Vaapi closing #27

[jrottenberg]

Following up from #106

[jrottenberg]

Checking why https://travis-ci.org/jrottenberg/ffmpeg/jobs/393451694 failed...

3.4 on Centos , weird.

@qmfrederik do you have usage note, so I can update the readme before the merge ?

ie how to do a docker run mounting the right devices to use the gpu.

[qmfrederik]

@jrottenberg For this to work, you need to:

• Run the container in privileged mode and mount /dev/dri from your host into the container (docker run --privileged -v /dev/dri:/dev/dri if I'm not mistaken)
• Have the Intel drivers up and running on your host. You can run vainfo (part of vainfo package on Ubuntu) to determine whether your graphics card has been recognized correctly.
• Run ffmpeg with the correct parameters, this is the same as when running ffmpeg natively. See https://trac.ffmpeg.org/wiki/Hardware/VAAPI

[jrottenberg]

Excellent, not too sure about the --privileged parameter, but yeah /dev/dri mount for sure.