[gst-devel] [mvojkovich at nvidia.com: [Xpert]Sixth draft of XvMC spec]
vishnu at pobox.com
vishnu at pobox.com
Tue Sep 25 16:57:04 CEST 2001
----- Forwarded message from Mark Vojkovich <mvojkovich at nvidia.com> -----
From: Mark Vojkovich <mvojkovich at nvidia.com>
To: xpert at XFree86.Org
Subject: [Xpert]Sixth draft of XvMC spec
List-Id: General X Discussion <xpert.XFree86.Org>
The functionality of XvMC is more or less complete. We'll need
better app coverage (there aren't any publicly available ones) and
more developer feedback before we can stamp a version 1.0 on it.
I considered writing a software reference driver, but there's not
much you could do with it due to mpeg licensing issues (couldn't
ship it with XFree86, for example).
I'll eventually get around to hacking an open source player
to use it (probably mpeg2play). But if somebody wants to beat
me to it, please do.
Attached is draft 6 of the API.
Mark.
X-Video Motion Compensation - A Proposal
Mark Vojkovich <markv at xfree86.org>
This is a sixth draft.
/* history */
first draft (9/6/00)
second draft (10/31/00) - Changed to allow acceleration at both
the motion compensation and IDCT level.
third draft (1/21/01) - Some refinements and subpicture support.
fourth draft (5/2/01) - Dual Prime clarification, add
XvMCSetAttribute.
fifth draft (6/26/01) - Change definition of XvMCCompositeSubpicture
plus some clarifications and fixed typographical errors.
sixth draft (9/24/01) - Added XVMC_SECOND_FIELD and removed
XVMC_PROGRESSIVE_FRAME and XVMC_TOP_FIELD_FIRST flags.
/* acknowledgements */
Thanks to Matthew J. Sottek from Intel for lots of input.
/********************************************************************/
OVERVIEW
/********************************************************************/
XvMC extends the X-Video extension (Xv) and makes use of the
familar concept of the XvPort. Ports have attributes that can be set
and queried through Xv. In XvMC ports can also have hardware motion
compensation contexts created for use with them. Ports which support
XvImages (ie. they have an "XV_IMAGE" port encoding as described in
the Xv version 2.2 API addendum) can be queried for the list of XvMCSurface
types they support. If they support any XvMCSurface types an
XvMCContext can be created for that port.
An XvMCContext describes the state of the motion compensation
pipeline. An individual XvMCContext can be created for use with
a single port, surface type, motion compensation type, width and
height combination. For example, a context might be created for a
particular port that does MPEG-2 motion compensation on 720 x 480
4:2:0 surfaces. Once the context is created, referencing it implies
the port, surface type, size and the motion compensation type. Contexts
may be "direct" or "indirect". For indirect contexts the X server
renders all video using the data passed to it by the client. For
direct contexts the client libraries render the video with little
or no interaction with the X server.
XvMCSurfaces are YCbCr buffers into which the motion compensation
hardware can render. The data in the buffers themselves are not client
accessible and may be stored in a hardware-specific format. Any
number of buffers can be created for use with a particular context
(resources permitting).
XvMC provides video acceleration starting at one of two places
in the video pipeline. Acceleration starting at the first point,
which we shall call the "Motion Compensation" level, begins after the
the dequantization IDCT at the place where motion compensation
is to be performed on the dequantized and inverse transformed blocks.
The second point, which we shall call the "IDCT" level, begins before
the dequantization and IDCT just after the Hufmann decoding.
Rendering is done by presenting the library with a target XvMCSurface
and up to two reference XvMCSurfaces for the motion compensation, a
buffer of 8x8 blocks and a command buffer which describes how to
use the 8x8 blocks along with motion compensation vectors to construct
the data in the target XvMCSurface. When the pipeline starts at the
IDCT level, Xv will perform the dequantization and IDCT on the blocks
before performing the motion compensation. A function is provided to
copy/overlay a portion of the XvMCSurface to a drawable with arbitrary
scaling.
XvMCSubpictures are separate surfaces that may be blended with the
target surface. Any number of XvMCSubpictures may be created for use
with a context (resources permitting). Both "backend" and "frontend"
subpicture behavior are supported.
/********************************************************************/
QUERYING THE EXTENSION
/********************************************************************/
/* Errors */
#define XvMCBadContext 0
#define XvMCBadSurface 1
#define XvMCBadSubpicture 2
Bool XvMCQueryExtension (Display *display, int *eventBase, int *errBase)
Returns True if the extension exists, False otherwise. Also returns
the error and event bases.
display - The connection to the server.
eventBase -
errBase - The returned event and error bases. Currently there
are no events defined.
Status XvMCQueryVersion (Display *display, int *major, int *minor)
Query the major and minor version numbers of the extension.
display - The connection to the server.
major -
minor - The returned major and minor version numbers.
/********************************************************************/
QUERYING SURFACE TYPES
/********************************************************************/
/* Chroma formats */
#define XVMC_CHROMA_FORMAT_420 0x00000001
#define XVMC_CHROMA_FORMAT_422 0x00000002
#define XVMC_CHROMA_FORMAT_444 0x00000003
/* XvMCSurfaceInfo Flags */
#define XVMC_OVERLAID_SURFACE 0x00000001
#define XVMC_BACKEND_SUBPICTURE 0x00000002
#define XVMC_SUBPICTURE_INDEPENDENT_SCALING 0x00000004
/* Motion Compensation types */
#define XVMC_IDCT 0x00010000
#define XVMC_MPEG_1 0x00000001
#define XVMC_MPEG_2 0x00000002
#define XVMC_H263 0x00000003
#define XVMC_MPEG_4 0x00000004
typedef struct {
int surface_type_id;
int chroma_format;
int color_description;
unsigned short max_width;
unsigned short max_height;
unsigned short subpicture_max_width;
unsigned short subpicture_max_height;
int mc_type;
int flags;
} XvMCSurfaceInfo;
surface_type_id - Unique descriptor for this surface type.
chroma_format - Chroma format of this surface (eg. XVMC_CHROMA_FORMAT_420,
XVMC_CHROMA_FORMAT_422, XVMC_CHROMA_FORMAT_444).
color_descriptor - Specification of the color characteristics
of the surface.
EDITORS NOTE: More research is needed on the types. The
============ goal is to allow the client to know if CCIR_601
luminance limiting, etc... is being applied and
other things of that nature. Is this really
needed?
max_width -
max_height - Maximum dimensions of the luma data in pixels.
subpicture_max_width -
subpicture_max_height - The Maximum dimensions of the subpicture
that can be created for use with this surface
Both fields are zero if subpictures are not
supported.
mc_type - The type of motion compensation available for this
surface. This consists of XVMC_MPEG_1, XVMC_MPEG_2, XVMC_H263
or XVMC_MPEG_4 possibly OR'd together with any of the following:
XVMC_IDCT - Acceleration starts at the IDCT level.
Acceleration starts at the motion compensation
level in the absence of this flag.
flags - Any combination of the following may be OR'd together.
XVMC_OVERLAID_SURFACE - Displayed data is overlaid and not
physically in the visible framebuffer.
XVMC_BACKEND_SUBPICTURE - The supicture is of the "backend"
variety. It is "frontend" otherwise.
There is more information on this in the
section on subpictures below.
XVMC_SUBPICTURE_INDEPENDENT_SCALING - The subpicture can be scaled
independently of the video
surface. See the section on
subpictures below.
XvMCSurfaceInfo * XvMCListSurfaceTypes(Display *dpy, XvPortID port, int *num)
Returns the number of surface types supported by the XvPort and an array
of XvMCSurfaceInfo describing each surface type. The returned array
should be freed with XFree().
dpy - The connection to the server.
port - The port we want to get the XvMCSurfaceInfo array for.
num - The number of elements returned in the array.
Errors:
XvBadPort - The requested port does not exist.
BadAlloc - There are insufficient resources to complete this request.
/********************************************************************/
CREATING A CONTEXT
/********************************************************************/
/* XvMCContext flags */
#define XVMC_DIRECT 0x00000001
typedef struct {
XID context_id;
int surface_type_id;
unsigned short width;
unsigned short height;
XVPortID port;
int flags;
void * privData; /* private to the library */
} XvMCContext;
context_id - An XID associated with the context.
surface_type_id - This refers to the XvMCSurfaceInfo that describes
the surface characteristics.
width -
height - The dimensions (of the luma data) this context supports.
port - The port that this context supports.
flags - Any combination may be OR'd together.
XVMC_DIRECT - This context is direct rendered.
Status XvMCCreateContext (
Display display,
XVPortID port,
int surface_type_id,
int width,
int height,
int flags,
XvMCContext * context
);
This creates a context by filling out the XvMCContext structure passed
to it and returning Success.
display - Specifies the connection to the server.
port - Specifies the port to create the context for.
surface_type_id -
width -
height - Specifies the surface type and dimensions that this
context will be used for. The surface_type_id corresponds
to the surface_type_id referenced by the XvMCSurfaceInfo.
The surface returned may be larger than the surface requested
(usually the next larger multiple of 16x16 pixels).
flags - Any of the following may by OR'd together:
XVMC_DIRECT - A direct context is requested.
If a direct context cannot be created the request
will not fail, rather, an indirect context will
be created instead.
context - Pointer to the pre-allocated XvMCContext structure.
Errors:
XvBadPort - The requested port does not exist.
BadValue - The dimensions requested are not supported by the
surface type.
BadMatch - The surface_type_id is not supported by the port.
BadAlloc - There are not sufficient resources to fulfill this
request.
Status XvMCDestroyContext (Display display, XvMCContext * context)
Destroys the specified context.
display - Specifies the connection to the server.
context - The context to be destroyed.
Errors:
XvMCBadContext - The XvMCContext is not valid.
-----------------------------------------------------------------
When a context accelerates starting at the IDCT level, additional
state is required for the dequantization. The following functions
are provided to set this state. If the particular function is not
supported for the mc_type of the XvMCSurfaceInfo, the function is a
no-op. All functions return Success when no error has occured.
These functions are all no-ops for motion compensation level contexts.
Status
XvMCLoadIntraQuantizerMatrix
XvMCLoadNonIntraQuantizerMatrix
XvMCLoadChromaIntraQuantizerMatrix
XvMCLoadChromaNonIntraQuantizerMatrix
(Display *display, XvMCContext * context, unsigned char matrix[64])
All contexts are created with default matricies particular to
their mc_type. Client specified matricies may be modified
by the library and/or server to conform to restrictions
imposed by the mc_type (for instance, the value of the DC
term). Matrix data is passed in the standard zig-zag scan
format.
EDITORS NOTE: Is a zig-zag scan desireable here?
============
For formats with separate Luma and Chroma matricies,
XvMCLoadIntraQuantizerMatrix and XvMCLoadNonIntraQuantizerMatrix
load both matricies. XvMCLoadChromaIntraQuantizerMatrix and
XvMCLoadChromaNonIntraQuantizerMatrix can be used to load
the chroma matricies individually. For formats without
separate matricies, the LoadChroma functions are noops.
Status XvMCSetQuantizerScale(Display *dis, XvMCContext * context, int scale)
The quantizer scale state can also be changed in the XvMCMacroBlock
structure. This value stays in effect until updated by another call
to XvMCSetQuantizerScale or is set in the XvMCMacroBlock structure.
The requested values may be clamped to within the allowable
ranges inherent to the mc_type.
Status XvMCSetIntraDCPrecision(Display *dis, XvMCContext * context, int prec)
The requested precision may be clamped or ignored as required
by the mc_type.
Errors:
XvMCBadContext - the context is not valid.
/*********************************************************************/
SURFACE CREATION
/*********************************************************************/
typedef struct {
XID surface_id;
XID context_id;
int surface_type_id;
unsigned short width;
unsigned short height;
void *privData; /* private to the library */
} XvMCSurface;
surface_id - An XID associated with the surface.
context_id - The XID of the context for which the surface was created.
surface_type_id - Derived from the context_id, it specifies the
XvMCSurfaceInfo describing the surface.
width -
height - The width and height of the luma data.
Status
XvMCCreateSurface(
Display *display,
XvMCContext * context;
XvMCSurface * surface;
);
Creates a surface (Frame) for use with the specified context.
The surface structure is filled out and Success is returned if no
error occured.
context - pointer to a valid context. The context implies
the surface type to be created, and its dimensions.
surface - pointer to a pre-allocated XvMCSurface structure.
Errors:
XvMCBadContext - the context is not valid.
BadAlloc - there are insufficient resources to complete
this operation.
Status XvMCDestroySurface(Display *display, XvMCSurface *surface);
Destroys the given surface.
display - Specifies the connection to the server.
surface - The surface to be destroyed.
Errors:
XvMCBadSurface - The XvMCSurface is not valid.
/*********************************************************************/
RENDERING A FRAME
/*********************************************************************/
typedef struct {
XID context_id;
unsigned int num_blocks;
short *blocks;
void *privData; /* private to the library */
} XvMCBlockArray;
num_blocks - Number of 64 element blocks in the blocks array.
context_id - XID of the context these blocks were allocated for.
blocks - Pointer to an array of (64 * num_blocks) shorts.
Status XvMCCreateBlocks (
Display *display,
XvMCContext *context,
unsigned int num_blocks,
XvMCBlockArray * block
);
This allocates an array of DCT blocks in the XvMCBlockArray
structure passed to it. Success is returned if no error occured.
display - The connection to the server.
context - The context the block array is being created for.
num_blocks - The number of 64 element short blocks to be allocated.
This number must be non-zero.
block - A pointer to a pre-allocated XvMCBlockArray structure.
Errors:
XvMCBadContext - the context is invalid.
BadAlloc - There are insufficient resources to complete the
operation.
BadValue - num_blocks was zero.
Status XvMCDestroyBlocks (Display *display, XvMCBlockArray * block)
Frees the given array.
display - The connection to the server.
block - The block array to be freed.
----------------------------------------------------------
#define XVMC_MB_TYPE_QUANT 0x01
#define XVMC_MB_TYPE_MOTION_FORWARD 0x02
#define XVMC_MB_TYPE_MOTION_BACKWARD 0x04
#define XVMC_MB_TYPE_PATTERN 0x08
#define XVMC_MB_TYPE_INTRA 0x10
#define XVMC_PREDICTION_FIELD 0x01
#define XVMC_PREDICTION_FRAME 0x02
#define XVMC_PREDICTION_DUAL_PRIME 0x03
#define XVMC_PREDICTION_16x8 0x02
#define XVMC_PREDICTION_4MV 0x04
#define XVMC_SELECT_FIRST_FORWARD 0x01
#define XVMC_SELECT_FIRST_BACKWARD 0x02
#define XVMC_SELECT_SECOND_FORWARD 0x04
#define XVMC_SELECT_SECOND_BACKWARD 0x08
#define XVMC_DCT_TYPE_FRAME 0x00
#define XVMC_DCT_TYPE_FIELD 0x01
typedef struct {
unsigned short x, y;
unsigned char macroblock_type;
unsigned char motion_type;
unsigned char motion_vertical_field_select;
unsigned char quantizer_scale;
short PMV[2][2][2];
unsigned int index;
unsigned short coded_block_pattern;
unsigned char dct_type;
unsigned char pad0; /* unused */
} XvMCMacroBlock;
x, y - location of the macroblock on the surface in units of macroblocks.
macroblock_type - can be any of the following flags OR'd together:
XVMC_MB_TYPE_QUANT - The quantizer scale should be updated with
the value in this structure. This flag is
ignored for motion compensation level contexts.
XVMC_MB_TYPE_MOTION_FORWARD - Forward motion prediction should
be done. This flag is ignored for
Intra frames.
XVMC_MB_TYPE_MOTION_BACKWARD - Backward motion prediction should
be done. This flag is ignored when
the frame is not bidirectionally
predicted.
XVMC_MB_TYPE_PATTERN - Blocks are referenced and they contain
differentials. The coded_block_pattern will
indicate the number of blocks and index will
note their locations in the block array.
XVMC_MB_TYPE_INTRA - Blocks are referenced and they are intra blocks.
The coded_block_pattern will indicate the number
of blocks and index will note their locations in
the block array. XVMC_MB_TYPE_PATTERN and
XVMC_MB_TYPE_INTRA are mutually exclusive. If
both are specified, XVMC_MB_TYPE_INTRA takes
precedence.
motion_type - If the surface is a field, the following are valid:
XVMC_PREDICTION_FIELD
XVMC_PREDICTION_16x8
XVMC_PREDICTION_DUAL_PRIME
If the surface is a frame, the following are valid:
XVMC_PREDICTION_FIELD
XVMC_PREDICTION_FRAME
XVMC_PREDICTION_DUAL_PRIME
motion_vertical_field_select - The following flags may be OR'd together
XVMC_SELECT_FIRST_FORWARD
XVMC_SELECT_FIRST_BACKWARD
XVMC_SELECT_SECOND_FORWARD
XVMC_SELECT_SECOND_BACKWARD
If the bit is set the bottom field is indicated.
If the bit is clear the top field is indicated.
X X X X D C B A
------- | | | |_ First vector forward
| | | |___ First vector backward
unused | |_____ Second vector forward
|_______ Second vector backward
quantizer_scale - This holds the quantizer scale. It is only valid
when XVMC_MB_TYPE_QUANT is set. This field is unused
for motion compensation level contexts.
PMV - The motion vector(s)
PMV[c][b][a]
a - This holds the vector. 0 = horizontal, 1 = vertical.
b - 0 = forward, 1 = backward.
c - 0 = first vector, 1 = second vector.
The motion vectors are used only when XVMC_MB_TYPE_MOTION_FORWARD
or XVMC_MB_TYPE_MOTION_BACKWARD are set.
DualPrime vectors must be fully decoded and placed in the PMV
array as follows.
Field structure:
vector[0][0][1:0] -> PMV[0][0][1:0]
vector[2][0][1:0] -> PMV[0][1][1:0]
Frame structure:
vector[0][0][1:0] -> PMV[0][0][1:0] top from top
vector[0][0][1:0] -> PMV[0][1][1:0] bottom from bottom
vector[2][0][1:0] -> PMV[1][0][1:0] top from bottom
vector[3][0][1:0] -> PMV[1][1][1:0] bottom from top
index - The offset in units of (64 * sizeof(short)) from the start of
the block array where this macroblock's DCT blocks, as indicated
by the coded_block_pattern, are stored.
coded_block_pattern - Indicates the blocks to be updated. The bitplanes
are specific to the mc_type of the surface. This
field is valid only if XVMC_MB_TYPE_PATTERN or
XVMC_MB_TYPE_INTRA are set. In that case the blocks
are differential or intra blocks respectively.
The bitplanes are described in ISO/IEC 13818-2
Figures 6.10-12.
dct_type - This field indicates whether frame pictures are frame DCT
coded or field DCT coded. ie XVMC_DCT_TYPE_FIELD or
XVMC_DCT_TYPE_FRAME.
typedef struct {
unsigned int num_blocks;
XID context_id;
XvMCMacroBlock *macro_blocks;
void *privData; /* private to the library */
} XvMCMacroBlockArray;
num_blocks - Number of XvMCMacroBlocks in the macro_blocks array.
context_id - XID of the context these macroblocks were allocated for.
macro_blocks - Pointer to an array of num_blocks XvMCMacroBlocks.
Status XvMCCreateMacroBlocks (
Display *display,
XvMCContext *context,
unsigned int num_blocks,
XvMCMacroBlockArray * blocks
);
This allocates an array of XvMCMacroBlocks in the XvMCMacroBlockArray
structure passed to it. Success is returned if no error occured.
display - The connection to the server.
context - The context the macroblock array is being created for.
num_blocks - The number of XvMCMacroBlocks to be allocated.
This number must be non-zero.
blocks - A pointer to a pre-allocated XvMCMacroBlockArray structure.
Errors:
XvMCBadContext - the context is invalid.
BadAlloc - There are insufficient resources to complete the
operation.
BadValue - num_blocks was zero.
Status XvMCDestroyMacroBlocks (Display *display, XvMCMacroBlockArray * block)
Frees the given array.
display - The connection to the server.
block - The macro block array to be freed.
------------------------------------------------------------
#define XVMC_TOP_FIELD 0x00000001
#define XVMC_BOTTOM_FIELD 0x00000002
#define XVMC_FRAME_PICTURE (XVMC_TOP_FIELD | XVMC_BOTTOM_FIELD)
#define XVMC_RESERVED_1 0x00000001 /* for backwards compatibility */
#define XVMC_RESERVED_2 0x00000002 /* for backwards compatibility */
#define XVMC_SECOND_FIELD 0x00000004
#define XVMC_SCAN_ORDER_ZIG_ZAG 0x00000000
#define XVMC_SCAN_ORDER_ALTERNATIVE_HORIZONTAL 0x00000001
#define XVMC_SCAN_ORDER_ALTERNATIVE_VERTICAL 0x00000002
#define XVMC_SCAN_ORDER_RASTER 0x00000003
Status XvMCRenderSurface(
Display *display,
XvMCContext *context,
unsigned int picture_structure,
Surface *target_surface,
Surface *past_surface,
Surface *future_surface,
unsigned int flags,
unsigned int scan_order,
unsigned int num_macroblocks,
unsigned int first_macroblock,
XvMCMacroBlockArray *macroblock_array,
XvMCBlockArray *blocks
);
This function renders the macroblocks passed to it. It will not
return until it has read all of the macroblocks, however, rendering
will usually not be completed by that time. The return of this
function means it is safe to touch the blocks and macroblock_array.
To synchronize rendering see the section on sychronization below.
display - The connection to the server.
context - The context used to render.
target_surface -
past_surface -
furture_surface -
The target_surface is required. If the future and past
surfaces are NULL, the target_surface is an "Intra" frame.
If the past surface is provided but not the future surface,
the target_surface is a "Predicted Inter" frame.
If both past and future surfaces are provided, the
target_surface is a "Bidirectionally-predicted Inter" frame.
Specifying a future surface without a past surface results
in a BadMatch.
All surfaces must belong to the same context.
picture_structure - XVMC_TOP_FIELD, XVMC_BOTTOM_FIELD or
XVMC_FRAME_PICTURE.
flags - Flags may include:
XVMC_SECOND_FIELD - For field pictures this indicates whether
the current field (top or bottom) is first
or second in the sequence.
scan_order - XVMC_SCAN_ORDER_RASTER, XVMC_SCAN_ORDER_ZIG_ZAG,
XVMC_SCAN_ORDER_ALTERNATIVE_HORIZONTAL or
XVMC_SCAN_ORDER_ALTERNATIVE_VERTICAL.
For motion compensation level acceleration, this
field is ignored and XVMC_SCAN_ORDER_RASTER is assumed.
EDITORS NOTE: Should this be in the XvMCMacroBlockArray instead?
============
num_macroblocks - The number of XvMCMacroBlock structures to execute in
the macroblock_array.
first_macroblock - The index of the first XvMCMacroBlock to process in the
macroblock_array.
blocks - The array of XvMCBlocks to be referenced by the XvMCMacroBlocks.
Errors:
XvMCBadContext - The context is not valid.
XvMCBadSurface - Any of the surfaces are not valid.
BadMatch - Any of the surfaces do not belong to the specified
context or a future surface was specified without
a past surface.
BadValue - Unrecognized data for either picture_structure or
scan_order.
/***********************************************************************/
DISPLAYING THE SURFACE
/***********************************************************************/
Status
XvMCPutSurface(
Display *display,
XvMCSurface *surface,
Drawable draw,
short srcx,
short srcy,
unsigned short srcw,
unsigned short srch,
short destx,
short desty,
unsigned short destw,
unsigned short desth,
int flags
);
Display the rectangle from the source defined by srcx/y/w/h scaled
to destw by desth and placed at (destx, desty) on the given drawable.
This function is not guaranteed to be pipelined with previous rendering
commands and may display the surface immediately. Therefore, the client
must query that the surface has finished rendering before calling this
function.
display - The connection to the server.
surface - The surface to copy/overlay from.
draw - The drawable to copy/overlay the video on.
srcx -
srcy -
srcw -
srch - The rectangle in the source area from the surface that is
to be displayed.
destx -
desty -
destw -
desth - The rectangle in the destination drawable where the scaled
source rectangle should be displayed.
flags - this indicates the field to be displayed and can be XVMC_TOP_FIELD,
XVMC_BOTTOM_FIELD or XVMC_FRAME_PICTURE. XVMC_FRAME_PICTURE
displays both fields (weave).
Errors:
XvMCBadSurface - The surface is not valid.
BadDrawable - The drawable does not exist.
Status XvMCHideSurface(Display *display, XvMCSurface *surface)
Stops display of a surface. This is only needed if the surface is an
overlaid surface as indicated in the XvMCSurfaceInfo - it is a no-op
otherwise.
display - The connection to the server.
surface - The surface to be hidden.
Errors:
XvMCBadSurface - The surface is not valid.
/***********************************************************************/
COMPOSITING THE SUBPICTURE
/***********************************************************************/
XvImageFormatValues * XvMCListSubpictureTypes (
Display * display,
XvPortID port,
int surface_type_id,
int *count_return
)
Returns an array of XvImageFormatValues supported by the surface_type_id
describing the surface. The surface_type_id is acquired from the
XvMCSurfaceInfo. This list should be freed with XFree().
display - Specifies the connection to the X-server.
port - Specifies the port we are interested in.
surface_type_id - Specifies the surface type for which we want to
query the supported subpicture types.
count_return - the size of the returned array.
Errors:
BadPort - The port doesn't exist.
BadAlloc - There are insufficient resources to complete this request.
BadMatch - The surface type is not supported on that port.
typedef struct {
XID subpicture_id;
XID context_id;
int xvimage_id;
unsigned short width;
unsigned short height;
int num_palette_entries;
int entry_bytes;
char component_order[4];
void *privData; /* private to the library */
} XvMCSubpicture;
subpicture_id - An XID associated with this subpicture.
context_id - The XID of the context this subpicture was created for.
xvimage_id - The id descriptor of the XvImage format that may be used
with this subpicture.
width -
height - The dimensions of the subpicture.
num_palette_entries - For paletted formats only. This is the number
of palette entries. It is zero for XvImages
without palettes.
entry_bytes - Each component is one byte and entry_bytes indicates
the number of components in each entry (eg. 3 for
YUV palette entries). This field is zero when
palettes are not used.
component_order - Is an array of ascii characters describing the order
of the components within the bytes. Only entry_bytes
characters of the string are used.
Status
XvMCCreateSubpicture (
Display *display,
XvMCContext *context,
XvMCSubpicture *subpicture,
unsigned short width,
unsigned short height,
int xvimage_id
)
This creates a subpicture by filling out the XvMCSubpicture structure
passed to it and returning Success.
display - Specifies the connection to the X-Server.
context - The context to create the subpicture for.
subpicture - Pre-allocated XvMCSubpicture structure to be filled
out by this function.
width -
height - The dimensions of the subpicture.
xvimage_id - The id describing the XvImage format.
Errors:
BadAlloc - There are insufficient resources to complete this request.
XvMCBadContext - The specified context does not exist.
BadMatch - The XvImage format id specified is not supported by
the context.
BadValue - If the size requested is larger than the max size reported
in the XvMCSurfaceInfo.
Status
XvMCClearSubpicture (
Display *display,
XvMCSubpicture *subpicture,
short x,
short y,
unsigned short width,
unsigned short height,
unsigned int color
)
Clear the area of the given subpicture to "color".
display - The connection to the server.
subpicture - The subpicture to clear.
x -
y -
width -
height - The rectangle in the subpicture to be cleared.
color - The data to fill the rectangle with.
Errors:
XvMCBadSubpicture - The subpicture is invalid.
Status
XvMCCompositeSubpicture (
Display *display,
XvMCSubpicture *subpicture,
XvImage *image,
short srcx,
short srcy,
unsigned short width,
unsigned short height,
short dstx,
short dsty
)
Copies the XvImage to the XvMCSubpicture.
display - The connection to the server.
subpicture - The subpicture used as the destination of the copy.
image - The XvImage to be used as the source of the copy.
XvImages should be of the shared memory variety for
indirect contexts.
srcx -
srcy -
width -
height - The rectangle from the image to be composited.
dstx -
dsty - The location in the subpicture where the source rectangle
should be composited.
Errors:
XvMCBadSubpicture - The subpicture is invalid.
BadMatch - The subpicture does not support the type of XvImage
passed to this function.
Status
XvMCDestroySubpicture (Display *display, XvMCSubpicture *subpicture)
Destroys the specified subpicture.
display - Specifies the connection to the X-server.
subpicture - The subpicture to be destroyed.
Errors:
XvMCBadSubpicture - The subpicture specified does not exist.
Status
XvMCSetSubpicturePalette (
Display *display,
XvMCSubpicture *subpicture,
unsigned char *palette
)
Set the subpicture's palette. This applies to paletted subpictures
only.
display - The connection to the server.
subpicture - The subpicture on which to change the palette.
palette - A pointer to an array holding the palette data. The
size of this array is
num_palette_entries * entry_bytes
in size. The order of the components in the palette
is described by the component_order in the XvMCSubpicture
structure.
Errors:
XvMCBadSubpicture - The subpicture specified does not exist.
BadMatch - The specified subpicture does not use palettes.
Status
XvMCBlendSubpicture (
Display *display,
XvMCSurface *target_surface,
XvMCSubpicture *subpicture,
short subx,
short suby,
unsigned short subw,
unsigned short subh,
short surfx,
short surfy,
unsigned short surfw,
unsigned short surfh
)
Status
XvMCBlendSubpicture2 (
Display *display,
XvMCSurface *source_surface,
XvMCSurface *target_surface,
XvMCSubpicture *subpicture,
short subx,
short suby,
unsigned short subw,
unsigned short subh,
short surfx,
short surfy,
unsigned short surfw,
unsigned short surfh
)
The behavior of these two functions is different depending on whether
or not the XVMC_BACKEND_SUBPICTURE flag is set in the XvMCSurfaceInfo.
XVMC_BACKEND_SUBPICTURE set:
XvMCBlendSubpicture associates the subpicture with the target_surface.
Both will be displayed at the next call to XvMCPutSurface. Additional
blends before the call to XvMCPutSurface simply overrides the association.
Both the target_surface and subpicture will query XVMC_DISPLAYING from
the call to XvMCPutSurface until they are no longer displaying. It is
safe to associate the subpicture and target_surface before rendering has
completed (while they still query XVMC_RENDERING) but it is not safe to
call XvMCPutSurface at that time.
XvMCBlendSubpicture2 copies the source_surface to the target_surface
and associates the subpicture with the target_surface. This essentially
calls XvMCBlendSubpicture on the target_surface after the copy. Both
the subpicture and target_surface will query XVMC_DISPLAYING from the
call to XvMCPutSurface until they are no longer displaying. The
source_surface will not query XVMC_DISPLAYING as a result of this function.
The copy is pipelined with the rendering and will cause XVMC_RENDERING
to be queried until the copy is done.
XVMC_BACKEND_SUBPICTURE not set ("frontend" behavior):
XvMCBlendSubpicture is a no-op in this case.
XvMCBlendSubpicture2 blends the source_surface and subpicture and
puts it in the target_surface. This does not effect the status of
the source surface but will cause the target_surface to query
XVMC_RENDERING until the blend is completed.
display - The connection to the server.
subpicture - The subpicture to be blended into the video.
target_surface - The surface to be displayed with the blended subpicture.
source_surface - Source surface prior to blending.
subx -
suby -
subw -
subh - The rectangle from the subpicture to be blended.
surfx -
surfy -
surfw -
surfh - The rectangle in the XvMCSurface to blend the subpicture rectangle
into. If XVMC_SUBPICTURE_INDEPENDENT_SCALING is not set in the
XvMCSurfaceInfo subw must be equal to surfw and subh must be
equal to surfh height or else a BadValue error occurs.
Errors:
XvMCBadSurface - Any of the surfaces are invalid.
XvMCBadSubpicture - The subpicture is invalid.
BadMatch - The subpicture or any of the surfaces do not belong to the
same context.
BadValue - XVMC_SUBPICTURE_INDEPENDENT_SCALING is set and the source
and destination rectangles are different sizes.
/***********************************************************************/
SURFACE SYNCHRONIZATION
/***********************************************************************/
#define XVMC_RENDERING 0x00000001
#define XVMC_DISPLAYING 0x00000002
Status
XvMCSyncSurface (Display *display, XvMCSurface *surface)
This function blocks until all rendering requests on the surface
have been completed.
display - The connection to the server.
surface - The surface to synchronize.
Errors:
XvMCBadSurface - The surface is not valid.
Status
XvMCFlushSurface (Display *display, XvMCSurface *surface)
This function commits pending rendering requests to ensure that
they will be completed in a finite amount of time.
display - The connnection to the server.
surface - The surface whos rendering requests should be flushed.
Errors:
XvMCBadSurface - The surface is not valid.
Status
XvMCGetSurfaceStatus (Display *display, XvMCSurface *surface, int *stat)
display - The connection to the server.
surface - The surface whos status is being queried.
stat - May be any of the following OR'd together:
XVMC_RENDERING - The last XvMCRenderSurface request has not completed
yet.
XVMC_DISPLAYING - The surface is currently being displayed or a
display is pending (ie. it is not safe to render
to it).
Errors:
XvMCBadSurface - The surface is not valid.
/***********************************************************************/
SUBPICTURE SYNCHRONIZATION
/***********************************************************************/
Status
XvMCSyncSubpicture (Display *display, XvMCSubpicture *subpicture)
This function blocks until all composite/clear requests on the supicture
have been completed.
display - The connection to the server.
subpicture - The subpicture to synchronize.
Errors:
XvMCBadSubpicture - The subpicture is not valid.
Status
XvMCFlushSubpicture (Display *display, XvMCSubpicture *subpicture)
This function commits pending composite/clear requests to ensure that
they will be completed in a finite amount of time.
display - The connection to the server.
subpicture - The subpicture whos compositing should be flushed.
Errors:
XvMCBadSubpicture - The surface is not valid.
Status
XvMCGetSubpictureStatus (Display *display, XvMCSubpicture *subpic, int *stat)
display - The connection to the server.
subpic - The subpicture whos status is being queried.
stat - may be any of the following OR'd together:
XVMC_RENDERING - The last XvMCCompositeSubpicture or XvMCClearSubpicture
request has not completed yet.
XVMC_DISPLAYING - The subpicture is currently being displayed or a
display is pending (ie. it is not safe to render
to it).
Errors:
XvMCBadSubpicture - The surface is not valid.
/********************************************************************/
ATTRIBUTES
/********************************************************************/
Context specific attribute functions are provided. These are
similar to their Xv Counterparts XvQueryPortAttributes, XvSetPortAttribute
and XvGetPortAttribute but their state is specific to the context.
XvAttribute *
XvMCQueryAttributes (
Display *display,
XvMCContext *context,
int *number
)
An array of XvAttributes of size "number" is returned by this function.
If there are no attributes, NULL is returned and number is set to 0.
The array may be freed with XFree().
display - The connection to the server.
context - The context whos attributes we are querying.
number - The returned number of recognized atoms.
Errors:
XvMCBadContext - The context is invalid.
Status
XvMCSetAttribute (
Display *display,
XvMCContext *context,
Atom attribute,
int value
)
This function sets a context-specific attribute and returns Success
if no error has occurred.
display - The connection to the server.
context - The context for which the attribute change is to go into effect.
attribute - The X Atom of the attribute to be changed.
value - The new value of the attribute.
Errors:
XvMCBadContext - The context is not valid.
BadValue - An invalid value was specified.
BadMatch - This attribute is not defined for this context.
Status
XvMCGetAttribute (
Display *display,
XvMCContext *context,
Atom attribute,
int *value
)
This function queries a context-specific attribute and return
Success and the value if no error has occurred.
display - The connection to the server.
context - The context whos attribute we are querying.
attribute - The X Atom of the attribute to be retrieved.
value - The returned attribute value.
Errors:
XvMCBadContext - The context is not valid.
BadMatch - This attribute is not defined for this context.
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