Kdenlive/Manual/Projektmenuen/Rendering/Renderingsprofilens parametre

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

Renderingsprofilens parametre - Hvordan man læser dem

De parametre, som bruges i renderingsprofiler kommer fra programmet ffmpeg.

Dette er et gennemarbejdet eksempel som viser, hvordan du kan forstå hvad disse parametre betyder ved hjælp af ffmpegs dokumentation.

I eksemplet ovenfor er parametrene:

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

Søger du i ffmpegs hjælpesider så ser du at:

et vigtigt tilvalg er

-f fmt            force format

videotilvalgene er:

-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

lystilvalgene er:

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

AVCodecContext AVOptions inkluderer:

-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

Alle tilvalgene i renderingsprofilen er således dokumenteret her i ffmpegs dokumentation.

Se også MLT-dokumentationen på ConsumerAvFormat.