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[FFmpeg-devel] doc/ffmpeg: Document VAAPI device creation options

Message ID 618521bf-0807-13a8-2530-12ff7a980dcf@jkqxz.net
State New
Headers show

Commit Message

Mark Thompson June 2, 2019, 10:57 p.m. UTC 
---
 doc/ffmpeg.texi | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)
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Patch

diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
index cd35eb49c8..ccd490d1a7 100644
--- a/doc/ffmpeg.texi
+++ b/doc/ffmpeg.texi
@@ -950,8 +950,32 @@  device type:
 
 @item vaapi
 @var{device} is either an X11 display name or a DRM render node.
-If not specified, it will attempt to open the default X11 display (@emph{$DISPLAY})
-and then the first DRM render node (@emph{/dev/dri/renderD128}).
+If not specified, it will attempt to open the first usable DRM render node
+(@emph{/dev/dri/renderD128}, @emph{/dev/dri/renderD129}, etc.).  If no render
+node is found then it will try the default X11 display (@emph{$DISPLAY}).
+
+Some options are also supported to guide the selection:
+@table @option
+@item connection_type
+Explicitly specify the connection type to use - @samp{x11} or @samp{drm}.
+@item kernel_driver
+Only consider DRM render nodes using the named kernel driver.
+@item driver
+Select the VA driver to load after the connection is open.  This does not
+affect the selection of the device itself.
+@end table
+
+Examples:
+@table @emph
+@item -init_hw_device vaapi:/dev/dri/renderD129
+Choose the device on the second DRM render node.
+@item -init_hw_device vaapi:,connection_type=drm,kernel_driver=amdgpu
+Choose a device on a DRM render node using the @emph{amdgpu} kernel driver,
+as found on most current AMD graphics devices.
+@item -init_hw_device vaapi:,kernel_driver=i915,driver=iHD
+Choose a device using the @emph{i915} kernel driver, and load the @emph{iHD}
+VA driver to use with it.
+@end table
 
 @item vdpau
 @var{device} is an X11 display name.