Methods > Waveform analysis > ExternalSoundAnalysisStart method

Remarks

Starts receiving a stream of sound data provided by an external source in order to perform a sound waveform analysis.

After invoking this method, the container application can start providing audio PCM data to the waveform analyzer component through a sequence of calls to the ExternalSoundAnalysisPushData method. Once the full PCM has been provided, the ExternalSoundAnalysisStop method must be called in order to start the waveform analysis.

Syntax

[Visual Basic]

control.ExternalSoundAnalysisStart (

nEncodeMode as enumRAWEncodeModes,

bIsBigEndian as enumBoolean,

nFrequency as Long,

nChannels as Long

) as enumWanErrorCodes

[C++]

short control.ExternalSoundAnalysisStart (

short nEncodeMode,

short bIsBigEndian,

long nFrequency,

long nChannels

);

Parameter	Description

nEncodeMode

Encode mode used to encode the RAW stream.

Supported values are the following:

Mnemonic constant	Numeric value	Meaning
RAW_ENCODE_PCM_U8	0	RAW PCM 8 bits Unsigned
RAW_ENCODE_PCM_S8	1	RAW PCM 8 bits Signed
RAW_ENCODE_PCM_S16	2	RAW PCM 16 bits Signed
RAW_ENCODE_PCM_S24	3	RAW PCM 24 bits Signed
RAW_ENCODE_PCM_S32	4	RAW PCM 32 bits Signed
RAW_ENCODE_FLOAT32	5	RAW 32 bits floating point
RAW_ENCODE_G711_ULAW	6	RAW G711 U-LAW
RAW_ENCODE_G711_ALAW	7	RAW G711 A-LAW
RAW_ENCODE_GSM_610	8	RAW GSM 6.10
RAW_ENCODE_DIALOGIC_VOX	9	RAW Dialogic ADPCM VOX

bIsBigEndian

Boolean flag that specifies if bits order inside the RAW stream are little-endian or big-endian

Supported values are the following:

Mnemonic Value	Meaning
BOOL_FALSE	The RAW stream is encoded using little-endian
BOOL_TRUE	The RAW stream is encoded using big-endian

nFrequency

Sample rate of the RAW stream (e.g. 44100)

nChannels

Number of channels of the RAW stream: 1 for Mono or 2 for Stereo

Return value

Value	Meaning

Negative value	An error occurred, check the LastError property value in order to see the error code meaning
enumWanErrorCodes.ERR_WAN_NOERROR (0)	The method call was successful.