about_audiostream_example.txt

语音输出流的例子

/*
 * ============================================================================
 *  Name     : about_audiostream_example.txt
 *  Part of  : AudioStreamExample
 *  Created  : 20.11.2003 by Nokia Forum
 *  Description:
 *		Definition of audio streaming example.
 *  Version  : 1.0
 *  Copyright: Nokia Corporation
 * ============================================================================
 */
 
 
 
   0. Overview (what is this example and what it does)
   
   Audio streamer example is an introductory level application demonstrating
   the use of audio streaming, using CMdaAudioInputStream for audio input
   and CMdaAudioOutputStream for audio output, and their respective callback
   classes MMdaAudioInputStreamCallback and MMdaAudioOutputStreamCallback.

   Audio streaming API provides functionality for recording audio stream into
   a buffer, and playback of the audio buffer.  For input stream the input
   gain can be set for satisfactory recording results, and the volumen for
   the output stream.  Sound balance can be set for both streams.   
   
   When the application is started, it displays application name on the
   screen.  The functionality of the program is operated via the menu.
   Operations for playing, recording and stopping the audio stream are 
   available.  Also, the recorded audio stream can be saved into a file
   and further loaded to be played again.

   This package contains an audio sample sample.aud in data directory.
   It's an actual sample, of fingers tapping the tabletop, recorded using 
   this application on Nokia 6600 phone.
   
   In this text file, the <audio streamer example dir> is used to REFERENCE
   to the directory in which the example files (including this txt file)
   have been EXTRACTED.
   
   
   1. Compatibility

   Audio streamer example application is compatible with S60 v2.0. It has been
   tested to work with the Nokia 6600 phone model.
   
   The S60 v2.0 SDK is mandatory, because audio streaming API was first 
   introduced in this particular release.
   
   

   2. Building
   
   To build the application, follow the following steps:
   

   	2a) go to: "<audio streamer example dir>\group"

   	2b) run: "bldmake bldfiles"
   	Note! Ensure that the sample.aud file located at
   	<audio streamer example dir>\data has been copied to:

	"c:\Symbian\7.0s\Series60_v20\Epoc32\wins\
	c\system\Apps\AudioStream\" -directory, 

	OR under the EPOC root of directory where S60 v2.0 
	SDK has been installed on the target machine.

	2c) run: "abld makefile thumb"

	2d) run: "abld built thumb urel"
   
   	
   	
   3. Installation to device (pkg file notes & instructions)

	3.1 installing the ready-to-use AudioStreamEx.SIS file 
	
	3.1 a) deliver (move) the AudioStreamEx.SIS into 
	       any S60 v2.0 compatible phone
	
	3.2 building the application from the compiled files
	
   	3.2a) go to "<audio streamer example dir>\install"
   	
   	3.2b) run: "makesis AudioStreamEx.pkg"
   	
   	3.2c) deliver (move) the created SIS file into 
   	your phone (model 6600 or any S60 v2.0 compatible phone)
   	
   	
   	
   4. Implementation notes

	During recording the audio samples are stored on a rotating buffer, 
	in this example the buffer consists of 3 blocks, of 700ms in length, 
	total size of 2100ms.  Because of the nature of the buffer (rotating), 
	the last 2100ms of the audio sampled will be stored in the buffer. 

	In current version of the Series 60 SDK, version 2.0, the internal 
	implementation of CMdaAudioInputStream causes a memory leak, which 
	causes the emulator to crash when exiting the application. The 
	bug appears even in the simplest implementation, as follows:

	CMdaAudioInputStream* myInputStream = CMdaAudioInputStream::NewL(*this);
	delete myInputStream;

   

   5. Running the example

	Launch the AudioStream application on your phone.
	A canvas displaying application name will appear,
        application is ready for use.

	The operations of the application are controlled
 	using the actions found in the menu.  Record will record
	incoming audio stream as long as stopped using the Stop
	menu item.  Play will playback the audio data stored
 	in the buffer.  Stop will stop the recording or playing
	of the audio data if record or playback are active.
	Save will store the audio data held in the buffer into
	a file.  Load will load the audio data from file into
 	the buffer.