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#ifndef __aop_h__
#define __aop_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;
/* 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;
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;
frac_t mul; /* length multiplier: how much does this instance change
the length of the buffer. */
}af_instance_t;
/*********************************************
// Control parameters
*/
/* The control system is divided into 3 levels
mandatory calls - all filters must answer to all of these
optional calls - are optional
filter specific calls - applies only to some filters
*/
#define AF_CONTROL_MANDATORY_BASE 0
#define AF_CONTROL_OPTIONAL_BASE 100
#define AF_CONTROL_FILTER_SPECIFIC_BASE 200
// MANDATORY CALLS
/* Reinitialize filter. The optional argument contains the new
configuration in form of a af_data_t struct. If the filter does not
support the new format the struct should be changed and AF_FALSE
should be returned. If the incoming and outgoing data streams are
identical the filter can return AF_DETACH. This will remove the
filter. */
#define AF_CONTROL_REINIT 1 + AF_CONTROL_MANDATORY_BASE
// OPTIONAL CALLS
// FILTER SPECIFIC CALLS
// Set output rate in resample
#define AF_CONTROL_RESAMPLE 1 + AF_CONTROL_FILTER_SPECIFIC_BASE
// Set output format in format
#define AF_CONTROL_FORMAT 2 + AF_CONTROL_FILTER_SPECIFIC_BASE
// Set number of output channels in channels
#define AF_CONTROL_CHANNELS 3 + AF_CONTROL_FILTER_SPECIFIC_BASE
// Set delay length in delay
#define AF_CONTROL_SET_DELAY_LEN 4 + AF_CONTROL_FILTER_SPECIFIC_BASE
/*********************************************
// 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_NA -3
/*********************************************
// Command line configuration switches
*/
typedef struct af_cfg_s{
int rate;
int format;
int bps;
int force;
char** list;
}af_cfg_t;
// Export functions
/* Init read configuration and create filter list accordingly. In and
out contains the format of the current movie and the formate of the
prefered output respectively */
int af_init(af_data_t* in, af_data_t* out);
// Uninit and remove all filters
void af_uninit();
// Filter data chunk through the filters in the list
af_data_t* af_play(af_data_t* data);
/* Calculate how long the output from the filters will be given the
input length "len" */
int af_outputlen(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". */
int af_inputlen(int len);
// 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 */
int af_lencalc(frac_t mul, int len);
/* 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)\
((af->data->len < af_lencalc(af->mul,data->len))?af_resize_local_buffer(af,data):AF_OK)
#ifndef min
#define min(a,b)(((a)>(b))?(b):(a))
#endif
#ifndef max
#define max(a,b)(((a)>(b))?(a):(b))
#endif
#ifndef AUDIO_FILTER
extern af_cfg_t af_cfg;
#endif /* AUDIO_FILTER */
#endif
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