Xvfb + ffmpeg recording producing only red rectangles

Question

I'm trying to record a process I've automated with xdotools. It appears to be working correctly, but all I see are solid red rectangles. The rectangles look like they're the correct size/position for the windows that I expect xdotools to navigate through, but I'm not getting a real picture.

Here's my xvfb and ffmpeg invocations

export DISPLAY=:99.0
Xvfb $DISPLAY -screen 0 1920x1080x16 &
ffmpeg -y -f x11grab -video_size 1920x1080 -i $DISPLAY intellij.mpg &

Here's the media info on the screen.webm produced by ffmpeg.

General
Complete name               : C:\vm-shared-folders\screen.webm
Format                      : WebM
Format version              : Version 2
File size                   : 208 KiB
Writing application         : Lavf58.20.100
Writing library             : Lavf58.20.100
IsTruncated                 : Yes

Video
ID                          : 1
Format                      : VP8
Codec ID                    : V_VP8
Width                       : 1 920 pixels
Height                      : 1 080 pixels
Display aspect ratio        : 16:9
Frame rate mode             : Constant
Frame rate                  : 30.000 FPS
Compression mode            : Lossy
Writing library             : Lavc58.35.100 libvpx
Default                     : Yes
Forced                      : No

score 1 · Accepted Answer · answered Jun 06 '20 at 18:34

These two commands gave me good output. I have no idea why they worked over the commands I put in above. I just kept tinkering with things until it worked.

Xvfb $DISPLAY -screen 0 1920x1080x24 &
ffmpeg -y -probesize 200M -f x11grab -video_size 1920x1080 -i "$DISPLAY" out.webm &

Xvfb + ffmpeg recording producing only red rectangles

1 Answers1