Archive:Kdenlive/Manual/Project Menu/Render/Render Profile Parameters

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 render profiles delivered by the melt project. These profiles are referenced by the properties=<profile> syntax. In the example illustrated the render profile is referencing lossless/H.264. This refers to a render profile found in file H.264 found on the system at /usr/share/mlt/presets/consumer/avformat/lossless

All the <profile> referenced in the render settings in kdenlive will be referring to profiles found at /usr/share/mlt/presets/consumer/avformat/ (on a default install). Note that you reference profiles 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 profile 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.

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:

a 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.