Hi Keiichi,

On Freitag, 20. Dezember 2019 16:26:50 CET Keiichi Watanabe wrote:
> Hi Dmitry,
> Thanks for the feedback.
> 
> On Thu, Dec 19, 2019 at 10:28 PM Dmitry Sepp
> 
> <dmitry.sepp@opensynergy.com> wrote:
> > Hi Keiichi,
> > 
> > Thank you for the update. Please see some comments below.
> > 
> > Also, we need to bring the virtio_video_control back as it is in fact used
> > by the driver to enumerate supported encoder controls. But yes, it still
> > needs to be documemnted, it's true.
> 
> Yeah, we need it eventually, but I'm wondering what is the difference
> between values set by SET_PARAMS and ones by controls.
> I saw your driver implementation has BITRATE, PROFILE and LEVEL as
> controls. What's the reason why you didn't add them in
> virtio_video_params?
> 

In fact I think the reasons was not to blow up the params structure. Also, 
virtio_video_param is used to inform the driver about the supported controls, very much 
like frame_formats, frame_sizes and so on. But for setting we probably can use the 
set_params structure, right.

> > On Mittwoch, 18. Dezember 2019 14:02:14 CET Keiichi Watanabe wrote:
> > > From: Dmitry Sepp <dmitry.sepp@opensynergy.com>
> > > 
> > > The virtio video encoder device and decoder device provide
> > > functionalities
> > > to encode and decode video stream respectively.
> > > Though video encoder and decoder are provided as different devices, they
> > > use a same protocol.
> > > 
> > > Signed-off-by: Dmitry Sepp <dmitry.sepp@opensynergy.com>
> > > Signed-off-by: Keiichi Watanabe <keiichiw@chromium.org>
> > > ---
> > > 
> > >  content.tex      |   1 +
> > >  virtio-video.tex | 579 +++++++++++++++++++++++++++++++++++++++++++++++
> > >  2 files changed, 580 insertions(+)
> > >  create mode 100644 virtio-video.tex
> > > 
> > > diff --git a/content.tex b/content.tex
> > > index 556b373..9e56839 100644
> > > --- a/content.tex
> > > +++ b/content.tex
> > > @@ -5743,6 +5743,7 @@ \subsubsection{Legacy Interface: Framing
> > > Requirements}\label{sec:Device \input{virtio-vsock.tex}
> > > 
> > >  \input{virtio-fs.tex}
> > >  \input{virtio-rpmb.tex}
> > > 
> > > +\input{virtio-video.tex}
> > > 
> > >  \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
> > > 
> > > diff --git a/virtio-video.tex b/virtio-video.tex
> > > new file mode 100644
> > > index 0000000..30e728d
> > > --- /dev/null
> > > +++ b/virtio-video.tex
> > > @@ -0,0 +1,579 @@
> > > +\section{Video Device}\label{sec:Device Types / Video Device}
> > > +
> > > +The virtio video encoder device and decoder device are virtual devices
> > > that +supports encoding and decoding respectively. Though the encoder
> > > and the decoder +are different devices, they use the same protocol.
> > > +
> > > +\subsection{Device ID}\label{sec:Device Types / Video Device / Device
> > > ID}
> > > +
> > > +\begin{description}
> > > +\item[30] encoder device
> > > +\item[31] decoder device
> > > +\end{description}
> > > +
> > > +\subsection{Virtqueues}\label{sec:Device Types / Video Device /
> > > Virtqueues} +
> > > +\begin{description}
> > > +\item[0] controlq - queue for sending control commands.
> > > +\item[1] eventq - queue for sending events happened in the device.
> > > +\end{description}
> > > +
> > > +\subsection{Feature bits}\label{sec:Device Types / Video Device /
> > > Feature
> > > bits} +
> > > +\begin{description}
> > > +\item[VIRTIO_VIDEO_F_RESOURCE_GUEST_PAGES (0)] Guest pages can be used
> > > for
> > > video +  buffers.
> > > +\end{description}
> > > +
> > > +\devicenormative{\subsubsection}{Feature bits}{Device Types / Video
> > > Device
> > > / Feature bits} +
> > > +The device MUST offer at least one of feature bits.
> > > +
> > > +\subsection{Device configuration layout}\label{sec:Device Types / Video
> > > Device / Device configuration layout} +
> > > +Video device configuration uses the following layout structure:
> > > +
> > > +\begin{lstlisting}
> > > +struct virtio_video_config {
> > > +        le32 max_cap_len;
> > > +};
> > > +\end{lstlisting}
> > > +