mpg123 advanced parameter API

Typedefs
typedef struct mpg123_pars_struct	mpg123_pars

Functions
MPG123_EXPORT mpg123_handle *	mpg123_parnew (mpg123_pars *mp, const char *decoder, int *error)
MPG123_EXPORT mpg123_pars *	mpg123_new_pars (int *error)
MPG123_EXPORT void	mpg123_delete_pars (mpg123_pars *mp)
MPG123_EXPORT int	mpg123_fmt_none (mpg123_pars *mp)
MPG123_EXPORT int	mpg123_fmt_all (mpg123_pars *mp)
MPG123_EXPORT int	mpg123_fmt (mpg123_pars *mp, long rate, int channels, int encodings)
MPG123_EXPORT int	mpg123_fmt2 (mpg123_pars *mp, long rate, int channels, int encodings)
MPG123_EXPORT int	mpg123_fmt_support (mpg123_pars *mp, long rate, int encoding)
MPG123_EXPORT int	mpg123_par (mpg123_pars *mp, enum mpg123_parms type, long value, double fvalue)
MPG123_EXPORT int	mpg123_par2 (mpg123_pars *mp, int type, long value, double fvalue)
MPG123_EXPORT int	mpg123_getpar (mpg123_pars *mp, enum mpg123_parms type, long *value, double *fvalue)
MPG123_EXPORT int	mpg123_getpar2 (mpg123_pars *mp, int type, long *value, double *fvalue)

Detailed Description

Direct access to a parameter set without full handle around it. Possible uses:

• Influence behaviour of library during initialization of handle (MPG123_VERBOSE).
• Use one set of parameters for multiple handles.

The functions for handling mpg123_pars (mpg123_par() and mpg123_fmt() family) directly return a fully qualified mpg123 error code, the ones operating on full handles normally MPG123_OK or MPG123_ERR, storing the specific error code itseld inside the handle.

Typedef Documentation

mpg123_pars

typedef struct mpg123_pars_struct mpg123_pars

Opaque structure for the libmpg123 decoder parameters.

Definition at line 1993 of file mpg123.h.

Function Documentation

mpg123_parnew()

MPG123_EXPORT mpg123_handle* mpg123_parnew	(	mpg123_pars *	mp,
		const char *	decoder,
		int *	error
	)

Create a handle with preset parameters.

Parameters

mp	parameter handle
decoder	decoder choice
error	error code return address

Returns

mpg123 handle

mpg123_new_pars()

MPG123_EXPORT mpg123_pars* mpg123_new_pars

(

int *

error

)

Allocate memory for and return a pointer to a new mpg123_pars

Parameters

error

error code return address

Returns

new parameter handle

mpg123_delete_pars()

MPG123_EXPORT void mpg123_delete_pars

(

mpg123_pars *

mp

)

Delete and free up memory used by a mpg123_pars data structure

Parameters

mp	parameter handle

mpg123_fmt_none()

MPG123_EXPORT int mpg123_fmt_none

(

mpg123_pars *

mp

)

Configure mpg123 parameters to accept no output format at all, use before specifying supported formats with mpg123_format

Parameters

mp	parameter handle

Returns

MPG123_OK on success

mpg123_fmt_all()

MPG123_EXPORT int mpg123_fmt_all

(

mpg123_pars *

mp

)

Configure mpg123 parameters to accept all formats (also any custom rate you may set) – this is default.

Parameters

mp	parameter handle

Returns

MPG123_OK on success

mpg123_fmt()

MPG123_EXPORT int mpg123_fmt	(	mpg123_pars *	mp,
		long	rate,
		int	channels,
		int	encodings
	)

Set the audio format support of a mpg123_pars in detail:

Parameters

mp	parameter handle
rate	The sample rate value (in Hertz).
channels	A combination of MPG123_STEREO and MPG123_MONO.
encodings	A combination of accepted encodings for rate and channels, p.ex MPG123_ENC_SIGNED16|MPG123_ENC_ULAW_8 (or 0 for no support).

Returns

MPG123_OK on success

mpg123_fmt2()

MPG123_EXPORT int mpg123_fmt2	(	mpg123_pars *	mp,
		long	rate,
		int	channels,
		int	encodings
	)

Set the audio format support of a mpg123_pars in detail:

Parameters

mp	parameter handle
rate	The sample rate value (in Hertz). Special value 0 means all rates (reason for this variant of mpg123_fmt).
channels	A combination of MPG123_STEREO and MPG123_MONO.
encodings	A combination of accepted encodings for rate and channels, p.ex MPG123_ENC_SIGNED16|MPG123_ENC_ULAW_8 (or 0 for no support).

Returns

MPG123_OK on success

mpg123_fmt_support()

MPG123_EXPORT int mpg123_fmt_support	(	mpg123_pars *	mp,
		long	rate,
		int	encoding
	)

Check to see if a specific format at a specific rate is supported by mpg123_pars.

Parameters

mp	parameter handle
rate	sampling rate
encoding	encoding

Returns

0 for no support (that includes invalid parameters), MPG123_STEREO, MPG123_MONO or MPG123_STEREO|MPG123_MONO.

mpg123_par()

MPG123_EXPORT int mpg123_par	(	mpg123_pars *	mp,
		enum mpg123_parms	type,
		long	value,
		double	fvalue
	)

Set a specific parameter in a par handle.

Note that this name is mapped to mpg123_par2() instead unless MPG123_ENUM_API is defined.

Parameters

mp	parameter handle
type	parameter choice
value	integer value
fvalue	floating point value

Returns

MPG123_OK on success

mpg123_par2()

MPG123_EXPORT int mpg123_par2	(	mpg123_pars *	mp,
		int	type,
		long	value,
		double	fvalue
	)

Set a specific parameter in a par handle. No enums.

This is actually called instead of mpg123_par() unless MPG123_ENUM_API is defined.

Parameters

mp	parameter handle
type	parameter choice (enum mpg123_parms)
value	integer value
fvalue	floating point value

Returns

MPG123_OK on success

mpg123_getpar()

MPG123_EXPORT int mpg123_getpar	(	mpg123_pars *	mp,
		enum mpg123_parms	type,
		long *	value,
		double *	fvalue
	)

Get a specific parameter from a par handle.

Note that this name is mapped to mpg123_getpar2() instead unless MPG123_ENUM_API is defined.

Parameters

mp	parameter handle
type	parameter choice
value	integer value return address
fvalue	floating point value return address

Returns

MPG123_OK on success

mpg123_getpar2()

MPG123_EXPORT int mpg123_getpar2	(	mpg123_pars *	mp,
		int	type,
		long *	value,
		double *	fvalue
	)

Get a specific parameter from a par handle. No enums.

This is actually called instead of mpg123_getpar() unless MPG123_ENUM_API is defined.

Parameters

mp	parameter handle
type	parameter choice (enum mpg123_parms)
value	integer value return address
fvalue	floating point value return address

Returns

MPG123_OK on success