86 lines
2.5 KiB
Groff
86 lines
2.5 KiB
Groff
.TH XvQueryEncodings __libmansuffix__ __vendorversion__ "libXv Functions"
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.SH NAME
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XvQueryEncodings \- return list of encodings for an adaptor
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.\"
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.SH SYNOPSIS
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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 "int XvQueryEncodings(Display *" dpy ", XvPortID " port ","
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.BI " unsigned int *" p_num_encodings ","
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.BI " XvEncodingInfo **" pp_encoding_info ");"
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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 encodings.
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.IP \fIp_num_encodings\fR 8
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A pointer to where the number of encodings supported
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by the adaptor is written.
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.IP \fIpp_encoding_info\fR 8
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A pointer to where the list of returned encoding information is returned.
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XvEncodingInfo has the following structure:
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.EX
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typedef struct {
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XvEncodingID encoding_id;
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char *name;
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unsigned long width;
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unsigned long height;
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XvRational rate;
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unsigned long num_encodings;
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} XvEncodingInfo;
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.EE
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.IP \fIencoding_id\fR 8
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Specifies the encoding-id of the encoding. The encoding-id is used to
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identify an encoding when a port's encoding attribute is changed.
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.IP \fIname\fR 8
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A pointer to a formatted string that identifies the encoding. The string
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has the format "\fItiming\fR-\fIsignaltype\fR". For example "ntsc-composite".
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.IP \fIwidth,height\fR 8
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The width and height, in pixels, of the decoded video image.
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.IP \fIrate\fR 8
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The field rate of the decoded video.
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.PP
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The XvRational structure is used to specify a fractional number.
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It has the following structure:
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.EX
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typedef struct {
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int numerator;
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int denominator;
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} XvRational;
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.EE
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The \fInumerator\fP and \fIdenominator\fP fields specify the
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appropriate parts of a fractional number.
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.\"
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.SH DESCRIPTION
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.BR XvQueryEncodings (__libmansuffix__)
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returns encoding information about an adaptor. Each
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encoding is described by the XvEncodingInfo structure described above. The
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encodings are identified by an encoding-id, which can be used to set or get
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the encoding attribute of a port.
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.SH RETURN VALUES
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.IP [Success] 8
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Returned if
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.BR XvQueryEncodings (__libmansuffix__)
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completed successfully.
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.IP [XvBadExtension] 8
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Returned if the Xv extension is unavailable.
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.IP [XvBadAlloc] 8
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Returned if
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.BR XvQueryEncodings (__libmansuffix__)
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failed to allocate memory to process the request.
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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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.\"
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.BR XvFreeEncodingInfo (__libmansuffix__)
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