Hi, At Thu, 27 Dec 2001 19:40:46 +0100, Thomas Tonino wrote: > > [EMAIL PROTECTED] wrote: > > > > >i.m using a winfast cm8738 sound card with digital addon board. > >i.d like to use the digital output to pipe ac3 signals from the > >dvb-s sat board to my dd receiver. > > > >i can.t playback clear sound thru the digital output > >(eg. madplay /mp3/test.mp3). i have VERY bad high clipping > >distortions. sound is good when connected thru the analog line > >output. > > > I have the same problems with driver versions 0.0.9beta9 and > 0.9.0beta10. The distortion is awful: it is caused by a signed/unsigned > mixup and under the resulting schreeching sound, one can barely hear > remains of the wanted output. > > To fix this, I changed card-cmipci.c under static snd_pcm_hardware_t > snd_cmipci_playback where it says formats: SNDRV_PCM_FMTBIT_S16_LE. iIf > you change the S16 to U16, the digital out will be fine. BUT then the > analog out has the same distortion you now have on digital. I assume > this is because the driver then is fed unsigned data, which suits the > digital out, but obviously messes up the analog. Hmm, perhaps there is a bit change done for 6ch hardware. On my wintek 4x, the driver works without problems.
> I've brought this up before on the list, but got no response - not from > people with the same problem, nor from people using this succesfully. > Maybe we both have a new chip revision that needs an extra bit fiddled? I guess yes. > > I hope my workaround helps you a bit, and I assume the same fix can be > applied to the record side as well to fix recording. Still would be much > happier if there was a real fix. Anyway, the attached patch will change the format of spdif i/o. For analog output S16_LE is used. This doesn't matter for the old chips, so if it's ok for you, i'll put it to cvs as a workaround. ciao, Takashi
cmipci-6ch-spdif.dif
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