mpv/libaf/af.h

#ifndef __aop_h__
#define __aop_h__

#include <stdio.h>

#include "af_mp.h"
#include "config.h"
#include "control.h"
#include "af_format.h"

struct af_instance_s;

// Audio data chunk
typedef struct af_data_s
{
  void* audio;  // data buffer
  int len;      // buffer length
  int rate;	// sample rate
  int nch;	// number of channels
  int format;	// format
  int bps; 	// bytes per sample
} af_data_t;

// Fraction, used to calculate buffer lengths
typedef struct frac_s
{
  int n; // Numerator
  int d; // Denominator
} frac_t;

int af_gcd(register int a, register int b);
void af_frac_cancel(frac_t *f);
void af_frac_mul(frac_t *out, const frac_t *in);

// Flags used for defining the behavior of an audio filter
#define AF_FLAGS_REENTRANT 	0x00000000
#define AF_FLAGS_NOT_REENTRANT 	0x00000001

/* Audio filter information not specific for current instance, but for
   a specific filter */ 
typedef struct af_info_s 
{
  const char *info;
  const char *name;
  const char *author;
  const char *comment;
  const int flags;
  int (*open)(struct af_instance_s* vf);
} af_info_t;

// Linked list of audio filters
typedef struct af_instance_s
{
  af_info_t* info;
  int (*control)(struct af_instance_s* af, int cmd, void* arg);
  void (*uninit)(struct af_instance_s* af);
  af_data_t* (*play)(struct af_instance_s* af, af_data_t* data);
  void* setup;	  // setup data for this specific instance and filter
  af_data_t* data; // configuration for outgoing data stream
  struct af_instance_s* next;
  struct af_instance_s* prev;  
  double delay; // Delay caused by the filter [ms]
  frac_t mul; /* length multiplier: how much does this instance change
		 the length of the buffer. */
}af_instance_t;

// Initialization flags
extern int* af_cpu_speed;

#define AF_INIT_AUTO		0x00000000
#define AF_INIT_SLOW		0x00000001
#define AF_INIT_FAST		0x00000002
#define AF_INIT_FORCE	  	0x00000003
#define AF_INIT_TYPE_MASK 	0x00000003

#define AF_INIT_INT		0x00000000
#define AF_INIT_FLOAT		0x00000004
#define AF_INIT_FORMAT_MASK	0x00000004

// Default init type 
#ifndef AF_INIT_TYPE
#if defined(HAVE_SSE) || defined(HAVE_3DNOW)
#define AF_INIT_TYPE (af_cpu_speed?*af_cpu_speed:AF_INIT_FAST)
#else
#define AF_INIT_TYPE (af_cpu_speed?*af_cpu_speed:AF_INIT_SLOW)
#endif
#endif

// Configuration switches
typedef struct af_cfg_s{
  int force;	// Initialization type
  char** list;	/* list of names of filters that are added to filter
		   list during first initialization of stream */
}af_cfg_t;

// Current audio stream
typedef struct af_stream_s
{
  // The first and last filter in the list
  af_instance_t* first;
  af_instance_t* last;
  // Storage for input and output data formats
  af_data_t input;
  af_data_t output;
  // Configuration for this stream
  af_cfg_t cfg;
}af_stream_t;

/*********************************************
// Return values
*/

#define AF_DETACH   2
#define AF_OK       1
#define AF_TRUE     1
#define AF_FALSE    0
#define AF_UNKNOWN -1
#define AF_ERROR   -2
#define AF_FATAL   -3



/*********************************************
// Export functions
*/

/* Initialize the stream "s". This function creates a new filter list
   if necessary according to the values set in input and output. Input
   and output should contain the format of the current movie and the
   formate of the preferred output respectively. The function is
   reentrant i.e. if called with an already initialized stream the
   stream will be reinitialized. If the binary parameter
   "force_output" is set, the output format will be converted to the
   format given in "s", otherwise the output fromat in the last filter
   will be copied "s". The return value is 0 if success and -1 if
   failure */
int af_init(af_stream_t* s, int force_output);

// Uninit and remove all filters
void af_uninit(af_stream_t* s);

/* Add filter during execution. This function adds the filter "name"
   to the stream s. The filter will be inserted somewhere nice in the
   list of filters. The return value is a pointer to the new filter,
   If the filter couldn't be added the return value is NULL. */
af_instance_t* af_add(af_stream_t* s, char* name);

// Uninit and remove the filter "af"
void af_remove(af_stream_t* s, af_instance_t* af);

/* Find filter in the dynamic filter list using it's name This
   function is used for finding already initialized filters */
af_instance_t* af_get(af_stream_t* s, char* name);

// Filter data chunk through the filters in the list
af_data_t* af_play(af_stream_t* s, af_data_t* data);

// send control to all filters, starting with the last until
// one accepts the command with AF_OK.
// Returns the accepting filter or NULL if none was found.
af_instance_t *af_control_any_rev (af_stream_t* s, int cmd, void* arg);

/* Calculate how long the output from the filters will be given the
   input length "len". The calculated length is >= the actual
   length */
int af_outputlen(af_stream_t* s, int len);

/* Calculate how long the input to the filters should be to produce a
   certain output length, i.e. the return value of this function is
   the input length required to produce the output length "len". The
   calculated length is <= the actual length */
int af_inputlen(af_stream_t* s, int len);

/* Calculate how long the input IN to the filters should be to produce
   a certain output length OUT but with the following three constraints:
   1. IN <= max_insize, where max_insize is the maximum possible input
      block length
   2. OUT <= max_outsize, where max_outsize is the maximum possible
      output block length
   3. If possible OUT >= len. 
   Return -1 in case of error */ 
int af_calc_insize_constrained(af_stream_t* s, int len,
			       int max_outsize,int max_insize);

/* Calculate the total delay caused by the filters */
double af_calc_delay(af_stream_t* s);

// Helper functions and macros used inside the audio filters

/* Helper function called by the macro with the same name only to be
   called from inside filters */
int af_resize_local_buffer(af_instance_t* af, af_data_t* data);

/* Helper function used to calculate the exact buffer length needed
   when buffers are resized. The returned length is >= than what is
   needed */
int af_lencalc(frac_t mul, af_data_t* data);

/* Helper function used to convert to gain value from dB. Returns
   AF_OK if of and AF_ERROR if fail */
int af_from_dB(int n, float* in, float* out, float k, float mi, float ma);
/* Helper function used to convert from gain value to dB. Returns
   AF_OK if of and AF_ERROR if fail */
int af_to_dB(int n, float* in, float* out, float k);
/* Helper function used to convert from ms to sample time*/
int af_from_ms(int n, float* in, int* out, int rate, float mi, float ma);
/* Helper function used to convert from sample time to ms */
int af_to_ms(int n, int* in, float* out, int rate); 
/* Helper function for testing the output format */
int af_test_output(struct af_instance_s* af, af_data_t* out);

float af_softclip(float a);

/** Print a list of all available audio filters */
void af_help(void);

/* Fill the missing parameters in the af_data_t structure.
   Used for stuffing bps with a value based on format. */
void af_fix_parameters(af_data_t *data);

/* Memory reallocation macro: if a local buffer is used (i.e. if the
   filter doesn't operate on the incoming buffer this macro must be
   called to ensure the buffer is big enough. */
#define RESIZE_LOCAL_BUFFER(a,d)\
((a->data->len < af_lencalc(a->mul,d))?af_resize_local_buffer(a,d):AF_OK)

/* Some other useful macro definitions*/
#ifndef min
#define min(a,b)(((a)>(b))?(b):(a))
#endif

#ifndef max
#define max(a,b)(((a)>(b))?(a):(b))
#endif

#ifndef clamp
#define clamp(a,min,max) (((a)>(max))?(max):(((a)<(min))?(min):(a)))
#endif

#ifndef sign
#define sign(a) (((a)>0)?(1):(-1)) 
#endif

#ifndef lrnd
#define lrnd(a,b) ((b)((a)>=0.0?(a)+0.5:(a)-0.5))
#endif

/* Error messages */

typedef struct af_msg_cfg_s
{
  int level;   	/* Message level for debug and error messages max = 2
		   min = -2 default = 0 */
  FILE* err;	// Stream to print error messages to
  FILE* msg;	// Stream to print information messages to
}af_msg_cfg_t;

extern af_msg_cfg_t af_msg_cfg; // Message 

#define AF_MSG_FATAL	-3 // Fatal error exit immediately
#define AF_MSG_ERROR    -2 // Error return gracefully
#define AF_MSG_WARN     -1 // Print warning but do not exit (can be suppressed)
#define AF_MSG_INFO	 0 // Important information
#define AF_MSG_VERBOSE	 1 // Print this if verbose is enabled 
#define AF_MSG_DEBUG0	 2 // Print if very verbose
#define AF_MSG_DEBUG1	 3 // Print if very very verbose 

/* Macro for printing error messages */
#ifndef af_msg
#define af_msg(lev, args... ) \
(((lev)<AF_MSG_WARN)?(fprintf(af_msg_cfg.err?af_msg_cfg.err:stderr, ## args )): \
(((lev)<=af_msg_cfg.level)?(fprintf(af_msg_cfg.msg?af_msg_cfg.msg:stdout, ## args )):0))
#endif

#endif /* __aop_h__ */