"Auto" hwdec uses wrong hw decoder module on optimus machines

[Doug McMahon]

By defaut vlc uses Automatic for hardware accelerated decoding. On an nvidia optimus machine where nvidia drivers are not installed vlc picks vdpau instead of one of the vaapi outs. The result is very poor playback, at least with h264.
Attached message log from vlc at fresh install defaults & one with the hwdec changed to one of the vaapi choices, this case x11

Notable -
Default (playback is terrible, large # dropped frames
avcodec debug: available hardware decoder output format 109 (vdpau)
avcodec debug: available hardware decoder output format 53 (vaapi_vld)
avcodec debug: available software decoder output format 0 (yuv420p)
core debug: looking for hw decoder module matching "any": 4 candidates

core debug: using hw decoder module "vdpau_avcodec"

Specified (playback is fine
avcodec debug: available hardware decoder output format 109 (vdpau)
avcodec debug: available hardware decoder output format 53 (vaapi_vld)
avcodec debug: available software decoder output format 0 (yuv420p)
core debug: looking for hw decoder module matching "vaapi_x11": 4 candidates

core debug: using hw decoder module "vaapi_x11"

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: vlc 2.2.1-5 [modified: usr/share/applications/vlc.desktop]
ProcVersionSignature: Ubuntu 4.3.0-5.16-generic 4.3.3
Uname: Linux 4.3.0-5-generic x86_64
ApportVersion: 2.19.3-0ubuntu3
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Jan 20 01:05:02 2016
InstallationDate: Installed on 2016-01-14 (5 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160114)
SourcePackage: vlc
UpgradeStatus: No upgrade log present (probably fresh install)

[Doug McMahon (mc3man)]

https://trac.videolan.org/vlc/ticket/16433

[Sebastian Ramacher (s-ramacher)]

See upstream issue.