ad.h File Reference

audio-decoder - wrapper around libsndfile and libav* More...

#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>

Go to the source code of this file.

Classes
struct	adinfo

Functions
void *	ad_open (const char *fn, struct adinfo *nfo)
int	ad_close (void *sf)
int64_t	ad_seek (void *sf, int64_t pos)
ssize_t	ad_read (void *sf, float *out, size_t len)
int	ad_get_bitrate (void *sf)
int	ad_info (void *sf, struct adinfo *nfo)
void	ad_clear_nfo (struct adinfo *nfo)
void	ad_free_nfo (struct adinfo *nfo)
int	ad_finfo (const char *, struct adinfo *)
ssize_t	ad_read_mono_dbl (void *, struct adinfo *, double *, size_t)
void	ad_dump_nfo (int dbglvl, struct adinfo *nfo)
void	ad_set_debuglevel (int lvl)

Detailed Description

audio-decoder - wrapper around libsndfile and libav*

Author

Robin Gareus robin.nosp@m.@gar.nosp@m.eus.o.nosp@m.rg

Copyright (C) 2011-2013 Robin Gareus robin.nosp@m.@gar.nosp@m.eus.o.nosp@m.rg Copyright (C) 2014-2023 Filipe Coelho falkt.nosp@m.x@fa.nosp@m.lktx..nosp@m.com

This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser Public License as published by the Free Software Foundation; either version 2.1, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Function Documentation

ad_clear_nfo()

void ad_clear_nfo

(

struct adinfo *

nfo

)

zero initialize the information struct. * (does not free nfo->meta_data)

Parameters

nfo	pointer to a adinfo struct

ad_close()

int ad_close

(

void *

sf

)

close an audio file and release decoder structures

Parameters

sf	decoder handle

Returns

0 on succees, -1 if sf was invalid or not open (return value can usually be ignored)

ad_dump_nfo()

void ad_dump_nfo	(	int	dbglvl,
		struct adinfo *	nfo )

calls dbg() to print file info to stderr.

Parameters

dbglvl
nfo

ad_finfo()

int ad_finfo	(	const char *	fn,
		struct adinfo *	nfo )

read file info combines ad_open() and ad_close()

ad_free_nfo()

void ad_free_nfo

(

struct adinfo *

nfo

)

free possibly allocated meta-data text

Parameters

nfo	pointer to a adinfo struct

ad_get_bitrate()

int ad_get_bitrate

(

void *

sf

)

get the current playing bit_rate

Parameters

sf	decoder handle

Returns

the bitrate in kbps or -1 on error.

ad_info()

int ad_info	(	void *	sf,
		struct adinfo *	nfo )

re-read the file information and meta-data.

this is not neccesary in general ad_open includes an inplicit call but meta-data may change in live-stream in which case en explicit call to ad_into is needed to update the inforation

Parameters

fn	file-name
nfo	pointer to a adinfo struct which will hold information about the file.

Returns

0 on succees, -1 if sf was invalid or not open

ad_open()

void * ad_open	(	const char *	fn,
		struct adinfo *	nfo )

open an audio file

Parameters

fn	file-name
nfo	pointer to a adinfo struct which will hold information about the file.

Returns

NULL on error, a pointer to an opaque soundfile-decoder object on success.

ad_read()

ssize_t ad_read	(	void *	sf,
		float *	out,
		size_t	len )

decode audio data chunk to raw interleaved channel floating point data

Parameters

sf	decoder handle
out	place to store data – must be large enough to hold (sizeof(float) * len) bytes.
len	number of samples (!) to read (should be a multiple of nfo->channels).

Returns

the number of read samples.

ad_read_mono_dbl()

ssize_t ad_read_mono_dbl	(	void *	sf,
		struct adinfo *	nfo,
		double *	d,
		size_t	len )

wrapper around ad_read, downmixes all channels to mono

ad_seek()

int64_t ad_seek	(	void *	sf,
		int64_t	pos )

seel to a given position in the file

Parameters

sf	decoder handle
pos	frame position to seek to in frames (1 frame = number-of-channel samples) from the start of the file.

Returns

the current position in frames (multi-channel samples) from the start of the file. On error this function returns -1.

ad_set_debuglevel()

void ad_set_debuglevel

(

int

lvl

)

set audio-decoder debug level – all info is printed to stderr.

Parameters

lvl	debug-level threshold -1: absolutley silent 0: errors only 1: errors + info 2: + debug 3: + low-level-debug info