From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A964C2D0C2 for ; Mon, 30 Dec 2019 12:16:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D56302071E for ; Mon, 30 Dec 2019 12:16:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727400AbfL3MQ0 (ORCPT ); Mon, 30 Dec 2019 07:16:26 -0500 Received: from plasma31.jpberlin.de ([80.241.56.82]:63759 "EHLO plasma31.jpberlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727376AbfL3MQ0 (ORCPT ); Mon, 30 Dec 2019 07:16:26 -0500 Received: from spamfilter03.heinlein-hosting.de (spamfilter03.heinlein-hosting.de [80.241.56.117]) by plasma.jpberlin.de (Postfix) with ESMTP id B83F810101E; Mon, 30 Dec 2019 13:16:18 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from plasma.jpberlin.de ([80.241.56.76]) by spamfilter03.heinlein-hosting.de (spamfilter03.heinlein-hosting.de [80.241.56.117]) (amavisd-new, port 10030) with ESMTP id oSb4bpOc9A72; Mon, 30 Dec 2019 13:16:16 +0100 (CET) Received: from webmail.opensynergy.com (unknown [217.66.60.5]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client CN "webmail.opensynergy.com", Issuer "GeoTrust EV RSA CA 2018" (not verified)) (Authenticated sender: opensynergy@jpberlin.de) by plasma.jpberlin.de (Postfix) with ESMTPSA id EB089100F43; Mon, 30 Dec 2019 13:16:15 +0100 (CET) Received: from os-lin-dmo.localnet (10.25.255.1) by MXS01.open-synergy.com (10.25.10.17) with Microsoft SMTP Server (TLS) id 14.3.468.0; Mon, 30 Dec 2019 13:16:15 +0100 From: Dmitry Sepp To: CC: Keiichi Watanabe , , , , , , , , , , , , , , , Subject: Re: [virtio-dev] Re: [PATCH v2 1/1] virtio-video: Add virtio video device specification Date: Mon, 30 Dec 2019 13:16:15 +0100 Message-ID: <2322065.f0tlG9Vh6p@os-lin-dmo> Organization: OpenSynergy In-Reply-To: <2932378.s8JBUXtX1Y@os-lin-dmo> References: <20191218130214.170703-1-keiichiw@chromium.org> <20191218130214.170703-2-keiichiw@chromium.org> <2932378.s8JBUXtX1Y@os-lin-dmo> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Originating-IP: [10.25.255.1] Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Donnerstag, 19. Dezember 2019 14:28:23 CET Dmitry Sepp 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. > > On Mittwoch, 18. Dezember 2019 14:02:14 CET Keiichi Watanabe wrote: > > From: Dmitry Sepp > > > > 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 > > Signed-off-by: Keiichi Watanabe > > --- > > > > 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} > > + > > +\begin{description} > > +\item[\field{max_cap_len}] defines the maximum length of a descriptor > > + required to call VIRTIO_VIDEO_GET_CAPABILITY in bytes. The device > > + MUST set this value. > > +\end{description} > > + > > +\subsection{Device Initialization}\label{sec:Device Types / Video Device > > / > > Device Initialization} + > > +\devicenormative{\subsubsection}{Device Initialization}{Device Types / > > Video Device / Device Initialization} + > > +The driver SHOULD query device capability by using the > > +VIRTIO_VIDEO_T_GET_CAPABILITY and use that information for the initial > > +setup. > > + > > +\subsection{Device Operation}\label{sec:Device Types / Video Device / > > Device Operation} + > > +The driver allocates input and output buffers and queues the buffers > > +to the device. The device performs operations on the buffers according > > +to the function in question. > > + > > +\subsubsection{Device Operation: Create stream} > > + > > +To process buffers, the device needs to associate them with a certain > > +video stream (essentially, a context). Streams are created by > > +VIRTIO_VIDEO_T_STREAM_CREATE with a default set of parameters > > +determined by the device. > > + > > +\subsubsection{Device Operation: Create buffers} > > + > > +Buffers are used to store the actual data as well as the relevant > > +metadata. Scatter lists are supported, so the buffer doesn't need to > > +be contiguous in guest physical memory. > > + > > +\begin{itemize*} > > +\item Use VIRTIO_VIDEO_T_RESOURCE_CREATE to create a virtio video > > + resource that is backed by a buffer allocated from the driver's > > + memory. > > +\item Use VIRTIO_VIDEO_T_RESOURCE_DESTROY to destroy a resource that > > + is no longer needed. > > +\end{itemize*} > > + > > +\subsubsection{Device Operation: Stream parameter control} > > + > > +\begin{itemize*} > > +\item Use VIRTIO_VIDEO_T_GET_PARAMS to get the current stream parameters > > for + input and output streams from the device. > > +\item Use VIRTIO_VIDEO_T_SET_PARAMS to provide new stream parameters to > > the + device. > > +\item After setting stream parameters, the driver may issue > > + VIRTIO_VIDEO_T_GET_PARAMS as some parameters of both input and output > > can be + changed implicitly by the device during the set operation. > > +\end{itemize*} > > + > > +\subsubsection{Device Operation: Process buffers} > > + > > +\begin{itemize*} > > +\item If the function and the buffer type require so, write data to > > +the buffer memory. > > +\item Use VIRTIO_VIDEO_T_RESOURCE_QUEUE to queue the buffer for > > +processing in the device. > > +\item The request completes asynchronously when the device has > > +finished with the buffer. > > +\end{itemize*} > > + > > +\subsubsection{Device Operation: Buffer processing control} > > + > > +\begin{itemize*} > > +\item Use VIRTIO_VIDEO_T_STREAM_DRAIN to ask the device to process and > > + return all of the already queued buffers. > > +\item Use VIRTIO_VIDEO_T_QUEUE_CLEAR to ask the device to return back > > + already queued buffers from the input or the output queue. This also > > + includes input or output buffers that can be currently owned by the > > + device's processing pipeline. > > +\end{itemize*} > > + > > +\subsubsection{Device Operation: Asynchronous events} > > + > > +While processing buffers, the device can send asynchronous event > > +notifications to the driver. The behaviour depends on the exact > > +stream. For example, the decoder device sends a resolution change > > +event when it encounters new resolution metadata in the stream. > > + > > +\subsubsection{Device Operation: Request header} > > + > > +All requests and responses on the control virt queue have a fixed > > +header using the following layout structure and definitions: > > + > > +\begin{lstlisting} > > +enum virtio_video_ctrl_type { > > + VIRTIO_VIDEO_CTRL_UNDEFINED = 0, > > + > > + /* request */ > > + VIRTIO_VIDEO_T_GET_CAPABILITY = 0x0100, > > + VIRTIO_VIDEO_T_STREAM_CREATE, > > + VIRTIO_VIDEO_T_STREAM_DESTROY, > > + VIRTIO_VIDEO_T_STREAM_DRAIN, > > + VIRTIO_VIDEO_T_RESOURCE_CREATE, > > + VIRTIO_VIDEO_T_RESOURCE_DESTROY, > > + VIRTIO_VIDEO_T_RESOURCE_QUEUE, > > + VIRTIO_VIDEO_T_QUEUE_CLEAR, > > + VIRTIO_VIDEO_T_SET_PARAMS, > > + VIRTIO_VIDEO_T_GET_PARAMS, > > + > > + /* response */ > > + VIRTIO_VIDEO_S_OK = 0x0200, > > + VIRTIO_VIDEO_S_OK_RESOURCE_QUEUE, > > + VIRTIO_VIDEO_S_OK_GET_PARAMS, > > + > > + VIRTIO_VIDEO_S_ERR_UNSPEC = 0x0300, > > + VIRTIO_VIDEO_S_ERR_OUT_OF_MEMORY, > > + VIRTIO_VIDEO_S_ERR_INVALID_RESOURCE_ID, > > + VIRTIO_VIDEO_S_ERR_INVALID_STREAM_ID, > > + VIRTIO_VIDEO_S_ERR_INVALID_PARAMETER, > > +}; > > + > > +struct virtio_video_ctrl_hdr { > > + le32 type; > > + le32 stream_id; > > + le32 len; /* Length of the structure in bytes. */ > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{type}] is the type of the driver request or the device > > +response. > > +\item[\field{stream_id}] specifies a target stream. > > +\item[\field{len}] is the length of data in bytes, which includes > > +length of the header. > > +\end{description} > > + > > +\subsubsection{Device Operation: controlq} > > + > > +\begin{description} > > + > > +\item[VIRTIO_VIDEO_T_GET_CAPABILITY] Retrieve information about > > +supported formats. > > + > > +The driver uses \field{struct virtio_video_get_capability} to send a > > +query request. > > + > > +\begin{lstlisting} > > +enum virtio_video_buf_type { > > + VIRTIO_VIDEO_BUF_TYPE_INPUT, > > + VIRTIO_VIDEO_BUF_TYPE_OUTPUT, > > +}; > > I personally didn't like the previous term: pin_type. But, to be honest, I > don't like the buf_type neither. Consider the GET/SET_PARAMS request: > buf_type there looks a bit unnatural. We are trying to get stream > parameters there, not some parameters of whatever buffer. Also I don't see > any strict reason to mimic v4l2 naming scheme. > > I'd better rename it to PORT_TYPE or QUEUE_TYPE. > > > + > > +struct virtio_video_get_capability { > > + struct virtio_video_ctrl_hdr hdr; > > + enum virtio_video_buf_type buf_type; > > +}; > > +\end{lstlisting} > > +\begin{description} > > +\item[\field{buf_type}] is the buffer type that the driver asks > > +information about. The driver MUST set either > > +\field{VIRTIO_VIDEO_BUF_TYPE_INPUT} or > > \field{VIRTIO_VIDEO_BUF_TYPE_OUTPUT}. +\end{description} > > + > > +The device responds a capability by using \field{struct > > +virtio_video_get_capability_resp}. > > +\begin{lstlisting} > > +enum virtio_video_format { > > + VIRTIO_VIDEO_FORMAT_UNDEFINED = 0, > > + /* Raw formats */ > > + VIRTIO_VIDEO_FORMAT_NV12 = 1, > > + VIRTIO_VIDEO_FORMAT_YUV420, > > + VIRTIO_VIDEO_FORMAT_YVU420, > > Let's add some variants of RGB, like RGBA, ARGB. We need it for the encoder > in particular . > > > + > > + /* Compressed formats */ > > + VIRTIO_VIDEO_FORMAT_H264 = 0x1001, > > + VIRTIO_VIDEO_FORMAT_VP8 = 0x1002, > > + VIRTIO_VIDEO_FORMAT_VP9 = 0x1003, > > Let's add H265, MPEG4, MPEG2. We already support and use them. > > Regards, > Dmitry. > > > +}; > > + > > +enum virtio_video_profile { > > + VIRTIO_VIDEO_PROFILE_UNDEFINED = 0, > > + > > + /* H.264 */ > > + VIRTIO_VIDEO_PROFILE_H264_MIN = 0x100, > > + VIRTIO_VIDEO_PROFILE_H264_BASELINE = > > VIRTIO_VIDEO_PROFILE_H264_BASELINE, + > > VIRTIO_VIDEO_PROFILE_H264_MAIN, > > + VIRTIO_VIDEO_PROFILE_H264_EXTENDED, > > + VIRTIO_VIDEO_PROFILE_H264_HIGH, > > + VIRTIO_VIDEO_PROFILE_H264_HIGH10PROFILE, > > + VIRTIO_VIDEO_PROFILE_H264_HIGH422PROFILE, > > + VIRTIO_VIDEO_PROFILE_H264_HIGH444PREDICTIVEPROFILE, > > + VIRTIO_VIDEO_PROFILE_H264_SCALABLEBASELINE, > > + VIRTIO_VIDEO_PROFILE_H264_SCALABLEHIGH, > > + VIRTIO_VIDEO_PROFILE_H264_STEREOHIGH, > > + VIRTIO_VIDEO_PROFILE_H264_MULTIVIEWHIGH, > > + VIRTIO_VIDEO_PROFILE_H264_MAX = > > VIRTIO_VIDEO_PROFILE_H264_MULTIVIEWHIGH, + > > + /* VP8 */ > > + VIRTIO_VIDEO_PROFILE_VP8_MIN = 0x200, > > + VIRTIO_VIDEO_PROFILE_VP8_ANY = VIRTIO_VIDEO_PROFILE_VP8_MIN, > > + VIRTIO_VIDEO_PROFILE_VP8_MAX = VIRTIO_VIDEO_PROFILE_VP8_ANY, > > + > > + /* VP9 */ > > + VIRTIO_VIDEO_PROFILE_VP9_MIN = 0x300, > > + VIRTIO_VIDEO_PROFILE_VP9_PROFILE0 = VIRTIO_VIDEO_PROFILE_VP9_MIN, > > + VIRTIO_VIDEO_PROFILE_VP9_PROFILE1, > > + VIRTIO_VIDEO_PROFILE_VP9_PROFILE2, > > + VIRTIO_VIDEO_PROFILE_VP9_PROFILE3, > > + VIRTIO_VIDEO_PROFILE_VP9_MAX = VIRTIO_VIDEO_PROFILE_VP9_PROFILE3, > > +}; > > + > > +struct virtio_video_format_range { > > + le32 min; > > + le32 max; > > + le32 step; > > + u8 paddings[4]; > > +}; > > + > > +struct virtio_video_format_desc { > > + le32 format; /* One of VIRTIO_VIDEO_FORMAT_* types */ > > + le32 profile; /* One of VIRTIO_VIDEO_PROFILE_* types */ > > + le64 mask; > > + struct virtio_video_format_range width; > > + struct virtio_video_format_range height; > > + le32 num_rates; > > + u8 padding[4]; > > + /* Followed by struct virtio_video_frame_rate frame_rates[] */ > > +}; > > + > > +struct virtio_video_get_capability_resp { > > + struct virtio_video_ctrl_hdr hdr; > > + le32 num_descs; > > + /* Followed by struct virtio_video_format_desc desc[] */ > > +}; > > +\end{lstlisting} > > + We also see the need to add a max_streams value to this structure so as to explicitly provide a limit on the number of streams the guest can create. Regards, Dmitry. > > +The format description \field{struct virtio_video_format_desc} > > +includes the following fields: > > +\begin{description} > > +\item[\field{format}] specifies an image format. The device MUST set one > > + of \field{enum virtio_video_format}. > > +\item[\field{profile}] specifies a profile of the compressed image format > > + specified in \field{format}. The driver SHOULD ignore this value if > > + \field{format} is a raw format. > > +\item[\field{mask}] is a bitset that represents the supported > > + combination of input and output format. If \textit{i}-th bit is set > > + in \field{mask} of \textit{j}-th \field{struct > > + virtio_video_format_desc} for input, the device supports encoding or > > + decoding from the \textit{j}-th input format to \textit{i}-th output > > + format. > > +\item[\field{width, height}] represents a range of resolutions > > + supported by the device. If its \field{step} is not applicable, its > > + \field{min} is equal to its \field{max}. > > +\item[\field{num_rates}] is the length of an array \field{frame_rates}. > > In > > case of decoder, the driver SHOULD ignore this value. > > +\item[\field{frame_rates}] is an array of supported frame rates. > > +\end{description} > > + > > +\item[VIRTIO_VIDEO_T_STREAM_CREATE] create a video stream (context) > > + within the device. > > + > > +\begin{lstlisting} > > +enum virtio_video_mem_type { > > + VIRTIO_VIDEO_MEM_TYPE_GUEST_PAGES, > > +}; > > + > > +struct virtio_video_stream_create { > > + struct virtio_video_ctrl_hdr hdr; > > + le32 in_mem_type; /* One of VIRTIO_VIDEO_MEM_TYPE_* types */ > > + le32 out_mem_type; /* One of VIRTIO_VIDEO_MEM_TYPE_* types */ > > + char debug_name[64]; > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{in_mem_type}] is a type of buffer management for input > > +buffers. The driver MUST set a value in \field{enum > > +virtio_video_mem_type}. > > +\item[\field{out_mem_type}] is a type of buffer management for output > > +buffers. The driver MUST set a value in \field{enum > > +virtio_video_mem_type}. > > +\item[\field{debug_name}] is a text string for a debug purpose. > > +\end{description} > > + > > +\item[VIRTIO_VIDEO_T_STREAM_DESTROY] destroy a video stream (context) > > + within the device. > > + > > +\begin{lstlisting} > > +struct virtio_video_stream_destroy { > > + struct virtio_video_ctrl_hdr hdr; > > +}; > > +\end{lstlisting} > > + > > +\item[VIRTIO_VIDEO_T_STREAM_DRAIN] ask the device to push all the > > + queued buffers through the pipeline. > > + > > +\begin{lstlisting} > > +struct virtio_video_stream_drain { > > + struct virtio_video_ctrl_hdr hdr; > > +}; > > +\end{lstlisting} > > + > > +\item[VIRTIO_VIDEO_T_RESOURCE_CREATE] create a resource descriptor > > + within the device. > > + > > +\begin{lstlisting} > > +struct virtio_video_mem_entry { > > + le64 addr; > > + le32 length; > > + u8 padding[4]; > > +}; > > + > > +struct virtio_video_resource_create { > > + struct virtio_video_ctrl_hdr hdr; > > + le32 resource_id; > > + le32 nr_entries; > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{resource_id}] internal id of the resource. > > +\item[\field{nr_entries}] number of \field{struct > > + virtio_video_mem_entry} memory entries. > > +\end{description} > > + > > +\item[VIRTIO_VIDEO_T_RESOURCE_DESTROY] destroy a resource descriptor > > + within the device. > > + > > +\begin{lstlisting} > > +struct virtio_video_resource_destroy { > > + struct virtio_video_ctrl_hdr hdr; > > + le32 resource_id; > > + u8 padding[4]; > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{resource_id}] internal id of the resource. > > +\end{description} > > + > > +\item[VIRTIO_VIDEO_T_RESOURCE_QUEUE] Add a buffer to the device's > > +queue. > > + > > +\begin{lstlisting} > > +#define VIRTIO_VIDEO_MAX_PLANES 8 > > + > > +struct virtio_video_resource_queue { > > + struct virtio_video_ctrl_hdr hdr; > > + le32 buf_type; > > + le32 resource_id; > > + le64 timestamp; > > + le32 nr_data_size; > > + le32 data_size[VIRTIO_VIDEO_MAX_PLANES]; > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{buf_type}] buf_type of the . > > +\item[\field{resource_id}] internal id of the resource. > > +\item[\field{timestamp}] an abstract sequence counter that can be used > > + for synchronisation. > > +\item[\field{nr_data_size}] number of \field{data_size} entries. > > +\item[\field{data_size}] number of data bytes within a plane. > > +\end{description} > > + > > +\begin{lstlisting} > > +enum virtio_video_buffer_flag { > > + VIRTIO_VIDEO_BUFFER_F_ERR = 0x0001, > > + VIRTIO_VIDEO_BUFFER_F_EOS = 0x0002, > > + /* Encoder only */ > > + VIRTIO_VIDEO_BUFFER_IFRAME = 0x0004, > > + VIRTIO_VIDEO_BUFFER_PFRAME = 0x0008, > > + VIRTIO_VIDEO_BUFFER_BFRAME = 0x0010, > > +}; > > + > > +struct virtio_video_resource_queue_resp { > > + struct virtio_video_ctrl_hdr hdr; > > + le64 timestamp; > > + le32 flags; /* One of VIRTIO_VIDEO_BUFFER_* flags */ > > + le32 size; /* Encoded size */ > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{timestamp}] an abstract sequence counter that can be used > > + for synchronisation. > > +\item[\field{flags}] mark specific buffers in the sequence. > > +\item[\field{size}] data size in the buffer (encoder only). > > +\end{description} > > + > > +The device sends a response to the queue request asynchronously when > > +it has finished processing the buffer. > > + > > +The device SHOULD mark a buffer that triggered a processing error with > > +the VIRTIO_VIDEO_BUFFER_F_ERR flag. > > + > > +The device MUST mark the last buffer with the > > +VIRTIO_VIDEO_BUFFER_F_EOS flag to denote completion of the drain > > +sequence. > > + > > +In case of encoder, to denote a particular frame type the devie MUST > > +mark the respective buffer with VIRTIO_VIDEO_BUFFER_IFRAME, > > +VIRTIO_VIDEO_BUFFER_PFRAME, VIRTIO_VIDEO_BUFFER_BFRAME. > > + > > +\item[VIRTIO_VIDEO_T_RESOURCE_QUEUE_CLEAR] Return already queued > > + buffers back from the input or the output queue of the device. The > > + device SHOULD return all of the buffers from the respective queue as > > + soon as possible without pushing the buffers through the processing > > + pipeline. > > + > > +\begin{lstlisting} > > +struct virtio_video_queue_clear { > > + struct virtio_video_ctrl_hdr hdr; > > + le32 buf_type; > > + u8 padding[4]; > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{buf_type}] buffer type. > > +\end{description} > > + > > +\item[VIRTIO_VIDEO_T_GET_PARAMS] Get parameters of the input or the > > + output of a stream. > > + > > +\begin{lstlisting} > > +struct virtio_video_plane_format { > > + le32 plane_size; > > + le32 stride; > > + u8 padding[4]; > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{plane_size}] size of the plane in bytes. > > +\item[\field{stride}] stride used for the plane in bytes. > > +\end{description} > > + > > +\begin{lstlisting} > > +struct virtio_video_params { > > + le32 buf_type; /* One of VIRTIO_VIDEO_BUF_TYPE_* types */ > > + le32 fourcc; /* One of VIRTIO_VIDEO_FOURCC_* types */ > > + le32 frame_width; > > + le32 frame_height; > > + le32 min_buffers; > > + le32 max_buffers; > > + le32 frame_rate; > > + struct virtio_video_crop { > > + le32 left; > > + le32 top; > > + le32 width; > > + le32 height; > > + } crop; > > + le32 num_planes; > > + struct virtio_video_plane_format > > plane_formats[VIRTIO_VIDEO_MAX_PLANES]; +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{frame_width}] the value to get/set. > > +\item[\field{frame_height}] the value to get/set. > > +\item[\field{pixel_format}] the value to get/set. > > +\item[\field{min_buffers}] minimum buffers required to handle the > > + format (r/o). > > +\item[\field{max_buffers}] maximum buffers required to handle the > > + format (r/o). > > +\item[\field{frame_rate}] the value to get/set. > > +\item[\field{crop}] cropping (composing) rectangle. > > +\item[\field{num_planes}] number of planes used to store pixel data > > +(r/o). > > +\item[\field{plane_formats}] description of each plane. > > +\end{description} > > + > > +\begin{lstlisting} > > +struct virtio_video_get_params { > > + struct virtio_video_ctrl_hdr hdr; > > + le32 buf_type; /* One of VIRTIO_VIDEO_BUF_TYPE_* types */ > > +}; > > + > > +struct virtio_video_get_params_resp { > > + struct virtio_video_ctrl_hdr hdr; > > + struct virtio_video_params params; > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{buf_type}] buffer type. > > +\item[\field{params}] parameter values. > > +\end{description} > > + > > +\item[VIRTIO_VIDEO_T_SET_PARAMS] Change parameters of a stream. > > + > > + > > +\begin{lstlisting} > > +struct virtio_video_set_params { > > + struct virtio_video_ctrl_hdr hdr; > > + struct virtio_video_params params; > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{params}] parameters to set. > > +\end{description} > > + > > +Setting stream parameters might have side effects within the device. > > +For example, the device MAY perform alignment of width and height, > > +change the number of planes it uses for the format, or do whatever > > +changes that are required to continue normal operation using the > > +updated parameters. It is up to the driver to check the parameter set > > +after the VIRTIO_VIDEO_T_SET_PARAMS request has been issued. > > + > > +\end{description} > > + > > +\subsubsection{Device Operation: eventq} > > + > > +The device can report events on the event queue. The driver initially > > +populates the queue with device-writeable buffers. When the device > > +needs to report an event, it fills a buffer and notifies the driver. > > +The driver consumes the report and adds a new buffer to the virtqueue. > > + > > +\begin{lstlisting} > > +enum virtio_video_event_type { > > + VIRTIO_VIDEO_EVENT_T_UNDEFINED = 0, > > + /* For all functions */ > > + VIRTIO_VIDEO_EVENT_T_ERROR_UNSPEC = 0x0100, > > + /* For decoder only */ > > + VIRTIO_VIDEO_EVENT_T_DECODER_RESOLUTION_CHANGED = 0x0200, > > +}; > > + > > +struct virtio_video_event { > > + le32 event_type; /* One of VIRTIO_VIDEO_EVENT_T_* types */ > > + le32 stream_id; > > + u8 padding[4]; > > +}; > > +\end{lstlisting} > > + > > +\begin{description} > > +\item[\field{event_type}] type of the triggered event . > > +\item[\field{stream_id}] id of the source stream. > > +\end{description} > > + > > +The device MUST send VIRTIO_VIDEO_EVENT_T_DECODER_RESOLUTION_CHANGED > > +whenever it encounters new resolution data in the stream. This > > +includes the case of the initial device configuration after metadata > > +has been parsed and the case of dynamic resolution change. > > --------------------------------------------------------------------- > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org