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  1. #1
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    Feb 2006
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    CMdaAudioInputStream - Sampling takes 700ms

    Hi,

    Does anyone know how to read small buffers with CMdaAudioInputStream?

    I'm using the standard ReadL Method

    iInputStream->ReadL(iStreamBuffer[iStreamIdx]->Data());

    where iStreamBuffer[iStreamIdx]->Data() points to a buffer of 300Bytes. This is 20ms of audio data. But for me it looks like CMdaAudioInputStream holds an internal buffer of 11200Bytes (700ms), because the ReadL operation in most cases returns after immediately (0ms), but uses 700ms in some case, probably when it has to fetch another internal buffer of 11200Bytes.

    Does anyone know how to work around this and decrease the sampling time?

  2. #2
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    Talking Re: CMdaAudioInputStream - Sampling takes 700ms

    i cannot help you in that, but i'd be grateful if you could visit my thread and answer my question

  3. #3
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    Nov 2005
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    California, USA
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    Re: CMdaAudioInputStream - Sampling takes 700ms

    I do observe the same problem. In my case the internal input buffer is 4096 bytes long (E60, Nokia 9500). There is no documented way around it.

    I would be nice if someone from Nokia could answer this.

  4. #4
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    Re: CMdaAudioInputStream - Sampling takes 700ms

    ..does somebody know of any contact address at nokia to get statements about these kind of issue?

  5. #5
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    Re: CMdaAudioInputStream - Sampling takes 700ms

    iam working on a DSP project on S80, and i can take as much as i want from samples using the following trick(actually iam taking 16msecond)
    i save the whole wave input to a file, and then read as much as i want from the file, and the header of a wav file is too easy to be extracted
    hope this helps

  6. #6
    Regular Contributor
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    Dec 2005
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    59

    Unhappy Re: CMdaAudioInputStream - Sampling takes 700ms

    Quote Originally Posted by elhasab
    ...i can take as much as i want from samples....
    i save the whole wave input to a file, and then read as much as i want from the file, and the header of a wav file is too easy to be extracted
    hope this helps
    That does not solve the problem of latency. The fact is that a long time passes after a particular bit of audio happens before you get to look at it. I have an application for a piano tuning program that I would like to port from the Pocket PC to the Nokia phones. But if this 700 msec. latency cannot be gotten around, my application will not work. A piano tuning application must analyze sound and present graphical feedback to the user in less than 80 msec. or else the user will notice the delay. It is very frustrating to try to tune a piano if there is any delay in the feedback to the user.

    Robert Scott
    Real-Time Specialties

  7. #7
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    Jan 2005
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    8

    Re: CMdaAudioInputStream - Sampling takes 700ms

    use buffer size less then 4096 and should be multiple of 320

    NB

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