Changes between Initial Version and Version 1 of Ticket #75, comment 38


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Timestamp:
Feb 6, 2014, 7:57:27 PM (10 years ago)
Author:
w.m.brul
Comment:

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  • Ticket #75, comment 38

    initial v1  
    33I have nu idea how to check that.
    44> If yes I have a good idea of why it sounds so weird ...:
    5 I doubt that that is the cause. The application is supposed to send the sound data in the format that the device driver can process. I think it sends the wrong format to the usbaudio.sys device driver. May be it is because I added the following line in MMPM2.INI for the USB Audio adapter:
    6 EXTNAMES=7,WAV,_AU,VOC,AU,SND,AIF,IFF
    7 Without that line it was not possible to play e.g. the cuckoo.wav file at all. There were no system sounds. I seem to recall that only the audio files recorded from the headset could be played back. I'll have to test this more...
     5I doubt that that is the cause. The application is supposed to send the sound data in the format that the device driver can process. I think it sends the wrong format to the usbaudio.sys device driver.
    86> http://en.wikipedia.org/wiki/G.711 explains which XOR mask you have to apply to those 8-bit samples for A-law and u-law encoded files. The code to XOR 8-bit data samples only in the sign bit in USBAUDIO.SYS is complete nonsense. I have almost completed an SSE optimized routine that will XOR all samples in a given buffer with an arbitrary bitmask. Just let me add it to the code ...