Problem with CMdaAudioOutputStream

[andrea993]

I've a problem with CMdaAudioOutputStream.
My stream is never completely played.

This is my MaoscBufferCopied function:

void RawPlayer::MaoscBufferCopied(TInt aError, const TDesC8& aBuffer)
	{
        if ((aError==KErrNone || aError==KErrAbort)  && iStream)
			State=STATE_WRITED;
		else
        {
			State=STATE_ERROR;
        }


           int by=iStream->GetBytes();


           iStream->Stop();
	}

I inserted this line to verify the problem: int "by=iStream->GetBytes();"

The value of "by" is ever a bit less than the length of aBuffer.
Why?

[wizard_hu_]

1) "Copied" is not "Played", when the API gives the buffer back to you it is still playing the data, just from a private copy of it
2) do you actually hear some problem?
3) if you have some 'framed' audio format (AMR, MP3), that also matters, fragment data can not be played until its ending part becomes available

[andrea993]

Yes I can hear some problem, it seems to occur when I play a stream and then I play another stream more short.

The data is raw format (unformatted)

[andrea993]

I've understand the problem but I don't know how can I solve it.

I call "iStream->Stop();" in "MaoscBufferCopied" and it don't finish to play the buffer.
On Nokia N8 I don't need to call "Stop()" function but in the S60v5 series if I don't call "Stop()" the callback "MaoscPlayComplete" is never called!

How can I solve the problem?

[pavarang]

Hello,
into "Symbian OS C++ for Mobile Phones Volume 3" I found:

To stop streaming, you have two options. Either you can just stop
writing buffers back to the stream when they are returned to you ­ in this
case, you get a callback to MaoscPlayComplete() with an error of
KErrUnderflow when all the data you have provided has been played
completely. This method ensures that all the data is played fully.
If you want to stop the streaming immediately, you should call Stop()
on the audio stream.
iStream->Stop();
In this case, you should expect the following callbacks:
· MaoscBufferCopied() with an error of KErrAbort for each
buffer that you have written to the stream but which has not yet been
returned
· MaoscPlayComplete() with an error of KErrCancel.
These callbacks happen synchronously from within the call to Stop().
By the time this call returns, you can be sure that streaming has terminated.

otherwise I don't have any other suggestions....

regards
pg

[andrea993]

"you can just stop writing buffers back to the stream when they are returned to you ­ in this
case, you get a callback to MaoscPlayComplete() with an error of
KErrUnderflow when all the data you have provided has been played
completely. This method ensures that all the data is played fully."

is interesting, but I don't understand when and what is returned to me ("when they are returned to you").

[wizard_hu_]

It probably refers to the buffers, in MaoscBufferCopied.

[andrea993]

And when is returned to me?

EDIT I've read this document, but the "stop" function is called immediately in MaoscBufferCopied

EDIT2:
I've insert these lines at the end of MaoscBufferCopied:

         int bynow,byafter;

         do
         {
            bynow=iStream->GetBytes();
            User::After(100);
            byafter=iStream->GetBytes();
         }
         while(bynow<byafter);

         iStream->Stop();

And it work correctly

EDIT3 It doesn't work correctly ever

[wizard_hu_]

And when is returned to me?

The story about CMdaAudioOutputStream is that WriteL builds a list of the passed descriptors, but generally it does not make a copy of them. However after a while the buffers get played, and they can be re-used or just deleted, etc. This is why you get "const TDesC8 &aBuffer" in MaoscBufferCopied, that is the buffer which is no longer needed by the stream. Because of this way of operation it is a good idea to have at least 2 buffers, while one is playing, the other can be used for generating/loading audio data.

EDIT2:
I've insert these lines at the end of MaoscBufferCopied:

         int bynow,byafter;

         do
         {
            bynow=iStream->GetBytes();
            User::After(100);
            byafter=iStream->GetBytes();
         }
         while(bynow<byafter);

         iStream->Stop();

And it work correctly

EDIT3 It doesn't work correctly ever

I do not understand the purpose of that Stop. Unfortunately I have missed it in the first post already, otherwise I would not have understood it there already.

[andrea993]

I do not understand the purpose of that Stop.

In the s60v5 series if I don't call Stop the callback maoscplaycompleted is not called at the end of the stream

[wizard_hu_]

Ok, but does it really matter? Do you have some explicit need for that callback?

[andrea993]

Yes, I need to know when the stream is completely played

[pavarang]

Yes, I need to know when the stream is completely played

But are you reading content from a file? Because in that case you know when you have entirely read the file.... ?
regards
pg

[andrea993]

But are you reading content from a file? Because in that case you know when you have entirely read the file.... ?
regards
pg

No, I read the stream from an HBufC
regards
A993

[pavarang]

No, I read the stream from an HBufC
regards
A993

well... you know when you reach the end of HBufC... ?