Kdenlive/Підручник/Меню «Проєкт»/Обробка/Параметри профілю обробки

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    Render Profile Parameters - How to read them

    Render Profile Parameters - How to read them - ver 0.9.10

    In version 0.9.10 the render profile parameters changed significantly.


    Kdenlive now makes use of "property presets" delivered by the melt project (see melt doco). These presets are referenced by the properties=<preset> syntax. In the example illustrated, the render profile is referencing lossless/H.264. This refers to a property preset found in file H.264 found on the system at /usr/share/mlt/presets/consumer/avformat/lossless.

    All the <presets> referenced in the render settings in Kdenlive will be referring to presets found at /usr/share/mlt/presets/consumer/avformat/ (on a default install). Note that you reference presets found in subdirectories of this folder using a <dirname>/<profile> syntax as shown in the example above.

    properties=lossless/H.264 
    g=120 
    crf=%quality 
    ab=%audiobitrate+'k'
    

    The preset files found at /usr/share/mlt/presets/consumer/avformat/ are simple text files that contain the melt parameters that define the rendering. An example is shown below. These are the same parameters that were used in earlier versions of Kdenlive — see next section for how to read those.

    Contents of lossless/H.264:

    f=mp4
    acodec=aac
    ab=384k
    vcodec=libx264
    intra=1
    vb=0
    g=0
    bf=0
    preset=medium
    qscale=1
    qp=0
    coder=ac
    
    meta.preset.extension=mp4
    meta.preset.note=Intra-frame only, lossless compressed MPEG-4 AVC with AAC audio
    

    Render Profile Parameters - How to read them - earlier versions of Kdenlive

    The parameters that go into a render profile derive from the ffmpeg program.

    This is a worked example to show how you can understand what these parameters mean using the ffmpeg documentation.

    In the example above the parameters are:

    f=dvd 
    vcodec=mpeg2video 
    acodec=mp2  
    b=5000k 
    maxrate=8000k 
    minrate=0 
    bufsize=1835008 
    mux_packet_s=2048 
    mux_rate=10080000 
    ab=192k 
    ar=48000 
    s=720x576 
    g=15 
    me_range=63 
    trellis=1 
    profile=dv_pal_wide 
    pass=2

    Looking up the ffmpeg help translates these parameters as shown below.

    Main option is:

    -f fmt            force format

    Video options are:

    -vcodec codec     force video codec ('copy' to copy stream)
    -pass n           select the pass number (1 or 2)
    -b bitrate        set bitrate (in bits/s)
    -vb bitrate       set bitrate (in bits/s)
    -s size           set frame size (WxH or abbreviation)
    -me_range         <int>   E.V.. limit motion vectors range (1023 for DivX player)
    -trellis          <int>   E.VA. rate-distortion optimal quantization
    

    Audio options are:

    -acodec codec     force audio codec ('copy' to copy stream)
    -ab bitrate       set bitrate (in bits/s)
    -ar rate          set audio sampling rate (in Hz)
    

    The AVCodecContext AVOptions include:

    -b                <int>   E.V.. set bitrate (in bits/s)
    -maxrate          <int>   E.V.. set max video bitrate tolerance (in bits/s)
    -minrate          <int>   E.V.. set min video bitrate tolerance (in bits/s)
    -g                <int>   E.V.. set the group of picture size
    

    So all the render profile options are documented here in the ffmpeg documentation.

    See also MLT doco on ConsumerAvFormat.

    See also HOWTO Produce 4k and 2K videos, YouTube compatible