Ron, S doesn't mean stereo, it means signed for 16-bit sample. The i810_audio support only signed 16-bit little-endian PCM. AFMT_MU_LAW is rarely supported by today's hardware. ChenLi Tien -----Original Message----- From: Ron Shacham [mailto:rs2194@columbia.edu] Sent: 2003/12/31 [星期三] 下午 05:27 To: linux-audio-dev(a)music.columbia.edu Cc: Subject: [linux-audio-dev] very limited formats Hello, this is my first time posting. I have been programming on my personal linux box (rh 8), and I've been unable to set any audio formats on the sound device other than 16-bit linear. For example, I try the following: int format = AFMT_MU_LAW; ioctl(audio_fd, SNDCTL_DSP_SETFMT, &format); I set this right after opening the device. Then, when I query for the format, it returns 16. The following: ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &mask); shows zeroes for everything except for AFMT_S16_NE I have integrated audio hardware (intel i810). I might also mention that I cannot get mono to work, but only stereo. Any ideas? Regards, Ron