108 lines
3.6 KiB
Groff
108 lines
3.6 KiB
Groff
.TH XvListImageFormats __libmansuffix__ __vendorversion__ "libXv Functions"
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.SH NAME
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XvListImageFormats \- return list of image formats supported by a video port
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.\"
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.SH SYNTAX
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.B #include <X11/extensions/Xvlib.h>
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.sp
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.nf
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.BI "XvImageFormatValues * XvListImageFormats (Display *" dpy ","
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.BI " XvPortID " port ", int *" p_num_formats ");"
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.fi
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.SH ARGUMENTS
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.\"
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.IP \fIdpy\fR 8
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Specifies the connection to the X server.
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.IP \fIport\fR 8
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Specifies the port whose adaptor is to be queried for its list of attributes.
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.IP \fIp_num_formats\fR 8
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A pointer to where the number of formats returned in the array is written.
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.\"
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.SH DESCRIPTION
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.BR XvListImageFormats (__libmansuffix__)
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returns the XvImageFormatValues supported by the specified port. This list
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should be freed with
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.BR XFree (__libmansuffix__).
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.SH RETURN VALUES
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XvImageFormatValues has the following structure:
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.EX
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typedef struct {
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int id; /* Unique descriptor for the format */
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int type; /* XvRGB, XvYUV */
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int byte_order; /* LSBFirst, MSBFirst */
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char guid[16]; /* Globally Unique IDentifier */
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int bits_per_pixel;
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int format; /* XvPacked, XvPlanar */
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int num_planes;
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/* for RGB formats */
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int depth;
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unsigned int red_mask;
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unsigned int green_mask;
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unsigned int blue_mask;
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/* for YUV formats */
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unsigned int y_sample_bits;
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unsigned int u_sample_bits;
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unsigned int v_sample_bits;
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unsigned int horz_y_period;
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unsigned int horz_u_period;
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unsigned int horz_v_period;
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unsigned int vert_y_period;
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unsigned int vert_u_period;
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unsigned int vert_v_period;
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char component_order[32]; /* eg. UYVY */
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int scanline_order; /* XvTopToBottom, XvBottomToTop */
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} XvImageFormatValues;
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.EE
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.IP \fIid\fR 8
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A unique descriptor for the format. This is often the FOURCC
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for the format, when applicable. This id is used to describe
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the format during XvImage creation.
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.IP \fItype\fR 8
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XvRGB or XvYUV.
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.IP \fIbyte_order\fR 8
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The byte order of the image. It is either LSBFirst or MSBFirst.
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.IP \fIguid\fR 8
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The Globally Unique IDentifier (also known as Universally Unique
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IDentifier). When not applicable, all characters are NULL.
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.IP \fIbits_per_pixel\fR 8
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The bits taken up (but not necessarily used) by each
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pixel. Note that for some planar formats which have
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fractional bits per pixel (such as IF09) this number
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may be rounded _down_.
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.IP \fIformat\fR 8
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XvPacked or XvPlanar.
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.IP \fInum_planes\fR 8
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The number of planes in planar formats.
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.IP \fIdepth\fR 8
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Significant bits per pixel.
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.IP "\fIred_mask, green_mask, blue_mask\fR" 8
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The red, green and blue bitmasks (RGB formats only).
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.IP \fI?_sample_bits\fR 8
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The size of each sample in bits (YUV formats only).
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.IP "\fIhorz_?_period, vert_?_period\fR" 8
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The period (in pixels) on which samples occur in the horizontal and vertical
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directions (YUV formats only).
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.IP \fIcomponent_order\fR 8
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Upper case ascii characters representing the order that samples are stored
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within packed formats.
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For planar formats this represents the ordering of the planes.
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.IP \fIscanline_order\fR 8
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XvTopToBottom or XvBottomToTop.
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.\"
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.SH NOTES
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Since some formats (particularly some planar YUV formats) may not be
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completely defined by the parameters above, the guid, when available,
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should provide the most accurate description of the format.
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.\"
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.SH DIAGNOSTICS
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.IP [XvBadPort] 8
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Generated if the requested port does not exist.
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.\"
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.SH SEE ALSO
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.BR XvCreateImage (__libmansuffix__),
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.BR XvCreateShmImage (__libmansuffix__)
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