audio module, including audio record and playback, audio encoding and decoding, volume and gain setting, (audio) echo cancellation, automatic gain function and so on More...

Collaboration diagram for IMP_Audio:

Data Structures
struct	IMPAudioIOAttr
	Audio input and output device attribute. More...

struct	IMPAudioFrame
	Audio frame structure. More...

struct	IMPAudioIChnParam
	Audio channel parameter structure. More...

struct	IMPAudioOChnState
	Data cache state structure of audio output channel. More...

struct	IMPAudioStream
	Define audio stream structure. More...

struct	IMPAudioEncChnAttr
	Define audio encoding channel attribute structure. More...

struct	IMPAudioEncEncoder
	Define the encoder attribute structure. More...

struct	IMPAudioDecChnAttr
	Define the decoded channel attribute structure. More...

struct	IMPAudioDecDecoder
	Define decoder attribute structure. More...

struct	IMPAudioAgcConfig
	Define AGC gain structure. More...

Macros
#define	MAX_AUDIO_FRAME_NUM 50
	Maximum number of audio frames.

Enumerations
enum	IMPBlock { BLOCK = 0, NOBLOCK = 1 }
	Audio stream blocking type. More...

enum	IMPAudioSampleRate { AUDIO_SAMPLE_RATE_8000 = 8000, AUDIO_SAMPLE_RATE_16000 = 16000, AUDIO_SAMPLE_RATE_24000 = 24000, AUDIO_SAMPLE_RATE_44100 = 44100, AUDIO_SAMPLE_RATE_48000 = 48000, AUDIO_SAMPLE_RATE_96000 = 96000 }
	Audio sampling rate definition. More...

enum	IMPAudioBitWidth { AUDIO_BIT_WIDTH_16 = 16 }
	Audio sampling precision definition. More...

enum	IMPAudioSoundMode { AUDIO_SOUND_MODE_MONO = 1, AUDIO_SOUND_MODE_STEREO = 2 }
	Audio channel mode definition. More...

enum	IMPAudioPalyloadType { PT_PCM = 0, PT_G711A = 1, PT_G711U = 2, PT_G726 = 3, PT_AEC = 4, PT_ADPCM = 5, PT_MAX = 6 }
	Define audio payload type enumeration.

enum	IMPAudioDecMode { ADEC_MODE_PACK = 0, ADEC_MODE_STREAM = 1 }
	Define the decoding method. More...

enum	Level_ns { NS_LOW, NS_MODERATE, NS_HIGH, NS_VERYHIGH }
	Defines level of noise suppression. More...

Functions
int	IMP_AI_SetPubAttr (int audioDevId, IMPAudioIOAttr *attr)
	Set audio input device attribute. More...

int	IMP_AI_GetPubAttr (int audioDevId, IMPAudioIOAttr *attr)
	Get the attribute of the audio input device. More...

int	IMP_AI_Enable (int audioDevId)
	Enable audio input device. More...

int	IMP_AI_Disable (int audioDevId)
	Disable audio input device. More...

int	IMP_AI_EnableChn (int audioDevId, int aiChn)
	Enable audio input channel. More...

int	IMP_AI_DisableChn (int audioDevId, int aiChn)
	Disable audio input channel. More...

int	IMP_AI_PollingFrame (int audioDevId, int aiChn, unsigned int timeout_ms)
	Polling audio stream cache. More...

int	IMP_AI_GetFrame (int audioDevId, int aiChn, IMPAudioFrame *frm, IMPBlock block)
	Get audio frame. More...

int	IMP_AI_ReleaseFrame (int audioDevId, int aiChn, IMPAudioFrame *frm)
	Release audio frame. More...

int	IMP_AI_SetChnParam (int audioDevId, int aiChn, IMPAudioIChnParam *chnParam)
	Set audio input channel parameters. More...

int	IMP_AI_GetChnParam (int audioDevId, int aiChn, IMPAudioIChnParam *chnParam)
	Set audio input channel parameters. More...

int	IMP_AI_EnableAec (int aiDevId, int aiChn, int aoDevId, int aoChn)
	Enable audio echo cancellation feature of the specified audio input and audio output. More...

int	IMP_AI_DisableAec (int aiDevId, int aiChn)
	Disable audio echo cancellation feature. More...

int	IMP_AI_EnableNs (IMPAudioIOAttr *attr, int mode)
	Enable specified audio input noise suppression. More...

int	IMP_AI_DisableNs (void)
	Disable noise suppression. More...

int	IMP_AI_EnableAgc (IMPAudioIOAttr *attr, IMPAudioAgcConfig agcConfig)
	Enable automatic gain of audio input. More...

int	IMP_AI_DisableAgc (void)
	Disable AI automatic gain feature. More...

int	IMP_AO_EnableAgc (IMPAudioIOAttr *attr, IMPAudioAgcConfig agcConfig)
	Enable audio output automatic gain feature. More...

int	IMP_AO_DisableAgc (void)
	Disable AO automatic gain feature. More...

int	IMP_AI_EnableHpf (IMPAudioIOAttr *attr)
	Enable audio input for high pass filtering. More...

int	IMP_AI_DisableHpf (void)
	Disable AI high pass filtering function. More...

int	IMP_AO_EnableHpf (IMPAudioIOAttr *attr)
	Enable audio output for high pass filtering. More...

int	IMP_AO_DisableHpf (void)
	Disable AO high pass filtering function. More...

int	IMP_AO_SetPubAttr (int audioDevId, IMPAudioIOAttr *attr)
	Set audio input and output device attribute. More...

int	IMP_AO_GetPubAttr (int audioDevId, IMPAudioIOAttr *attr)
	Get audio input and output device attribute. More...

int	IMP_AO_Enable (int audioDevId)
	Enable audio output device. More...

int	IMP_AO_Disable (int audioDevId)
	Disable audio output device. More...

int	IMP_AO_EnableChn (int audioDevId, int aoChn)
	Enable audio output channel. More...

int	IMP_AO_DisableChn (int audioDevId, int aoChn)
	Disable audio output channel. More...

int	IMP_AO_SendFrame (int audioDevId, int aoChn, IMPAudioFrame *data, IMPBlock block)
	Send audio output frame. More...

int	IMP_AO_PauseChn (int audioDevId, int aoChn)
	Pause audio output channel. More...

int	IMP_AO_ResumeChn (int audioDevId, int aoChn)
	Resume audio output channel. More...

int	IMP_AO_ClearChnBuf (int audioDevId, int aoChn)
	Clear the current audio data cache in the audio output channel. More...

int	IMP_AO_QueryChnStat (int audioDevId, int aoChn, IMPAudioOChnState *status)
	Query the current audio data cache status in the audio output channel. More...

int	IMP_AENC_CreateChn (int aeChn, IMPAudioEncChnAttr *attr)
	Create audio encode channel. More...

int	IMP_AENC_DestroyChn (int aeChn)
	Destory audio encode channel. More...

int	IMP_AENC_SendFrame (int aeChn, IMPAudioFrame *frm)
	Send audio encoding audio frame. More...

int	IMP_AENC_PollingStream (int AeChn, unsigned int timeout_ms)
	Polling encoded audio stream cache. More...

int	IMP_AENC_GetStream (int aeChn, IMPAudioStream *stream, IMPBlock block)
	Get the encoded stream. More...

int	IMP_AENC_ReleaseStream (int aeChn, IMPAudioStream *stream)
	Releases the stream from the audio encoding channel. More...

int	IMP_AENC_RegisterEncoder (int handle, IMPAudioEncEncoder encoder)
	Register encoder. More...

int	IMP_AENC_ReleaseEncoder (int *handle)
	Release encoder. More...

int	IMP_ADEC_CreateChn (int adChn, IMPAudioDecChnAttr *attr)
	Create audio decode channel. More...

int	IMP_ADEC_DestroyChn (int adChn)
	Destory audio decoding channel. More...

int	IMP_ADEC_SendStream (int adChn, IMPAudioStream *stream, IMPBlock block)
	Send audio stream to audio decoding channel. More...

int	IMP_ADEC_PollingStream (int AdChn, unsigned int timeout_ms)
	Polling decode audio stream cache. More...

int	IMP_ADEC_GetStream (int adChn, IMPAudioStream *stream, IMPBlock block)
	Get the decoded stream. More...

int	IMP_ADEC_ReleaseStream (int adChn, IMPAudioStream *stream)
	Release of the stream from the audio decoding channel. More...

int	IMP_ADEC_ClearChnBuf (int adChn)
	Clears the current audio data cache in the audio decode channel. More...

int	IMP_ADEC_RegisterDecoder (int handle, IMPAudioDecDecoder decoder)
	Register decoder. More...

int	IMP_ADEC_ReleaseDecoder (int *handle)
	Unregister Decoder. More...

int	IMP_AI_SetVol (int audioDevId, int aiChn, int aiVol)
	ACODEC configuration. More...

int	IMP_AI_GetVol (int audioDevId, int aiChn, int *vol)
	Get the volume of the audio input. More...

int	IMP_AI_SetVolMute (int audioDevId, int aiChn, int mute)
	Set audio input mute. More...

int	IMP_AO_SetVol (int audioDevId, int aoChn, int aoVol)
	Set audio output channel volume. More...

int	IMP_AO_GetVol (int audioDevId, int aoChn, int *vol)
	Get audio output channel volume. More...

int	IMP_AO_SetVolMute (int audioDevId, int aoChn, int mute)
	Set audio output mute. More...

int	IMP_AI_SetGain (int audioDevId, int aiChn, int aiGain)
	Set audio input gain. More...

int	IMP_AI_GetGain (int audioDevId, int aiChn, int *aiGain)
	Get AI gain value. More...

int	IMP_AO_SetGain (int audioDevId, int aoChn, int aoGain)
	Set audio output gain. More...

int	IMP_AO_GetGain (int audioDevId, int aoChn, int *aoGain)
	Get audio output gain. More...

int	IMP_AO_Soft_Mute (int audioDevId, int aoChn)
	Output soft mute control. More...

int	IMP_AO_Soft_UNMute (int audioDevId, int aoChn)
	Output soft unmute control. More...

int	IMP_AI_GetFrameAndRef (int audioDevId, int aiChn, IMPAudioFrame frm, IMPAudioFrame ref, IMPBlock block)
	Get audio frame and output reference frame. More...

int	IMP_AI_EnableAecRefFrame (int audioDevId, int aiChn, int audioAoDevId, int aoChn)
	Open access reference frame. More...

int	IMP_AI_DisableAecRefFrame (int audioDevId, int aiChn, int audioAoDevId, int aoChn)
	Close access to the reference frame. More...

int	IMP_AO_CacheSwitch (int audioDevId, int aoChn, int cache_en)
	close audio play cache More...

int	IMP_AO_FlushChnBuf (int audioDevId, int aoChn)

Variables
IMPAudioSampleRate	samplerate
	Audio sampling rate.

IMPAudioBitWidth	bitwidth
	Audio sampling precision.

IMPAudioSoundMode	soundmode
	Audio channel mode.

int	frmNum
	Number of cached frames, range: [2, MAX_AUDIO_FRAME_NUM].

int	numPerFrm
	Number of sample points per frame.

int	chnCnt
	Number of channels supported.

IMPAudioBitWidth	bitwidth
	Audio sampling precision.

IMPAudioSoundMode	soundmode
	Audio channel mode.

uint32_t *	virAddr
	Audio frame data virtual address.

uint32_t	phyAddr
	Audio frame data physical address.

int64_t	timeStamp
	Audio frame data time stamp.

int	seq
	Audio frame data serial number.

int	len
	Audio frame data length.

int	usrFrmDepth
	Audio frame buffer depth.

int	Rev
	retain

int	chnTotalNum
	The total number of cached output channel.

int	chnFreeNum
	Free cache blocks.

int	chnBusyNum
	The number of cache be used.

uint8_t *	stream
	Data stream pointer.

uint32_t	phyAddr
	Data stream physical address.

int	len
	Audio stream length.

int64_t	timeStamp
	time stamp

int	seq
	Audio stream serial number.

IMPAudioPalyloadType	type
	Audio payload data type.

int	bufSize
	buf size, in order to frame the unit, [2 ~ MAX_AUDIO_FRAME_NUM]

uint32_t *	value
	Protocol attribute pointer.

IMPAudioPalyloadType	type
	Encoding protocol type.

int	maxFrmLen
	Maximum code stream length.

char	name [16]
	encoder name

int(*	openEncoder )(void encoderAttr, void encoder)

int(*	encoderFrm )(void encoder, IMPAudioFrame data, unsigned char outbuf, int outLen)

int(*	closeEncoder )(void *encoder)

IMPAudioPalyloadType	type
	Audio decoding protocol type.

int	bufSize
	Audio decoder cache size.

IMPAudioDecMode	mode
	Decoding mode.

void *	value
	Specific protocol attribute pointer.

IMPAudioPalyloadType	type
	Audio decoding protocol type.

char	name [16]
	Audio encoder name.

int(*	openDecoder )(void decoderAttr, void decoder)

int(*	decodeFrm )(void decoder, unsigned char inbuf, int inLen, unsigned short outbuf, int outLen, int *chns)

int(*	getFrmInfo )(void decoder, void info)

int(*	closeDecoder )(void *decoder)

int	TargetLevelDbfs
	Gain level, the value of [0, 31], this refers to the target volume level, the unit is dB, is negative value. More...

int	CompressionGaindB
	Set the maximum gain value, [0, 90], 0 represents no gain, the greater the value, the higher the gain. More...

Detailed Description

audio module, including audio record and playback, audio encoding and decoding, volume and gain setting, (audio) echo cancellation, automatic gain function and so on

1 overview

Audio function includes 5 modules: audio input, audio output, audio echo cancellation, audio encoding and audio decoding.
The existence of the audio input and audio output is the concept of the equipment and the channel, we all know that a MIC is a Device, and also can have multiple Channel input.
Similarly a SPK is a playback Device, and can also have multiple Channel output.
One Device supports only one Channel in this current version of the audio API.
Audio echo cancellation is located in the audio input interface, explicit explanation is embodied in the functional description.
Audio encoding, the current audio API can support such format audio coding: PT_G711A, PT_G711U and PT_G726 , when it comes to add a new encoding method, it is a must to register the encoder.
Audio decoding, the current audio API can support such format audio coding: PT_G711A, PT_G711U and PT_G726 , when it comes to add a new decoding method, it is a must to register the decoder.

2

The following is a detailed description of each module

2.1 Audio input

Audio input Device ID correspondence, 0: corresponding digital MIC; 1: corresponding simulation MIC
Audio input Channel, the current API only supports single channel.
Set the audio input volume, volume range: [-30 ~ 120]. - 30 represents mute, 120 represents the amplification of sound to 30dB, step 0.5dB. 60 means that the volume is set to a critical point,
in that case ,software does not increase or decrease the volume, when the volume value is less than 60, for each drop of 1, the volume is reduced by 0.5dB; when the volume value is greater than 60, for each rise of 1 the volume is increased by 0.5dB.

2.2 Audio output

Audio output Device ID correspondence, 0: corresponding to the default SPK; 1: MIC corresponding to other SPK
Audio output Channel,the current API only supports single channel.
Set the audio output volume, volume range: [-30 ~ 120]. - 30 represents mute, 120 represents the amplification of sound to 30dB, step 0.5dB. 60 means that the volume is set to a critical point,
in that case ,software does not increase or decrease the volume, when the volume value is less than 60, for each drop of 1, the volume is reduced by 0.5dB; when the volume value is greater than 60, for each rise of 1 the volume is increased by 0.5dB.

2.3 Audio echo cancellation(AEC)

Audio echo cancellation function belongs to the audio input interface, so to enable echo cancellation, you must first enable audio input device and channel.
Audio echo cancellation currently supports audio sampling rate of 8K and 16K. A frame data sample number is the multiple of 10ms audio data (e.g., 8K sampling rate, the data fed into: 8000 x 2 / 100 = 160byte integer multiple).
Audio echo cancellation for different devices and different packages will have different sound effects.
Adaptive support is not available in Audio Echo Cancellation (the AEC is not automatically configured), so for different devices there will be different echo cancellation parameters,
The parameter file of the Audio echo cancellation is located in the /etc/webrtc_profile.ini configuration file.
The profile format is as follows (Main need to debug the three parameters):
[Set_Far_Frame]
Frame_V=0.3
[Set_Near_Frame]
Frame_V=0.1
delay_ms=150
[Set_Far_Frame] represents the remote(far-end) parameter, the SPK represents the playback data parameters.
Fram_V represents audio amplitude scaling, the playback data can be adjusted by adjusting these parameters (this is used only for echo cancellation).
[Set_Near_Frame] represents the proximal(near-end) parameter, the MIC represents record data parameters.
Fram_V represents the audio amplitude ratio, the adjustment of these parameters can adjust the amplitude of the recording data (this is only used for echo cancellation).
Delay_ms, because of the delay between software and hardware, and the position between the SPK and MIC(they are placed at a certain distance), the SPK playback data will be processed by the MIC again. So, there will be some delay because the SPK data will have some impact on the MIC data.
This time represents the time difference of the playback data in data recording. (delay to assure that there won't be any echo at all).

2.4 Audio encoding

The current audio API supports PT_G711A, PT_G711U and PT_G726 format audio coding, if you need to add a new encoding method, you need to call the IMP_AENC_RegisterEncoder interface to register the encoder.

2.5 Audio decoding

The current audio API supports PT_G711A, PT_G711U and PT_G726 format audio decoding, if you need to add a new decoding method, you need to call the IMP_ADEC_RegisterDecoder interface to register the decoder.

Enumeration Type Documentation

enum IMPAudioBitWidth

Audio sampling precision definition.

Enumerator
AUDIO_BIT_WIDTH_16	16bit sampling precision

enum IMPAudioDecMode

Define the decoding method.

Enumerator
ADEC_MODE_PACK	Pack decoding.
ADEC_MODE_STREAM	Stream decoding.

enum IMPAudioSampleRate

Audio sampling rate definition.

Enumerator
AUDIO_SAMPLE_RATE_8000	8KHz sampling rate
AUDIO_SAMPLE_RATE_16000	16KHz sampling rate
AUDIO_SAMPLE_RATE_24000	24KHz sampling rate
AUDIO_SAMPLE_RATE_44100	44.1KHz sampling rate
AUDIO_SAMPLE_RATE_48000	48KHz sampling rate
AUDIO_SAMPLE_RATE_96000	96KHz sampling rate

enum IMPAudioSoundMode

Audio channel mode definition.

Enumerator
AUDIO_SOUND_MODE_MONO	Single channel.
AUDIO_SOUND_MODE_STEREO	Double channel.

enum IMPBlock

Audio stream blocking type.

Enumerator
BLOCK	block
NOBLOCK	not block

enum Level_ns

Defines level of noise suppression.

Enumerator
NS_LOW	Low level noise suppression.
NS_MODERATE	Medium level noise suppression.
NS_HIGH	High level noise suppression.
NS_VERYHIGH	Maximum level noise suppression.

Function Documentation

int IMP_ADEC_ClearChnBuf ( int adChn )

Clears the current audio data cache in the audio decode channel.

Parameters

[in] adChn channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_ADEC_CreateChn	(	int	adChn,
		IMPAudioDecChnAttr *	attr
	)

Create audio decode channel.

Parameters

[in]	adChn	channel number
[in]	attr	Channel attribute pointer.

Return values

0	success.
non-0	failure.

Remarks: sample code
1 int adChn = 0;

2 IMPAudioDecChnAttr attr;

3 attr.type = PT_G711A;

4 attr.bufSize = 20;

5 attr.mode = ADEC_MODE_PACK;

6 ret = IMP_ADEC_CreateChn(adChn, &attr);

7 if(ret != 0) {

8 IMP_LOG_ERR(TAG, "imp audio decoder create channel failed\n");

9 return ret;

10 }

Attention: no.

int IMP_ADEC_DestroyChn ( int adChn )

Destory audio decoding channel.

Parameters

[in] adChn channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_ADEC_GetStream	(	int	adChn,
		IMPAudioStream *	stream,
		IMPBlock	block
	)

Get the decoded stream.

Parameters

[in]	adChn	channel number
[in]	stream	Get decoded stream
[in]	block	Blocking / non blocking identifier.

Return values

0	success.
non-0	failure.

Remarks: See the IMP_ADEC_SendFrame function description for further instructions.

Attention: no.

int IMP_ADEC_PollingStream	(	int	AdChn,
		unsigned int	timeout_ms
	)

Polling decode audio stream cache.

Parameters

[in]	AdChn	audio decode input channel number
[in]	timeout_ms	polling timeout time

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: The current interface is used before using IMP_ADEC_GetStream. After calling successfully the current interface, we will have the audio encoding data ready then you can use the IMP_ADEC_GetStream to get the encoded data.

int IMP_ADEC_RegisterDecoder	(	int *	handle,
		IMPAudioDecDecoder *	decoder
	)

Register decoder.

Parameters

[in]	ps32handle	register handle
[in]	decoder	Decoder attributes structure.

Return values

0	success.
non-0	failure.

Remarks: sample code
1 int handle_g711a = 0;

2 IMPAudioDecDecoder my_decoder;

3 sprintf(my_decoder.name, "%s", "MY_G711A");

4 my_decoder.openDecoder = NULL; // Decoder callback function

5 my_decoder.decodeFrm = MY_G711A_Decode_Frm; // Decoder callback function

6 my_decoder.getFrmInfo = NULL; // Decoder callback function

7 my_decoder.closeDecoder = NULL; // Decoder callback function

8

9 // Register decoder

10 ret = IMP_ADEC_RegisterDecoder(&handle_g711a, &my_decoder);

11 if(ret != 0) {

12 IMP_LOG_ERR(TAG, "IMP_ADEC_RegisterDecoder failed\n");

13 return ret;

14 }

15

16 // use decoder

17 int adChn = 0;

18 IMPAudioDecChnAttr attr;

19 attr.type = handle_g711a; // The encoder type is equal to the value of the handle_g711a returned by the successfully registered.

20 attr.bufSize = 20;

21 attr.mode = ADEC_MODE_PACK;

22 // create decode channel

23 ret = IMP_ADEC_CreateChn(adChn, &attr);

24 if(ret != 0) {

25 IMP_LOG_ERR(TAG, "imp audio decoder create channel failed\n");

26 return ret;

27 }

Attention: After registration, the use of the method as well as the use of SDK comes with an decoder.; After registration, the use of the method and the use of SDK in the decoder are all the same. (After registration, clients' methods and SDK prebuilt functions are considered as the SDK functions, that means the clients can change the content of the SDK as they wish)

int IMP_ADEC_ReleaseDecoder ( int * handle )

Unregister Decoder.

Parameters

[in] ps32handle Register handle (the handle obtained at the time of registration of the decoder).

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_ADEC_ReleaseStream	(	int	adChn,
		IMPAudioStream *	stream
	)

Release of the stream from the audio decoding channel.

Parameters

[in]	adChn	channel number
[in]	stream	audio stream pointer

Return values

0	success.
non-0	failure.

Remarks: See the IMP_ADEC_SendFrame function description.

Attention: no.

int IMP_ADEC_SendStream	(	int	adChn,
		IMPAudioStream *	stream,
		IMPBlock	block
	)

Send audio stream to audio decoding channel.

Parameters

[in]	adChn	channel number
[in]	stream	audio stream
[in]	block	Blocking / non blocking identifier.

Return values

0	success.
non-0	failure.

Remarks: sample code
1 while(1) {

2 // Get the data that needs to be decoded

3 ret = fread(buf_g711, 1, IMP_AUDIO_BUF_SIZE/2, file_g711);

4 if(ret < IMP_AUDIO_BUF_SIZE/2)

5 break;

6

7 // Send decoding stream

8 IMPAudioStream stream_in;

9 stream_in.stream = (uint8_t *)buf_g711;

10 stream_in.len = ret;

11 ret = IMP_ADEC_SendStream(adChn, &stream_in, BLOCK);

12 if(ret != 0) {

13 IMP_LOG_ERR(TAG, "imp audio encode send frame failed\n");

14 return ret;

15 }

16

17 // Get decoded data

18 IMPAudioStream stream_out;

19 ret = IMP_ADEC_GetStream(adChn, &stream_out, BLOCK);

20 if(ret != 0) {

21 IMP_LOG_ERR(TAG, "imp audio decoder get stream failed\n");

22 return ret;

23 }

24

25 // Use decoded data

26 fwrite(stream_out.stream, 1, stream_out.len, file_pcm);

27

28 // Release decoded data

29 ret = IMP_ADEC_ReleaseStream(adChn, &stream_out);

30 if(ret != 0) {

31 IMP_LOG_ERR(TAG, "imp audio decoder release stream failed\n");

32 return ret;

33 }

34 }

Attention: no.

int IMP_AENC_CreateChn	(	int	aeChn,
		IMPAudioEncChnAttr *	attr
	)

Create audio encode channel.

Parameters

[in]	aeChn	channel number
[in]	attr	Audio encode channel attribute pointer.

Return values

0	success.
non-0	failure.

Remarks: sample code
1 int AeChn = 0;

2 IMPAudioEncChnAttr attr;

3 attr.type = PT_G711A;

4 attr.bufSize = 20;

5 ret = IMP_AENC_CreateChn(AeChn, &attr);

6 if(ret != 0) {

7 IMP_LOG_ERR(TAG, "Audio encode create channel failed\n");

8 return ret;

9 }

Attention: The Current SDK supports PT_G711A, PT_G711U and PT_G726 encoding.
So the use of SDK encoding, only needs attr.type = PT_G711A.
How to use a custom encoder? You need to register the encoder, the sample code is in the registration interface instructions.

int IMP_AENC_DestroyChn ( int aeChn )

Destory audio encode channel.

Parameters

[in] aeChn channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: Supporting the use of IMP_AENC_CreateChn.

int IMP_AENC_GetStream	(	int	aeChn,
		IMPAudioStream *	stream,
		IMPBlock	block
	)

Get the encoded stream.

Parameters

[in]	aeChn	channel number
[in]	stream	Get audio encoding
[in]	block	Blocking / non blocking identifier.

Return values

0	success.
non-0	failure.

Remarks: see the IMP_AENC_SendFrame function description for deeper understanding.

Attention: no.

int IMP_AENC_PollingStream	(	int	AeChn,
		unsigned int	timeout_ms
	)

Polling encoded audio stream cache.

Parameters

[in]	AeChn	Audio encoding input channel number.
[in]	timeout_ms	Polling timeout time

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: The current interface is used before using IMP_AENC_GetStream. After calling successfully the current interface, we will have the audio encoding data ready then you can use the IMP_AENC_GetStream to get the encoded data.

int IMP_AENC_RegisterEncoder	(	int *	handle,
		IMPAudioEncEncoder *	encoder
	)

Register encoder.

Parameters

[in]	ps32handle	register handle
[in]	encoder	Encoder attribute structure.

Return values

0	success.
non-0	failure.

Remarks: sample code
1 int handle_g711a = 0;

2 IMPAudioEncEncoder my_encoder;

3 my_encoder.maxFrmLen = 1024;

4 sprintf(my_encoder.name, "%s", "MY_G711A");

5 my_encoder.openEncoder = NULL; // Encoder callback function

6 my_encoder.encoderFrm = MY_G711A_Encode_Frm; // Encoder callback function

7 my_encoder.closeEncoder = NULL; // Encoder callback function

8

9 ret = IMP_AENC_RegisterEncoder(&handle_g711a, &my_encoder);

10 if(ret != 0) {

11 IMP_LOG_ERR(TAG, "IMP_AENC_RegisterEncoder failed\n");

12 return ret;

13 }

14

15 // use encoder

16 int AeChn = 0;

17 IMPAudioEncChnAttr attr;

18 attr.type = handle_g711a; // The encoder type is equal to the value of the handle_g711a returned by the successfully registered.

19 attr.bufSize = 20;

20 ret = IMP_AENC_CreateChn(AeChn, &attr);

21 if(ret != 0) {

22 IMP_LOG_ERR(TAG, "imp audio encode create channel failed\n");

23 return ret;

24 }

Attention: After registration, the use of the method and the use of SDK in the encoder are all the same. (After registration, clients' methods and SDK prebuilt functions are considered as the SDK functions, that means the clients can change the content of the SDK as they wish)

int IMP_AENC_ReleaseEncoder ( int * handle )

Release encoder.

Parameters

[in] ps32handle Register handle (the handle obtained at the time of registration of the encoder).

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AENC_ReleaseStream	(	int	aeChn,
		IMPAudioStream *	stream
	)

Releases the stream from the audio encoding channel.

Parameters

[in]	aeChn	channel number
[in]	stream	Get audio stream pointer

Return values

0	success.
non-0	failure.

Remarks: see the IMP_AENC_SendFrame function description.

Attention: no.

int IMP_AENC_SendFrame	(	int	aeChn,
		IMPAudioFrame *	frm
	)

Send audio encoding audio frame.

Parameters

[in]	aeChn	channel number
[in]	frm	Audio frame structure pointer.

Return values

0	success.
non-0	failure.

Remarks: sample code
1 while(1) {

2 // Read a frame of data

3 ret = fread(buf_pcm, 1, IMP_AUDIO_BUF_SIZE, file_pcm);

4 if(ret < IMP_AUDIO_BUF_SIZE)

5 break;

6

7 // encode

8 IMPAudioFrame frm;

9 frm.virAddr = (uint32_t *)buf_pcm;

10 frm.len = ret;

11 ret = IMP_AENC_SendFrame(AeChn, &frm);

12 if(ret != 0) {

13 IMP_LOG_ERR(TAG, "imp audio encode send frame failed\n");

14 return ret;

15 }

16

17 // Get encode stream

18 IMPAudioStream stream;

19 ret = IMP_AENC_GetStream(AeChn, &stream, BLOCK);

20 if(ret != 0) {

21 IMP_LOG_ERR(TAG, "imp audio encode get stream failed\n");

22 return ret;

23 }

24

25 // Use encode stream

26 fwrite(stream.stream, 1, stream.len, file_g711);

27

28 // Release encode stream

29 ret = IMP_AENC_ReleaseStream(AeChn, &stream);

30 if(ret != 0) {

31 IMP_LOG_ERR(TAG, "imp audio encode release stream failed\n");

32 return ret;

33 }

34 }

Attention: no.

int IMP_AI_Disable ( int audioDevId )

Disable audio input device.

Parameters

[in] audioDevId Audio device number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: It supports the use of IMP_AI_Enable. IMP_AI_Disable must be performed before putting the system in sleeping mode.

int IMP_AI_DisableAec	(	int	aiDevId,
		int	aiChn
	)

Disable audio echo cancellation feature.

Parameters

[in]	aiDevId	Audio input device number
[in]	aiChn	audio input channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_DisableAecRefFrame	(	int	audioDevId,
		int	aiChn,
		int	audioAoDevId,
		int	aoChn
	)

Close access to the reference frame.

Parameters

[in]	audioDevId	audio device number.
[in]	aiChn	audio input channel number.
[in]	audioAoDevId	audio output device number.
[in]	aoChn	audio output channel number.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_DisableAgc ( void )

Disable AI automatic gain feature.

Parameters

no.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_DisableChn	(	int	audioDevId,
		int	aiChn
	)

Disable audio input channel.

Parameters

[in]	audioDevId	Audio device number
[in]	aiChn	Audio input channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: It supports the use of IMP_AI_EnableChn.

int IMP_AI_DisableHpf ( void )

Disable AI high pass filtering function.

Parameters

no.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_DisableNs ( void )

Disable noise suppression.

Parameters

no.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_Enable ( int audioDevId )

Enable audio input device.

Parameters

[in] audioDevId Audio device number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_EnableAec	(	int	aiDevId,
		int	aiChn,
		int	aoDevId,
		int	aoChn
	)

Enable audio echo cancellation feature of the specified audio input and audio output.

Parameters

[in]	aiDevId	Need to perform audio echo cancellation of the audio input device number.
[in]	aiChn	Need to perform audio echo cancellation of the audio input channel number.
[in]	aoDevId	Need to perform audio echo cancellation of the audio output device number.
[in]	aoChn	Need to perform audio echo cancellation of the audio output channel number.

Return values

0	success.
non-0	failure.

Remarks: The Audio echo cancellation for different devices and different packages will have different sound effects.; Adaptive support is not available in Audio Echo Cancellation (the AEC is not automatically configured), so for different devices there will be different echo cancellation parameters,; Only use the functional effect is not really good.; The parameter file of the Audio echo cancellation is located in the /etc/webrtc_profile.ini configuration file.; The profile format is as follows (Main need to debug the three parameters):; [Set_Far_Frame]; Frame_V=0.3; [Set_Near_Frame]; Frame_V=0.1; delay_ms=150; [Set_Far_Frame] represents the remote(far-end) parameter, the SPK represents the playback data parameters.; Fram_V represents audio amplitude scaling, the playback data can be adjusted by adjusting these parameters (this is used only for echo cancellation).; [Set_Near_Frame] represents the proximal(near-end) parameter, the MIC represents record data parameters.; Fram_V represents the audio amplitude ratio, the adjustment of these parameters can adjust the amplitude of the recording data (this is only used for echo cancellation).; Delay_ms, because of the delay between software and hardware, and the position between the SPK and MIC(they are placed at a certain distance), the SPK playback data will be processed by the MIC again. So, there will be some delay because the SPK data will have some impact on the MIC data.; This time represents the time difference of the playback data in data recording. (delay to assure that there won't be any echo at all).

Attention: In fact, the interface will only check for aiDevId and aiChn, but it is better to enabele these two channels at the same time and then call the current one.
when the audio input channel is closed, the Audio Echo Cancellation feature also is turned off. In case of using it again, you will have to turn it on.

int IMP_AI_EnableAecRefFrame	(	int	audioDevId,
		int	aiChn,
		int	audioAoDevId,
		int	aoChn
	)

Open access reference frame.

Parameters

[in]	audioDevId	audio device number.
[in]	aiChn	audio input channel number.
[in]	audioAoDevId	audio output device number.
[in]	aoChn	audio output channel number.

Return values

0	success.
non-0	failure.

Remarks: Use this current interface before using IMP_AI_GetFrameAndRef.

Attention: no.

int IMP_AI_EnableAgc	(	IMPAudioIOAttr *	attr,
		IMPAudioAgcConfig	agcConfig
	)

Enable automatic gain of audio input.

Parameters

[in]	attr	Requires automatic gain of the audio attribute.
[in]	agcConfig	Automatic gain parameter configuration, configuration magnification.

Return values

0	success.
non-0	failure.

Remarks: Note the configuration of the AGC. agcConfig amplification's main parameters have their own configuration, check the specific gain IMPAudioAgcConfig instructions.; Note that AGC can gain sound amplification, but if the gain parameter is not appropriate, it will lead to broken noise, please adjust carefully the parameters.

Attention: Audio echo cancellation contains the AGC function, which means it is not required to perform automatic gain if the echo cancellation is enabled.

int IMP_AI_EnableChn	(	int	audioDevId,
		int	aiChn
	)

Enable audio input channel.

Parameters

[in]	audioDevId	Audio device number
[in]	aiChn	Audio input channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: Must first enable device.

int IMP_AI_EnableHpf ( IMPAudioIOAttr * attr )

Enable audio input for high pass filtering.

Parameters

[in] attr need high pass filtering of audio attribute.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: Audio echo cancellation contains the HPF function, if Audio Echo Cancellation is enabled, so HPF will be automatically enabled.

int IMP_AI_EnableNs	(	IMPAudioIOAttr *	attr,
		int	mode
	)

Enable specified audio input noise suppression.

Parameters

[in]	attr	Noise suppression is required for the audio attribute.
[in]	mode	Noise suppression level 0 ~ 3, see Level_ns.

Return values

0	success.
non-0	failure.

Remarks: The mode parameter of noise suppression represents the noise suppression level (range [0 ~ 3]), the higher the level, the cleaner the noise suppression.; However, The cleaner the noise is, more details of the sound will be lost, here we have a contradiction so we need to make tradeoff while processing the noise suppression.

Attention: Audio echo cancellation contains the noise suppression function, if the audio echo cancellation is enabled, it is not required to enable the noise suppression.

int IMP_AI_GetChnParam	(	int	audioDevId,
		int	aiChn,
		IMPAudioIChnParam *	chnParam
	)

Set audio input channel parameters.

Parameters

[in]	audioDevId	audio device number
[in]	aiChn	audio input channel number
[out]	chnParam	audio channel parameters

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_GetFrame	(	int	audioDevId,
		int	aiChn,
		IMPAudioFrame *	frm,
		IMPBlock	block
	)

Get audio frame.

Parameters

[in]	audioDevId	Audio device number
[in]	aiChn	Audio input channel number
[out]	frm	Audio frame structure pointer.
[in]	block	Blocking / non blocking identifier.

Return values

0	success.
non-0	failure.

Remarks: Sample code
1 IMPAudioFrame frm;

2 // Get audio frame

3 ret = IMP_AI_GetFrame(devID, chnID, &frm, BLOCK);

4 if(ret != 0) {

5 IMP_LOG_ERR(TAG, "Audio Get Frame Data error\n");

6 return ret;

7 }

8

9 fwrite(frm.virAddr, 1, frm.len, record_file); // use audio frame data

10

11 // Release audio frame

12 ret = IMP_AI_ReleaseFrame(devID, chnID, &frm);

13 if(ret != 0) {

14 IMP_LOG_ERR(TAG, "Audio release frame data error\n");

15 return ret;

16 }

Attention: no.

int IMP_AI_GetFrameAndRef	(	int	audioDevId,
		int	aiChn,
		IMPAudioFrame *	frm,
		IMPAudioFrame *	ref,
		IMPBlock	block
	)

Get audio frame and output reference frame.

Parameters

[in]	audioDevId	audio device number.
[in]	aiChn	audio input channel number.
[out]	frm	audio frame structure pointer.
[out]	ref	reference frame structure pointer.
[in]	block	block and non-block identitifier.

Return values

0	success.
non-0	failure.

Remarks: Sample code
1 IMPAudioFrame frm;

2 IMPAudioFrame ref;

3 // Get audio frame and output reference frame

4 ret = IMP_AI_GetFrameAndRef(devID, chnID, &frm, &ref, BLOCK);

5 if(ret != 0) {

6 IMP_LOG_ERR(TAG, "Audio Get Frame Data error\n");

7 return ret;

8 }

9

10 fwrite(frm.virAddr, 1, frm.len, record_file); // Use audio frame data

11 fwrite(ref.virAddr, 1, ref.len, ref_file); // Use audio reference frame

12

13 // Release audio frame

14 ret = IMP_AI_ReleaseFrame(devID, chnID, &frm);

15 if(ret != 0) {

16 IMP_LOG_ERR(TAG, "Audio release frame data error\n");

17 return ret;

18 }

Attention: no.

int IMP_AI_GetGain	(	int	audioDevId,
		int	aiChn,
		int *	aiGain
	)

Get AI gain value.

Parameters

[in]	audioDevId	Audio input device number
[in]	aiChn	Audio input channel number
[out]	aiGain	audio input gain

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_GetPubAttr	(	int	audioDevId,
		IMPAudioIOAttr *	attr
	)

Get the attribute of the audio input device.

Parameters

[in]	audioDevId	Audio device number
[out]	attr	Audio device attribute pointer

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_GetVol	(	int	audioDevId,
		int	aiChn,
		int *	vol
	)

Get the volume of the audio input.

Parameters

[in]	aiDevId	Audio input device number
[in]	aiChn	Audio input channel number
[out]	vol	audio input volume

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AI_PollingFrame	(	int	audioDevId,
		int	aiChn,
		unsigned int	timeout_ms
	)

Polling audio stream cache.

Parameters

[in]	audioDevId	Audio device number
[in]	aiChn	Audio input channel number
[in]	timeout_ms	Polling timeout time.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: Use the interface before using IMP_AI_GetFrame, and when the interface is called successfully, then the audio data is ready, and you can use IMP_AI_GetFrame to get audio data.

int IMP_AI_ReleaseFrame	(	int	audioDevId,
		int	aiChn,
		IMPAudioFrame *	frm
	)

Release audio frame.

Parameters

[in]	audioDevId	Audio device number
[in]	aiChn	Audio input channel number
[in]	frm	Audio frame structure pointer

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: It supports the use of IMP_AI_GetFrame.

int IMP_AI_SetChnParam	(	int	audioDevId,
		int	aiChn,
		IMPAudioIChnParam *	chnParam
	)

Set audio input channel parameters.

Parameters

[in]	audioDevId	Audio device number
[in]	aiChn	audio input channel number
[in]	chnParam	audio frame structure pointer

Return values

0	success.
non-0	failure.

Remarks: sample code
1 int chnID = 0;

2 IMPAudioIChnParam chnParam;

3 chnParam.usrFrmDepth = 20;

4 ret = IMP_AI_SetChnParam(devID, chnID, &chnParam);

5 if(ret != 0) {

6 IMP_LOG_ERR(TAG, "set ai %d channel %d attr err: %d\n", devID, chnID, ret);

7 return ret;

8 }

Attention: Supporting the use of IMP_AI_EnableChn.

int IMP_AI_SetGain	(	int	audioDevId,
		int	aiChn,
		int	aiGain
	)

Set audio input gain.

Parameters

[in]	audioDevId	Audio input device number
[in]	aiChn	Audio input channel number
[out]	aiGain	Audio input gain, range [0 ~ 31].

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: aiGain range of [0 ~ 31], if the input value is less than 0, then the value of aiGain will be set to 0 if the value is greater than 31, the value of aiGain will be set to 31

int IMP_AI_SetPubAttr	(	int	audioDevId,
		IMPAudioIOAttr *	attr
	)

Set audio input device attribute.

Parameters

[in]	audioDevId	Audio device number
[in]	attr	Audio device attribute pointer

Return values

0	success.
non-0	failure.

Remarks: Sample code
1 int devID = 1;

2 IMPAudioIOAttr attr;

3 attr.samplerate = AUDIO_SAMPLE_RATE_8000;

4 attr.bitwidth = AUDIO_BIT_WIDTH_16;

5 attr.soundmode = AUDIO_SOUND_MODE_MONO;

6 attr.frmNum = 20;

7 attr.numPerFrm = 400;

8 attr.chnCnt = 1;

9 ret = IMP_AI_SetPubAttr(devID, &attr);

10 if(ret != 0) {

11 IMP_LOG_ERR(TAG, "Set Audio in %d attr err: %d\n", devID, ret);

12 return ret;

13 }

Attention: Need to be called before IMP_AI_Enable.

int IMP_AI_SetVol	(	int	audioDevId,
		int	aiChn,
		int	aiVol
	)

ACODEC configuration.

Set audio input volume.

Parameters

[in]	aiDevId	audio input device number
[in]	aiChn	audio input channel number
[in]	aiVol	audio input volume

Return values

0	success.
non-0	failure.

Remarks: volume in the range of [-30 ~ 120]. - 30 represents mute, 120 is to amplify the sound of to 30dB, step 0.5dB.; 60 is to set the volume to a critical point. In this case, the software does not increase or decrease the volume, when the volume value is less than 60, for each drop of 1, the volume is decreased by 0.5dB; when the volume value is greater than 60, for each rise of 1, the volume is increased by 0.5dB.

sample code

 int volume = 60;
 ret = IMP_AI_SetVol(devID, chnID, volume);
 if(ret != 0) {
         IMP_LOG_ERR(TAG, "Audio Record set volume failed\n");
         return ret;
 }

Attention: If the input of the aiVol exceeds the range of [-30 ~ 120]. when it is less than -30 it will take -30 as value, more than 120 it will be considered as 120.

int IMP_AI_SetVolMute	(	int	audioDevId,
		int	aiChn,
		int	mute
	)

Set audio input mute.

Parameters

[in]	aiDevId	Audio input device number
[in]	aiChn	Audio input channel number
[out]	mute	Audio input mute flag, mute = 0: off mute, mute = 1: on mute.

Return values

0	success.
non-0	failure.

Remarks: By calling the interface, it can be muted immediately.

Attention: no.

int IMP_AO_CacheSwitch	(	int	audioDevId,
		int	aoChn,
		int	cache_en
	)

close audio play cache

Parameters

[in]	audioDevId	audio device number.
[in]	aoChn	audio output channel number.
[in]	cache_en	switch of control cache.

Return values

0	success
non-0	failure.

Remarks: no

Attention: no.

int IMP_AO_ClearChnBuf	(	int	audioDevId,
		int	aoChn
	)

Clear the current audio data cache in the audio output channel.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_Disable ( int audioDevId )

Disable audio output device.

Parameters

[in] audioDevId audio device number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_DisableAgc ( void )

Disable AO automatic gain feature.

Parameters

no.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_DisableChn	(	int	audioDevId,
		int	aoChn
	)

Disable audio output channel.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_DisableHpf ( void )

Disable AO high pass filtering function.

Parameters

no.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_Enable ( int audioDevId )

Enable audio output device.

Parameters

[in] audioDevId audio device number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: The IMP_AO_SetPubAttr. must be called before

int IMP_AO_EnableAgc	(	IMPAudioIOAttr *	attr,
		IMPAudioAgcConfig	agcConfig
	)

Enable audio output automatic gain feature.

Parameters

[in]	attr	need automatic gain of the audio attribute.
[in]	agcConfig	automatic gain parameter configuration, configuration magnification.

Return values

0	success.
non-0	failure.

Remarks: agcConfig amplification's main parameters have their own configuration, check the specific gain IMPAudioAgcConfig instructions.; Note that AGC can gain sound amplification, but if the gain parameter is not appropriate, it will lead to broken noise, please adjust carefully the parameters.

Attention: Audio echo cancellation contains the AGC function, which means it is not required to perform automatic gain if the echo cancellation is enabled.

int IMP_AO_EnableChn	(	int	audioDevId,
		int	aoChn
	)

Enable audio output channel.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_EnableHpf ( IMPAudioIOAttr * attr )

Enable audio output for high pass filtering.

Parameters

[in] attr need high pass filtering of audio attribute.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: Audio echo cancellation contains the HPF function, if audio echo cancellation is enabled, so you do not need to enable HPF.

int IMP_AO_GetGain	(	int	audioDevId,
		int	aoChn,
		int *	aoGain
	)

Get audio output gain.

Parameters

[in]	audioDevId	audio output device number.
[in]	aoChn	audio output channel number.
[out]	aoGain	audio output gain.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_GetPubAttr	(	int	audioDevId,
		IMPAudioIOAttr *	attr
	)

Get audio input and output device attribute.

Parameters

[in]	audioDevId	audio device number
[out]	attr	audio output device attribute pointer

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_GetVol	(	int	audioDevId,
		int	aoChn,
		int *	vol
	)

Get audio output channel volume.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number
[out]	aoVol	audio output volume

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_PauseChn	(	int	audioDevId,
		int	aoChn
	)

Pause audio output channel.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_QueryChnStat	(	int	audioDevId,
		int	aoChn,
		IMPAudioOChnState *	status
	)

Query the current audio data cache status in the audio output channel.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number
[out]	status	Cache state structure pointer.

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_ResumeChn	(	int	audioDevId,
		int	aoChn
	)

Resume audio output channel.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_SendFrame	(	int	audioDevId,
		int	aoChn,
		IMPAudioFrame *	data,
		IMPBlock	block
	)

Send audio output frame.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number
[in]	data	audio frame sturcture pointer
[in]	block	Blocking / non blocking identifier.

Return values

0	success.
non-0	failure.

Remarks: sample code
1 while(1) {

2 size = fread(buf, 1, IMP_AUDIO_BUF_SIZE, play_file);

3 if(size < IMP_AUDIO_BUF_SIZE)

4 break;

5

6 IMPAudioFrame frm;

7 frm.virAddr = (uint32_t *)buf;

8 frm.len = size;

9 ret = IMP_AO_SendFrame(devID, chnID, &frm, BLOCK);

10 if(ret != 0) {

11 IMP_LOG_ERR(TAG, "send Frame Data error\n");

12 return ret;

13 }

14 }

Attention: no.

int IMP_AO_SetGain	(	int	audioDevId,
		int	aoChn,
		int	aoGain
	)

Set audio output gain.

Parameters

[in]	audioDevId	Audio output device number
[in]	aoChn	audio output channel number
[out]	aoGain	Audio output gain, range [0 ~ 0xcb].

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: aoGain range of [0 ~ 31], if the input value is less than 0, then the value of aoGain will be set to 0.
aoGain if the value is greater than 31, the value of aiGain will be set to 31

int IMP_AO_SetPubAttr	(	int	audioDevId,
		IMPAudioIOAttr *	attr
	)

Set audio input and output device attribute.

Parameters

[in]	audioDevId	audio device number
[in]	attr	audio output device attribute pointer

Return values

0	success.
non-0	failure.

Remarks: no.

Attention: no.

int IMP_AO_SetVol	(	int	audioDevId,
		int	aoChn,
		int	aoVol
	)

Set audio output channel volume.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number
[in]	aoVol	audio output volume

Return values

0	success.
non-0	failure.

Remarks: volume in the range of [-30 ~ 120]. - 30 represents mute, 120 is to amplify the sound of to 30dB, step 0.5dB.; 60 is to set the volume to a critical point. In this case, the software does not increase or decrease the volume, when the volume value is less than 60, for each drop of 1, the volume is decreased by 0.5dB; when the volume value is greater than 60, for each rise of 1, the volume is increased by 0.5dB.

Attention: If the input of the aiVol exceeds the range of [-30 ~ 120], when it is less than -30 it will take -30 as value , more than 120 it will be 120.

int IMP_AO_SetVolMute	(	int	audioDevId,
		int	aoChn,
		int	mute
	)

Set audio output mute.

Parameters

[in]	audioDevId	audio device number
[in]	aoChn	audio output channel number
[out]	mute	Audio output mute flag, mute = 0: off mute, mute = 1: on mute.

Return values

0	success.
non-0	failure.

Remarks: By calling the interface, it can be muted immediately.

Attention: no.

int IMP_AO_Soft_Mute	(	int	audioDevId,
		int	aoChn
	)

Output soft mute control.

Parameters

[in]	audioDevId	Audio output device number.
[in]	aoChn	Audio input channel number.

Return values

0	success.
non-0	failure.

Remarks: when this interface is called, it wil not be directly in silence mode from normal playback state. It will slow down gradually, until it reaches the silence mode.

Attention: no.

int IMP_AO_Soft_UNMute	(	int	audioDevId,
		int	aoChn
	)

Output soft unmute control.

Parameters

[in]	audioDevId	Audio output device number.
[in]	aoChn	Audio input channel number.

Return values

0	success.
non-0	failure.

Remarks: when this interface is called, it will not directly restore the current volume. It will gradually increase the volume from silence mode until the volume reaches a set of good volume.

Attention: no.

Variable Documentation

int CompressionGaindB

Set the maximum gain value, [0, 90], 0 represents no gain, the greater the value, the higher the gain.

int TargetLevelDbfs

Gain level, the value of [0, 31], this refers to the target volume level, the unit is dB, is negative value.

The smaller the value, the greater the volume.

Data Structures

Macros

Enumerations

Functions

Variables

Detailed Description

1 overview

2

2.1 Audio input

2.2 Audio output

2.3 Audio echo cancellation(AEC)

2.4 Audio encoding

2.5 Audio decoding

Enumeration Type Documentation

Function Documentation

Variable Documentation