Takashi Iwai wrote: > >For output of PCM over SPDIF, you need to turn on only "IEC958 Output >Switch". Please check alsa-driver/docs/CMIPCI.txt for more details. > The option "IEC958 Output Switch" indeed neatly enables the digital output with a quiet signal. When I enable the "IEC958 DAC To Out" switch I get very distorted output. I'm using XMMS or MPG123 with OSS emulation.
Reading the docs made me want to start with a clean slate. Unloaded all the driver modules, built alsaplayer and used alsaplayer -d hw:0,2 test.mp3. This is a 44 KHz MP3. Still the same full scale signal on the DAT which seems to be almost pure distortion. Maybe there is a signed/unsigned problem someplace? After exiting alsaplayer, the DAT recorder still shows a 0 dB VU level (i.e. full signal) but there is no sound on the headphone output. Hmmm. Maybe what should be 0 volts output is giving a full scale output instead? Finally a register dump after running the last test, with quiet but full scale output: [root@draak root]# cat /proc/asound/card0/cmipci C-Media PCI 00: 02 00 00 00 04: 00 0c 00 00 08: 13 00 29 00 0c: 00 00 00 08 10: c0 00 00 00 14: 00 00 a0 00 18: 00 00 00 04 1c: 00 00 fe ff 20: 10 40 00 00 24: 00 31 00 02 28: ff ff ff ff 2c: ff ff ff ff 30: 00 00 00 00 34: 00 00 00 00 38: 00 00 00 00 3c: 00 00 00 00 > > >Takashi > I hope this sheds some more light. By the way, the ohphone teleconferencing software mentioned on the list can be found at http://www.openh323.org/ . Nice software! Thomas _______________________________________________ Alsa-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-user
