Re: [PATCH v2 0/1] VirtIO video device specification

Dmitry Sepp
2019-12-20T15:59:05Z

Hi Keiichi,

On Mittwoch, 18. Dezember 2019 14:02:13 CET Keiichi Watanabe wrote:
> Hi,
> This is the 2nd version of virtio-video patch. The PDF is available in [1].
> The first version was sent at [2].
>
> Any feedback would be appreciated. Thank you.
>
> Best,
> Keiichi
>
> [1]:
> https://drive.google.com/drive/folders/1eT5fEckBoor2iHZR4f4GLxYzFMVapOFx?us
> p=sharing [2]: https://markmail.org/message/gc6h25acct22niut
>
> Change log:
>
> v2:
> * Removed functionalities except encoding and decoding.
> * Splited encoder and decoder into different devices that use the same
> protocol. * Replaced GET_FUNCS with GET_CAPABILITY.
> * Updated structs for capabilities.
> - Defined new structs and enums such as image formats, profiles, range
> (min, max, step), etc
> * For virtio_video_pixel_format, chose a naming convention that is used
> in DRM. We removed XBGR, NV21 and I422, as they are not used in the
> current draft implementation. https://lwn.net/Articles/806416/
> - Removed virtio_video_control, whose usage was not documented yet and
> which is not necessary for the simplest decoding scenario.
> - Removed virtio_video_desc, as it is no longer needed.
> * Updated struct virtio_video_config for changes around capabilities.
> * Added a way to represent supported combinations of formats.
> - A field "mask" in virtio_video_format_desc plays this role.
> * Removed VIRTIO_VIDEO_T_STREAM_{START,STOP} because they don't play any
> meaningful roles. * Removed VIRTIO_VIDEO_T_STREAM_{ATTACH, DETACH}_BACKING
> and merged them into RESOURCE_{CREATE, DESTROY}. * Added a way to
> notify/specify resource creation method.
> - Added a feature flag.
> - Defined enum virtio_video_mem_type.
> - Added new fields in video_stream_create.
> * Modified fields in virtio_video_params.
> - Added crop information.
> * Removed enum virtio_video_channel_type because we can get this information
> by image format.
Could you please explain this? How do you get the information?

Suppose you have some piece of HW on the host side that wants I420 as one
contig buffer w/ some offsets. But on the driver side, say, gralloc gives you
three separate buffers, one per channel. How do we pass those to the device
then?

Best regards,
Dmitry.

> * Renamed virtio_video_pin to virtio_video_buf_type.
> - It's similar to V4L2_BUF_TYPE_VIDEO_{OUTPUT, CAPTURE}.
> * Added an error event.
> * Reordered some subsections.
> * Changed styles to make it consistent with other devices.
>
> Dmitry Sepp (1):
> virtio-video: Add virtio video device specification
>
> content.tex | 1 +
> virtio-video.tex | 579 +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 580 insertions(+)
> create mode 100644 virtio-video.tex
>
> --
> 2.24.1.735.g03f4e72817-goog