In the meantime, could be there by any chance any way to get better quality from the headphone jack? I can plug my headphones to the screen to get audio from HDMI and get decent quality but the headphone jack has horrible noise in it? Why is that? Is there any workaround?Gert van Loo wrote:nrf said:
@Gert: sorry to sound silly but I am missing something here: how is the sound produced by default in the PI? Isn't that via the PCM/I2S which then created the PWM right and left that drive the headphone?
No, the PWM is driven straight from the GPU using sound-to-PWM software specially written for the Raspberry-Pi. The sound can come from the ALSA driver which passes ARM messages to the GPU. Unless you're playing video+sound which the GPU can all do without talking to the ARM. The same holds for the sound up the HDMI cable: all different streams. So if you want sound out of your I2S you have to first convert it to the right format and then use the I2S/PCM module to push it out.
pluggy wrote:In the lifetime of this thread the situation has changed. The early posts are from early last year when the Pi didn't have I2S and they were bemoaning the fact. Around October last year the Revision 2 boards were brought out and I2S had been put on. So if you bought a Pi from late last year it will have I2S. The revision 2 boards have 2 mounting holes in them, the Revision 1 boards don't.