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  1. Member
    Join Date
    Feb 2018
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    Logy Bay, Newfoundland, Canada
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    I'm trying to do a simple scale using ffmpeg with -vf to scale a file that is currently 720:480 to 720:400. I do NOT want to keep the original aspect ratio. I want to compress the vertical dimension without changing the horizontal dimension. But ffmpeg ignores the horizontal scale value that I input on the command line. Instead, it resizes the image to the vertical scale that I input but keeps the original aspect ratio. The output file always comes out with the same aspect ratio as the original file. This seems like it should be straight forward. What am I doing wrong? BTW, I can change the aspect ratio using Handbrake with a Custom Anamorphic setting, but I'd like to know how to do this directly in ffmpeg. Thanks.

    ffmpeg.exe" -i "INPUT.mkv" -vf "scale=720:400" OUTPUT.mkv
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  2. ffmpeg.exe" -i "INPUT.mkv" -vf "scale=720:400,setsar=1/1" OUTPUT.mkv

    (P.S.: Usually we want to upscale for anamorphic content as to not lose resolution. I.e. stretch horizontally instead of compress vertically.)
    Last edited by sneaker; 26th Feb 2018 at 17:08.
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  3. Member
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    Feb 2018
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    Logy Bay, Newfoundland, Canada
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    Originally Posted by sneaker View Post
    setsar=1/1

    (P.S.: Usually we want to upscale for anamorphic content as to not lose resolution. I.e. stretch horizontally instead of compress vertically.)
    Thanks! I looked at a lot of documentation on the web about the scaling with ffmpeg but never saw any comment about the "setsar" option. It works great. I wonder why other sites don't mention it.

    BTW, I understand about the preference for horizontal stretching when upscaling. I was just using a simple example to get help with the scaling problem I was having. Thanks again!
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