[FFmpeg-devel] [PATCH] ffmpeg_qsv: use -hwaccel_device to specify a device for VAAPI backend

Xiang, Haihao haihao.xiang at intel.com
Wed Sep 2 07:28:05 EEST 2020


On Wed, 2020-09-02 at 04:20 +0000, Soft Works wrote:
> > -----Original Message-----
> > From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> > Haihao Xiang
> > Sent: Wednesday, September 2, 2020 6:01 AM
> > To: ffmpeg-devel at ffmpeg.org
> > Cc: Haihao Xiang <haihao.xiang at intel.com>
> > Subject: [FFmpeg-devel] [PATCH] ffmpeg_qsv: use -hwaccel_device to
> > specify a device for VAAPI backend
> > 
> > According to the FFmpeg documentation, -hwaccel_device can be used to
> > select a device for hardware acceleration
> > 
> > Example:
> > ffmpeg -hwaccel qsv -hwaccel_device /dev/dri/renderD129 -c:v h264_qsv \ -i
> > in.h264 -c:v hevc_qsv out.h265
> 
> No. The docs say about hwaccel_device
> 
> It can either refer to an existing device created with 
> -init_hw_device by name, 
> 
> => /dev/dri/renderD129 is not an existing device name
> 
> or it can create a new device as if ‘-init_hw_device’ 
> type:hwaccel_device were called immediately before.
> 
> => /dev/dri/renderD129 is not a valid string for init_hw_device
> 
> 
> Hence, the patch doesn't make sense.

in https://trac.ffmpeg.org/wiki/Hardware/VAAPI, 

If only one stream is being used, -hwaccel_device can also accept a device path
directly

ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -i ...

I think it can be applied to qsv too.



> 
> Kind regards,
> softworkz
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