> -----Original Message----- > From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of > Rogozhkin, Dmitry V > Sent: Wednesday, September 2, 2020 9:00 AM > To: ffmpeg-devel@ffmpeg.org > Subject: Re: [FFmpeg-devel] [PATCH] ffmpeg_qsv: use -hwaccel_device to > specify a device for VAAPI backend > > On Wed, 2020-09-02 at 04:28 +0000, Xiang, Haihao wrote: > > On Wed, 2020-09-02 at 04:20 +0000, Soft Works wrote: > > > > -----Original Message----- > > > > From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf > Of > > > > Haihao Xiang > > > > Sent: Wednesday, September 2, 2020 6:01 AM > > > > To: ffmpeg-devel@ffmpeg.org > > > > Cc: Haihao Xiang <haihao.xi...@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 > > Well, it seems that's where documentation does not reflect the reality since > (as pointed by Haihao below) https://trac.ffmpeg.org/wiki/Hardware/VAAPI > is full of contradictory examples. > > > > > > > > > > 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. > > > > I agree. Part of ffmpeg help: > -hwaccel hwaccel name use HW accelerated decoding > -hwaccel_device devicename select a device for HW acceleration > > To me specifying device via -hwaccel_device in the way it is being suggest in > commit is pretty intuitive and is better than explain people that there is - > qsv_device for that purpose. Niceness of -hwaccel_device is that it is not > tight to particular acceleration, hence easier to work with for end users.
In case of QSV, the usage of hwaccel_device is already defined: device selects a value in ‘MFX_IMPL_*’. Allowed values are: auto sw hw auto_any hw_any hw2 hw3 hw4 I agree that it would be more intuitive, but you can't just give it a different meaning from one day to another and break functionality. Kind regards, softworkz _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
