Name

XvQueryEncodings - return list of encodings for an adaptor

Syntax

#include


XvQueryEncodings(Display *dpy, XvPortID port,
                 unsigned int *p_num_encodings,
                 XvEncodingInfo **pp_encoding_info);

Arguments

_d_p_y Specifies the connection to the X server.
_X_v_P_o_r_t_I_D Specifies the port whose adaptor is to be queried for its
list of encodings.
_p___n_u_m___e_n_c_o_d_i_n_g_s A pointer to where the number of encodings supported
by the adaptor is written.
_p_p___e_n_c_o_d_i_n_g___i_n_f_o A pointer to where the list of returned
encoding information is returned. XvEncodingInfo has the following structure:
        

typedef struct { XvEncodingID encoding_id; char *name; unsigned long width; unsigned long height; XvRational rate; unsigned long num_encodings; } XvEncodingInfo;

_e_n_c_o_d_i_n_g___i_d Specifies the encoding-id of the encoding. The encoding-id is used to
identify an encoding when a port's encoding attribute is changed.
_n_a_m_e A pointer to a formatted string that identifies the encoding. The string
has the format "_t_i_m_i_n_g_-_s_i_g_n_a_l_t_y_p_e". For example "ntsc-composite".
_w_i_d_t_h_,_h_e_i_g_h_t The width and height, in pixels, of the decoded video image.
_r_a_t_e The field rate of the decoded video.

The XvRational structure is used to specify a fractional number. It has the following structure:

        

typedef struct { int numerator; int denominator; } XvRational;

The _n_u_m_e_r_a_t_o_r and _d_e_n_o_m_i_n_a_t_o_r fields specify the appropriate parts of a fractional number.

Description

XvQueryEncodings(3) returns encoding information about an adaptor. Each encoding is described by the XvEncodingInfo structure described above. The encodings are identified by an encoding-id, which can be used to set or get the encoding attribute of a port.

Returned Values

[Success] Returned if XvQueryEncodings(3) completed successfully.
[XvBadExtension] Returned if the Xv extension is unavailable.
[XvBadAlloc] Returned if XvQueryEncodings(3) failed to allocate memory to process
the request.

Diagnostics

[XvBadPort] Generated if the requested port does not exist.

See Also

XvFreeEncodingInfo(3)