NewLC - Multichannel Sound using CMdaAudioOutputStream (v1.1) - Comments

Multichannel Sound using CMdaAudioOutputStream (v1.1)

ten foot ninja — Thu, 20 Apr 2006 21:31:10 +0200

Hello, I am writing a game (its a single threaded app, not exe) and when i use the stream to play a sound on my 3650 or my 6.1 emulator, nothing happens. MaoscOpenComplete gets called very seldomly and randomly, maybe 5% of the time. If i disable all game code, same results.

However, when i run my game on my 6670 (OS7) it runs perfectly all the time and makes me very happy.

this is very frustrating. Setting up the audio stream is very easy and doesn't leave much room for error. I'm not sure why this doesn't work on OS6.1. If anyone knows, or at least has suggestions as to where i can look for answers (i've combed the web quite thoroughly) I'd be very grateful for any help. Thanks in advance!

Multichannel Sound using CMdaAudioOutputStream (v1.1)

ten foot ninja — Thu, 20 Apr 2006 06:09:14 +0200

Hello, my game doesn't call MaoscOpenComplete() regularly on the SOS6.1. It gets called maybe 10% of the time, and it seems to have nothing to do with whatever code changes i have made and is very random. The behaviour is the same on my 3650, but on my 6670 (using SOS7) it always gets called and works wonderfully all the time.

I am making a single threaded app, not exe, and i am using GapiDraw (if that matters). When i disable all drawing code, the behaviour is the same. Does anyone have any idea why this may happen? Thanks for any help in advance!

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

Anonymous — Mon, 26 Dec 2005 22:49:38 +0100

Hi zeep,

Firstly I want to say that this is a very good article, and has been very helpful for me. However I have a question regarding the actual stream mixing. In the example you described how to mix streams of the exact same lenght(BUFFERSIZE), but what If I want to mix streams of different lenght? An example might be the game backround music and some sound effects(the music is long whilst the sfx are short).

thanks for you reply :)

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

Panayotis — Sun, 18 Dec 2005 07:22:07 +0100

Hi Zeep,

I know very well how to use threads in Symbian and I agree with you that the best way to go on with this case is to use threads. However, I am stuck.

I am trying to use the CMdaAudioOutputStream / MMdaAudioOutputStreamCallBack from a server/exe. The problem is that the callback methods are never called back.

Inside my EXE/DLL server I create a thread which does everything, i.e.:

1) It creates a TrapCleanup

2) It creates and installs an Active Scheduler

3) It creates a couple of other objects

4) Constructs on the heap the Audio Observer object which implements the MMdaAudioOutputStreamCallBack.

5) Constructs on the heap the CMdaAudioOutputStream object passing the reference of the Audio Observer object i create on step (4).

6) Then, I open the CMdaAudioOutputStream object. (the callback is not called).

7) Then, I wait on a semaphore for another thread to put something in my queue (I have a queue with text segments).

However, I would expect that while waiting on the semaphore on step 7, the callback to be called by the MMF framework; I am talking about the callback on the MMdaAudioOutputStreamCallBack::MaoscOpenComplete().

But it is never called.

In summary, though I do everything on a thread, I never get a callback from the MMF that the stream is openned successfully.

Maybe, it is something that I miss that I have to put into the thread. Or maybe I need to use two threads. However, I do not know which piece of code to put in one thread and which piece of code to put on another.

Can you please help me on what I am doing wrong?

Thanks in advance Panayotis

> Little correction

saju — Tue, 04 Oct 2005 06:09:45 +0200

Hi , why u used 8 bit wav files for mixing? although the device supports 16 bit sound?

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

sum — Tue, 08 Mar 2005 03:06:47 +0100

This article are really useful!! Thanks so much~~

I would like to know that , is it possible to play/mix midi and wave together by this?

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

1011 10 — Thu, 07 Oct 2004 15:57:50 +0200

Great tutorial.But i was just wondering,is there anyway i cld fill in the buff with data from a telephone call.

How do i get audio from etel? any ideas?

thnkx a LOT

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

Mike — Mon, 20 Sep 2004 10:59:48 +0200

You shall call CMdaAudioOutputStream::SetAudioPropertiesL, and if it leaves with KErrNotSupported, you should try different frequency. There's no other way.

And note: some Series60 devices do not support 16KHz frequency, only 22050, or even other. So hard-coding 16KHz is asking for trouble.

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

Andy — Thu, 02 Sep 2004 08:15:36 +0200

This code violates many of the basic rules of Symbian C++ programming. Your implementation of the interface should also inherit from CBase, since it allocates memory dynamically. Also, it allocates stuff in the constructor; instead, you should use 2-phased construction. Also, you have methods that leave, without the trailing L in the methods. So the caller is not aware that the method may leave, thus possibly leading to memory leaks. Also, you are using non-Symbian data types (should use TInt instead of int etc).

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

Anonymous — Fri, 13 Aug 2004 19:52:16 +0200

where is the wav file defined which will be opened? sorry for the noob question..

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

zeep — Wed, 04 Aug 2004 20:38:16 +0200

The series 60 phone plays 16000 samples per second. I want 32 buffers per second (which should be fast enough for games) so we get a sample buffer size of 16000/32=512. You could try to make the buffer smaller but keep in mind that the overhead grows this way. I also think that the device uses an additional internal sound buffer you can not circumvent. Sound output without any delay at all, to my knowledge, is not possible. (Even on PC hardware there is a small delay) Hope this answered your question ;)

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

anhndb — Wed, 04 Aug 2004 10:39:09 +0200

Could you explain me : // buffer is 16000 / 32 = 512 samples #define BUFFERSIZE 512

Why 16000? Why 32?

I want to playback immediately the audio stream received from another Symbian phone. What is the size for the buffer?

Series 60 Developer Platform 1.0/2.0: SoundMixer Example v1.0

Anonymous — Thu, 27 May 2004 17:37:33 +0200

http://www.forum.nokia.com/main/1,6566,040,00.html?fsrParam=3-3-/main/0,,1_32_30,00.html&fileID=4544

> Multichannel Sound using CMdaAudioOutputStream (v1.1)

Anonymous — Thu, 27 May 2004 17:36:19 +0200

Hi, Nokia released a Sound-Mixing-Multithreaded example. You can download it here:

> Zeep Sound engine

Anonymous — Tue, 03 Feb 2004 16:26:07 +0100

Hi, did you figure out why it was crashing? I'm getting this now.

cheers,

paris

Multichannel Sound using CMdaAudioOutputStream (v1.1)

zeep — Fri, 13 Jun 2003 09:21:21 +0200

This article tries to give the reader a rough introduction on how to implement multichannel sound. The reader should have basic knowledge on programming in Symbian and the will to experiment a bit. My target device is Nokia Series 60. But my code snippets should also work on any other Symbian device.