So, what's the current status of everything?


It's quite telling that in the two decades I've been using Linux as my primary OS, the biggest, most headache-inducing problems I've encountered have almost always been caused by software written or maintained by Poettering. I've never met the guy, but I seriously despise his software design principles.

While I've generally avoided PulseAudio on my PCs, my wish to be able to switch from bluetooth headset (for calls, headphone usage, etc) to built-in speakers, on the fly, on the Pyra, unfortunately makes PulseAudio too convenient to avoid.

I really wish I had taken deeper, higher-level programming classes when I attended university. I would very much enjoy making it my daily hobby to remake everything Poettering has done, but done better. And by "better" I mean, without his tendency to force his assumptions on use-cases into the software.

Don't get me wrong, the guy is a seriously skilled programmer. I have respect for what he has done. I simply disagree with his design principles (and what I've seen of his attitude) very strongly.
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Back on topic - nice to see things are progressing well. I also like that the audio chip in the Pyra seems like it could be quite good. The audio quality in the Pandora was my favorite part of it, and while I'm not sure if the Pyra will reach quite that level, it's good to know it wont be far behind. @MWeston has his name forever recognized in my mind as the genius behind the Pandora's incredible audio capability.
 
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Back when kde 3 was fresh and modern, output switching on the fly worked like a charm with kdes inbuild sound settings.
It is a lie that there are no alterantives, but apparently they have been forgotten, lost in data nirvana.
When programming a playback tool it is very easy to switch a soundcard while playing, heck you even have to restart the card whenever the buffer runs empty anyway.
The other part that is needed comes from alsa, dmix, a virtual mixing card that acts as target for all audio programs so that none of them blocks the real hardware.
So why is it so hard to combine booth? This sounds like you only need to set a new output target and have the dmix code restarting without sending an error to the music playing program.
 
I just did a quick test run with my own unit and the current Debian buster we're using.

I booted up and played some videos with FireFox. The speakers really sound beautiful - until they start to overdrive when you turn up the volume too much, but we're working on that.
Not all videos had sound (probably because we don't have non-free codecs installed), but with the ones that played, PulseAudio had around 7 - 11% CPU power while FireFox / Webcontent was using 57% most of the time.

It plays nicely in Windows and fullscreen as well.

Touchscreen is a bit non-responsive directly at the edges, but that's something that's normal for a resistive touchscreen if you don't have lot of space. I worked without any issues and very responsive in the main areas.
Sometimes it registered a wrong value, but these are things the driver can fix.

So yeah, we're getting there.
 
Djoga'Ro said:
Since the newly introduced values would be to be expected somewhere inbetween their respective predecessors and successors, but you pull 'em up/down to equal their respective predecessors, I'd say that's introducing more sine waves to the content. I guess, at those samplerates the new content is in too high frequencies to be heard or even to be reproduced in playback. I wonder what became of a sine wave - say at 440Hz - originally sampled at 2kHz, then brought to a rate of 4kHz.
Click to expand...
Nearest neighbor interpolation like that is actually quite common in signal processing. You may get a clearer picture of the process by thinking about images. If you double every pixel the result is a bit pixelated but still recognizable image. Linear interpolation would average the subsamples and produce a bit blurry image (bilinear interpolation in images). Back to sounds, a 48->96 kHZ NN-interpolated signal in *principle* causes exactly* the same physical movement in the speaker as the 48 kHZ one would. If you plot out the resulting analog signal you'll see why.

* not exactly exactly, but close enough for this comparison.
 
One Moment please: You allready play some Emulators?? Dos this means our MP Pyra want be just Doorstoppers in Two Months ?? , Or are they only Emus from the Debian Repo who needs to Optimice ??
 
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trix said:
It's quite telling that in the two decades I've been using Linux as my primary OS, the biggest, most headache-inducing problems I've encountered have almost always been caused by software written or maintained by Poettering. I've never met the guy, but I seriously despise his software design principles.

While I've generally avoided PulseAudio on my PCs, my wish to be able to switch from bluetooth headset (for calls, headphone usage, etc) to built-in speakers, on the fly, on the Pyra, unfortunately makes PulseAudio too convenient to avoid.
Click to expand...

Yep. I have never gotten audio to work on my raspberry pi with pulse. With alsa and alsamixer it works great and outputs can be changed.
 
bzar said:
Nearest neighbor interpolation like that is actually quite common in signal processing. You may get a clearer picture of the process by thinking about images. If you double every pixel the result is a bit pixelated but still recognizable image. Linear interpolation would average the subsamples and produce a bit blurry image (bilinear interpolation in images). Back to sounds, a 48->96 kHZ NN-interpolated signal in *principle* causes exactly* the same physical movement in the speaker as the 48 kHZ one would. If you plot out the resulting analog signal you'll see why.

* not exactly exactly, but close enough for this comparison.
Click to expand...

I'm hardly an expert, but I always imagined that modern audio processors do some sort of interpolation to bring the digital signal up to the DACs native sample-rate, and then filtered the signal in analogue-land to eliminate any interesting artefacts left over from the time quantisation.

Trying to interpret a sample-stream as a stepped wave seems clearly the worst option for audio. Real sounds don't have sharp edges in them like that! (Except, perhaps, for detonations and extremely violent impacts?). Other things aside, you'll have trouble finding a loudspeaker that can accurately reproduce step functions...
 
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Djoga'Ro said:
I wonder what became of a sine wave - say at 440Hz - originally sampled at 2kHz, then brought to a rate of 4kHz.
Click to expand...
I did that, for the record. The interference on the 4k version seemed to support the tone, and make it louder and sound brighter; in 2k it sounds like it's going through a low pass filter. My code doesn't generate a pure stable sin wave though; it adds odd harmonics to fill out the tone.
 
matzesu said:
One Moment please: You allready play some Emulators?? Dos this means our MP Pyra want be just Doorstoppers in Two Months ?? , Or are they only Emus from the Debian Repo who needs to Optimice ??
Click to expand...

Just installed via standard Debian Repo. Stella works fine, but other emulators like Nestopia use GL for graphics output... and as that's currently being done in software, it's really slow. :)
But yeah, DOSBox and Stella work fine :)
 
Stella was for Atari VCS ?? So from Pacman up to these at these whyred XXX games ?? (at this time it was a scandal, today its just funny)..

Dosbox is cool, when i find my few Game Disquettes, as i now have a USB 3,5 ° Disk Drive..

Unfortunaly, on Pandora, Dosbox was too divicult for me, as i cant remember it had a Option to just pick up the Games from a Folder via GUI and Run them..

The C64 Emu had a Option to just chose a File, ..

Maybe im not that good as a Pandora Owner..

EDIT: OK, just looked at Wikipedia: Stella is for VCS /2600 Atari..
 
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I don't understand something from the device pictured on the right. Those squares at the bottom appear to be position for stereo speakers - in portrait mode. Not much room for any separation of the audio that way. Wouldn't it make more sense to place those top and bottom? The device would then have stereo sound in landscape mode and have better symmetry.

Stereo in landscape mode makes perfect sense - movies, games, whatnot.
Stereo in portrait mode though? I can't think of any reason for it.
 
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