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  1. I am trying to convert an mp4 file to flv.

    I would just like a straight conversion.

    I typed avconv -i file.mp4 file.flv

    The conversion occurred but the video is blocky.

    I have looked at info avconv, in terminal, but can't see the best method.

    Advice please.
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  2. You mean copy without re-encoding? https://libav.org/docs/avconv.html#Stream-copy

    avconv -i file.mp4 -map 0 -c copy file.flv



    But: what are you trying to achieve? There isn't really any good use for the flv container in 2017.
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  3. I am trying to reduce the mp4 file as much as I can without too much loss of quality. I would expect encoding to flv.
    in the case of file.flv.

    Are there examples of the code used, such as the equation you have given?

    Thanks

    Ps. Would this work
    avconv -i file.mp3 -map 0 file.flv -map 0

    Not sure of the -map 0
    Last edited by anon_private; 2nd May 2017 at 06:31.
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  4. Originally Posted by anon_private View Post
    I am trying to reduce the mp4 file as much as I can without too much loss of quality. I would expect encoding to flv.
    in the case of file.flv.

    Are there examples of the code used, such as the equation you have given?
    Ok, so you want to decrease the size of the mp4. You don't want flv (trust me).

    For that we need to re-encode one or more of the file's tracks. Usually the video track is the largest so it makes most sense to encode that but leave the other tracks as is. You should look at your source file in MediaInfo. Often (not always) it will tell you how big the tracks are in relation to each other.

    You could recode the video using x264 but copy the audio using:
    avconv -i "input.mp4" -map 0 -c:v libx264 -crf 20 -c:a copy "output.mp4"

    Lower crf = higher quality = bigger file size. In the documentation you can also look up -preset to increase compression. Or use libx265. There is no simple "reduce file size as much as possible without losing too much quality" option. The file size of -crf cannot be predicted. If necessary you can switch to -bitrate encoding (ideally using 2 passes).

    Originally Posted by anon_private View Post
    Ps. Would this work
    avconv -i file.mp3 -map 0 file.flv -map 0
    No. You can look up the meaning and examples of -map in the documentation I linked.
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