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stream_encoder.h

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Jan 1, 2012
Jan 1, 2012
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/* libFLAC - Free Lossless Audio Codec library
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* Copyright (C) 2000-2009 Josh Coalson
* Copyright (C) 2011-2016 Xiph.Org Foundation
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*
* 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.
*
* - Neither the name of the Xiph.org Foundation nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* 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 FOUNDATION 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.
*/
#ifndef FLAC__STREAM_ENCODER_H
#define FLAC__STREAM_ENCODER_H
#include <stdio.h> /* for FILE */
#include "export.h"
#include "format.h"
#include "stream_decoder.h"
#ifdef __cplusplus
extern "C" {
#endif
/** \file include/FLAC/stream_encoder.h
*
* \brief
* This module contains the functions which implement the stream
* encoder.
*
* See the detailed documentation in the
* \link flac_stream_encoder stream encoder \endlink module.
*/
/** \defgroup flac_encoder FLAC/ \*_encoder.h: encoder interfaces
* \ingroup flac
*
* \brief
* This module describes the encoder layers provided by libFLAC.
*
* The stream encoder can be used to encode complete streams either to the
* client via callbacks, or directly to a file, depending on how it is
* initialized. When encoding via callbacks, the client provides a write
* callback which will be called whenever FLAC data is ready to be written.
* If the client also supplies a seek callback, the encoder will also
* automatically handle the writing back of metadata discovered while
* encoding, like stream info, seek points offsets, etc. When encoding to
* a file, the client needs only supply a filename or open \c FILE* and an
* optional progress callback for periodic notification of progress; the
* write and seek callbacks are supplied internally. For more info see the
* \link flac_stream_encoder stream encoder \endlink module.
*/
/** \defgroup flac_stream_encoder FLAC/stream_encoder.h: stream encoder interface
* \ingroup flac_encoder
*
* \brief
* This module contains the functions which implement the stream
* encoder.
*
* The stream encoder can encode to native FLAC, and optionally Ogg FLAC
* (check FLAC_API_SUPPORTS_OGG_FLAC) streams and files.
*
* The basic usage of this encoder is as follows:
* - The program creates an instance of an encoder using
* FLAC__stream_encoder_new().
* - The program overrides the default settings using
* FLAC__stream_encoder_set_*() functions. At a minimum, the following
* functions should be called:
* - FLAC__stream_encoder_set_channels()
* - FLAC__stream_encoder_set_bits_per_sample()
* - FLAC__stream_encoder_set_sample_rate()
* - FLAC__stream_encoder_set_ogg_serial_number() (if encoding to Ogg FLAC)
* - FLAC__stream_encoder_set_total_samples_estimate() (if known)
* - If the application wants to control the compression level or set its own
* metadata, then the following should also be called:
* - FLAC__stream_encoder_set_compression_level()
* - FLAC__stream_encoder_set_verify()
* - FLAC__stream_encoder_set_metadata()
* - The rest of the set functions should only be called if the client needs
* exact control over how the audio is compressed; thorough understanding
* of the FLAC format is necessary to achieve good results.
* - The program initializes the instance to validate the settings and
* prepare for encoding using
* - FLAC__stream_encoder_init_stream() or FLAC__stream_encoder_init_FILE()
* or FLAC__stream_encoder_init_file() for native FLAC
* - FLAC__stream_encoder_init_ogg_stream() or FLAC__stream_encoder_init_ogg_FILE()
* or FLAC__stream_encoder_init_ogg_file() for Ogg FLAC
* - The program calls FLAC__stream_encoder_process() or
* FLAC__stream_encoder_process_interleaved() to encode data, which
* subsequently calls the callbacks when there is encoder data ready
* to be written.
* - The program finishes the encoding with FLAC__stream_encoder_finish(),
* which causes the encoder to encode any data still in its input pipe,
* update the metadata with the final encoding statistics if output
* seeking is possible, and finally reset the encoder to the
* uninitialized state.
* - The instance may be used again or deleted with
* FLAC__stream_encoder_delete().
*
* In more detail, the stream encoder functions similarly to the
* \link flac_stream_decoder stream decoder \endlink, but has fewer
* callbacks and more options. Typically the client will create a new
* instance by calling FLAC__stream_encoder_new(), then set the necessary
* parameters with FLAC__stream_encoder_set_*(), and initialize it by
* calling one of the FLAC__stream_encoder_init_*() functions.
*
* Unlike the decoders, the stream encoder has many options that can
* affect the speed and compression ratio. When setting these parameters
* you should have some basic knowledge of the format (see the
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* <A HREF="../documentation_format_overview.html">user-level documentation</A>
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* or the <A HREF="../format.html">formal description</A>). The
* FLAC__stream_encoder_set_*() functions themselves do not validate the
* values as many are interdependent. The FLAC__stream_encoder_init_*()
* functions will do this, so make sure to pay attention to the state
* returned by FLAC__stream_encoder_init_*() to make sure that it is
* FLAC__STREAM_ENCODER_INIT_STATUS_OK. Any parameters that are not set
* before FLAC__stream_encoder_init_*() will take on the defaults from
* the constructor.
*
* There are three initialization functions for native FLAC, one for
* setting up the encoder to encode FLAC data to the client via
* callbacks, and two for encoding directly to a file.
*
* For encoding via callbacks, use FLAC__stream_encoder_init_stream().
* You must also supply a write callback which will be called anytime
* there is raw encoded data to write. If the client can seek the output
* it is best to also supply seek and tell callbacks, as this allows the
* encoder to go back after encoding is finished to write back
* information that was collected while encoding, like seek point offsets,
* frame sizes, etc.
*
* For encoding directly to a file, use FLAC__stream_encoder_init_FILE()
* or FLAC__stream_encoder_init_file(). Then you must only supply a
* filename or open \c FILE*; the encoder will handle all the callbacks
* internally. You may also supply a progress callback for periodic
* notification of the encoding progress.
*
* There are three similarly-named init functions for encoding to Ogg
* FLAC streams. Check \c FLAC_API_SUPPORTS_OGG_FLAC to find out if the
* library has been built with Ogg support.
*
* The call to FLAC__stream_encoder_init_*() currently will also immediately
* call the write callback several times, once with the \c fLaC signature,
* and once for each encoded metadata block. Note that for Ogg FLAC
* encoding you will usually get at least twice the number of callbacks than
* with native FLAC, one for the Ogg page header and one for the page body.
*
* After initializing the instance, the client may feed audio data to the
* encoder in one of two ways:
*
* - Channel separate, through FLAC__stream_encoder_process() - The client
* will pass an array of pointers to buffers, one for each channel, to
* the encoder, each of the same length. The samples need not be
* block-aligned, but each channel should have the same number of samples.
* - Channel interleaved, through
* FLAC__stream_encoder_process_interleaved() - The client will pass a single
* pointer to data that is channel-interleaved (i.e. channel0_sample0,
* channel1_sample0, ... , channelN_sample0, channel0_sample1, ...).
* Again, the samples need not be block-aligned but they must be
* sample-aligned, i.e. the first value should be channel0_sample0 and
* the last value channelN_sampleM.
*
* Note that for either process call, each sample in the buffers should be a
* signed integer, right-justified to the resolution set by
* FLAC__stream_encoder_set_bits_per_sample(). For example, if the resolution
* is 16 bits per sample, the samples should all be in the range [-32768,32767].
*
* When the client is finished encoding data, it calls
* FLAC__stream_encoder_finish(), which causes the encoder to encode any
* data still in its input pipe, and call the metadata callback with the
* final encoding statistics. Then the instance may be deleted with
* FLAC__stream_encoder_delete() or initialized again to encode another
* stream.
*
* For programs that write their own metadata, but that do not know the
* actual metadata until after encoding, it is advantageous to instruct
* the encoder to write a PADDING block of the correct size, so that
* instead of rewriting the whole stream after encoding, the program can
* just overwrite the PADDING block. If only the maximum size of the
* metadata is known, the program can write a slightly larger padding
* block, then split it after encoding.
*
* Make sure you understand how lengths are calculated. All FLAC metadata
* blocks have a 4 byte header which contains the type and length. This
* length does not include the 4 bytes of the header. See the format page
* for the specification of metadata blocks and their lengths.
*
* \note
* If you are writing the FLAC data to a file via callbacks, make sure it
* is open for update (e.g. mode "w+" for stdio streams). This is because
* after the first encoding pass, the encoder will try to seek back to the
* beginning of the stream, to the STREAMINFO block, to write some data
* there. (If using FLAC__stream_encoder_init*_file() or
* FLAC__stream_encoder_init*_FILE(), the file is managed internally.)
*
* \note
* The "set" functions may only be called when the encoder is in the
* state FLAC__STREAM_ENCODER_UNINITIALIZED, i.e. after
* FLAC__stream_encoder_new() or FLAC__stream_encoder_finish(), but
* before FLAC__stream_encoder_init_*(). If this is the case they will
* return \c true, otherwise \c false.
*
* \note
* FLAC__stream_encoder_finish() resets all settings to the constructor
* defaults.
*
* \{
*/
/** State values for a FLAC__StreamEncoder.
*
* The encoder's state can be obtained by calling FLAC__stream_encoder_get_state().
*
* If the encoder gets into any other state besides \c FLAC__STREAM_ENCODER_OK
* or \c FLAC__STREAM_ENCODER_UNINITIALIZED, it becomes invalid for encoding and
* must be deleted with FLAC__stream_encoder_delete().
*/
typedef enum {
FLAC__STREAM_ENCODER_OK = 0,
/**< The encoder is in the normal OK state and samples can be processed. */
FLAC__STREAM_ENCODER_UNINITIALIZED,
/**< The encoder is in the uninitialized state; one of the
* FLAC__stream_encoder_init_*() functions must be called before samples
* can be processed.
*/
FLAC__STREAM_ENCODER_OGG_ERROR,
/**< An error occurred in the underlying Ogg layer. */
FLAC__STREAM_ENCODER_VERIFY_DECODER_ERROR,
/**< An error occurred in the underlying verify stream decoder;
* check FLAC__stream_encoder_get_verify_decoder_state().
*/
FLAC__STREAM_ENCODER_VERIFY_MISMATCH_IN_AUDIO_DATA,
/**< The verify decoder detected a mismatch between the original
* audio signal and the decoded audio signal.
*/
FLAC__STREAM_ENCODER_CLIENT_ERROR,
/**< One of the callbacks returned a fatal error. */
FLAC__STREAM_ENCODER_IO_ERROR,
/**< An I/O error occurred while opening/reading/writing a file.
* Check \c errno.
*/
FLAC__STREAM_ENCODER_FRAMING_ERROR,
/**< An error occurred while writing the stream; usually, the
* write_callback returned an error.
*/
FLAC__STREAM_ENCODER_MEMORY_ALLOCATION_ERROR
/**< Memory allocation failed. */
} FLAC__StreamEncoderState;
/** Maps a FLAC__StreamEncoderState to a C string.
*
* Using a FLAC__StreamEncoderState as the index to this array
* will give the string equivalent. The contents should not be modified.
*/
extern FLAC_API const char * const FLAC__StreamEncoderStateString[];
/** Possible return values for the FLAC__stream_encoder_init_*() functions.
*/
typedef enum {
FLAC__STREAM_ENCODER_INIT_STATUS_OK = 0,
/**< Initialization was successful. */
FLAC__STREAM_ENCODER_INIT_STATUS_ENCODER_ERROR,
/**< General failure to set up encoder; call FLAC__stream_encoder_get_state() for cause. */
FLAC__STREAM_ENCODER_INIT_STATUS_UNSUPPORTED_CONTAINER,
/**< The library was not compiled with support for the given container
* format.
*/
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_CALLBACKS,
/**< A required callback was not supplied. */
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_NUMBER_OF_CHANNELS,
/**< The encoder has an invalid setting for number of channels. */
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_BITS_PER_SAMPLE,
/**< The encoder has an invalid setting for bits-per-sample.
* FLAC supports 4-32 bps but the reference encoder currently supports
* only up to 24 bps.
*/
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_SAMPLE_RATE,
/**< The encoder has an invalid setting for the input sample rate. */
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_BLOCK_SIZE,
/**< The encoder has an invalid setting for the block size. */
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_MAX_LPC_ORDER,
/**< The encoder has an invalid setting for the maximum LPC order. */
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_QLP_COEFF_PRECISION,
/**< The encoder has an invalid setting for the precision of the quantized linear predictor coefficients. */
FLAC__STREAM_ENCODER_INIT_STATUS_BLOCK_SIZE_TOO_SMALL_FOR_LPC_ORDER,
/**< The specified block size is less than the maximum LPC order. */
FLAC__STREAM_ENCODER_INIT_STATUS_NOT_STREAMABLE,
/**< The encoder is bound to the <A HREF="../format.html#subset">Subset</A> but other settings violate it. */
FLAC__STREAM_ENCODER_INIT_STATUS_INVALID_METADATA,
/**< The metadata input to the encoder is invalid, in one of the following ways:
* - FLAC__stream_encoder_set_metadata() was called with a null pointer but a block count > 0
* - One of the metadata blocks contains an undefined type
* - It contains an illegal CUESHEET as checked by FLAC__format_cuesheet_is_legal()
* - It contains an illegal SEEKTABLE as checked by FLAC__format_seektable_is_legal()
* - It contains more than one SEEKTABLE block or more than one VORBIS_COMMENT block
*/
FLAC__STREAM_ENCODER_INIT_STATUS_ALREADY_INITIALIZED
/**< FLAC__stream_encoder_init_*() was called when the encoder was
* already initialized, usually because
* FLAC__stream_encoder_finish() was not called.
*/
} FLAC__StreamEncoderInitStatus;
/** Maps a FLAC__StreamEncoderInitStatus to a C string.
*
* Using a FLAC__StreamEncoderInitStatus as the index to this array
* will give the string equivalent. The contents should not be modified.
*/
extern FLAC_API const char * const FLAC__StreamEncoderInitStatusString[];
/** Return values for the FLAC__StreamEncoder read callback.
*/
typedef enum {
FLAC__STREAM_ENCODER_READ_STATUS_CONTINUE,
/**< The read was OK and decoding can continue. */
FLAC__STREAM_ENCODER_READ_STATUS_END_OF_STREAM,
/**< The read was attempted at the end of the stream. */
FLAC__STREAM_ENCODER_READ_STATUS_ABORT,
/**< An unrecoverable error occurred. */
FLAC__STREAM_ENCODER_READ_STATUS_UNSUPPORTED
/**< Client does not support reading back from the output. */
} FLAC__StreamEncoderReadStatus;
/** Maps a FLAC__StreamEncoderReadStatus to a C string.
*
* Using a FLAC__StreamEncoderReadStatus as the index to this array
* will give the string equivalent. The contents should not be modified.
*/
extern FLAC_API const char * const FLAC__StreamEncoderReadStatusString[];
/** Return values for the FLAC__StreamEncoder write callback.
*/
typedef enum {
FLAC__STREAM_ENCODER_WRITE_STATUS_OK = 0,
/**< The write was OK and encoding can continue. */
FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR
/**< An unrecoverable error occurred. The encoder will return from the process call. */
} FLAC__StreamEncoderWriteStatus;
/** Maps a FLAC__StreamEncoderWriteStatus to a C string.
*
* Using a FLAC__StreamEncoderWriteStatus as the index to this array
* will give the string equivalent. The contents should not be modified.
*/
extern FLAC_API const char * const FLAC__StreamEncoderWriteStatusString[];
/** Return values for the FLAC__StreamEncoder seek callback.
*/
typedef enum {
FLAC__STREAM_ENCODER_SEEK_STATUS_OK,
/**< The seek was OK and encoding can continue. */
FLAC__STREAM_ENCODER_SEEK_STATUS_ERROR,
/**< An unrecoverable error occurred. */
FLAC__STREAM_ENCODER_SEEK_STATUS_UNSUPPORTED
/**< Client does not support seeking. */
} FLAC__StreamEncoderSeekStatus;
/** Maps a FLAC__StreamEncoderSeekStatus to a C string.
*
* Using a FLAC__StreamEncoderSeekStatus as the index to this array
* will give the string equivalent. The contents should not be modified.
*/
extern FLAC_API const char * const FLAC__StreamEncoderSeekStatusString[];
/** Return values for the FLAC__StreamEncoder tell callback.
*/
typedef enum {
FLAC__STREAM_ENCODER_TELL_STATUS_OK,
/**< The tell was OK and encoding can continue. */
FLAC__STREAM_ENCODER_TELL_STATUS_ERROR,
/**< An unrecoverable error occurred. */
FLAC__STREAM_ENCODER_TELL_STATUS_UNSUPPORTED
/**< Client does not support seeking. */
} FLAC__StreamEncoderTellStatus;
/** Maps a FLAC__StreamEncoderTellStatus to a C string.
*
* Using a FLAC__StreamEncoderTellStatus as the index to this array
* will give the string equivalent. The contents should not be modified.
*/
extern FLAC_API const char * const FLAC__StreamEncoderTellStatusString[];
/***********************************************************************
*
* class FLAC__StreamEncoder
*
***********************************************************************/
struct FLAC__StreamEncoderProtected;
struct FLAC__StreamEncoderPrivate;
/** The opaque structure definition for the stream encoder type.
* See the \link flac_stream_encoder stream encoder module \endlink
* for a detailed description.
*/
typedef struct {
struct FLAC__StreamEncoderProtected *protected_; /* avoid the C++ keyword 'protected' */
struct FLAC__StreamEncoderPrivate *private_; /* avoid the C++ keyword 'private' */
} FLAC__StreamEncoder;
/** Signature for the read callback.
*
* A function pointer matching this signature must be passed to
* FLAC__stream_encoder_init_ogg_stream() if seeking is supported.
* The supplied function will be called when the encoder needs to read back
* encoded data. This happens during the metadata callback, when the encoder
* has to read, modify, and rewrite the metadata (e.g. seekpoints) gathered
* while encoding. The address of the buffer to be filled is supplied, along
* with the number of bytes the buffer can hold. The callback may choose to
* supply less data and modify the byte count but must be careful not to
* overflow the buffer. The callback then returns a status code chosen from
* FLAC__StreamEncoderReadStatus.
*
* Here is an example of a read callback for stdio streams:
* \code
* FLAC__StreamEncoderReadStatus read_cb(const FLAC__StreamEncoder *encoder, FLAC__byte buffer[], size_t *bytes, void *client_data)
* {
* FILE *file = ((MyClientData*)client_data)->file;
* if(*bytes > 0) {
* *bytes = fread(buffer, sizeof(FLAC__byte), *bytes, file);
* if(ferror(file))
* return FLAC__STREAM_ENCODER_READ_STATUS_ABORT;
* else if(*bytes == 0)
* return FLAC__STREAM_ENCODER_READ_STATUS_END_OF_STREAM;
* else
* return FLAC__STREAM_ENCODER_READ_STATUS_CONTINUE;
* }
* else
* return FLAC__STREAM_ENCODER_READ_STATUS_ABORT;
* }
* \endcode
*
* \note In general, FLAC__StreamEncoder functions which change the
* state should not be called on the \a encoder while in the callback.
*
* \param encoder The encoder instance calling the callback.
* \param buffer A pointer to a location for the callee to store
* data to be encoded.
* \param bytes A pointer to the size of the buffer. On entry
* to the callback, it contains the maximum number
* of bytes that may be stored in \a buffer. The
* callee must set it to the actual number of bytes
* stored (0 in case of error or end-of-stream) before
* returning.
* \param client_data The callee's client data set through
* FLAC__stream_encoder_set_client_data().
* \retval FLAC__StreamEncoderReadStatus
* The callee's return status.
*/
typedef FLAC__StreamEncoderReadStatus (*FLAC__StreamEncoderReadCallback)(const FLAC__StreamEncoder *encoder, FLAC__byte buffer[], size_t *bytes, void *client_data);
/** Signature for the write callback.
*
* A function pointer matching this signature must be passed to
* FLAC__stream_encoder_init*_stream(). The supplied function will be called
* by the encoder anytime there is raw encoded data ready to write. It may
* include metadata mixed with encoded audio frames and the data is not
* guaranteed to be aligned on frame or metadata block boundaries.
*
* The only duty of the callback is to write out the \a bytes worth of data
* in \a buffer to the current position in the output stream. The arguments
* \a samples and \a current_frame are purely informational. If \a samples
* is greater than \c 0, then \a current_frame will hold the current frame
* number that is being written; otherwise it indicates that the write
* callback is being called to write metadata.
*
* \note
* Unlike when writing to native FLAC, when writing to Ogg FLAC the
* write callback will be called twice when writing each audio
* frame; once for the page header, and once for the page body.
* When writing the page header, the \a samples argument to the
* write callback will be \c 0.
*
* \note In general, FLAC__StreamEncoder functions which change the
* state should not be called on the \a encoder while in the callback.
*
* \param encoder The encoder instance calling the callback.
* \param buffer An array of encoded data of length \a bytes.
* \param bytes The byte length of \a buffer.
* \param samples The number of samples encoded by \a buffer.
* \c 0 has a special meaning; see above.
* \param current_frame The number of the current frame being encoded.
* \param client_data The callee's client data set through
* FLAC__stream_encoder_init_*().
* \retval FLAC__StreamEncoderWriteStatus
* The callee's return status.
*/
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typedef FLAC__StreamEncoderWriteStatus (*FLAC__StreamEncoderWriteCallback)(const FLAC__StreamEncoder *encoder, const FLAC__byte buffer[], size_t bytes, uint32_t samples, uint32_t current_frame, void *client_data);
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/** Signature for the seek callback.
*
* A function pointer matching this signature may be passed to
* FLAC__stream_encoder_init*_stream(). The supplied function will be called
* when the encoder needs to seek the output stream. The encoder will pass
* the absolute byte offset to seek to, 0 meaning the beginning of the stream.
*
* Here is an example of a seek callback for stdio streams:
* \code
* FLAC__StreamEncoderSeekStatus seek_cb(const FLAC__StreamEncoder *encoder, FLAC__uint64 absolute_byte_offset, void *client_data)
* {
* FILE *file = ((MyClientData*)client_data)->file;
* if(file == stdin)
* return FLAC__STREAM_ENCODER_SEEK_STATUS_UNSUPPORTED;
* else if(fseeko(file, (off_t)absolute_byte_offset, SEEK_SET) < 0)
* return FLAC__STREAM_ENCODER_SEEK_STATUS_ERROR;
* else
* return FLAC__STREAM_ENCODER_SEEK_STATUS_OK;
* }
* \endcode
*
* \note In general, FLAC__StreamEncoder functions which change the
* state should not be called on the \a encoder while in the callback.
*
* \param encoder The encoder instance calling the callback.
* \param absolute_byte_offset The offset from the beginning of the stream
* to seek to.
* \param client_data The callee's client data set through
* FLAC__stream_encoder_init_*().
* \retval FLAC__StreamEncoderSeekStatus
* The callee's return status.
*/
typedef FLAC__StreamEncoderSeekStatus (*FLAC__StreamEncoderSeekCallback)(const FLAC__StreamEncoder *encoder, FLAC__uint64 absolute_byte_offset, void *client_data);
/** Signature for the tell callback.
*
* A function pointer matching this signature may be passed to
* FLAC__stream_encoder_init*_stream(). The supplied function will be called
* when the encoder needs to know the current position of the output stream.
*
* \warning
* The callback must return the true current byte offset of the output to
* which the encoder is writing. If you are buffering the output, make
* sure and take this into account. If you are writing directly to a
* FILE* from your write callback, ftell() is sufficient. If you are
* writing directly to a file descriptor from your write callback, you
* can use lseek(fd, SEEK_CUR, 0). The encoder may later seek back to
* these points to rewrite metadata after encoding.
*
* Here is an example of a tell callback for stdio streams:
* \code
* FLAC__StreamEncoderTellStatus tell_cb(const FLAC__StreamEncoder *encoder, FLAC__uint64 *absolute_byte_offset, void *client_data)
* {
* FILE *file = ((MyClientData*)client_data)->file;
* off_t pos;
* if(file == stdin)
* return FLAC__STREAM_ENCODER_TELL_STATUS_UNSUPPORTED;
* else if((pos = ftello(file)) < 0)
* return FLAC__STREAM_ENCODER_TELL_STATUS_ERROR;
* else {
* *absolute_byte_offset = (FLAC__uint64)pos;
* return FLAC__STREAM_ENCODER_TELL_STATUS_OK;
* }
* }
* \endcode
*
* \note In general, FLAC__StreamEncoder functions which change the
* state should not be called on the \a encoder while in the callback.
*
* \param encoder The encoder instance calling the callback.
* \param absolute_byte_offset The address at which to store the current
* position of the output.
* \param client_data The callee's client data set through
* FLAC__stream_encoder_init_*().
* \retval FLAC__StreamEncoderTellStatus
* The callee's return status.
*/
typedef FLAC__StreamEncoderTellStatus (*FLAC__StreamEncoderTellCallback)(const FLAC__StreamEncoder *encoder, FLAC__uint64 *absolute_byte_offset, void *client_data);
/** Signature for the metadata callback.
*
* A function pointer matching this signature may be passed to
* FLAC__stream_encoder_init*_stream(). The supplied function will be called
* once at the end of encoding with the populated STREAMINFO structure. This
* is so the client can seek back to the beginning of the file and write the
* STREAMINFO block with the correct statistics after encoding (like
* minimum/maximum frame size and total samples).
*
* \note In general, FLAC__StreamEncoder functions which change the
* state should not be called on the \a encoder while in the callback.
*
* \param encoder The encoder instance calling the callback.
* \param metadata The final populated STREAMINFO block.
* \param client_data The callee's client data set through
* FLAC__stream_encoder_init_*().
*/
typedef void (*FLAC__StreamEncoderMetadataCallback)(const FLAC__StreamEncoder *encoder, const FLAC__StreamMetadata *metadata, void *client_data);
/** Signature for the progress callback.
*
* A function pointer matching this signature may be passed to
* FLAC__stream_encoder_init*_file() or FLAC__stream_encoder_init*_FILE().
* The supplied function will be called when the encoder has finished
* writing a frame. The \c total_frames_estimate argument to the
* callback will be based on the value from
* FLAC__stream_encoder_set_total_samples_estimate().
*
* \note In general, FLAC__StreamEncoder functions which change the
* state should not be called on the \a encoder while in the callback.
*
* \param encoder The encoder instance calling the callback.
* \param bytes_written Bytes written so far.
* \param samples_written Samples written so far.
* \param frames_written Frames written so far.
* \param total_frames_estimate The estimate of the total number of
* frames to be written.
* \param client_data The callee's client data set through
* FLAC__stream_encoder_init_*().
*/
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typedef void (*FLAC__StreamEncoderProgressCallback)(const FLAC__StreamEncoder *encoder, FLAC__uint64 bytes_written, FLAC__uint64 samples_written, uint32_t frames_written, uint32_t total_frames_estimate, void *client_data);
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/***********************************************************************
*
* Class constructor/destructor
*
***********************************************************************/
/** Create a new stream encoder instance. The instance is created with
* default settings; see the individual FLAC__stream_encoder_set_*()
* functions for each setting's default.
*
* \retval FLAC__StreamEncoder*
* \c NULL if there was an error allocating memory, else the new instance.
*/
FLAC_API FLAC__StreamEncoder *FLAC__stream_encoder_new(void);
/** Free an encoder instance. Deletes the object pointed to by \a encoder.
*
* \param encoder A pointer to an existing encoder.
* \assert
* \code encoder != NULL \endcode
*/
FLAC_API void FLAC__stream_encoder_delete(FLAC__StreamEncoder *encoder);
/***********************************************************************
*
* Public class method prototypes
*
***********************************************************************/
/** Set the serial number for the FLAC stream to use in the Ogg container.
*
* \note
* This does not need to be set for native FLAC encoding.
*
* \note
* It is recommended to set a serial number explicitly as the default of '0'
* may collide with other streams.
*
* \default \c 0
* \param encoder An encoder instance to set.
* \param serial_number See above.
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
FLAC_API FLAC__bool FLAC__stream_encoder_set_ogg_serial_number(FLAC__StreamEncoder *encoder, long serial_number);
/** Set the "verify" flag. If \c true, the encoder will verify it's own
* encoded output by feeding it through an internal decoder and comparing
* the original signal against the decoded signal. If a mismatch occurs,
* the process call will return \c false. Note that this will slow the
* encoding process by the extra time required for decoding and comparison.
*
* \default \c false
* \param encoder An encoder instance to set.
* \param value Flag value (see above).
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
FLAC_API FLAC__bool FLAC__stream_encoder_set_verify(FLAC__StreamEncoder *encoder, FLAC__bool value);
/** Set the <A HREF="../format.html#subset">Subset</A> flag. If \c true,
* the encoder will comply with the Subset and will check the
* settings during FLAC__stream_encoder_init_*() to see if all settings
* comply. If \c false, the settings may take advantage of the full
* range that the format allows.
*
* Make sure you know what it entails before setting this to \c false.
*
* \default \c true
* \param encoder An encoder instance to set.
* \param value Flag value (see above).
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
FLAC_API FLAC__bool FLAC__stream_encoder_set_streamable_subset(FLAC__StreamEncoder *encoder, FLAC__bool value);
/** Set the number of channels to be encoded.
*
* \default \c 2
* \param encoder An encoder instance to set.
* \param value See above.
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
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FLAC_API FLAC__bool FLAC__stream_encoder_set_channels(FLAC__StreamEncoder *encoder, uint32_t value);
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/** Set the sample resolution of the input to be encoded.
*
* \warning
* Do not feed the encoder data that is wider than the value you
* set here or you will generate an invalid stream.
*
* \default \c 16
* \param encoder An encoder instance to set.
* \param value See above.
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
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FLAC_API FLAC__bool FLAC__stream_encoder_set_bits_per_sample(FLAC__StreamEncoder *encoder, uint32_t value);
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/** Set the sample rate (in Hz) of the input to be encoded.
*
* \default \c 44100
* \param encoder An encoder instance to set.
* \param value See above.
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
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FLAC_API FLAC__bool FLAC__stream_encoder_set_sample_rate(FLAC__StreamEncoder *encoder, uint32_t value);
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/** Set the compression level
*
* The compression level is roughly proportional to the amount of effort
* the encoder expends to compress the file. A higher level usually
* means more computation but higher compression. The default level is
* suitable for most applications.
*
* Currently the levels range from \c 0 (fastest, least compression) to
* \c 8 (slowest, most compression). A value larger than \c 8 will be
* treated as \c 8.
*
* This function automatically calls the following other \c _set_
* functions with appropriate values, so the client does not need to
* unless it specifically wants to override them:
* - FLAC__stream_encoder_set_do_mid_side_stereo()
* - FLAC__stream_encoder_set_loose_mid_side_stereo()
* - FLAC__stream_encoder_set_apodization()
* - FLAC__stream_encoder_set_max_lpc_order()
* - FLAC__stream_encoder_set_qlp_coeff_precision()
* - FLAC__stream_encoder_set_do_qlp_coeff_prec_search()
* - FLAC__stream_encoder_set_do_escape_coding()
* - FLAC__stream_encoder_set_do_exhaustive_model_search()
* - FLAC__stream_encoder_set_min_residual_partition_order()
* - FLAC__stream_encoder_set_max_residual_partition_order()
* - FLAC__stream_encoder_set_rice_parameter_search_dist()
*
* The actual values set for each level are:
* <table>
* <tr>
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* <td><b>level</b></td>
* <td>do mid-side stereo</td>
* <td>loose mid-side stereo</td>
* <td>apodization</td>
* <td>max lpc order</td>
* <td>qlp coeff precision</td>
* <td>qlp coeff prec search</td>
* <td>escape coding</td>
* <td>exhaustive model search</td>
* <td>min residual partition order</td>
* <td>max residual partition order</td>
* <td>rice parameter search dist</td>
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* </tr>
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* <tr> <td><b>0</b></td> <td>false</td> <td>false</td> <td>tukey(0.5)<td> <td>0</td> <td>0</td> <td>false</td> <td>false</td> <td>false</td> <td>0</td> <td>3</td> <td>0</td> </tr>
* <tr> <td><b>1</b></td> <td>true</td> <td>true</td> <td>tukey(0.5)<td> <td>0</td> <td>0</td> <td>false</td> <td>false</td> <td>false</td> <td>0</td> <td>3</td> <td>0</td> </tr>
* <tr> <td><b>2</b></td> <td>true</td> <td>false</td> <td>tukey(0.5)<td> <td>0</td> <td>0</td> <td>false</td> <td>false</td> <td>false</td> <td>0</td> <td>3</td> <td>0</td> </tr>
* <tr> <td><b>3</b></td> <td>false</td> <td>false</td> <td>tukey(0.5)<td> <td>6</td> <td>0</td> <td>false</td> <td>false</td> <td>false</td> <td>0</td> <td>4</td> <td>0</td> </tr>
* <tr> <td><b>4</b></td> <td>true</td> <td>true</td> <td>tukey(0.5)<td> <td>8</td> <td>0</td> <td>false</td> <td>false</td> <td>false</td> <td>0</td> <td>4</td> <td>0</td> </tr>
* <tr> <td><b>5</b></td> <td>true</td> <td>false</td> <td>tukey(0.5)<td> <td>8</td> <td>0</td> <td>false</td> <td>false</td> <td>false</td> <td>0</td> <td>5</td> <td>0</td> </tr>
* <tr> <td><b>6</b></td> <td>true</td> <td>false</td> <td>tukey(0.5);partial_tukey(2)<td> <td>8</td> <td>0</td> <td>false</td> <td>false</td> <td>false</td> <td>0</td> <td>6</td> <td>0</td> </tr>
* <tr> <td><b>7</b></td> <td>true</td> <td>false</td> <td>tukey(0.5);partial_tukey(2)<td> <td>12</td> <td>0</td> <td>false</td> <td>false</td> <td>false</td> <td>0</td> <td>6</td> <td>0</td> </tr>
* <tr> <td><b>8</b></td> <td>true</td> <td>false</td> <td>tukey(0.5);partial_tukey(2);punchout_tukey(3)</td> <td>12</td> <td>0</td> <td>false</td> <td>false</td> <td>false</td> <td>0</td> <td>6</td> <td>0</td> </tr>
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* </table>
*
* \default \c 5
* \param encoder An encoder instance to set.
* \param value See above.
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
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FLAC_API FLAC__bool FLAC__stream_encoder_set_compression_level(FLAC__StreamEncoder *encoder, uint32_t value);
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/** Set the blocksize to use while encoding.
*
* The number of samples to use per frame. Use \c 0 to let the encoder
* estimate a blocksize; this is usually best.
*
* \default \c 0
* \param encoder An encoder instance to set.
* \param value See above.
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
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FLAC_API FLAC__bool FLAC__stream_encoder_set_blocksize(FLAC__StreamEncoder *encoder, uint32_t value);
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/** Set to \c true to enable mid-side encoding on stereo input. The
* number of channels must be 2 for this to have any effect. Set to
* \c false to use only independent channel coding.
*
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* \default \c true
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* \param encoder An encoder instance to set.
* \param value Flag value (see above).
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
FLAC_API FLAC__bool FLAC__stream_encoder_set_do_mid_side_stereo(FLAC__StreamEncoder *encoder, FLAC__bool value);
/** Set to \c true to enable adaptive switching between mid-side and
* left-right encoding on stereo input. Set to \c false to use
* exhaustive searching. Setting this to \c true requires
* FLAC__stream_encoder_set_do_mid_side_stereo() to also be set to
* \c true in order to have any effect.
*
* \default \c false
* \param encoder An encoder instance to set.
* \param value Flag value (see above).
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
FLAC_API FLAC__bool FLAC__stream_encoder_set_loose_mid_side_stereo(FLAC__StreamEncoder *encoder, FLAC__bool value);
/** Sets the apodization function(s) the encoder will use when windowing
* audio data for LPC analysis.
*
* The \a specification is a plain ASCII string which specifies exactly
* which functions to use. There may be more than one (up to 32),
* separated by \c ';' characters. Some functions take one or more
* comma-separated arguments in parentheses.
*
* The available functions are \c bartlett, \c bartlett_hann,
* \c blackman, \c blackman_harris_4term_92db, \c connes, \c flattop,
* \c gauss(STDDEV), \c hamming, \c hann, \c kaiser_bessel, \c nuttall,
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* \c rectangle, \c triangle, \c tukey(P), \c partial_tukey(n[/ov[/P]]),
* \c punchout_tukey(n[/ov[/P]]), \c welch.
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*
* For \c gauss(STDDEV), STDDEV specifies the standard deviation
* (0<STDDEV<=0.5).
*
* For \c tukey(P), P specifies the fraction of the window that is
* tapered (0<=P<=1). P=0 corresponds to \c rectangle and P=1
* corresponds to \c hann.
*
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* Specifying \c partial_tukey or \c punchout_tukey works a little
* different. These do not specify a single apodization function, but
* a series of them with some overlap. partial_tukey specifies a series
* of small windows (all treated separately) while punchout_tukey
* specifies a series of windows that have a hole in them. In this way,
* the predictor is constructed with only a part of the block, which
* helps in case a block consists of dissimilar parts.
*
* The three parameters that can be specified for the functions are
* n, ov and P. n is the number of functions to add, ov is the overlap
* of the windows in case of partial_tukey and the overlap in the gaps
* in case of punchout_tukey. P is the fraction of the window that is
* tapered, like with a regular tukey window. The function can be
* specified with only a number, a number and an overlap, or a number
* an overlap and a P, for example, partial_tukey(3), partial_tukey(3/0.3)
* and partial_tukey(3/0.3/0.5) are all valid. ov should be smaller than 1
* and can be negative.
*
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* Example specifications are \c "blackman" or
* \c "hann;triangle;tukey(0.5);tukey(0.25);tukey(0.125)"
*
* Any function that is specified erroneously is silently dropped. Up
* to 32 functions are kept, the rest are dropped. If the specification
* is empty the encoder defaults to \c "tukey(0.5)".
*
* When more than one function is specified, then for every subframe the
* encoder will try each of them separately and choose the window that
* results in the smallest compressed subframe.
*
* Note that each function specified causes the encoder to occupy a
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* floating point array in which to store the window. Also note that the
* values of P, STDDEV and ov are locale-specific, so if the comma
* separator specified by the locale is a comma, a comma should be used.
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*
* \default \c "tukey(0.5)"
* \param encoder An encoder instance to set.
* \param specification See above.
* \assert
* \code encoder != NULL \endcode
* \code specification != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
FLAC_API FLAC__bool FLAC__stream_encoder_set_apodization(FLAC__StreamEncoder *encoder, const char *specification);
/** Set the maximum LPC order, or \c 0 to use only the fixed predictors.
*
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* \default \c 8
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* \param encoder An encoder instance to set.
* \param value See above.
* \assert
* \code encoder != NULL \endcode
* \retval FLAC__bool
* \c false if the encoder is already initialized, else \c true.
*/
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FLAC_API FLAC__bool FLAC__stream_encoder_set_max_lpc_order(FLAC__StreamEncoder *encoder, uint32_t value);
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/** Set the precision, in bits, of the quantized linear predictor
* coefficients, or \c 0 to let the encoder select it based on the
* blocksize.
*
* \note
* In the current implementation, qlp_coeff_precision + bits_per_sample must
* be less than 32.
*
* \default \c 0
* \param encoder An encoder instance to set.
* \param value See above.