XvListImageFormats(3)

1XvListImageFormats(3)           libXv Functions          XvListImageFormats(3)
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Name

6       XvListImageFormats  - return list of image formats supported by a video
7       port
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Syntax

10       #include <X11/extensions/Xvlib.h>
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12       XvImageFormatValues * XvListImageFormats (Display *dpy,
13                        XvPortID port,  int *p_num_formats);
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Arguments

16       dpy     Specifies the connection to the X server.
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18       port    Specifies the port whose adaptor is to be queried for its  list
19               of attributes.
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21       p_num_formats
22               A  pointer to where the number of formats returned in the array
23               is written.
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Description

26       XvListImageFormats(3) returns the XvImageFormatValues supported by  the
27       specified port. This list should be freed with XFree(3).
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Returned Values

30       XvImageFormatValues has the following structure:
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32           typedef struct {
33             int id;                      /* Unique descriptor for the format */
34             int type;                    /* XvRGB, XvYUV */
35             int byte_order;              /* LSBFirst, MSBFirst */
36             char guid[16];               /* Globally Unique IDentifier */
37             int bits_per_pixel;
38             int format;                  /* XvPacked, XvPlanar */
39             int num_planes;
40
41             /* for RGB formats */
42             int depth;
43             unsigned int red_mask;
44             unsigned int green_mask;
45             unsigned int blue_mask;
46
47             /* for YUV formats */
48             unsigned int y_sample_bits;
49             unsigned int u_sample_bits;
50             unsigned int v_sample_bits;
51             unsigned int horz_y_period;
52             unsigned int horz_u_period;
53             unsigned int horz_v_period;
54             unsigned int vert_y_period;
55             unsigned int vert_u_period;
56             unsigned int vert_v_period;
57             char component_order[32];    /* eg. UYVY */
58             int scanline_order;          /* XvTopToBottom, XvBottomToTop */
59           } XvImageFormatValues;
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61
62       id      A  unique  descriptor for the format.  This is often the FOURCC
63               for the format, when applicable.  This id is used  to  describe
64               the format during XvImage creation.
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66       type    XvRGB or XvYUV.
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68       byte_order
69               The  byte  order  of  the image.  It is either LSBFirst or MSB‐
70               First.
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72       guid    The Globally  Unique  IDentifier  (also  known  as  Universally
73               Unique  IDentifier).   When  not applicable, all characters are
74               NULL.
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76       bits_per_pixel
77               The bits taken up (but not necessarily  used)  by  each  pixel.
78               Note  that  for  some planar formats which have fractional bits
79               per pixel (such as IF09) this number may be rounded _down_.
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81       format  XvPacked or XvPlanar.
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83       num_planes
84               The number of planes in planar formats.
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86       depth   Significant bits per pixel.
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88       red_mask, green_mask, blue_mask
89               The red, green and blue bitmasks (RGB formats only).
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91       ?_sample_bits
92               The size of each sample in bits (YUV formats only).
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94       horz_?_period, vert_?_period
95               The period (in pixels) on which samples occur in the horizontal
96               and vertical directions (YUV formats only).
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98       component_order
99               Upper case ascii characters representing the order that samples
100               are stored within packed formats.  For planar formats this rep‐
101               resents the ordering of the planes.
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103       scanline_order
104               XvTopToBottom or XvBottomToTop.
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Notes

107       Since  some  formats  (particularly some planar YUV formats) may not be
108       completely defined by the parameters above, the guid,  when  available,
109       should provide the most accurate description of the format.
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Diagnostics

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