ref: 61f4c085c402af665b436f6d010d61107551d8a3
dir: /sys/src/cmd/audio/libvorbis/vorbis/vorbisenc.h/
/********************************************************************
* *
* 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