aac_fdk::AACEncoderFDK Class Reference

Encodes PCM data to the AAC format and writes the result to a stream. More...

#include <AACEncoderFDK.h>

Public Member Functions
	AACEncoderFDK ()
	Empty Constructor.
	AACEncoderFDK (AACCallbackFDK cb)
	Default constructor.
	~AACEncoderFDK ()
	Destructor.
	AACEncoderFDK (Stream &out_stream)
void	setOutput (Print &out_stream)
	Defines the output stream.
void	setDataCallback (AACCallbackFDK cb)
	Defines the callback method.
void	setBitrate (int bitrate)
	Total encoder bitrate. This parameter is mandatory and interacts with AACENC_BITRATEMODE. More...
void	setAudioObjectType (int aot)
	Audio object type. See ::AUDIO_OBJECT_TYPE in FDK_audio.h. More...
void	setAfterburner (bool afterburner)
	This parameter controls the use of the afterburner feature. The afterburner is a type of analysis by synthesis algorithm which increases the audio quality but also the required processing power. It is recommended to always activate this if additional memory consumption and processing power consumption is not a problem. If increased MHz and memory consumption are an issue then the MHz and memory cost of this optional module need to be evaluated against the improvement in audio quality on a case by case basis. More...
void	setSpectralBandReplication (int eld_sbr)
	Configure SBR independently of the chosen Audio Object Type ::AUDIO_OBJECT_TYPE. This parameter is for ELD audio object type only. More...
void	setVariableBitrateMode (int vbr)
	Bitrate mode. Configuration can be different kind of bitrate configurations: More...
void	setOutputBufferSize (int outbuf_size)
	Set the Output Buffer Size object. More...
void	setAudioInfo (AudioInfo from)
	Defines the Audio Info.
void	begin ()
	Opens the encoder - Please call setAudioInfo before.
void	begin (AudioInfo info)
	Opens the encoder More...
bool	begin (int input_channels, int input_sample_rate, int input_bits_per_sample)
	Opens the encoder More...
int32_t	write (uint8_t *in_ptr, int in_size)
	write PCM data to be converted to AAC - The size is in bytes
void	end ()
	closes the processing and release resources
UINT	getParameter (const AACENC_PARAM param)
	determines a decoder parameter
int	setParameter (AACENC_PARAM param, uint32_t value)
	sets an encoder parameter
	operator boolean ()

Protected Member Functions
bool	setup ()
	starts the processing
int	updateParams ()
	Updates all parameters with the values defined by the setter methods.
void	provideResult (uint8_t *data, size_t len)
	return the result PWM data
void	setEncoderModules (UINT encModules)
	Specify encoder modules to be supported in this encoder (0x01: AAC module,0x02: SBR module,0x04: PS module,0x10: Metadata module). E.g. (0x01|0x02|0x04|0x10) - Use 0 for all modules.
const char *	setupErrorText (int no)
	convert error code to error text

Protected Attributes
int	vbr = 0
int	bitrate = 0
int	ch = 0
int	format
int	sample_rate
int	channels =2
int	bits_per_sample
int	aot = 2
bool	afterburner = false
int	eld_sbr = 0
HANDLE_AACENCODER	handle
CHANNEL_MODE	mode
AACENC_InfoStruct	info = { 0 }
AACENC_BufDesc	in_buf = { 0 }
AACENC_BufDesc	out_buf = { 0 }
AACENC_InArgs	in_args = { 0 }
AACENC_OutArgs	out_args = { 0 }
int	in_identifier = IN_AUDIO_DATA
int	in_elem_size
int	out_identifier = OUT_BITSTREAM_DATA
int	out_elem_size =1
uint8_t *	outbuf = nullptr
int	out_size = 2048
AACENC_ERROR	err
bool	active = false
AACCallbackFDK	aacCallback =nullptr
UINT	encModules = 0x01
UINT	openEncModules = 0
int	openChannels = 0
int	sce =0
int	cpe =0
Print *	out

Detailed Description

Encodes PCM data to the AAC format and writes the result to a stream.

Member Function Documentation

begin() [1/2]

void aac_fdk::AACEncoderFDK::begin ( AudioInfo  info )

inline

Opens the encoder

Parameters

info

Returns

int

begin() [2/2]

bool aac_fdk::AACEncoderFDK::begin ( int  input_channels, int  input_sample_rate, int  input_bits_per_sample  )

inline

Opens the encoder

Parameters

input_channels
input_sample_rate
input_bits_per_sample

Returns

int 0 => ok; error with negative number

setAfterburner()

void aac_fdk::AACEncoderFDK::setAfterburner ( bool  afterburner )

inline

This parameter controls the use of the afterburner feature. The afterburner is a type of analysis by synthesis algorithm which increases the audio quality but also the required processing power. It is recommended to always activate this if additional memory consumption and processing power consumption is not a problem. If increased MHz and memory consumption are an issue then the MHz and memory cost of this optional module need to be evaluated against the improvement in audio quality on a case by case basis.

• 0: Disable afterburner (default).
• 1: Enable afterburner.

setAudioObjectType()

void aac_fdk::AACEncoderFDK::setAudioObjectType ( int  aot )

inline

Audio object type. See ::AUDIO_OBJECT_TYPE in FDK_audio.h.

• 2: MPEG-4 AAC Low Complexity.
• 5: MPEG-4 AAC Low Complexity with Spectral Band Replication (HE-AAC).
• 29: MPEG-4 AAC Low Complexity with Spectral Band Replication and Parametric Stereo (HE-AAC v2). This configuration can be used only with stereo input audio data.
• 23: MPEG-4 AAC Low-Delay.
• 39: MPEG-4 AAC Enhanced Low-Delay. Since there is no ::AUDIO_OBJECT_TYPE for ELD in combination with SBR defined, enable SBR explicitely by AACENC_SBR_MODE parameter. The ELD v2 212 configuration can be configured by AACENC_CHANNELMODE parameter.
• 129: MPEG-2 AAC Low Complexity.
• 132: MPEG-2 AAC Low Complexity with Spectral Band Replication (HE-AAC).

Please note that the MPEG-2 AOT's basically disables non-existing Perceptual Noise Substitution tool in AAC encoder and controls the MPEG_ID flag in adts header. The MPEG-2 AOT doesn't prohibit specific transport formats.

setBitrate()

void aac_fdk::AACEncoderFDK::setBitrate ( int  bitrate )

inline

Total encoder bitrate. This parameter is mandatory and interacts with AACENC_BITRATEMODE.

• CBR: Bitrate in bits/second.
• VBR: Variable bitrate. Bitrate argument will be ignored. See suppBitrates for details.

setOutputBufferSize()

void aac_fdk::AACEncoderFDK::setOutputBufferSize ( int  outbuf_size )

inline

Set the Output Buffer Size object.

Parameters

outbuf_size

setSpectralBandReplication()

void aac_fdk::AACEncoderFDK::setSpectralBandReplication ( int  eld_sbr )

inline

Configure SBR independently of the chosen Audio Object Type ::AUDIO_OBJECT_TYPE. This parameter is for ELD audio object type only.

• -1: Use ELD SBR auto configurator (default).
• 0: Disable Spectral Band Replication.
• 1: Enable Spectral Band Replication.

setVariableBitrateMode()

void aac_fdk::AACEncoderFDK::setVariableBitrateMode ( int  vbr )

inline

Bitrate mode. Configuration can be different kind of bitrate configurations:

• 0: Constant bitrate, use bitrate according to AACENC_BITRATE. (default) Within none LD/ELD ::AUDIO_OBJECT_TYPE, the CBR mode makes use of full allowed bitreservoir. In contrast, at Low-Delay ::AUDIO_OBJECT_TYPE the bitreservoir is kept very small.
• 1: Variable bitrate mode, very low bitrate.
• 2: Variable bitrate mode, low bitrate.
• 3: Variable bitrate mode, medium bitrate.
• 4: Variable bitrate mode, high bitrate.
• 5: Variable bitrate mode, very high bitrate.

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The documentation for this class was generated from the following file:

• src/AACEncoderFDK.h