GST_MAKE_FOURCC()

#define GST_MAKE_FOURCC(a,b,c,d)        (guint32)((a)|(b)<<8|(c)<<16|(d)<<24)

will transform four characters into a host-endiannness guint32 fourcc:

guint32 fourcc = GST_MAKE_FOURCC ('M','J','P','G');

GST_STR_FOURCC()

#define GST_STR_FOURCC(f)               (guint32)(((f)[0])|((f)[1]<<8)|((f)[2]<<16)|((f)[3]<<24))

Creates a fourcc from an input string. The input string should consisnt of at least four characters (this is not checked for!).

guint32 fourcc = GST_STR_FOURCC("MJPG");

GST_FOURCC_FORMAT

#define GST_FOURCC_FORMAT "%c%c%c%c"

Can be used to properly output a fourcc (a guint32) value in a printf()-style text message.

printf ("fourcc: %" GST_FOURCC_FORMAT "\n", GST_FOURCC_ARGS (fcc));

GST_FOURCC_ARGS()

#define     GST_FOURCC_ARGS(fourcc)

Can be used to properly output a fourcc (a guint32) value in a printf()-style text message.

printf ("fourcc: %" GST_FOURCC_FORMAT "\n", GST_FOURCC_ARGS (fcc));

GST_VALUE_HOLDS_FOURCC()

#define GST_VALUE_HOLDS_FOURCC(x)       (G_VALUE_HOLDS(x, gst_type_fourcc))

Checks if the give GValue contains a FOURCC value.

GST_VALUE_HOLDS_INT_RANGE()

#define GST_VALUE_HOLDS_INT_RANGE(x)    (G_VALUE_HOLDS(x, gst_type_int_range))

Checks if the give GValue contains a INT_RANGE value.

GST_VALUE_HOLDS_DOUBLE_RANGE()

#define GST_VALUE_HOLDS_DOUBLE_RANGE(x) (G_VALUE_HOLDS(x, gst_type_double_range))

Checks if the give GValue contains a DOUBLE_RANGE value.

GST_VALUE_HOLDS_LIST()

#define GST_VALUE_HOLDS_LIST(x)         (G_VALUE_HOLDS(x, gst_type_list))

Checks if the give GValue contains a LIST value.

GST_VALUE_HOLDS_FIXED_LIST()

#define GST_VALUE_HOLDS_FIXED_LIST(x)   (G_VALUE_HOLDS(x, gst_type_fixed_list))

Checks if the give GValue contains a FIXED_LIST value.

GST_VALUE_HOLDS_CAPS()

#define GST_VALUE_HOLDS_CAPS(x)		(G_VALUE_HOLDS(x, GST_TYPE_CAPS))

Checks if the give GValue contains a CAPS value.

GST_VALUE_HOLDS_FRACTION()

#define GST_VALUE_HOLDS_FRACTION(x)	(G_VALUE_HOLDS(x, gst_type_fraction))

Checks if the give GValue contains a FRACTION value.

GST_VALUE_LESS_THAN

#define GST_VALUE_LESS_THAN              (-1)

Indicates that the first value provided to a comparison function (gst_value_compare()) is lesser than the second one.

GST_VALUE_EQUAL

#define GST_VALUE_EQUAL                   0

Indicates that the first value provided to a comparison function (gst_value_compare()) is equal to the second one.

GST_VALUE_GREATER_THAN

#define GST_VALUE_GREATER_THAN            1

Indicates that the first value provided to a comparison function (gst_value_compare()) is greater than the second one.

GST_VALUE_UNORDERED

#define GST_VALUE_UNORDERED               2

Indicates that the comparison function (gst_value_compare()) can not determine a order for the two provided values.

GstValueCompareFunc ()

int         (*GstValueCompareFunc)          (const GValue *value1,
                                             const GValue *value2);

GstValueSerializeFunc ()

char*       (*GstValueSerializeFunc)        (const GValue *value1);

GstValueDeserializeFunc ()

gboolean    (*GstValueDeserializeFunc)      (GValue *dest,
                                             const char *s);

GstValueUnionFunc ()

int         (*GstValueUnionFunc)            (GValue *dest,
                                             const GValue *value1,
                                             const GValue *value2);

GstValueIntersectFunc ()

int         (*GstValueIntersectFunc)        (GValue *dest,
                                             const GValue *value1,
                                             const GValue *value2);

Functions having this type calculate the intersection of value1 and value2. If the intersection is non-empty, the result is placed in dest and TRUE is returned. If the intersection is empty, dest is unmodified and FALSE is returned.

GstValueSubtractFunc ()

int         (*GstValueSubtractFunc)         (GValue *dest,
                                             const GValue *minuend,
                                             const GValue *subtrahend);

struct GstValueTable

struct GstValueTable {

  GType type;
  GstValueCompareFunc compare;
  GstValueSerializeFunc serialize;
  GstValueDeserializeFunc deserialize;

};

gst_type_is_fixed ()

gboolean    gst_type_is_fixed               (GType type);

Tests if the given GType, if available in a GstStructure (or any other container) will contain a "fixed" (which means: one possible value) or an "unfixed" (which means: multiple possible values, such as data lists or data ranges) value.

gst_value_is_fixed ()

gboolean    gst_value_is_fixed              (const GValue *value);

Tests if the given GValue, if available in a GstStructure (or any other container) contains a "fixed" (which means: one value) or an "unfixed" (which means: multiple possible values, such as data lists or data ranges) value.

gst_value_register ()

void        gst_value_register              (const GstValueTable *table);

Registers functions to perform calculations on GValues of a given type.

gst_value_init_and_copy ()

void        gst_value_init_and_copy         (GValue *dest,
                                             const GValue *src);

Initialises the target value to be of the same type as source and then copies the contents from source to target.

gst_value_serialize ()

gchar*      gst_value_serialize             (const GValue *value);

tries to transform the given value into a string representation that allows getting back this string later on using gst_value_deserialize().

gst_value_deserialize ()

gboolean    gst_value_deserialize           (GValue *dest,
                                             const gchar *src);

Tries to deserialize a string into the type specified by the given GValue. If the operation succeeds, TRUE is returned, FALSE otherwise.

gst_value_list_append_value ()

void        gst_value_list_append_value     (GValue *value,
                                             const GValue *append_value);

Appends append_value to the GstValueList in value.

gst_value_list_prepend_value ()

void        gst_value_list_prepend_value    (GValue *value,
                                             const GValue *prepend_value);

Prepends prepend_value to the GstValueList in value.

gst_value_list_concat ()

void        gst_value_list_concat           (GValue *dest,
                                             const GValue *value1,
                                             const GValue *value2);

Concatenates copies of value1 and value2 into a list. The value dest is initialized to the type GST_TYPE_LIST.

gst_value_list_get_size ()

guint       gst_value_list_get_size         (const GValue *value);

Gets the number of values contained in value.

gst_value_list_get_value ()

G_CONST_RETURN GValue* gst_value_list_get_value
                                            (const GValue *value,
                                             guint index);

Gets the value that is a member of the list contained in value and has the index index.

gst_value_set_fourcc ()

void        gst_value_set_fourcc            (GValue *value,
                                             guint32 fourcc);

Sets value to fourcc.

gst_value_get_fourcc ()

guint32     gst_value_get_fourcc            (const GValue *value);

Gets the fourcc contained in value.

gst_value_set_int_range ()

void        gst_value_set_int_range         (GValue *value,
                                             int start,
                                             int end);

Sets value to the range specified by start and end.

gst_value_get_int_range_min ()

int         gst_value_get_int_range_min     (const GValue *value);

Gets the minimum of the range specified by value.

gst_value_get_int_range_max ()

int         gst_value_get_int_range_max     (const GValue *value);

Gets the maximum of the range specified by value.

gst_value_set_double_range ()

void        gst_value_set_double_range      (GValue *value,
                                             double start,
                                             double end);

Sets value to the range specified by start and end.

gst_value_get_double_range_min ()

double      gst_value_get_double_range_min  (const GValue *value);

Gets the minimum of the range specified by value.

gst_value_get_double_range_max ()

double      gst_value_get_double_range_max  (const GValue *value);

Gets the maximum of the range specified by value.

gst_value_get_caps ()

G_CONST_RETURN GstCaps* gst_value_get_caps  (const GValue *value);

Gets the contents of value.

gst_value_set_caps ()

void        gst_value_set_caps              (GValue *value,
                                             const GstCaps *caps);

Sets the contents of value to coorespond to caps. The actual GstCaps structure is copied before it is used.

gst_value_get_fraction_numerator ()

int         gst_value_get_fraction_numerator
                                            (const GValue *value);

Gets the numerator of the fraction specified by value.

gst_value_get_fraction_denominator ()

int         gst_value_get_fraction_denominator
                                            (const GValue *value);

Gets the denominator of the fraction specified by value.

gst_value_set_fraction ()

void        gst_value_set_fraction          (GValue *value,
                                             int numerator,
                                             int denominator);

Sets value to the fraction specified by numerator over denominator. The fraction gets reduced to the smallest numerator and denominator, and if necessary the sign is moved to the numerator.

gst_value_fraction_multiply ()

gboolean    gst_value_fraction_multiply     (GValue *product,
                                             const GValue *factor1,
                                             const GValue *factor2);

Multiplies the two GValues containing a GstFraction and sets product to the product of the two fractions.

gst_value_compare ()

int         gst_value_compare               (const GValue *value1,
                                             const GValue *value2);

Compares value1 and value2. If value1 and value2 cannot be compared, the function returns GST_VALUE_UNORDERED. Otherwise, if value1 is greater than value2, GST_VALUE_GREATER is returned. If value1 is less than value2, GST_VALUE_LESSER is returned. If the values are equal, GST_VALUE_EQUAL is returned.

gst_value_can_compare ()

gboolean    gst_value_can_compare           (const GValue *value1,
                                             const GValue *value2);

Determines if value1 and value2 can be compared.

gst_value_union ()

gboolean    gst_value_union                 (GValue *dest,
                                             const GValue *value1,
                                             const GValue *value2);

Creates a GValue cooresponding to the union of value1 and value2.

gst_value_can_union ()

gboolean    gst_value_can_union             (const GValue *value1,
                                             const GValue *value2);

Determines if value1 and value2 can be non-trivially unioned. Any two values can be trivially unioned by adding both of them to a GstValueList. However, certain types have the possibility to be unioned in a simpler way. For example, an integer range and an integer can be unioned if the integer is a subset of the integer range. If there is the possibility that two values can be unioned, this function returns TRUE.

gst_value_register_union_func ()

void        gst_value_register_union_func   (GType type1,
                                             GType type2,
                                             GstValueUnionFunc func);

Registers a union function that can create a union between GValues of the type type1 and type2.

gst_value_subtract ()

gboolean    gst_value_subtract              (GValue *dest,
                                             const GValue *minuend,
                                             const GValue *subtrahend);

Subtracts subtrahend from minuend and stores the result in dest. Note that this means subtraction as in sets, not as in mathematics.

gst_value_can_subtract ()

gboolean    gst_value_can_subtract          (const GValue *minuend,
                                             const GValue *subtrahend);

Checks if it's possible to subtract subtrahend from minuend.

gst_value_register_subtract_func ()

void        gst_value_register_subtract_func
                                            (GType minuend_type,
                                             GType subtrahend_type,
                                             GstValueSubtractFunc func);

Registers func as a function capable of subtracting the values of subtrahend_type from values of minuend_type.

gst_value_intersect ()

gboolean    gst_value_intersect             (GValue *dest,
                                             const GValue *value1,
                                             const GValue *value2);

Calculates the intersection of two values. If the values have a non-empty intersection, the value representing the intersection is placed in dest. If the intersection is non-empty, dest is not modified.

gst_value_can_intersect ()

gboolean    gst_value_can_intersect         (const GValue *value1,
                                             const GValue *value2);

Determines if intersecting two values will produce a valid result. Two values will produce a valid intersection if they have the same type, or if there is a method (registered by gst_value_register_intersection_func) to calculate the intersection.

gst_value_register_intersect_func ()

void        gst_value_register_intersect_func
                                            (GType type1,
                                             GType type2,
                                             GstValueIntersectFunc func);