Final Cut Express: Small File Size, Highest quality possible

Discussion in 'Digital Video' started by mstevantoni, Nov 27, 2012.

  1. macrumors newbie

    Nov 27, 2012

    I need to export my 24min film to make it a file size of under 2gb and preferably .mov format. Right now the full .mov file is 14gb.

    Keeping the highest possible quality is very important. I tried .mp4 but the footage looked choppy.

  2. thread starter macrumors newbie

    Nov 27, 2012
  3. macrumors 6502

    Nov 28, 2011
    Stuttgart, Germany
    Do you have any software you can use? Or would you like to have some free software recommended. You gave us very little information to work with, that's maybe why no one has answered yet.

    If you have Apple Compressor, use any preset that will not reduce the resolution and encode the video in H.264 (for example a videosharing-Preset). Then tweak the video bitrate so you end up with a file below 2GB.

    If you don't have a conversion tool and don't want to spend money, I would do the following: Get Handbrake to convert your video. You will end up with a .mp4 file. If you need a .mov container, just use this little tool I programmed to change the container without reencoding (same size, very fast, no quality loss).

    For both methods, you will have to set the average video bitrate accordingly to end up with 2GB. That requires some math.

    1. Your video is 21 minutes long. That's 21*60 = 1260 seconds.

    2. If you have stereo audio channels, I assume you will end up with 192kb/s for the audio stream. That's ( 192kb/s * 1260 s ) = 241920 kb. 1 Byte is 8 bit, so that gives you ( 241920 / 8 ) = 30240 kB. That's ( 30240 / 1024 ) = 29.53 MB for the sound. Let's say 50 MB, to be sure.

    3. You get the point? Do the same for video, but the other way around:
    1950 MB
    => (1950 * 1024) = 1996800 kB
    => (1996800 * 8) = 15974400 kb
    => (15974400 kb / 1260 s) = 12678 kb/s

    I would try 12500 kb/s as setting for the average video bitrate. This video explains how you can set the bitrate in Compressor and where it will show the the resulting file size. In Handbrake, setting the average bitrate is pretty self-explanatory, but you will have to wait and see how big the file is gonna be. Unless someone did the math for you. ;)

    Next time, try to give a little more information about your problem (resolution, number of audio channels, software you use/have, etc...) and more people might be inclined to help you if it's an emergency. ;)
  4. macrumors 6502a


    Oct 15, 2004
    Brooklyn NY
    What you want to use is H.264 encoding. Set your export settings to quicktime movie, h.264. You can chose the bitrate. Go for something like 5000Kbps. This will get you a file around 1GB in size.
  5. macrumors 6502

    Nov 28, 2011
    Stuttgart, Germany
    Oh, additionally: .mov or .mp4 is only the container for the video. It has nothing to do with the file size, the used codec or the quality. You can easily switch between containers.

    Currently, the best codec out there is H.264, so you should use that. Than, if you have a size restriction, you can calculate the maximum bitrate (in your case around 12500 kb/s). If you have both this, the quality of the video won't change a lot anymore. So, if your .mp4 file was 2GB in size, that is roughly what your video is gonna look like at that compression.

    You will get slightly better results if you use a better encoder (e.g. Compressor instead of Handbrake/ffmpeg), but it won't change completely. If you have the option in your encoder, pick "2-pass encoding", that could actually make a difference... although also just a minor one.

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