[FFmpeg-user] How to grab the desktop in the webm format

[Cley Faye]

2016-05-28 22:59 GMT+02:00 Alexandre Almeida <lugarparaler at selodigital.net>:

> Output #0, webm, to 'capture20.webm':
>  Metadata:
>    encoder         : Lavf57.25.100
>    Stream #0:0: Video: h264 (libx264), yuv444p, 1600x900, q=-1--1, 30
> fps, 1k tbn, 30 t
> bc
>    Metadata:
>      encoder         : Lavc57.24.102 libx264
>    Side data:
>      unknown side data type 10 (24 bytes)
>    Stream #0:1: Audio: opus (libopus), 48000 Hz, stereo, s16, 96 kb/s
>    Metadata:
>      encoder         : Lavc57.24.102 libopus
> Stream mapping:
>  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
>  Stream #1:0 -> #0:1 (pcm_s16le (native) -> opus (libopus))
> Press [q] to stop, [?] for help
> [x11grab @ 0x55f90b8bcb80] Thread message queue blocking; consider
> raising the thread_qu
> eue_size option (current value: 8)
> [alsa @ 0x55f90b8c4280] Thread message queue blocking; consider
> raising the thread_queue
> _size option (current value: 8)
> [webm @ 0x55f90b8d4b40] Only VP8 or VP9 video and Vorbis or Opus audio
> and WebVTT subtit
> les are supported for WebM.
>

​Since you did not provide any command line, we can only guess, but it
looks like you never specified which codec to use for the video stream.
Doing so will most likely help.
Note that VP9 encoding is sort of slow, I have no idea how ffmpeg will
behave if the input gets too far ahead from the output.​