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  1. Member
    Join Date
    Mar 2011
    Location
    Paris, France
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    Hello

    I shot a video of a concert that I need to further compress from its original 2.7GB so I can share it with friends.

    Here's the original file:
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576 [SAR 64:45 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 448 kb/s
    Sound should be preserved as much as possible, but video isn't as important.

    I was thinking of using the following options to run ffmpeg (version N-46469-gc995644 on Windows):
    Code:
    ffmpeg -i input.mpg -c:v libx264 -vf scale=iw/2:-1 -preset faster -c:a ac3 -ab 192k output.smaller.mp4
    What do you think?

    Thank yoou.
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  2. Sound should be preserved as much as possible, ...
    then don't reencode it,....
    but video isn't as important.
    a. denoise/smooth the video
    b. use a higher crf value or use 2pass and lower the bitrate
    c. use a slower preset

    alternatively simple share just the audio,...
    Last edited by Selur; 8th Apr 2013 at 06:19.
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  3. Member
    Join Date
    Mar 2011
    Location
    Paris, France
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    Thank you.

    Can FFmpeg do this? If yes, how?
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  4. http://ffmpeg.org/ffmpeg.html
    • as denoiser, ffmpeg has hq3n3d -> http://ffmpeg.org/ffmpeg-filters.html#hqdn3d
      so in example: "-vf hqdn3d" will use the default values
    • a slower x264 preset can be chosen through: -preset X
      X can be: ultrafast, superfast, veryfast, faster, fast, medium (which is like removing -preset X), slow, slower, veryslow, placebo
    • the rate factor can be changed by: -crf X
      (X is between 1 and 61, the lower the ratefactor the higher the quality -> larger file size; the default is 23, use a higher value to lower the quality and effective bitrate
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  5. Member
    Join Date
    Mar 2011
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    Paris, France
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    Thanks much. I ran this, and will see how it goes:
    Code:
    ffmpeg -i input.mpg -c:v libx264 -vf scale=iw/2:-1 -vf hqdn3d -preset slower -crf 24 -c:a ac3 -ab 192k output.mp4
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