Shift vorbisenc API docs into doxygen 2/2 (add doxygen)

Until now the libvorbisenc API has been documented via static html
pages in doc/vorbisenc/.  This patch moves that documentation into the
vorbisenc.h header.

For the most part, the text was copied unchanged, except where doxygen
was better able to say something in its own way.  For example, the
\deprecated tag changed the format of deprecation messages.  A few
trivial misspelling's were fixed, including some that doxygen caught.
Some of the narrative flow of the original was lost, as doxygen
reorders documentation according to its own plan, so I changed a few
phrases on account of this loss of context.

Some ordinary comments in the header were obviated by the doxygen and
removed.

Neither the overview documentation in overview.html nor the examples
in examples.html are included in the header, nor are the functions
that are exposed by including vorbisenc.h but which are actually
declared in codecs.h.

Patch from Douglas Bagnall <douglas@paradise.net.nz>.

svn path=/trunk/vorbis/; revision=16789

1 files changed, 316 insertions, 10 deletions

diff --git a/include/vorbis/vorbisenc.h b/include/vorbis/vorbisenc.h
index 6948a220..d04fca4f 100644
--- a/include/vorbis/vorbisenc.h
+++ b/include/vorbis/vorbisenc.h
@@ -15,6 +15,12 @@
 
  ********************************************************************/
 
+/** \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_
 
@@ -25,6 +31,32 @@ extern "C"
 
 #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,
@@ -33,6 +65,35 @@ extern int vorbis_encode_init(vorbis_info *vi,
                               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,
@@ -41,6 +102,30 @@ extern int vorbis_encode_setup_managed(vorbis_info *vi,
                                        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,
@@ -48,6 +133,28 @@ extern int vorbis_encode_setup_vbr(vorbis_info *vi,
                                   float quality /* quality level from 0. (lo) to 1. (hi) */
                                   );
 
+/**
+ * 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,
@@ -55,56 +162,255 @@ extern int vorbis_encode_init_vbr(vorbis_info *vi,
                                   float base_quality /* quality level from 0. (lo) to 1. (hi) */
                                   );
 
+/**
+ * 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;
-
+  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;
-
+  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;
+  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;
 };
 
 
-  /* new rate setup */
+/**
+ * \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
 
   /* deprecated rate management supported only for compatability */
+
+/**
+ * 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
-
-