On Wed, Jul 19, 2023 at 02:39:44PM +0200, Takashi Iwai wrote:
On Wed, 19 Jul 2023 14:27:21 +0200, Ico Bukvic wrote:
Thank you, Takashi.
On Raspberry Pi 400 (one with built-in keyboard, although any RPi or Linux computer with HDMI monitor with loudspeakers will do), open pd-l2ork (a variant of pure-data available at http://bit.ly/pd-l2ork; pure-data also has this same problem) and enable DSP. Do the same after changing audio settings via the Preferences window (Edit->Preferences), where you can switch among backends (ALSA vs Portaudio, vs JACK; JACK does not work with any setting). If you have proper audio settings (0 in, 2 out, and a supported SR, r.g. 44,1kHz), you will hear the buzz, and will also hear the desired audio produced (e.g. by running Media->Audio Tester) faintly, with buzz bring at the forefront. Or, you will hear everything OK (default Pulse settings), or nothing. ALSA and PortAudio settings are default Raspbian(RPi)/Ubuntu (desktop). Thank you.
Well, the question is how the ALSA PCM device is opened, how configured and how played. As Geraldo already suggested, VC4 HDMI on RPi has a special format with IEC958 encoding. Also it has IEC958 status bit setups. So, for example, if you'd need to play a normal PCM stream with aplay, you'd need to open the device with "hdmi:$CARD" device -- then the rest is done in alsa-lib's plugin, and that's almost equivalent with what PA does.
Hi Takashi, thanks for taking Ico's report. Perhaps the right configuration that he needs to use aplay could be: https://github.com/alsa-project/alsa-lib/blob/master/src/conf/cards/vc4-hdmi...
That is, if I understand correctly?
Thanks, Geraldo Nascimento