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faredu
0 Posts |
 Posted - 18 Jan 2007 : 11:10:55
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I am writing a program to test audio playing and recording of ADS pruducts. I need setting the volume of speaker and microphone
waveOutSetVolume is working, Is there a API that is like waveInSetVolume?
Thanks very much!!! |
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jjoseph
47 Posts |
Posted - 18 Jan 2007 : 13:22:49
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Hi,
waveOutSetVolume is a Windows CE API call. You are right, there does not appear to be a waveInSetVolume, but you might want to investigate this functionality through the Audio Mixer API calls. An MSDN link about the audio mixer can be found here: MSDN Article
But do not expect it to be as simple as waveInSetVolume would be.
You could also try accessing the AC97 Codec directly in a fashion similar to Forum Topic 1245, but if you plan on moving eventually to Windows CE 6.0, direct hardware access may no longer be allowed in user applications. |
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ctacke
877 Posts |
Posted - 18 Jan 2007 : 14:19:39
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There is no global or generic API for setting microphone gain. Many devices use codecs that support auto-gain control (AGC) and it would be either ineffective or conflicting to have such an API.
The typical mechanism that an OEM would implement to support something like this would be a few custom messages for the driver. For example lets assume the driver supported a command like SET_MIC_GAIN, then your app would do something like this:
DWORD gainLevel = myDesiredGain;
hWave = waveInOpen(...);
waveInMessage(hWave, SET_MIC_GAIN, gainLevel, 0);
A typical architecture for codecs that support AGC would be to turn on AGC if the level passed in is set to -1, otherwise set it to the specified level.
Of course this does not mean that the ADS audio driver supports this mechanism, it's simply an example of how it might be implemented to be friendly for typical application developers. |
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faredu
0 Posts |
Posted - 23 Jan 2007 : 00:58:54
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jjoseph:
I have try mixer API, it work on WinXP but not WinCE, the return value of mixerGetNumDevs on WinCE always is zero
ctacke:
SET_MIC_GAIN can not be found any where, would you please tell me a URL or something else?
Thanks! |
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faredu
0 Posts |
Posted - 23 Jan 2007 : 01:00:19
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jjoseph:
I have try mixer API, it work on WinXP but not WinCE, the return value of mixerGetNumDevs on WinCE always is zero
ctacke:
SET_MIC_GAIN can not be found any where, would you please tell me a URL or something else?
Thanks! |
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ctacke
877 Posts |
Posted - 23 Jan 2007 : 08:37:52
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| Correct, it cannot be found because, as I said in my original post, it is an "example of how it might be implemented." There is no inherent mechanism to set this in CE and it's up to the OEM to provide such capability depending on the audio hardware present on the board. |
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faredu
0 Posts |
Posted - 24 Jan 2007 : 10:02:12
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There is a "software way" to change the gain level: get the captured data, multiply each byte by a factor. it's hardware-independent
Hope this is not bad for development of applications
Thanks! |
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Is thaere waveInSetVolume?
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