Class unavclWaveCodecDevice

Unit

unaVC_wave

Declaration

type unavclWaveCodecDevice = class(unavclInOutWavePipe)

Description

Audio stream conversion from one supported format to another. It can convert PCM stream to other format (compression) or other format to PCM (decompression).

Usage: If components has no provider component with formatProvider=true, specify PCM stream parameters before activating: pcm_SamplesPerSec, pcm_BitsPerSample and pcm_NumChannels.

Set formatTag property to specify the audio format you wish to compress to or decompress from. Refer to WAVE_FORMAT_XXXX constants from unaMsAcmAPI.pas unit for possible values of this property, or you can use the output of amcEnum demo to receive the list of installed formats.

Set inputIsPCM to true, if you wish to convert PCM stream to another audio format (compression). Set inputIsPCM to false, if you wish to convert some audio format to PCM stream (decompression).

Example: refer to the vcTalkNow demo. It has c_codec_serverOut component, which is a consumer of waveIn_server component.

That means PCM stream, produced by waveIn_server will be passed to c_codec_serverOut automatically. It also has ip_server as a consumer. That means compressed audio stream will be passed to ip_server automatically.

Hierarchy

• tComponent
• unavclInOutPipe
• unavclInOutWavePipe
• unavclWaveCodecDevice

Overview

Methods

	function setNonPCMFormat(format: PWAVEFORMATEXTENSIBLE): bool;
	function applyDeviceFormat(format: PWAVEFORMATEXTENSIBLE; isSrc: bool = true): bool; override;
	function getFormatExchangeData(out data: pointer): uint; override;
	procedure AfterConstruction(); override;
	procedure createNewDevice(); override;
	procedure doSetDriverLibrary(const value: wString); override;
	procedure doSetDriverMode(value: unaAcmCodecDriverMode); override;
	procedure initWaveParams(); override;
	procedure onDriverChanged(); override;

Properties

	property calcVolume;
	property codec: unaMsAcmCodec read getCodec;
	property driverLibrary;
	property driverMode;
	property enableDataProcessing;
	property formatTag;
	property formatTagImmunable default true;
	property inputIsPcm;
	property isFormatProvider default true;
	property minActiveTime;
	property minVolumeLevel;
	property onThreshold;
	property silenceDetectionMode;

Description

Methods

	function setNonPCMFormat(format: PWAVEFORMATEXTENSIBLE): bool;
Sets non-PCM format for ACM codec device.

	function applyDeviceFormat(format: PWAVEFORMATEXTENSIBLE; isSrc: bool = true): bool; override;
Applies PCM format for ACM codec device.

	function getFormatExchangeData(out data: pointer): uint; override;
Returns format exchange data of the codec.

	procedure AfterConstruction(); override;

	procedure createNewDevice(); override;
Creates ACM codec device.

	procedure doSetDriverLibrary(const value: wString); override;

	procedure doSetDriverMode(value: unaAcmCodecDriverMode); override;

	procedure initWaveParams(); override;

	procedure onDriverChanged(); override;
Notifies ACM codec device about driver change.

Properties

	property calcVolume;

	property codec: unaMsAcmCodec read getCodec;
Returns ACM codec device.

	property driverLibrary;
When driverMode is set to unacdm_installable this property specifies the name of driver library to use. Refer to MSDN documentation for more information about installable drivers.

	property driverMode;
ACM driver mode. When set to unacdm_acm, codec uses ACM to access stream conversion routines. unacdm_installable tells codec to use installable driver, specified by driverLibrary. unacdm_internal is not currently used.

	property enableDataProcessing;
Specifies whether the component would perform any data conversion.

	property formatTag;

	property formatTagImmunable default true;
Codecs usually does not use the format tag provided by other PCM devices.

	property inputIsPcm;

	property isFormatProvider default true;
codec component is usually a format provider–so default value for was changed to true.

	property minActiveTime;

	property minVolumeLevel;

	property onThreshold;

	property silenceDetectionMode;

(c) 2012 Lake of Soft