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  1. Member
    Join Date
    Mar 2011
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    Paris, France
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    Hello

    I have a 360MB file that I'd like to shrink down to a smaller size. It's for viewing on a computer, so it doesn't have to be 4K quality:

    Code:
    ffmpeg.exe -i input.mp4
    
    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
      Metadata:
        major_brand     : mp42
        minor_version   : 0
        compatible_brands: isommp42
        creation_time   : 2015-07-29 11:47:51
      Duration: 00:52:04.44, start: 0.000000, bitrate: 929 kb/s
    
        Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv), 720x406 [SAR 1:1 DAR 360:203], 800 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc (default)
        Metadata:
          creation_time   : 2015-07-29 11:47:51
          handler_name    : Mainconcept MP4 Video Media Handler
          encoder         : AVC Coding
    
        Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 125 kb/s (default)
        Metadata:
          creation_time   : 2015-07-29 11:47:51
          handler_name    : Mainconcept MP4 Sound Media Handler
    What settings could I try in ffmeg to get down to eg. 100 or 200MB?

    Thank you.
    Last edited by yetanotherlogin; 4th Aug 2015 at 04:48.
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  2. Member
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    Jan 2007
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    why ??
    what PC could you wish to view this, that 360mb is too large a file

    or is the real problem you want to send it somewhere and you upload time is slow

    i sure would not make it any smaller
    IMO 360 is too small for a 52min video
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  3. Code:
    file size = bitrate * running time
    Plus a little overhead for the container. Bitrate is the combined bitrate of all streams. So if you want a smaller file encode with a lower bitrate for the video, audio, or both.
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  4. Member
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    Mar 2011
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    Paris, France
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    Thanks. How can I do this with ffmpeg?
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  5. Originally Posted by yetanotherlogin View Post
    Thanks. How can I do this with ffmpeg?
    Set the bitrate

    -b:v for video -b:a for audio

    Or if you only want to adjust the video, you can use -c:a copy to copy the audio, or re-encode both to reduce both
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  6. Member
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    Mar 2011
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    Amazing: Even when using a much lower bitrate for video, I can't tell the difference from the original although the filesize is 1/3 of the original.

    200 + 128 = 328kbps total bitrate
    Code:
    ffmpeg -i input.mp4 -b:v 200k -c:v libx264 -vf scale=640:360 -pix_fmt yuv420p -c:a aac -strict experimental -b:a 128k -ac 2 -ar 44100 -threads 2 -f mp4 output.mp4
    Thanks!
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