Hi Klaus, when I implemented Java Sound's DirectSound implementation, the DirectSound specs stated (and I could verify by way of tests) that requesting more than 16-bits or more than 2 channels would just "expand" the soundcard's stereo, 16-bit signal to the required format. So you could get 8 channels with 32-bits, but it was just 4 times the stereo signal, and the 32-bits was just extrapolated from the original 16-bits signal.
That's why it was limited to maximum of 2 channels and 16 bits, to not wrongly provide a line with e.g. 24 bits, where the lower 8 bits are just extrapolated. Further, using multi channel will raise the problem "which channels?", that's why we need an additional parameter to specify a channel mask. The MS docs gives a good introduction: http://www.microsoft.com/whdc/device/audio/multichaud.mspx Now, AudioFormat.properties are the intended way of specifying a channel mask, and "validBitsPerSample", and so on. However, when defining AudioFormat.properties, we must make sure that they are usable in the same way on Linux, Solaris, possibly MacOS. But the main, first problem remains how to prevent DirectSound from emulating multi-channel/high resolution audio. Java Sound must never wrongly pretend a certain quality... Regards, Florian On 9/24/2007 11:22 AM, Klaus Jaensch wrote: > Hello, > > I would like to record multi-channel 24-bit audio with the > DirectSound JavaSound implementation under Windows. > > But the audio formats defined in > > j2se/src/windows/native/com/sun/media/sound/PLATFORM_API_WinOS_DirectSound.cpp > > are limited to 8/16bit and 1 or 2 channels. > > I would like to discuss how this limitation could be removed. > > For testing multichannel capabilities of JavaSound I extended > channelsArray up to 8 channels and bitsArray for > 24/32 bit recordings, then compiled dsound.dll and tested recording. > It worked fine, so it's a pity that the recording formats are restricted > to basic formats. > > The question is how to make multi-channel possible without changing > the supported defaults formats, which can be queried by > isFormatSupported(AudioFormat). > > Regards, > > Klaus > > ------------------------------------------ > Klaus Jaensch > Muenchen > Germany > > Institut fuer Phonetik und Sprachverarbeitung > Schellingstr.3/II > 80799 München > > EMail: [EMAIL PROTECTED] -- Florian Bomers Bome Software ------------------------------------------------------- Music Software, Development Tools: http://www.bome.com Java Sound extensions, plugins: http://www.tritonus.org The Java Sound Resources: http://www.jsresources.org ------------------------------------------------------- Please quote this email in your reply. Thanks!
