Hi all, I have a consumer-level setup audio question. My research project uses a Raspberry Pi in conjunction with a small portable monitor that has built-in loudspeakers that are to be used via HDMI connection. The goal here is portability and minimal cost. Curiously, when trying to connect to monitor's loudspeakers (via HDMI) using ALSA, no matter what settings I pick, at worst I cannot get audio out, and at best, get a buzzy sound whose waveform is in the attached image. The sound is clearly periodic and impulse-like. It happens every 59 samples. Changing sample rate increases pitch, suggesting 59 samples remain constant regardless of the sampling rate. When playing the actual audio, you can hear it in the background, but this buzz is easily overpowering it. Changing sample rate or bit depth, or buffering, makes no difference. Selecting 8 channels for output (one of HDMI's standards, as far as I can tell), sometimes manages to output a tiny chunk of a good audio sample, and then goes silent. Now, even more curiously, when using the portaudio backend and connecting to the default pulseaudio sink, works just fine. What could be causing this discrepancy? Best, Ico -- Ivica Ico Bukvic, D.M.A. Director, Creativity + Innovation Director, Human-Centered Design iPhD Institute for Creativity, Arts, and Technology Virginia Tech Creative Technologies in Music School of Performing Arts – 0141 Blacksburg, VA 24061 (540) 231-6139 ico@xxxxxx ci.icat.vt.edu l2ork.icat.vt.edu ico.bukvic.net
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