[FFmpeg-devel] [PATCH 5/5] lavd: Add KMS frame grabber

[Mark Thompson]

On 15/09/17 00:15, Andy Furniss wrote:
> Andy Furniss wrote:
>> Mark Thompson wrote:
>>> ---
>>> Now sets the trusted packet flag; otherwise unchanged.
>>>
>>>
>>>   configure                |   1 +
>>>   libavdevice/Makefile     |   1 +
>>>   libavdevice/alldevices.c |   1 +
>>>   libavdevice/kmsgrab.c    | 455 +++++++++++++++++++++++++++++++++++++++++++++++
>>>   4 files changed, 458 insertions(+)
>>>   create mode 100644 libavdevice/kmsgrab.c
>>>
>>> diff --git a/configure b/configure
>>> index 6581c53c1a..76a7591ceb 100755
>>> --- a/configure
>>> +++ b/configure
>>> @@ -3040,6 +3040,7 @@ gdigrab_indev_select="bmp_decoder"
>>>   iec61883_indev_deps="libiec61883"
>>>   jack_indev_deps="jack"
>>>   jack_indev_deps_any="sem_timedwait dispatch_dispatch_h"
>>> +kmsgrab_indev_deps="libdrm"
>>
>> Doesn't get built for me = doesn't show up as indev after configure anything special needed?
> 
> Never mind I found --enable-libdrm (had tried --enable-kmsgrab)

I assume you're going to try AMD + Mesa + VAAPI.

VAAPI_DISABLE_INTERLACE=1 ./ffmpeg_g -y -format bgr0 -device /dev/dri/card1 -f kmsgrab -i - -vsync 0 -init_hw_device vaapi=v:/dev/dri/renderD129 -filter_hw_device v -vf 'hwmap,scale_vaapi=w=1920:h=1080:format=nv12' -c:v h264_vaapi -profile 578 -bf 0 out.mp4

Three Mesa issues I had to get around:

* Device derivation doesn't work because the Mesa driver doesn't want to initialise on the DRM master device for some reason; making the matching device separately does work.
* Against current git, you need to reapply the VAAPI_DISABLE_INTERLACE patch and use it - if not, the colour conversion just barfs because it wants interlaced surfaces.
* The postproc scaler seems to only write the luma plane when converting from RGB - this is also visible when uploading normal RGB images, so just a bug somewhere.

With that, it works to record the screen in greyscale...

I have some other Mesa stuff to do queued up (libva2 with VAAPI export for EGL import on AMD), so I'll pursue these further soonish.

- Mark