jul 3, 2008
    Location:
    Edinburgh, U.K.
    #4
    . . . which equates to roughly 8GB per hour. For archive purposes, you may be better off storing the un-transcoded AVCHD files: a good way to do this is to use Disk Utility to make a disk image, copy the entire card contents to it, and archive this image which, when "mounted" with iMovie open, will be treated as if you had connected the camcorder directly by USB.

    Archiving the transcoded AIC files will gobble up about 5 to 6 times as much space as the original AVCHD clips.
     
  5. dlegend macrumors 6502

    Joined:
    Jan 11, 2009
    Location:
    Northern VA (outside DC)
    #5
    according to imovie it's 13 GB/hour for SD, and I think it said 25 GB/hour for HD. That's according to their FAQ section, obviously you camera may be different.
     
  6. ftaok macrumors 601

    ftaok

    Joined:
    Jan 23, 2002
    Location:
    East Coast
    #6
    I went back and did a quick look-see.

    http://support.apple.com/kb/HT2704?viewlocale=en_US

    Apple's quoting 49 GB/hr for AIC-1080/60i.

    As for SD the 13 GB/hr is close enough. I've seen it quoted anywhere between 11 to 13 GB/hr ... depending on whether you add in the audio or not. DV is 25Mbps, plus something for audio. I think it's 26.5 Mbps overall.
     
  7. dlegend macrumors 6502

    Joined:
    Jan 11, 2009
    Location:
    Northern VA (outside DC)
    #7
    "You can choose any supported hard disk that’s connected to your computer with a FireWire cable. It takes about 13 GB to store an hour of standard definition (DV) video and 40 GB to store an hour of high definition (HD) video, so make sure you have enough space on the disk you choose. The amount of free space on each available disk is shown in parentheses next to the disk’s name in the pop-up menu." - According to iMovie 08 getting stared guide page 12.

    It wouldn't surprise me that it's about 49 GBs for 1080.

    So to answer the original question roughly 3-4 times more than SD.
     
  8. tcgjeukens macrumors regular

    tcgjeukens

    Joined:
    May 16, 2007
    Location:
    IJsselstein, the Netherlands
    #8
    Space on what?

    When capturing either SD or HD on a DV tape, one hour is roughly 11Gb/hour.
    When "log & capturing" to Mac 11Gb remains 11Gb/hour ... unless you transcode to anything else than the codec used for storage on tape.

    For SD iMovie, FCE and FCP do not require transcoding. The DV signal can be edited natively.
    For HD iMovie and FCE must transcode to AIC. This means an explosion in size to the figures mentioned in the other posts.
    In case you use FCP you do not need to transcode the 11Gb coming from tape. FCP can work with the native format.

    In case you start using AVCHD, the story is different. In that case you will not be using tape based media.
    Today AVCHD must be transcoded before editing on a Mac is possible. Transcode to AIC or ProRes. Rule of thumb. 1Gb on solid media will be 7Gb when transcoded.

    Have fun.

    Coen
     
  9. macuser154 thread starter macrumors 6502

    Joined:
    Jan 17, 2009
    Location:
    UK
    #9
    Wow, thankyou all for your responses.

    Just another question. My camera has an 8GB memory stick, would I be able to shoot a couple of hours of video in HD with that stick? Or should I just stick to SD?
     
  10. tcgjeukens macrumors regular

    tcgjeukens

    Joined:
    May 16, 2007
    Location:
    IJsselstein, the Netherlands
    #10
    macuser154,

    The manual of your camera will contain a table with the recording capacity.

    In case you shoot HD 1920x1080 with the AVCHD codec, 8Gb will buy you slightly more than one hour.
    For any lower resolution time goes up.

    Check your manual and/or marketing leaflet.

    Coen
     
  11. ftaok macrumors 601

    ftaok

    Joined:
    Jan 23, 2002
    Location:
    East Coast
    #11
    Just some quick math.

    You stated previously that your Sony records at 15 Mbps. I'm guessing that you have several other recording bit rate options.

    Here's what you do.

    Multiply your bit rate (in Mbps) by 0.44 and you get your "recording size" (in GB/hr).

    In your case above ... 15 x 0.44 = 6.6 GB/hr

    Just to confuse you further, your 8 GB memory card isn't actually 8 GB. It's actually 7.4 GB. The conversion factor is 0.93 in case you wanted to know.

    If you want more footage to fit, then record at a lower bit rate ... but it's probably better to record at the highest quality and buy a second memory card and/or carry a laptop with you to off-load footage.

    ft
     
  12. dlegend macrumors 6502

    Joined:
    Jan 11, 2009
    Location:
    Northern VA (outside DC)
    #12
    If your camera takes memory sticks you can always buy more and switch them out when the first one fills up.
     

Share This Page