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authorAlan Coopersmith <alan.coopersmith@oracle.com>2013-06-27 22:14:36 -0700
committerAlan Coopersmith <alan.coopersmith@oracle.com>2013-06-27 22:14:36 -0700
commit77d5c8d90e81139391a57710095784cde0476b9c (patch)
tree914314451559c3a7b4accabce90bd3cca9394bce /xv-protocol-v2.txt
parent1a96222d64cde75e20fd9bb7a717cf269c7e9a59 (diff)
Trim trailing whitespace
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Diffstat (limited to 'xv-protocol-v2.txt')
-rw-r--r--xv-protocol-v2.txt216
1 files changed, 108 insertions, 108 deletions
diff --git a/xv-protocol-v2.txt b/xv-protocol-v2.txt
index 31e2013..d018184 100644
--- a/xv-protocol-v2.txt
+++ b/xv-protocol-v2.txt
@@ -41,8 +41,8 @@
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- Copyright 1991 by Digital Equipment Corporation, Maynard, Massachusetts,
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ Copyright 1991 by Digital Equipment Corporation, Maynard, Massachusetts,
and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
All Rights Reserved
@@ -55,24 +55,24 @@
advertising or publicity pertaining to distribution of the software
without specific, written prior permission.
- DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
- ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
- DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
- ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
- IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
- OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
+ ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
+ DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
+ ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
+ IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Preface
-------
-
+
The following is an outline for an X video extension protocol. It
is preliminary and subject to change. My goal in writing this was
to fix some the shortcomings of existing overly simplistic
extensions while avoiding pitfalls in an overly complex extension.
-
+
Your feedback is desired, and since the major design directions
have been stable for some time, feel free to hammer on the details
of the protocol.
@@ -95,10 +95,10 @@
with several groups, including
Project Athena's Visual Computing Group
- The MIT X Consortium
+ The MIT X Consortium
The MIT Media Lab's Interactive Cinema Group
-
-
+
+
Changes
-------
@@ -139,7 +139,7 @@
Introduction
------------
-
+
Video technology is moving very quickly. Standards for processing
high resolution video are currently a hot topic of discussion
internationally, and it will soon be possible to process video
@@ -147,47 +147,47 @@
does not attempt to address issues of digital video. Its purpose
is to provide a mechanism for support of current and near term
interactive video technology.
-
+
It is somewhat ironic that Xv contains nothing particularly
innovative. It takes a minimalistic approach, and without a doubt
it could have been defined years ago, and with several revisions.
So, the life expectancy of Xv is not long. Nevertheless, it may
undergo further revision and experimentation that will help our
progress towards digital video systems.
-
+
One premise of the Xv extension is that the X server is not alone.
A separate video server is often used to manage other aspects of
video processing, though the partition between what the X server
does and what a video server does is a matter of great debate.
-
+
Model
-----
-
+
This extension models video monitor capabilities in the X Window
System. Some advanced monitors support the simultaneous display
of multiple video signals (into separate windows), and that is
prepresented here through the ability to display video from
multiple video input adaptors into X drawables.
-
+
Some monitors support multiple video encodings (mostly for
internationalization purposes) either through switches or
automatic detection, thus each video adaptor specifies the set of
encodings it supports.
-
+
The requests to display video from an adaptor into a drawable are
modeled after the core PutImage request, though extended to
support scaling and source clipping.
-
+
Video output is also supported and is symmetric with the video
input function, though fewer GC components are used.
-
-
+
+
Mechanism
---------
-
+
The Xv extension does the following:
-
+
-- lists available video adaptors
-- identifies the number of ports each adaptor supports
-- describes what drawable formats each adaptor supports
@@ -197,35 +197,35 @@
-- grabs and ungrabs ports
-- sets and gets port attributes
-- delivers event notification
-
+
-
+
Adaptors
--------
-
+
A display may have multiple video input and output adaptors. An
adaptor may support multiple simultaneously active ports, and in
some cases the number of ports has no fixed limit.
-
+
An input port receives encoded video data and converts it to a
stream of data used to update a drawable. An output port samples
data from a drawable and produces a stream of encoded video data.
-
+
The ADAPTORINFO structure is used to describe a video adaptor.
-
+
ADAPTORINFO:
[base-id: PORT
num-ports: CARD16
type: SETofADAPTORTYPE
formats: LISTofFORMAT
name: STRING]
-
+
ADAPTORTYPE: {Input, Output}
FORMAT:
[depth: CARD8
visual: VISUALID]
-
+
The base-id field specifies the XID of the first port of the
adaptor. The `num-ports' field specifies how many ports the
adaptor supports. The ports of the adaptor have XIDs in the range
@@ -248,24 +248,24 @@
necessarily imply that simultaneous operation is supported.
-
+
Errors
------
-
+
Port
-
+
A Port error is returned if any request names a PORT that does not
exist.
-
+
Encoding
-
+
An Encoding error is returned if any request names an ENCODINGID
that does not exist.
-
+
Query Requests
-------------------
@@ -277,19 +277,19 @@
The QueryExtension request returns the extension version and
revision numbers.
-
+
QueryAdaptors
win: WINDOW
==>
adaptors: LISTofADAPTORINFO
-
+
The QueryAdaptors request returns the video adaptor information for
the screen of the specified window.
-
+
Errors: {Window}
- QueryEncodings
+ QueryEncodings
port: PORT
==>
encodings: LISTofENCODINGINFO
@@ -304,28 +304,28 @@
name: STRING
width, height: CARD16
rate: FRACTION]
-
+
The `encoding' field identifies an encoding supported by a port.
Its value is unique for a screen. Width and height specify the
size of the video image and rate specifies the rate at which
fields of image information are encoded.
-
+
An encoding is identified by a string that names the encoding.
Encoding naming conventions need to be established (i.e.,
something along the lines of font naming, but simpler)
-
+
FRACTION
[numerator, denominator: INT32]
-
+
The FRACTION structure is used to specify a fractional number.
Errors: {Port}
-
+
Put Video Requests
------------------
-
+
PutVideo
port: PORT
drawable: DRAWABLE
@@ -334,12 +334,12 @@
vid-w, vid-h: CARD16
drw-x, drw-y: INT16
drw-w, drw-h: CARD16
-
+
The PutVideo request writes video into a drawable. The position
and size of the source rectangle is specified by vid-x, vid-y,
vid-w, and vid-h. The position and size of the destination
rectangle is specified by drw-x, drw-y, drw-w, drw-h.
-
+
Video data is clipped to the bounds of the video encoding, scaled
to the requested drawable region size (or the closest size
supported), and clipped to the bounds of the drawable.
@@ -356,10 +356,10 @@
HardError is generated for the drawable.
GC components: subwindow-mode, clip-x-origin, clip-y-origin, clip-mask.
-
+
Errors: {Match, Value, GContext, Port, Alloc}
-
-
+
+
PutStill
port: PORT
drawable: DRAWABLE
@@ -368,13 +368,13 @@
vid-w, vid-h: CARD16
drw-x, drw-y: INT16
drw-w, drw-h: CARD16
-
+
The PutStill request writes a single frame of video into a
drawable. The position and size of the source rectangle is
specified by vid-x, vid-y, vid-w, and vid-h. The position and
size of the destination rectangle is specified by drw-x, drw-y,
drw-w, drw-h.
-
+
Video data is clipped to the bounds of the video encoding, scaled
to the requested drawable region size (or the closest size
supported) and clipped to the bounds of the drawable.
@@ -386,14 +386,14 @@
drawable.
GC components: subwindow-mode, clip-x-origin, clip-y-origin, clip-mask.
-
+
Errors: {Match, Value, GContext, Port, Alloc}
-
+
-
+
Get Video Requests
------------------
-
+
GetVideo
port: PORT
drawable: DRAWABLE
@@ -402,12 +402,12 @@
vid-w, vid-h: CARD16
drw-x, drw-y: INT16
drw-w, drw-h: CARD16
-
+
The GetVideo request outputs video from a drawable. The position
and size of the destination rectangle is specified by vid-x,
vid-y, vid-w, and vid-h. The position and size of the source
rectangle is specified by drw-x, drw-y, drw-w, and drw-h.
-
+
Drawable data is clipped to the bounds of the drawable, scaled to
the requested video region size (or the closest size supported)
and clipped to the bounds of the video encoding. The contents of
@@ -423,10 +423,10 @@
GC components: subwindow-mode, clip-x-origin, clip-y-origin,
clip-mask.
-
+
Errors: {Match, Value, GContext, Port, Alloc}
-
-
+
+
GetStill
port: PORT
drawable: DRAWABLE
@@ -435,12 +435,12 @@
vid-w, vid-h: CARD16
drw-x, drw-y: INT16
drw-w, drw-h: CARD16
-
+
The GetStill request outputs video from a drawable. The position
and size of the destination rectangle is specified by vid-x,
vid-y, vid-w, and vid-h. The position and size of the source
rectangle is specified by drw-x, drw-y, drw-w, and drw-h.
-
+
Drawable data is clipped to the bounds of the drawable, scaled to
the requested video region size (or the closest size supported)
and clipped to the bounds of the video encoding. The contents of
@@ -453,70 +453,70 @@
GC components: subwindow-mode, clip-x-origin, clip-y-origin,
clip-mask.
-
+
Errors: {Match, Value, GContext, Port, Alloc}
-
-
+
+
-
+
Grab Requests
-------------
-
+
GrabPort
- port: PORT
+ port: PORT
timestamp: {TIMESTAMP, CurrentTime}
==>
status: {Success, AlreadyGrabbed, InvalidTime}
-
+
The GrabPort request grabs a port. While a port is grabbed, only
video requests from the grabbing client are permitted.
-
+
If timestamp specifies a time older than the current port time, a
status of InvalidTime is returned. If the port is already grabbed
by another client, a status of AlreadyGrabbed is returned.
Otherwise a status of Success is returned. The port time is
updated when the following requests are processed: GrabPort,
UngrabPort, PutVideo, PutStill, GetVideo, GetStill
-
+
If the port is actively processing video for another client, the
video is preempted, and an VideoNotify event with detail Preempted
is generated for its drawable.
Errors: {Port}
-
-
+
+
UngrabPort
- port: PORT
+ port: PORT
timestamp: {TIMESTAMP, CurrentTime}
-
+
The UngrabPort request ungrabs a port. If timestamp specifies a
time before the last connection request time of this port, the
request is ignored.
-
+
Errors: {Port}
-
+
Other Requests
--------------
-
+
StopVideo
port: PORT
drawable: DRAWABLE
-
+
The StopVideo request stops active video for the specified port
and drawable. If the port isn't processing video, or if it is
processing video in a different drawable, the request is ignored.
When video is stopped a VideoNotify event with detail Stopped is
generated for the associated drawable.
- Errors: {Drawable, Port}
+ Errors: {Drawable, Port}
+
-
SelectVideoNotify
drawable: DRAWABLE
onoff: BOOL
-
+
The SelectVideoNotify request enables or disables VideoNotify
event delivery to the requesting client. VideoNotify events are
generated when video starts and stops.
@@ -527,14 +527,14 @@
SelectPortNotify
port: PORT
onoff: BOOL
-
+
The SelectPortNotify request enables or disables PortNotify event
delivery to the requesting client. PortNotify events are
generated when port attributes are changed using SetPortAttribute.
Errors: {Port}
-
+
QueryBestSize
port: PORT
motion: BOOL
@@ -542,7 +542,7 @@
drw-w, drw-h: CARD16
==>
actual-width, actual-height: CARD16
-
+
The QueryBestSize request returns, for the given source size and
desired destination size, the closest destination size that the
port adaptor supports. The returned size will be equal
@@ -553,30 +553,30 @@
The retuned size is also chosen to maintain the requested aspect ratio
if possible.
-
+
Errors: {Port}
-
+
-
+
SetPortAttribute
port: PORT
attribute: ATOM
value: INT32
-
+
The SetPortAttribute request sets the value of a port attribute.
The port attribute is identified by the attribute atom. The
following strings are guaranteed to generate valid atoms using the
InternAtom request.
- String Type
+ String Type
-----------------------------------------------------------------
-
+
"XV_ENCODING" ENCODINGID
- "XV_HUE" [-1000..1000]
- "XV_SATURATION" [-1000..1000]
- "XV_BRIGHTNESS" [-1000..1000]
+ "XV_HUE" [-1000..1000]
+ "XV_SATURATION" [-1000..1000]
+ "XV_BRIGHTNESS" [-1000..1000]
"XV_CONTRAST" [-1000..1000]
-
+
If the given attribute doesn't match an attribute supported by the
port adaptor a Match error is generated. The supplied encoding
@@ -593,14 +593,14 @@
notification using SelectPortNotify.
Errors: {Port, Match, Value}
-
-
+
+
GetPortAttribute
port: PORT
attribute: ATOM
==>
- value: INT32
-
+ value: INT32
+
The GetPortAttribute request returns the current value of the
attribute identified by the given atom. If the given atom
@@ -613,7 +613,7 @@
Events
------
-
+
VideoNotify
drawable: DRAWABLE
port: PORT
@@ -635,18 +635,18 @@
A Preempted reason is generated when video is stopped by a
conflicting request.
-
+
A HardError reason is generated when the video port cannot
initiate or continue processing a video request because of an
underlying transmission or reception error.
-
+
PortNotify
port: PORT
attribute: ATOM
value: INT32
time: TIMESTAMP
-
+
The PortNotify event is generated when a SetPortAttribute request
is processed. The event is delivered to all clients that have
performed a SelectPortNotify request for the port. The event