How to reduce large file size of low-res video without losing quality?

Discussion in 'Digital Video' started by mrat93, Sep 7, 2015.

  1. mrat93 macrumors 65816

    mrat93

    Joined:
    Dec 30, 2006
    #1
    I'm converting old home movies to digital format using iMovie HD 6 and an old Sony digital 8 camcorder via FireWire. Once I export the videos from the original ~30GB .dv files to .mov, the file size is roughly 2GB per hour of video at 720x540 or 640x480 resolution. Of course, this shouldn't be the case. Any suggestions?
     
  2. marshzd macrumors newbie

    Joined:
    May 11, 2011
    #2
    Actually that's not too far off for a good quality version of those videos. But you can probably get away with less. I'd use a program like MPEG Streamclip, Compressor, or maybe VLC (been a while since I've tried VLC) and just reduce the bitrate.

    For that low of filesize, you can probably do 700-1000kbps. Test like 20 seconds of the video and see how it looks. Adjust the bitrate after and see what you can do.
     
  3. Unami macrumors 6502a

    Joined:
    Jul 27, 2010
    Location:
    Austria
    #3
    try handbrake for compressing the original .dvs

    as marshzd said, 2gb/h sounds good, but you can bring that down to 500mb if you sacrifice some quality.
     
  4. AcesHigh87 macrumors 6502a

    AcesHigh87

    Joined:
    Jan 11, 2009
    Location:
    New Brunswick, Canada
    #4
    Short answer: not possible. Less file size = less quality. Plain and simple.

    Long Answer: it is possible to get acceptable quality without the file size being too big. What's Savin you is the resolution being small. If you were working with 1080 files under thing under 8mbps would look pretty awful. However, at that resolution, 700kb - 1mb should be fine.

    As mentioned, something like MPEG streamclip could do the job in the simplest way possible. In my experience though I like to export straight out again rather than compressing the file. What settings are you using on export? Mainly bitrate and codec. This will help in deciding if it's better to compress a file you have or if it's better to export with different settings.

    P.S the file size not changing when you change the resolution actually makes perfect sense, just doesn't seem like it should. The bitrate is likely the same on both (each second of video has, for example, 1mb of data) so the only effect resolution will have is how many pieces that data has to fill. Fewer pixels = better quality pixels. The file size will only change if the bitrate changes.
     
  5. mrat93 thread starter macrumors 65816

    mrat93

    Joined:
    Dec 30, 2006
    #5
    Thanks for all the replies, people. I tried reducing the bitrate to 1000kbps but it was noticeably lower quality, especially in darker areas of the frame. I'll just manage with the storage I have and get a bigger SSD when I need it. I also have a decent amount of Google Drive storage as a backup.
     
  6. AcesHigh87 macrumors 6502a

    AcesHigh87

    Joined:
    Jan 11, 2009
    Location:
    New Brunswick, Canada
    #6
    Just curious: if it's just to store the files why go with a more expensive SSD option? ISB 3 drives can be bought for cheap (1TB is around $100 these days or less) and has plenty of speed for storing and playing movie files.

    Also, if you want more help feel free to respond to my question regarding codec. That could be where you are getting into trouble.
     
  7. mrat93 thread starter macrumors 65816

    mrat93

    Joined:
    Dec 30, 2006
    #7
    My only machine is a MacBook Pro with a 480GB SSD plus a 750GB hard drive I'd ideally like to have everything fit within the Photos app on my main drive. I'm about to be away for a few days, but when I get back, I'll look into the codec and bitrate. I'm not sure if QuickTime HD 6 gives all that info. The reason I'm using QT6 is because apparently it's the best for importing videos from a handcam. Thanks again!
     
  8. AcesHigh87 macrumors 6502a

    AcesHigh87

    Joined:
    Jan 11, 2009
    Location:
    New Brunswick, Canada
    #8
    I believe you mean iMovie HD 6, not QT. if so you are probably accurate, at least without more costly options.

    If the options aren't visible in iMovie just open the exported file in Quicktime and hit command+I. That should show you bitrate and codec.
     
  9. SuperBrown macrumors member

    Joined:
    Jan 15, 2008
    Location:
    Hollywoodland
    #9
    Think of it this way, a DVD that holds a two hour movie is roughly 4.7 GBs and the resolution of a DVD is 640X480 (480i), so 2GB per hour is actually right on the money and full 480i resolution. I'd say best bet is to save the 30GBs of originals on a backup drive and make compressed copies using handbrake to something smaller and more usable. Best of luck!
     

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