vanqosa.blogg.se - Kdenlive ffmpeg options

bf=2 2 consecutive B-frames (youtube recommendation).

This will avoid recording light flickering effect in North America power grid. This is the framerate I shoot the video with and this is the framerate I use to publish video.

global_quality=21 -coder 1 vq=21 preset=slow following some of the recommendations from this stackoverflow answer on intricacies of nvidia encoder.

acodec=aac ab=384k use AAC audio codec with bitrate 384k.

vcodec=nvenc_h264 utilize nvidia hardware acceleration.

Here's my rationale for each of these encoding options. The thing these settings don't have is bitrate limit, however in the videos I've encoded, I didn't notice exceeding bitrate it always seem to be under 15Mbps. It was just the DISPLAY business that had to be fixed.F=mp4 vcodec=nvenc_h264 acodec=aac ab=384k g=15 profile:v=high global_quality=21 -coder 1 vq=21 -r 29.97 preset=slow bf=2 movflags=faststart pix_fmt=yuv420p In fact, I don't seem to need this ffmpeg option to get a screen grab.

Note also KDE documentation talks about a need to obtain an ffmpeg binary compiled with -enable-x11grab (or more properly, -enable-libxcb) in order for kdenlive screen grab to work. The 21.12.3 version I was using didn't show me the error output from the ffmpeg command, and it was only by chance I tried the 22.04 version this evening (which was scheduled for release tomorrow but I guess it went out early) and it did now show that error output. Note that kdenlive screen grab has some wonky behaviour, which made it harder for me to understand this problem.

However, for some reason I got a Qt error doing that, and so I couldn't tell if that was a useful workaround or not. In the user's gdm3 session that is on :1 by default, I also tried to set DISPLAY :0 in an xterm and start kdenlive from the command line in that xterm.

I also tried to understand if it is possible to have gdm3 put the user on DISPLAY :0 as a default at boot time through some custom configuration, but couldn't figure it out. So if you don't mind switching window manager, that could be a way to do it. When I tried the lightdm manager, I found that it still has the older convention of putting the user on the :0 DISPLAY, which is compatible with kdenlive screen grab. From what I can see, kdenlive is hard-coded to use DISPLAY :0, while ubuntu and gnome/gdm have switched (around ubuntu 18?) to put the user on DISPLAY :1.