egra: agg mini code cleanups

[iv.d.git] / clibcelt / d / libcelt.d

/* Copyright (c) 2007-2008 CSIRO
   Copyright (c) 2007-2009 Xiph.Org Foundation
   Copyright (c) 2008-2012 Gregory Maxwell
   Written by Jean-Marc Valin and Gregory Maxwell */
/*
   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   - Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.

   - Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
   OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
module iv.libcelt /*is aliced*/;
pragma(lib, "celt");
import iv.alice;
extern(C) nothrow @nogc:

/**
   @file opus_types.h
   @brief Opus reference implementation types
*/

alias opus_int16 = short;
alias opus_uint16 = ushort;
alias opus_int32 = int;
alias opus_uint32 = uint;


/**
 * @file opus_defines.h
 * @brief Opus reference implementation constants
 */

/** @defgroup opus_errorcodes Error codes
 * @{
 */
/** No error @hideinitializer*/
enum OPUS_OK = 0;
/** One or more invalid/out of range arguments @hideinitializer*/
enum OPUS_BAD_ARG = -1;
/** Not enough bytes allocated in the buffer @hideinitializer*/
enum OPUS_BUFFER_TOO_SMALL = -2;
/** An internal error was detected @hideinitializer*/
enum OPUS_INTERNAL_ERROR = -3;
/** The compressed data passed is corrupted @hideinitializer*/
enum OPUS_INVALID_PACKET = -4;
/** Invalid/unsupported request number @hideinitializer*/
enum OPUS_UNIMPLEMENTED = -5;
/** An encoder or decoder structure is invalid or already freed @hideinitializer*/
enum OPUS_INVALID_STATE = -6;
/** Memory allocation has failed @hideinitializer*/
enum OPUS_ALLOC_FAIL = -7;
/**@}*/

/** These are the actual Encoder CTL ID numbers.
  * They should not be used directly by applications.
  * In general, SETs should be even and GETs should be odd.*/
enum OPUS_SET_APPLICATION_REQUEST = 4000;
enum OPUS_GET_APPLICATION_REQUEST = 4001;
enum OPUS_SET_BITRATE_REQUEST = 4002;
enum OPUS_GET_BITRATE_REQUEST = 4003;
enum OPUS_SET_MAX_BANDWIDTH_REQUEST = 4004;
enum OPUS_GET_MAX_BANDWIDTH_REQUEST = 4005;
enum OPUS_SET_VBR_REQUEST = 4006;
enum OPUS_GET_VBR_REQUEST = 4007;
enum OPUS_SET_BANDWIDTH_REQUEST = 4008;
enum OPUS_GET_BANDWIDTH_REQUEST = 4009;
enum OPUS_SET_COMPLEXITY_REQUEST = 4010;
enum OPUS_GET_COMPLEXITY_REQUEST = 4011;
enum OPUS_SET_INBAND_FEC_REQUEST = 4012;
enum OPUS_GET_INBAND_FEC_REQUEST = 4013;
enum OPUS_SET_PACKET_LOSS_PERC_REQUEST = 4014;
enum OPUS_GET_PACKET_LOSS_PERC_REQUEST = 4015;
enum OPUS_SET_DTX_REQUEST = 4016;
enum OPUS_GET_DTX_REQUEST = 4017;
enum OPUS_SET_VBR_CONSTRAINT_REQUEST = 4020;
enum OPUS_GET_VBR_CONSTRAINT_REQUEST = 4021;
enum OPUS_SET_FORCE_CHANNELS_REQUEST = 4022;
enum OPUS_GET_FORCE_CHANNELS_REQUEST = 4023;
enum OPUS_SET_SIGNAL_REQUEST = 4024;
enum OPUS_GET_SIGNAL_REQUEST = 4025;
enum OPUS_GET_LOOKAHEAD_REQUEST = 4027;
/* enum OPUS_RESET_STATE = 4028; */
enum OPUS_GET_SAMPLE_RATE_REQUEST = 4029;
enum OPUS_GET_FINAL_RANGE_REQUEST = 4031;
enum OPUS_GET_PITCH_REQUEST = 4033;
enum OPUS_SET_GAIN_REQUEST = 4034;
enum OPUS_GET_GAIN_REQUEST = 4045; /* Should have been 4035 */
enum OPUS_SET_LSB_DEPTH_REQUEST = 4036;
enum OPUS_GET_LSB_DEPTH_REQUEST = 4037;
enum OPUS_GET_LAST_PACKET_DURATION_REQUEST = 4039;
enum OPUS_SET_EXPERT_FRAME_DURATION_REQUEST = 4040;
enum OPUS_GET_EXPERT_FRAME_DURATION_REQUEST = 4041;
enum OPUS_SET_PREDICTION_DISABLED_REQUEST = 4042;
enum OPUS_GET_PREDICTION_DISABLED_REQUEST = 4043;
/* Don't use 4045, it's already taken by OPUS_GET_GAIN_REQUEST */
enum OPUS_SET_PHASE_INVERSION_DISABLED_REQUEST = 4046;
enum OPUS_GET_PHASE_INVERSION_DISABLED_REQUEST = 4047;

/** @defgroup opus_ctlvalues Pre-defined values for CTL interface
  * @see opus_genericctls, opus_encoderctls
  * @{
  */
/* Values for the various encoder CTLs */
enum OPUS_AUTO = -1000; /**<Auto/default setting @hideinitializer*/
enum OPUS_BITRATE_MAX = -1; /**<Maximum bitrate @hideinitializer*/

/** Best for most VoIP/videoconference applications where listening quality and intelligibility matter most
 * @hideinitializer */
enum OPUS_APPLICATION_VOIP = 2048;
/** Best for broadcast/high-fidelity application where the decoded audio should be as close as possible to the input
 * @hideinitializer */
enum OPUS_APPLICATION_AUDIO = 2049;
/** Only use when lowest-achievable latency is what matters most. Voice-optimized modes cannot be used.
 * @hideinitializer */
enum OPUS_APPLICATION_RESTRICTED_LOWDELAY = 2051;

enum OPUS_SIGNAL_VOICE = 3001; /**< Signal being encoded is voice */
enum OPUS_SIGNAL_MUSIC = 3002; /**< Signal being encoded is music */
enum OPUS_BANDWIDTH_NARROWBAND = 1101; /**< 4 kHz bandpass @hideinitializer*/
enum OPUS_BANDWIDTH_MEDIUMBAND = 1102; /**< 6 kHz bandpass @hideinitializer*/
enum OPUS_BANDWIDTH_WIDEBAND = 1103; /**< 8 kHz bandpass @hideinitializer*/
enum OPUS_BANDWIDTH_SUPERWIDEBAND = 1104; /**<12 kHz bandpass @hideinitializer*/
enum OPUS_BANDWIDTH_FULLBAND = 1105; /**<20 kHz bandpass @hideinitializer*/

enum OPUS_FRAMESIZE_ARG = 5000; /**< Select frame size from the argument (default) */
enum OPUS_FRAMESIZE_2_5_MS = 5001; /**< Use 2.5 ms frames */
enum OPUS_FRAMESIZE_5_MS = 5002; /**< Use 5 ms frames */
enum OPUS_FRAMESIZE_10_MS = 5003; /**< Use 10 ms frames */
enum OPUS_FRAMESIZE_20_MS = 5004; /**< Use 20 ms frames */
enum OPUS_FRAMESIZE_40_MS = 5005; /**< Use 40 ms frames */
enum OPUS_FRAMESIZE_60_MS = 5006; /**< Use 60 ms frames */
enum OPUS_FRAMESIZE_80_MS = 5007; /**< Use 80 ms frames */
enum OPUS_FRAMESIZE_100_MS = 5008; /**< Use 100 ms frames */
enum OPUS_FRAMESIZE_120_MS = 5009; /**< Use 120 ms frames */

/**@}*/


/** @defgroup opus_encoderctls Encoder related CTLs
  *
  * These are convenience macros for use with the \c opus_encode_ctl
  * interface. They are used to generate the appropriate series of
  * arguments for that call, passing the correct type, size and so
  * on as expected for each particular request.
  *
  * Some usage examples:
  *
  * @code
  * int ret;
  * ret = opus_encoder_ctl(enc_ctx, OPUS_SET_BANDWIDTH(OPUS_AUTO));
  * if (ret != OPUS_OK) return ret;
  *
  * opus_int32 rate;
  * opus_encoder_ctl(enc_ctx, OPUS_GET_BANDWIDTH(&rate));
  *
  * opus_encoder_ctl(enc_ctx, OPUS_RESET_STATE);
  * @endcode
  *
  * @see opus_genericctls, opus_encoder
  * @{
  */

/+TODO
/** Configures the encoder's computational complexity.
  * The supported range is 0-10 inclusive with 10 representing the highest complexity.
  * @see OPUS_GET_COMPLEXITY
  * @param[in] x <tt>opus_int32</tt>: Allowed values: 0-10, inclusive.
  *
  * @hideinitializer */
#define OPUS_SET_COMPLEXITY(x) OPUS_SET_COMPLEXITY_REQUEST, __opus_check_int(x)
/** Gets the encoder's complexity configuration.
  * @see OPUS_SET_COMPLEXITY
  * @param[out] x <tt>opus_int32 *</tt>: Returns a value in the range 0-10,
  *                                      inclusive.
  * @hideinitializer */
#define OPUS_GET_COMPLEXITY(x) OPUS_GET_COMPLEXITY_REQUEST, __opus_check_int_ptr(x)

/** Configures the bitrate in the encoder.
  * Rates from 500 to 512000 bits per second are meaningful, as well as the
  * special values #OPUS_AUTO and #OPUS_BITRATE_MAX.
  * The value #OPUS_BITRATE_MAX can be used to cause the codec to use as much
  * rate as it can, which is useful for controlling the rate by adjusting the
  * output buffer size.
  * @see OPUS_GET_BITRATE
  * @param[in] x <tt>opus_int32</tt>: Bitrate in bits per second. The default
  *                                   is determined based on the number of
  *                                   channels and the input sampling rate.
  * @hideinitializer */
#define OPUS_SET_BITRATE(x) OPUS_SET_BITRATE_REQUEST, __opus_check_int(x)
/** Gets the encoder's bitrate configuration.
  * @see OPUS_SET_BITRATE
  * @param[out] x <tt>opus_int32 *</tt>: Returns the bitrate in bits per second.
  *                                      The default is determined based on the
  *                                      number of channels and the input
  *                                      sampling rate.
  * @hideinitializer */
#define OPUS_GET_BITRATE(x) OPUS_GET_BITRATE_REQUEST, __opus_check_int_ptr(x)

/** Enables or disables variable bitrate (VBR) in the encoder.
  * The configured bitrate may not be met exactly because frames must
  * be an integer number of bytes in length.
  * @see OPUS_GET_VBR
  * @see OPUS_SET_VBR_CONSTRAINT
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>0</dt><dd>Hard CBR. For LPC/hybrid modes at very low bit-rate, this can
  *               cause noticeable quality degradation.</dd>
  * <dt>1</dt><dd>VBR (default). The exact type of VBR is controlled by
  *               #OPUS_SET_VBR_CONSTRAINT.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_VBR(x) OPUS_SET_VBR_REQUEST, __opus_check_int(x)
/** Determine if variable bitrate (VBR) is enabled in the encoder.
  * @see OPUS_SET_VBR
  * @see OPUS_GET_VBR_CONSTRAINT
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>0</dt><dd>Hard CBR.</dd>
  * <dt>1</dt><dd>VBR (default). The exact type of VBR may be retrieved via
  *               #OPUS_GET_VBR_CONSTRAINT.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_VBR(x) OPUS_GET_VBR_REQUEST, __opus_check_int_ptr(x)

/** Enables or disables constrained VBR in the encoder.
  * This setting is ignored when the encoder is in CBR mode.
  * @warning Only the MDCT mode of Opus currently heeds the constraint.
  *  Speech mode ignores it completely, hybrid mode may fail to obey it
  *  if the LPC layer uses more bitrate than the constraint would have
  *  permitted.
  * @see OPUS_GET_VBR_CONSTRAINT
  * @see OPUS_SET_VBR
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>0</dt><dd>Unconstrained VBR.</dd>
  * <dt>1</dt><dd>Constrained VBR (default). This creates a maximum of one
  *               frame of buffering delay assuming a transport with a
  *               serialization speed of the nominal bitrate.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_VBR_CONSTRAINT(x) OPUS_SET_VBR_CONSTRAINT_REQUEST, __opus_check_int(x)
/** Determine if constrained VBR is enabled in the encoder.
  * @see OPUS_SET_VBR_CONSTRAINT
  * @see OPUS_GET_VBR
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>0</dt><dd>Unconstrained VBR.</dd>
  * <dt>1</dt><dd>Constrained VBR (default).</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_VBR_CONSTRAINT(x) OPUS_GET_VBR_CONSTRAINT_REQUEST, __opus_check_int_ptr(x)

/** Configures mono/stereo forcing in the encoder.
  * This can force the encoder to produce packets encoded as either mono or
  * stereo, regardless of the format of the input audio. This is useful when
  * the caller knows that the input signal is currently a mono source embedded
  * in a stereo stream.
  * @see OPUS_GET_FORCE_CHANNELS
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>#OPUS_AUTO</dt><dd>Not forced (default)</dd>
  * <dt>1</dt>         <dd>Forced mono</dd>
  * <dt>2</dt>         <dd>Forced stereo</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_FORCE_CHANNELS(x) OPUS_SET_FORCE_CHANNELS_REQUEST, __opus_check_int(x)
/** Gets the encoder's forced channel configuration.
  * @see OPUS_SET_FORCE_CHANNELS
  * @param[out] x <tt>opus_int32 *</tt>:
  * <dl>
  * <dt>#OPUS_AUTO</dt><dd>Not forced (default)</dd>
  * <dt>1</dt>         <dd>Forced mono</dd>
  * <dt>2</dt>         <dd>Forced stereo</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_FORCE_CHANNELS(x) OPUS_GET_FORCE_CHANNELS_REQUEST, __opus_check_int_ptr(x)

/** Configures the maximum bandpass that the encoder will select automatically.
  * Applications should normally use this instead of #OPUS_SET_BANDWIDTH
  * (leaving that set to the default, #OPUS_AUTO). This allows the
  * application to set an upper bound based on the type of input it is
  * providing, but still gives the encoder the freedom to reduce the bandpass
  * when the bitrate becomes too low, for better overall quality.
  * @see OPUS_GET_MAX_BANDWIDTH
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>OPUS_BANDWIDTH_NARROWBAND</dt>    <dd>4 kHz passband</dd>
  * <dt>OPUS_BANDWIDTH_MEDIUMBAND</dt>    <dd>6 kHz passband</dd>
  * <dt>OPUS_BANDWIDTH_WIDEBAND</dt>      <dd>8 kHz passband</dd>
  * <dt>OPUS_BANDWIDTH_SUPERWIDEBAND</dt><dd>12 kHz passband</dd>
  * <dt>OPUS_BANDWIDTH_FULLBAND</dt>     <dd>20 kHz passband (default)</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_MAX_BANDWIDTH(x) OPUS_SET_MAX_BANDWIDTH_REQUEST, __opus_check_int(x)

/** Gets the encoder's configured maximum allowed bandpass.
  * @see OPUS_SET_MAX_BANDWIDTH
  * @param[out] x <tt>opus_int32 *</tt>: Allowed values:
  * <dl>
  * <dt>#OPUS_BANDWIDTH_NARROWBAND</dt>    <dd>4 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_MEDIUMBAND</dt>    <dd>6 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_WIDEBAND</dt>      <dd>8 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_SUPERWIDEBAND</dt><dd>12 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_FULLBAND</dt>     <dd>20 kHz passband (default)</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_MAX_BANDWIDTH(x) OPUS_GET_MAX_BANDWIDTH_REQUEST, __opus_check_int_ptr(x)

/** Sets the encoder's bandpass to a specific value.
  * This prevents the encoder from automatically selecting the bandpass based
  * on the available bitrate. If an application knows the bandpass of the input
  * audio it is providing, it should normally use #OPUS_SET_MAX_BANDWIDTH
  * instead, which still gives the encoder the freedom to reduce the bandpass
  * when the bitrate becomes too low, for better overall quality.
  * @see OPUS_GET_BANDWIDTH
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>#OPUS_AUTO</dt>                    <dd>(default)</dd>
  * <dt>#OPUS_BANDWIDTH_NARROWBAND</dt>    <dd>4 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_MEDIUMBAND</dt>    <dd>6 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_WIDEBAND</dt>      <dd>8 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_SUPERWIDEBAND</dt><dd>12 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_FULLBAND</dt>     <dd>20 kHz passband</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_BANDWIDTH(x) OPUS_SET_BANDWIDTH_REQUEST, __opus_check_int(x)

/** Configures the type of signal being encoded.
  * This is a hint which helps the encoder's mode selection.
  * @see OPUS_GET_SIGNAL
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>#OPUS_AUTO</dt>        <dd>(default)</dd>
  * <dt>#OPUS_SIGNAL_VOICE</dt><dd>Bias thresholds towards choosing LPC or Hybrid modes.</dd>
  * <dt>#OPUS_SIGNAL_MUSIC</dt><dd>Bias thresholds towards choosing MDCT modes.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_SIGNAL(x) OPUS_SET_SIGNAL_REQUEST, __opus_check_int(x)
/** Gets the encoder's configured signal type.
  * @see OPUS_SET_SIGNAL
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>#OPUS_AUTO</dt>        <dd>(default)</dd>
  * <dt>#OPUS_SIGNAL_VOICE</dt><dd>Bias thresholds towards choosing LPC or Hybrid modes.</dd>
  * <dt>#OPUS_SIGNAL_MUSIC</dt><dd>Bias thresholds towards choosing MDCT modes.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_SIGNAL(x) OPUS_GET_SIGNAL_REQUEST, __opus_check_int_ptr(x)


/** Configures the encoder's intended application.
  * The initial value is a mandatory argument to the encoder_create function.
  * @see OPUS_GET_APPLICATION
  * @param[in] x <tt>opus_int32</tt>: Returns one of the following values:
  * <dl>
  * <dt>#OPUS_APPLICATION_VOIP</dt>
  * <dd>Process signal for improved speech intelligibility.</dd>
  * <dt>#OPUS_APPLICATION_AUDIO</dt>
  * <dd>Favor faithfulness to the original input.</dd>
  * <dt>#OPUS_APPLICATION_RESTRICTED_LOWDELAY</dt>
  * <dd>Configure the minimum possible coding delay by disabling certain modes
  * of operation.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_APPLICATION(x) OPUS_SET_APPLICATION_REQUEST, __opus_check_int(x)
/** Gets the encoder's configured application.
  * @see OPUS_SET_APPLICATION
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>#OPUS_APPLICATION_VOIP</dt>
  * <dd>Process signal for improved speech intelligibility.</dd>
  * <dt>#OPUS_APPLICATION_AUDIO</dt>
  * <dd>Favor faithfulness to the original input.</dd>
  * <dt>#OPUS_APPLICATION_RESTRICTED_LOWDELAY</dt>
  * <dd>Configure the minimum possible coding delay by disabling certain modes
  * of operation.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_APPLICATION(x) OPUS_GET_APPLICATION_REQUEST, __opus_check_int_ptr(x)

/** Gets the total samples of delay added by the entire codec.
  * This can be queried by the encoder and then the provided number of samples can be
  * skipped on from the start of the decoder's output to provide time aligned input
  * and output. From the perspective of a decoding application the real data begins this many
  * samples late.
  *
  * The decoder contribution to this delay is identical for all decoders, but the
  * encoder portion of the delay may vary from implementation to implementation,
  * version to version, or even depend on the encoder's initial configuration.
  * Applications needing delay compensation should call this CTL rather than
  * hard-coding a value.
  * @param[out] x <tt>opus_int32 *</tt>:   Number of lookahead samples
  * @hideinitializer */
#define OPUS_GET_LOOKAHEAD(x) OPUS_GET_LOOKAHEAD_REQUEST, __opus_check_int_ptr(x)

/** Configures the encoder's use of inband forward error correction (FEC).
  * @note This is only applicable to the LPC layer
  * @see OPUS_GET_INBAND_FEC
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>0</dt><dd>Disable inband FEC (default).</dd>
  * <dt>1</dt><dd>Enable inband FEC.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_INBAND_FEC(x) OPUS_SET_INBAND_FEC_REQUEST, __opus_check_int(x)
/** Gets encoder's configured use of inband forward error correction.
  * @see OPUS_SET_INBAND_FEC
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>0</dt><dd>Inband FEC disabled (default).</dd>
  * <dt>1</dt><dd>Inband FEC enabled.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_INBAND_FEC(x) OPUS_GET_INBAND_FEC_REQUEST, __opus_check_int_ptr(x)

/** Configures the encoder's expected packet loss percentage.
  * Higher values trigger progressively more loss resistant behavior in the encoder
  * at the expense of quality at a given bitrate in the absence of packet loss, but
  * greater quality under loss.
  * @see OPUS_GET_PACKET_LOSS_PERC
  * @param[in] x <tt>opus_int32</tt>:   Loss percentage in the range 0-100, inclusive (default: 0).
  * @hideinitializer */
#define OPUS_SET_PACKET_LOSS_PERC(x) OPUS_SET_PACKET_LOSS_PERC_REQUEST, __opus_check_int(x)
/** Gets the encoder's configured packet loss percentage.
  * @see OPUS_SET_PACKET_LOSS_PERC
  * @param[out] x <tt>opus_int32 *</tt>: Returns the configured loss percentage
  *                                      in the range 0-100, inclusive (default: 0).
  * @hideinitializer */
#define OPUS_GET_PACKET_LOSS_PERC(x) OPUS_GET_PACKET_LOSS_PERC_REQUEST, __opus_check_int_ptr(x)

/** Configures the encoder's use of discontinuous transmission (DTX).
  * @note This is only applicable to the LPC layer
  * @see OPUS_GET_DTX
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>0</dt><dd>Disable DTX (default).</dd>
  * <dt>1</dt><dd>Enabled DTX.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_DTX(x) OPUS_SET_DTX_REQUEST, __opus_check_int(x)
/** Gets encoder's configured use of discontinuous transmission.
  * @see OPUS_SET_DTX
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>0</dt><dd>DTX disabled (default).</dd>
  * <dt>1</dt><dd>DTX enabled.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_DTX(x) OPUS_GET_DTX_REQUEST, __opus_check_int_ptr(x)
/** Configures the depth of signal being encoded.
  *
  * This is a hint which helps the encoder identify silence and near-silence.
  * It represents the number of significant bits of linear intensity below
  * which the signal contains ignorable quantization or other noise.
  *
  * For example, OPUS_SET_LSB_DEPTH(14) would be an appropriate setting
  * for G.711 u-law input. OPUS_SET_LSB_DEPTH(16) would be appropriate
  * for 16-bit linear pcm input with opus_encode_float().
  *
  * When using opus_encode() instead of opus_encode_float(), or when libopus
  * is compiled for fixed-point, the encoder uses the minimum of the value
  * set here and the value 16.
  *
  * @see OPUS_GET_LSB_DEPTH
  * @param[in] x <tt>opus_int32</tt>: Input precision in bits, between 8 and 24
  *                                   (default: 24).
  * @hideinitializer */
#define OPUS_SET_LSB_DEPTH(x) OPUS_SET_LSB_DEPTH_REQUEST, __opus_check_int(x)
/** Gets the encoder's configured signal depth.
  * @see OPUS_SET_LSB_DEPTH
  * @param[out] x <tt>opus_int32 *</tt>: Input precision in bits, between 8 and
  *                                      24 (default: 24).
  * @hideinitializer */
#define OPUS_GET_LSB_DEPTH(x) OPUS_GET_LSB_DEPTH_REQUEST, __opus_check_int_ptr(x)

/** Configures the encoder's use of variable duration frames.
  * When variable duration is enabled, the encoder is free to use a shorter frame
  * size than the one requested in the opus_encode*() call.
  * It is then the user's responsibility
  * to verify how much audio was encoded by checking the ToC byte of the encoded
  * packet. The part of the audio that was not encoded needs to be resent to the
  * encoder for the next call. Do not use this option unless you <b>really</b>
  * know what you are doing.
  * @see OPUS_GET_EXPERT_FRAME_DURATION
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>OPUS_FRAMESIZE_ARG</dt><dd>Select frame size from the argument (default).</dd>
  * <dt>OPUS_FRAMESIZE_2_5_MS</dt><dd>Use 2.5 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_5_MS</dt><dd>Use 5 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_10_MS</dt><dd>Use 10 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_20_MS</dt><dd>Use 20 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_40_MS</dt><dd>Use 40 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_60_MS</dt><dd>Use 60 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_80_MS</dt><dd>Use 80 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_100_MS</dt><dd>Use 100 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_120_MS</dt><dd>Use 120 ms frames.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_EXPERT_FRAME_DURATION(x) OPUS_SET_EXPERT_FRAME_DURATION_REQUEST, __opus_check_int(x)
/** Gets the encoder's configured use of variable duration frames.
  * @see OPUS_SET_EXPERT_FRAME_DURATION
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>OPUS_FRAMESIZE_ARG</dt><dd>Select frame size from the argument (default).</dd>
  * <dt>OPUS_FRAMESIZE_2_5_MS</dt><dd>Use 2.5 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_5_MS</dt><dd>Use 5 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_10_MS</dt><dd>Use 10 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_20_MS</dt><dd>Use 20 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_40_MS</dt><dd>Use 40 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_60_MS</dt><dd>Use 60 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_80_MS</dt><dd>Use 80 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_100_MS</dt><dd>Use 100 ms frames.</dd>
  * <dt>OPUS_FRAMESIZE_120_MS</dt><dd>Use 120 ms frames.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_EXPERT_FRAME_DURATION(x) OPUS_GET_EXPERT_FRAME_DURATION_REQUEST, __opus_check_int_ptr(x)

/** If set to 1, disables almost all use of prediction, making frames almost
  * completely independent. This reduces quality.
  * @see OPUS_GET_PREDICTION_DISABLED
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>0</dt><dd>Enable prediction (default).</dd>
  * <dt>1</dt><dd>Disable prediction.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_PREDICTION_DISABLED(x) OPUS_SET_PREDICTION_DISABLED_REQUEST, __opus_check_int(x)
/** Gets the encoder's configured prediction status.
  * @see OPUS_SET_PREDICTION_DISABLED
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>0</dt><dd>Prediction enabled (default).</dd>
  * <dt>1</dt><dd>Prediction disabled.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_PREDICTION_DISABLED(x) OPUS_GET_PREDICTION_DISABLED_REQUEST, __opus_check_int_ptr(x)
+/
/**@}*/

/** @defgroup opus_genericctls Generic CTLs
  *
  * These macros are used with the \c opus_decoder_ctl and
  * \c opus_encoder_ctl calls to generate a particular
  * request.
  *
  * When called on an \c OpusDecoder they apply to that
  * particular decoder instance. When called on an
  * \c OpusEncoder they apply to the corresponding setting
  * on that encoder instance, if present.
  *
  * Some usage examples:
  *
  * @code
  * int ret;
  * opus_int32 pitch;
  * ret = opus_decoder_ctl(dec_ctx, OPUS_GET_PITCH(&pitch));
  * if (ret == OPUS_OK) return ret;
  *
  * opus_encoder_ctl(enc_ctx, OPUS_RESET_STATE);
  * opus_decoder_ctl(dec_ctx, OPUS_RESET_STATE);
  *
  * opus_int32 enc_bw, dec_bw;
  * opus_encoder_ctl(enc_ctx, OPUS_GET_BANDWIDTH(&enc_bw));
  * opus_decoder_ctl(dec_ctx, OPUS_GET_BANDWIDTH(&dec_bw));
  * if (enc_bw != dec_bw) {
  *   printf("packet bandwidth mismatch!\n");
  * }
  * @endcode
  *
  * @see opus_encoder, opus_decoder_ctl, opus_encoder_ctl, opus_decoderctls, opus_encoderctls
  * @{
  */

/** Resets the codec state to be equivalent to a freshly initialized state.
  * This should be called when switching streams in order to prevent
  * the back to back decoding from giving different results from
  * one at a time decoding.
  * @hideinitializer */
enum OPUS_RESET_STATE = 4028;

/+TODO
/** Gets the final state of the codec's entropy coder.
  * This is used for testing purposes,
  * The encoder and decoder state should be identical after coding a payload
  * (assuming no data corruption or software bugs)
  *
  * @param[out] x <tt>opus_uint32 *</tt>: Entropy coder state
  *
  * @hideinitializer */
#define OPUS_GET_FINAL_RANGE(x) OPUS_GET_FINAL_RANGE_REQUEST, __opus_check_uint_ptr(x)

/** Gets the encoder's configured bandpass or the decoder's last bandpass.
  * @see OPUS_SET_BANDWIDTH
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>#OPUS_AUTO</dt>                    <dd>(default)</dd>
  * <dt>#OPUS_BANDWIDTH_NARROWBAND</dt>    <dd>4 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_MEDIUMBAND</dt>    <dd>6 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_WIDEBAND</dt>      <dd>8 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_SUPERWIDEBAND</dt><dd>12 kHz passband</dd>
  * <dt>#OPUS_BANDWIDTH_FULLBAND</dt>     <dd>20 kHz passband</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_BANDWIDTH(x) OPUS_GET_BANDWIDTH_REQUEST, __opus_check_int_ptr(x)

/** Gets the sampling rate the encoder or decoder was initialized with.
  * This simply returns the <code>Fs</code> value passed to opus_encoder_init()
  * or opus_decoder_init().
  * @param[out] x <tt>opus_int32 *</tt>: Sampling rate of encoder or decoder.
  * @hideinitializer
  */
#define OPUS_GET_SAMPLE_RATE(x) OPUS_GET_SAMPLE_RATE_REQUEST, __opus_check_int_ptr(x)

/** If set to 1, disables the use of phase inversion for intensity stereo,
  * improving the quality of mono downmixes, but slightly reducing normal
  * stereo quality. Disabling phase inversion in the decoder does not comply
  * with RFC 6716, although it does not cause any interoperability issue and
  * is expected to become part of the Opus standard once RFC 6716 is updated
  * by draft-ietf-codec-opus-update.
  * @see OPUS_GET_PHASE_INVERSION_DISABLED
  * @param[in] x <tt>opus_int32</tt>: Allowed values:
  * <dl>
  * <dt>0</dt><dd>Enable phase inversion (default).</dd>
  * <dt>1</dt><dd>Disable phase inversion.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_SET_PHASE_INVERSION_DISABLED(x) OPUS_SET_PHASE_INVERSION_DISABLED_REQUEST, __opus_check_int(x)
/** Gets the encoder's configured phase inversion status.
  * @see OPUS_SET_PHASE_INVERSION_DISABLED
  * @param[out] x <tt>opus_int32 *</tt>: Returns one of the following values:
  * <dl>
  * <dt>0</dt><dd>Stereo phase inversion enabled (default).</dd>
  * <dt>1</dt><dd>Stereo phase inversion disabled.</dd>
  * </dl>
  * @hideinitializer */
#define OPUS_GET_PHASE_INVERSION_DISABLED(x) OPUS_GET_PHASE_INVERSION_DISABLED_REQUEST, __opus_check_int_ptr(x)
+/
/**@}*/

/** @defgroup opus_decoderctls Decoder related CTLs
  * @see opus_genericctls, opus_encoderctls, opus_decoder
  * @{
  */

/+TODO
/** Configures decoder gain adjustment.
  * Scales the decoded output by a factor specified in Q8 dB units.
  * This has a maximum range of -32768 to 32767 inclusive, and returns
  * OPUS_BAD_ARG otherwise. The default is zero indicating no adjustment.
  * This setting survives decoder reset.
  *
  * gain = pow(10, x/(20.0*256))
  *
  * @param[in] x <tt>opus_int32</tt>:   Amount to scale PCM signal by in Q8 dB units.
  * @hideinitializer */
#define OPUS_SET_GAIN(x) OPUS_SET_GAIN_REQUEST, __opus_check_int(x)
/** Gets the decoder's configured gain adjustment. @see OPUS_SET_GAIN
  *
  * @param[out] x <tt>opus_int32 *</tt>: Amount to scale PCM signal by in Q8 dB units.
  * @hideinitializer */
#define OPUS_GET_GAIN(x) OPUS_GET_GAIN_REQUEST, __opus_check_int_ptr(x)

/** Gets the duration (in samples) of the last packet successfully decoded or concealed.
  * @param[out] x <tt>opus_int32 *</tt>: Number of samples (at current sampling rate).
  * @hideinitializer */
#define OPUS_GET_LAST_PACKET_DURATION(x) OPUS_GET_LAST_PACKET_DURATION_REQUEST, __opus_check_int_ptr(x)

/** Gets the pitch of the last decoded frame, if available.
  * This can be used for any post-processing algorithm requiring the use of pitch,
  * e.g. time stretching/shortening. If the last frame was not voiced, or if the
  * pitch was not coded in the frame, then zero is returned.
  *
  * This CTL is only implemented for decoder instances.
  *
  * @param[out] x <tt>opus_int32 *</tt>: pitch period at 48 kHz (or 0 if not available)
  *
  * @hideinitializer */
#define OPUS_GET_PITCH(x) OPUS_GET_PITCH_REQUEST, __opus_check_int_ptr(x)
+/
/**@}*/

/** @defgroup opus_libinfo Opus library information functions
  * @{
  */

/** Converts an opus error code into a human readable string.
  *
  * @param[in] error <tt>int</tt>: Error number
  * @returns Error string
  */
const(char)* opus_strerror (int error);
const(char)[] opus_strerr (int error) {
  auto s = opus_strerror(error);
  if (s !is null) {
    uint len = 0;
    while (s[len]) ++len;
    return s[0..len];
  }
  return null;
}

/** Gets the libopus version string.
  *
  * Applications may look for the substring "-fixed" in the version string to
  * determine whether they have a fixed-point or floating-point build at
  * runtime.
  *
  * @returns Version string
  */
/**@}*/
const(char)* opus_get_version_string ();
const(char)[] opus_get_version_str () {
  auto s = opus_get_version_string();
  if (s !is null) {
    uint len = 0;
    while (s[len]) ++len;
    return s[0..len];
  }
  return null;
}


/**
  @file opus_custom.h
  @brief Opus-Custom reference implementation API
 */

enum OPUS_CUSTOM_MAX_PACKET = 1275;


/** @defgroup opus_custom Opus Custom
  * @{
  *  Opus Custom is an optional part of the Opus specification and
  * reference implementation which uses a distinct API from the regular
  * API and supports frame sizes that are not normally supported.\ Use
  * of Opus Custom is discouraged for all but very special applications
  * for which a frame size different from 2.5, 5, 10, or 20 ms is needed
  * (for either complexity or latency reasons) and where interoperability
  * is less important.
  *
  * In addition to the interoperability limitations the use of Opus custom
  * disables a substantial chunk of the codec and generally lowers the
  * quality available at a given bitrate. Normally when an application needs
  * a different frame size from the codec it should buffer to match the
  * sizes but this adds a small amount of delay which may be important
  * in some very low latency applications. Some transports (especially
  * constant rate RF transports) may also work best with frames of
  * particular durations.
  *
  * Libopus only supports custom modes if they are enabled at compile time.
  *
  * The Opus Custom API is similar to the regular API but the
  * @ref opus_encoder_create and @ref opus_decoder_create calls take
  * an additional mode parameter which is a structure produced by
  * a call to @ref opus_custom_mode_create. Both the encoder and decoder
  * must create a mode using the same sample rate (fs) and frame size
  * (frame size) so these parameters must either be signaled out of band
  * or fixed in a particular implementation.
  *
  * Similar to regular Opus the custom modes support on the fly frame size
  * switching, but the sizes available depend on the particular frame size in
  * use. For some initial frame sizes on a single on the fly size is available.
  */

/** Contains the state of an encoder. One encoder state is needed
    for each stream. It is initialized once at the beginning of the
    stream. Do *not* re-initialize the state for every frame.
   @brief Encoder state
 */
struct OpusCustomEncoder;

/** State of the decoder. One decoder state is needed for each stream.
    It is initialized once at the beginning of the stream. Do *not*
    re-initialize the state for every frame.
   @brief Decoder state
 */
struct OpusCustomDecoder;

/** The mode contains all the information necessary to create an
    encoder. Both the encoder and decoder need to be initialized
    with exactly the same mode, otherwise the output will be
    corrupted.
   @brief Mode configuration
 */
struct OpusCustomMode;

/** Creates a new mode struct. This will be passed to an encoder or
  * decoder. The mode MUST NOT BE DESTROYED until the encoders and
  * decoders that use it are destroyed as well.
  * @param [in] Fs <tt>int</tt>: Sampling rate (8000 to 96000 Hz)
  * @param [in] frame_size <tt>int</tt>: Number of samples (per channel) to encode in each
  *        packet (64 - 1024, prime factorization must contain zero or more 2s, 3s, or 5s and no other primes)
  * @param [out] error <tt>int*</tt>: Returned error code (if NULL, no error will be returned)
  * @return A newly created mode
  */
OpusCustomMode* opus_custom_mode_create(opus_int32 Fs, int frame_size, int* error);

/** Destroys a mode struct. Only call this after all encoders and
  * decoders using this mode are destroyed as well.
  * @param [in] mode <tt>OpusCustomMode*</tt>: Mode to be freed.
  */
void opus_custom_mode_destroy (OpusCustomMode* mode);


/** Gets the size of an OpusCustomEncoder structure.
  * @param [in] mode <tt>OpusCustomMode *</tt>: Mode configuration
  * @param [in] channels <tt>int</tt>: Number of channels
  * @returns size
  */
int opus_custom_encoder_get_size (const(OpusCustomMode)* mode, int channels) /*OPUS_ARG_NONNULL(1)*/;

/** Initializes a previously allocated encoder state
  * The memory pointed to by st must be the size returned by opus_custom_encoder_get_size.
  * This is intended for applications which use their own allocator instead of malloc.
  * @see opus_custom_encoder_create(),opus_custom_encoder_get_size()
  * To reset a previously initialized state use the OPUS_RESET_STATE CTL.
  * @param [in] st <tt>OpusCustomEncoder*</tt>: Encoder state
  * @param [in] mode <tt>OpusCustomMode *</tt>: Contains all the information about the characteristics of
  *  the stream (must be the same characteristics as used for the
  *  decoder)
  * @param [in] channels <tt>int</tt>: Number of channels
  * @return OPUS_OK Success or @ref opus_errorcodes
  */
int opus_custom_encoder_init (OpusCustomEncoder* st, const(OpusCustomMode)* mode, int channels) /*OPUS_ARG_NONNULL(1) OPUS_ARG_NONNULL(2)*/;


/** Creates a new encoder state. Each stream needs its own encoder
  * state (can't be shared across simultaneous streams).
  * @param [in] mode <tt>OpusCustomMode*</tt>: Contains all the information about the characteristics of
  *  the stream (must be the same characteristics as used for the
  *  decoder)
  * @param [in] channels <tt>int</tt>: Number of channels
  * @param [out] error <tt>int*</tt>: Returns an error code
  * @return Newly created encoder state.
*/
OpusCustomEncoder* opus_custom_encoder_create (const(OpusCustomMode)* mode, int channels, int* error) /*OPUS_ARG_NONNULL(1)*/;


/** Destroys a an encoder state.
  * @param[in] st <tt>OpusCustomEncoder*</tt>: State to be freed.
  */
void opus_custom_encoder_destroy (OpusCustomEncoder* st);

/** Encodes a frame of audio.
  * @param [in] st <tt>OpusCustomEncoder*</tt>: Encoder state
  * @param [in] pcm <tt>float*</tt>: PCM audio in float format, with a normal range of +/-1.0.
  *          Samples with a range beyond +/-1.0 are supported but will
  *          be clipped by decoders using the integer API and should
  *          only be used if it is known that the far end supports
  *          extended dynamic range. There must be exactly
  *          frame_size samples per channel.
  * @param [in] frame_size <tt>int</tt>: Number of samples per frame of input signal
  * @param [out] compressed <tt>char *</tt>: The compressed data is written here. This may not alias pcm and must be at least maxCompressedBytes long.
  * @param [in] maxCompressedBytes <tt>int</tt>: Maximum number of bytes to use for compressing the frame
  *          (can change from one frame to another)
  * @return Number of bytes written to "compressed".
  *       If negative, an error has occurred (see error codes). It is IMPORTANT that
  *       the length returned be somehow transmitted to the decoder. Otherwise, no
  *       decoding is possible.
  */
int opus_custom_encode_float (OpusCustomEncoder* st, const(float)* pcm, int frame_size, void* compressed, int maxCompressedBytes) /*OPUS_ARG_NONNULL(1) OPUS_ARG_NONNULL(2) OPUS_ARG_NONNULL(4)*/;

/** Encodes a frame of audio.
  * @param [in] st <tt>OpusCustomEncoder*</tt>: Encoder state
  * @param [in] pcm <tt>opus_int16*</tt>: PCM audio in signed 16-bit format (native endian).
  *          There must be exactly frame_size samples per channel.
  * @param [in] frame_size <tt>int</tt>: Number of samples per frame of input signal
  * @param [out] compressed <tt>char *</tt>: The compressed data is written here. This may not alias pcm and must be at least maxCompressedBytes long.
  * @param [in] maxCompressedBytes <tt>int</tt>: Maximum number of bytes to use for compressing the frame
  *          (can change from one frame to another)
  * @return Number of bytes written to "compressed".
  *       If negative, an error has occurred (see error codes). It is IMPORTANT that
  *       the length returned be somehow transmitted to the decoder. Otherwise, no
  *       decoding is possible.
 */
int opus_custom_encode (OpusCustomEncoder* st, const(opus_int16)* pcm, int frame_size, void* compressed, int maxCompressedBytes) /*OPUS_ARG_NONNULL(1) OPUS_ARG_NONNULL(2) OPUS_ARG_NONNULL(4)*/;

/** Perform a CTL function on an Opus custom encoder.
  *
  * Generally the request and subsequent arguments are generated
  * by a convenience macro.
  * @see opus_encoderctls
  */
int opus_custom_encoder_ctl (OpusCustomEncoder* /*OPUS_RESTRICT*/st, int request, ...) /*OPUS_ARG_NONNULL(1)*/;


/** Gets the size of an OpusCustomDecoder structure.
  * @param [in] mode <tt>OpusCustomMode *</tt>: Mode configuration
  * @param [in] channels <tt>int</tt>: Number of channels
  * @returns size
  */
int opus_custom_decoder_get_size (const(OpusCustomMode)* mode, int channels) /*OPUS_ARG_NONNULL(1)*/;

/** Initializes a previously allocated decoder state
  * The memory pointed to by st must be the size returned by opus_custom_decoder_get_size.
  * This is intended for applications which use their own allocator instead of malloc.
  * @see opus_custom_decoder_create(),opus_custom_decoder_get_size()
  * To reset a previously initialized state use the OPUS_RESET_STATE CTL.
  * @param [in] st <tt>OpusCustomDecoder*</tt>: Decoder state
  * @param [in] mode <tt>OpusCustomMode *</tt>: Contains all the information about the characteristics of
  *  the stream (must be the same characteristics as used for the
  *  encoder)
  * @param [in] channels <tt>int</tt>: Number of channels
  * @return OPUS_OK Success or @ref opus_errorcodes
  */
int opus_custom_decoder_init (OpusCustomDecoder* st, const(OpusCustomMode)* mode, int channels) /*OPUS_ARG_NONNULL(1) OPUS_ARG_NONNULL(2)*/;


/** Creates a new decoder state. Each stream needs its own decoder state (can't
  * be shared across simultaneous streams).
  * @param [in] mode <tt>OpusCustomMode</tt>: Contains all the information about the characteristics of the
  *          stream (must be the same characteristics as used for the encoder)
  * @param [in] channels <tt>int</tt>: Number of channels
  * @param [out] error <tt>int*</tt>: Returns an error code
  * @return Newly created decoder state.
  */
OpusCustomDecoder* opus_custom_decoder_create (const(OpusCustomMode)* mode, int channels, int* error) /*OPUS_ARG_NONNULL(1)*/;

/** Destroys a an decoder state.
  * @param[in] st <tt>OpusCustomDecoder*</tt>: State to be freed.
  */
void opus_custom_decoder_destroy (OpusCustomDecoder* st);

/** Decode an opus custom frame with floating point output
  * @param [in] st <tt>OpusCustomDecoder*</tt>: Decoder state
  * @param [in] data <tt>char*</tt>: Input payload. Use a NULL pointer to indicate packet loss
  * @param [in] len <tt>int</tt>: Number of bytes in payload
  * @param [out] pcm <tt>float*</tt>: Output signal (interleaved if 2 channels). length
  *  is frame_size*channels*sizeof(float)
  * @param [in] frame_size Number of samples per channel of available space in *pcm.
  * @returns Number of decoded samples or @ref opus_errorcodes
  */
int opus_custom_decode_float (OpusCustomDecoder* st, const(void)* data, int len, float* pcm, int frame_size) /*OPUS_ARG_NONNULL(1) OPUS_ARG_NONNULL(4)*/;

/** Decode an opus custom frame
  * @param [in] st <tt>OpusCustomDecoder*</tt>: Decoder state
  * @param [in] data <tt>char*</tt>: Input payload. Use a NULL pointer to indicate packet loss
  * @param [in] len <tt>int</tt>: Number of bytes in payload
  * @param [out] pcm <tt>opus_int16*</tt>: Output signal (interleaved if 2 channels). length
  *  is frame_size*channels*sizeof(opus_int16)
  * @param [in] frame_size Number of samples per channel of available space in *pcm.
  * @returns Number of decoded samples or @ref opus_errorcodes
  */
int opus_custom_decode (OpusCustomDecoder* st, const(void)* data, int len, opus_int16* pcm, int frame_size) /*OPUS_ARG_NONNULL(1) OPUS_ARG_NONNULL(4)*/;

/** Perform a CTL function on an Opus custom decoder.
  *
  * Generally the request and subsequent arguments are generated
  * by a convenience macro.
  * @see opus_genericctls
  */
int opus_custom_decoder_ctl (OpusCustomDecoder* /*OPUS_RESTRICT*/st, int request, ...) /*OPUS_ARG_NONNULL(1)*/;

/**@}*/