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vorbisenc.h (16990B)

---

/********************************************************************
*                                                                  *
* THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
*                                                                  *
* THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2001             *
* by the Xiph.Org Foundation https://xiph.org/                     *
*                                                                  *
********************************************************************

function: vorbis encode-engine setup

********************************************************************/

/** \file
* Libvorbisenc is a convenient API for setting up an encoding
* environment using libvorbis. Libvorbisenc encapsulates the
* actions needed to set up the encoder properly.
*/

#ifndef _OV_ENC_H_
#define _OV_ENC_H_

#ifdef __cplusplus
extern "C"
{
#endif /* __cplusplus */

#include "codec.h"

/**
* This is the primary function within libvorbisenc for setting up managed
* bitrate modes.
*
* Before this function is called, the \ref vorbis_info
* struct should be initialized by using vorbis_info_init() from the libvorbis
* API.  After encoding, vorbis_info_clear() should be called.
*
* The max_bitrate, nominal_bitrate, and min_bitrate settings are used to set
* constraints for the encoded file.  This function uses these settings to
* select the appropriate encoding mode and set it up.
*
* \param vi               Pointer to an initialized \ref vorbis_info struct.
* \param channels         The number of channels to be encoded.
* \param rate             The sampling rate of the source audio.
* \param max_bitrate      Desired maximum bitrate (limit). -1 indicates unset.
* \param nominal_bitrate  Desired average, or central, bitrate. -1 indicates unset.
* \param min_bitrate      Desired minimum bitrate. -1 indicates unset.
*
* \return Zero for success, and negative values for failure.
*
* \retval 0          Success.
* \retval OV_EFAULT  Internal logic fault; indicates a bug or heap/stack corruption.
* \retval OV_EINVAL  Invalid setup request, eg, out of range argument.
* \retval OV_EIMPL   Unimplemented mode; unable to comply with bitrate request.
*/
extern int vorbis_encode_init(vorbis_info *vi,
                             long channels,
                             long rate,

                             long max_bitrate,
                             long nominal_bitrate,
                             long min_bitrate);

/**
* This function performs step-one of a three-step bitrate-managed encode
* setup.  It functions similarly to the one-step setup performed by \ref
* vorbis_encode_init but allows an application to make further encode setup
* tweaks using \ref vorbis_encode_ctl before finally calling \ref
* vorbis_encode_setup_init to complete the setup process.
*
* Before this function is called, the \ref vorbis_info struct should be
* initialized by using vorbis_info_init() from the libvorbis API.  After
* encoding, vorbis_info_clear() should be called.
*
* The max_bitrate, nominal_bitrate, and min_bitrate settings are used to set
* constraints for the encoded file.  This function uses these settings to
* select the appropriate encoding mode and set it up.
*
* \param vi                Pointer to an initialized vorbis_info struct.
* \param channels          The number of channels to be encoded.
* \param rate              The sampling rate of the source audio.
* \param max_bitrate       Desired maximum bitrate (limit). -1 indicates unset.
* \param nominal_bitrate   Desired average, or central, bitrate. -1 indicates unset.
* \param min_bitrate       Desired minimum bitrate. -1 indicates unset.
*
* \return Zero for success, and negative for failure.
*
* \retval 0           Success
* \retval OV_EFAULT   Internal logic fault; indicates a bug or heap/stack corruption.
* \retval OV_EINVAL   Invalid setup request, eg, out of range argument.
* \retval OV_EIMPL    Unimplemented mode; unable to comply with bitrate request.
*/
extern int vorbis_encode_setup_managed(vorbis_info *vi,
                                      long channels,
                                      long rate,

                                      long max_bitrate,
                                      long nominal_bitrate,
                                      long min_bitrate);

/**
* This function performs step-one of a three-step variable bitrate
* (quality-based) encode setup.  It functions similarly to the one-step setup
* performed by \ref vorbis_encode_init_vbr() but allows an application to
* make further encode setup tweaks using \ref vorbis_encode_ctl() before
* finally calling \ref vorbis_encode_setup_init to complete the setup
* process.
*
* Before this function is called, the \ref vorbis_info struct should be
* initialized by using \ref vorbis_info_init() from the libvorbis API.  After
* encoding, vorbis_info_clear() should be called.
*
* \param vi        Pointer to an initialized vorbis_info struct.
* \param channels  The number of channels to be encoded.
* \param rate      The sampling rate of the source audio.
* \param quality   Desired quality level, currently from -0.1 to 1.0 (lo to hi).
*
* \return Zero for success, and negative values for failure.
*
* \retval  0          Success
* \retval  OV_EFAULT  Internal logic fault; indicates a bug or heap/stack corruption.
* \retval  OV_EINVAL  Invalid setup request, eg, out of range argument.
* \retval  OV_EIMPL   Unimplemented mode; unable to comply with quality level request.
*/
extern int vorbis_encode_setup_vbr(vorbis_info *vi,
                                 long channels,
                                 long rate,

                                 float quality
                                 );

/**
* This is the primary function within libvorbisenc for setting up variable
* bitrate ("quality" based) modes.
*
*
* Before this function is called, the vorbis_info struct should be
* initialized by using vorbis_info_init() from the libvorbis API. After
* encoding, vorbis_info_clear() should be called.
*
* \param vi           Pointer to an initialized vorbis_info struct.
* \param channels     The number of channels to be encoded.
* \param rate         The sampling rate of the source audio.
* \param base_quality Desired quality level, currently from -0.1 to 1.0 (lo to hi).
*
*
* \return Zero for success, or a negative number for failure.
*
* \retval 0           Success
* \retval OV_EFAULT   Internal logic fault; indicates a bug or heap/stack corruption.
* \retval OV_EINVAL   Invalid setup request, eg, out of range argument.
* \retval OV_EIMPL    Unimplemented mode; unable to comply with quality level request.
*/
extern int vorbis_encode_init_vbr(vorbis_info *vi,
                                 long channels,
                                 long rate,

                                 float base_quality
                                 );

/**
* This function performs the last stage of three-step encoding setup, as
* described in the API overview under managed bitrate modes.
*
* Before this function is called, the \ref vorbis_info struct should be
* initialized by using vorbis_info_init() from the libvorbis API, one of
* \ref vorbis_encode_setup_managed() or \ref vorbis_encode_setup_vbr() called to
* initialize the high-level encoding setup, and \ref vorbis_encode_ctl()
* called if necessary to make encoding setup changes.
* vorbis_encode_setup_init() finalizes the highlevel encoding structure into
* a complete encoding setup after which the application may make no further
* setup changes.
*
* After encoding, vorbis_info_clear() should be called.
*
* \param vi Pointer to an initialized \ref vorbis_info struct.
*
* \return Zero for success, and negative values for failure.
*
* \retval  0           Success.
* \retval  OV_EFAULT  Internal logic fault; indicates a bug or heap/stack corruption.
*
* \retval OV_EINVAL   Attempt to use vorbis_encode_setup_init() without first
* calling one of vorbis_encode_setup_managed() or vorbis_encode_setup_vbr() to
* initialize the high-level encoding setup
*
*/
extern int vorbis_encode_setup_init(vorbis_info *vi);

/**
* This function implements a generic interface to miscellaneous encoder
* settings similar to the classic UNIX 'ioctl()' system call.  Applications
* may use vorbis_encode_ctl() to query or set bitrate management or quality
* mode details by using one of several \e request arguments detailed below.
* vorbis_encode_ctl() must be called after one of
* vorbis_encode_setup_managed() or vorbis_encode_setup_vbr().  When used
* to modify settings, \ref vorbis_encode_ctl() must be called before \ref
* vorbis_encode_setup_init().
*
* \param vi      Pointer to an initialized vorbis_info struct.
*
* \param number Specifies the desired action; See \ref encctlcodes "the list
* of available requests".
*
* \param arg void * pointing to a data structure matching the request
* argument.
*
* \retval 0          Success. Any further return information (such as the result of a
* query) is placed into the storage pointed to by *arg.
*
* \retval OV_EINVAL  Invalid argument, or an attempt to modify a setting after
* calling vorbis_encode_setup_init().
*
* \retval OV_EIMPL   Unimplemented or unknown request
*/
extern int vorbis_encode_ctl(vorbis_info *vi,int number,void *arg);

/**
* \deprecated This is a deprecated interface. Please use vorbis_encode_ctl()
* with the \ref ovectl_ratemanage2_arg struct and \ref
* OV_ECTL_RATEMANAGE2_GET and \ref OV_ECTL_RATEMANAGE2_SET calls in new code.
*
* The \ref ovectl_ratemanage_arg structure is used with vorbis_encode_ctl()
* and the \ref OV_ECTL_RATEMANAGE_GET, \ref OV_ECTL_RATEMANAGE_SET, \ref
* OV_ECTL_RATEMANAGE_AVG, \ref OV_ECTL_RATEMANAGE_HARD calls in order to
* query and modify specifics of the encoder's bitrate management
* configuration.
*/
struct ovectl_ratemanage_arg {
 int    management_active; /**< nonzero if bitrate management is active*/
/** hard lower limit (in kilobits per second) below which the stream bitrate
   will never be allowed for any given bitrate_hard_window seconds of time.*/
 long   bitrate_hard_min;
/** hard upper limit (in kilobits per second) above which the stream bitrate
   will never be allowed for any given bitrate_hard_window seconds of time.*/
 long   bitrate_hard_max;
/** the window period (in seconds) used to regulate the hard bitrate minimum
   and maximum*/
 double bitrate_hard_window;
/** soft lower limit (in kilobits per second) below which the average bitrate
   tracker will start nudging the bitrate higher.*/
 long   bitrate_av_lo;
/** soft upper limit (in kilobits per second) above which the average bitrate
   tracker will start nudging the bitrate lower.*/
 long   bitrate_av_hi;
/** the window period (in seconds) used to regulate the average bitrate
   minimum and maximum.*/
 double bitrate_av_window;
/** Regulates the relative centering of the average and hard windows; in
   libvorbis 1.0 and 1.0.1, the hard window regulation overlapped but
   followed the average window regulation. In libvorbis 1.1 a bit-reservoir
   interface replaces the old windowing interface; the older windowing
   interface is simulated and this field has no effect.*/
 double bitrate_av_window_center;
};

/**
* \name struct ovectl_ratemanage2_arg
*
* The ovectl_ratemanage2_arg structure is used with vorbis_encode_ctl() and
* the OV_ECTL_RATEMANAGE2_GET and OV_ECTL_RATEMANAGE2_SET calls in order to
* query and modify specifics of the encoder's bitrate management
* configuration.
*
*/
struct ovectl_ratemanage2_arg {
 int    management_active; /**< nonzero if bitrate management is active */
/** Lower allowed bitrate limit in kilobits per second */
 long   bitrate_limit_min_kbps;
/** Upper allowed bitrate limit in kilobits per second */
 long   bitrate_limit_max_kbps;
 long   bitrate_limit_reservoir_bits; /**<Size of the bitrate reservoir in bits */
/** Regulates the bitrate reservoir's preferred fill level in a range from 0.0
* to 1.0; 0.0 tries to bank bits to buffer against future bitrate spikes, 1.0
* buffers against future sudden drops in instantaneous bitrate. Default is
* 0.1
*/
 double bitrate_limit_reservoir_bias;
/** Average bitrate setting in kilobits per second */
 long   bitrate_average_kbps;
/** Slew rate limit setting for average bitrate adjustment; sets the minimum
*  time in seconds the bitrate tracker may swing from one extreme to the
*  other when boosting or damping average bitrate.
*/
 double bitrate_average_damping;
};


/**
* \name vorbis_encode_ctl() codes
*
* \anchor encctlcodes
*
* These values are passed as the \c number parameter of vorbis_encode_ctl().
* The type of the referent of that function's \c arg pointer depends on these
* codes.
*/
/*@{*/

/**
* Query the current encoder bitrate management setting.
*
*Argument: <tt>struct ovectl_ratemanage2_arg *</tt>
*
* Used to query the current encoder bitrate management setting. Also used to
* initialize fields of an ovectl_ratemanage2_arg structure for use with
* \ref OV_ECTL_RATEMANAGE2_SET.
*/
#define OV_ECTL_RATEMANAGE2_GET      0x14

/**
* Set the current encoder bitrate management settings.
*
* Argument: <tt>struct ovectl_ratemanage2_arg *</tt>
*
* Used to set the current encoder bitrate management settings to the values
* listed in the ovectl_ratemanage2_arg. Passing a NULL pointer will disable
* bitrate management.
*/
#define OV_ECTL_RATEMANAGE2_SET      0x15

/**
* Returns the current encoder hard-lowpass setting (kHz) in the double
* pointed to by arg.
*
* Argument: <tt>double *</tt>
*/
#define OV_ECTL_LOWPASS_GET          0x20

/**
*  Sets the encoder hard-lowpass to the value (kHz) pointed to by arg. Valid
*  lowpass settings range from 2 to 99.
*
* Argument: <tt>double *</tt>
*/
#define OV_ECTL_LOWPASS_SET          0x21

/**
*  Returns the current encoder impulse block setting in the double pointed
*  to by arg.
*
* Argument: <tt>double *</tt>
*/
#define OV_ECTL_IBLOCK_GET           0x30

/**
*  Sets the impulse block bias to the the value pointed to by arg.
*
* Argument: <tt>double *</tt>
*
*  Valid range is -15.0 to 0.0 [default]. A negative impulse block bias will
*  direct to encoder to use more bits when incoding short blocks that contain
*  strong impulses, thus improving the accuracy of impulse encoding.
*/
#define OV_ECTL_IBLOCK_SET           0x31

/**
*  Returns the current encoder coupling setting in the int pointed
*  to by arg.
*
* Argument: <tt>int *</tt>
*/
#define OV_ECTL_COUPLING_GET         0x40

/**
*  Enables/disables channel coupling in multichannel encoding according to arg.
*
* Argument: <tt>int *</tt>
*
*  Zero disables channel coupling for multichannel inputs, nonzer enables
*  channel coupling.  Setting has no effect on monophonic encoding or
*  multichannel counts that do not offer coupling.  At present, coupling is
*  available for stereo and 5.1 encoding.
*/
#define OV_ECTL_COUPLING_SET         0x41

 /* deprecated rate management supported only for compatibility */

/**
* Old interface to querying bitrate management settings.
*
* Deprecated after move to bit-reservoir style management in 1.1 rendered
* this interface partially obsolete.

* \deprecated Please use \ref OV_ECTL_RATEMANAGE2_GET instead.
*
* Argument: <tt>struct ovectl_ratemanage_arg *</tt>
*/
#define OV_ECTL_RATEMANAGE_GET       0x10
/**
* Old interface to modifying bitrate management settings.
*
*  deprecated after move to bit-reservoir style management in 1.1 rendered
*  this interface partially obsolete.
*
* \deprecated Please use \ref OV_ECTL_RATEMANAGE2_SET instead.
*
* Argument: <tt>struct ovectl_ratemanage_arg *</tt>
*/
#define OV_ECTL_RATEMANAGE_SET       0x11
/**
* Old interface to setting average-bitrate encoding mode.
*
* Deprecated after move to bit-reservoir style management in 1.1 rendered
* this interface partially obsolete.
*
*  \deprecated Please use \ref OV_ECTL_RATEMANAGE2_SET instead.
*
* Argument: <tt>struct ovectl_ratemanage_arg *</tt>
*/
#define OV_ECTL_RATEMANAGE_AVG       0x12
/**
* Old interface to setting bounded-bitrate encoding modes.
*
* deprecated after move to bit-reservoir style management in 1.1 rendered
* this interface partially obsolete.
*
*  \deprecated Please use \ref OV_ECTL_RATEMANAGE2_SET instead.
*
* Argument: <tt>struct ovectl_ratemanage_arg *</tt>
*/
#define OV_ECTL_RATEMANAGE_HARD      0x13

/*@}*/



#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif