Using ffmpeg with xvfb renders a cropped version of the screen

Question

I'm using the following command to render a video of a chrome browser running inside a virtual frame buffer (using xvfb):

ffmpeg -f x11grab -i :5 -s `DISPLAY=:5 xdpyinfo | grep 'dimensions:'|awk '{print $2}'` -r 30 tests.mpg

When I omit the DISPLAY=:5 xdpyinfo | grep 'dimensions:'|awk '{print $2}', it will render at about 1024x768, so I invoked xdpyinfo to get the resolution of the display and tell ffmpeg about it.

But when I use the command, it shows the same cropped area, only stretched to fit the resolution I gave ffmpeg.

I would like to be able to record the whole virtual frame buffer without cropping or stretching. Is there a way to do so?

I have compiled ffmpeg from source just this morning, running v2.8.git

Complete console output missing. – llogan Sep 23 '15 at 15:50 — llogan, Sep 23 '15 at 15:50

score 4 · Accepted Answer · answered Sep 23 '15 at 20:21

The arguments that come after -i control the output, not the input.

To set the source resolution use -video_size with the xdpyinfo output before the -i. For the framerate use -framerate.

The format for the x11grab input is [hostname]:display_number.screen_number[+x_offset,y_offset].

ffmpeg -video_size `DISPLAY=:5 xdpyinfo | grep 'dimensions:'|awk '{print $2}'` -framerate 30 -f x11grab -i :5.0+0,0 output.mpg

Check the docs and the guide: https://trac.ffmpeg.org/wiki/Capture/Desktop

This was the answer. Thank you! It was a bit confusing for me. — Jeff Huijsmans, Sep 24 '15 at 14:47

Using ffmpeg with xvfb renders a cropped version of the screen

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