User talk:Jusa
Revision as of 08:45, 26 October 2014
Page 15 of this PDF http://linuxplumbersconf.org/2009/slides/Jyri-Sarha-audio_miniconf_slides.pdf shows a block diagram of the N900 audio system (or at least what I assume is the N900 audio system). Is there any chance you can expand on which algorithms (e.g. stw, xprot, eap, aep, drc, eq, iir, fir etc) match with the blocks marked "Mic EQ", "music processing", "recording processing", "transducer processing" and "call audio processing"?
I have been examining the Meego code and the Harmattan code (both the open bits in pulseaudio-modules-meego and the closed bits in pulseaudio-nokia) with a view to possibly using the blobs or parts of them for the Neo900 audio work (since they are more open than the ones on the N900). Comparing what Meego has to what Fremantle has, it would appear as though the Meego and Harmattan blobs are missing functions labeled stw. Are you aware of any other pieces in the Meego or Harmattan blobs that are missing or that might have been built differently? (ignoring anything to do with different versions or compilers, PulseAudio, libc or other things, just talking about the actual algorithms and such in the pulseaudio-nokia blobs).
Or for that matter anything that is present in the Meego or Harmattan blobs but isn't used on Fremantle?
Other than the cmtspeech stuff, are you aware of anything in the nokia Fremantle Pulseaudio blobs that talks to or is dependent on the N900 cellular modem?
Which of these Nokia algorithms are necessary for safe system functioning and which are just going to give not-so-nice audio if we dont have them? Obviously xprot is something we probably need in order to protect the speakers/earpiece/etc from damage but what else? (the cellular modem we are using in the Neo900 already does all sorts of voice processing so identifying which bits we need and which bits we can leave to the cellular modem will save us a lot of time)
Are you aware of open-source implementations of algorithms similar to the proprietary Nokia ones?
Do you know if the stereo widening stuff is actually used on the N900 on Fremantle? All of the .parameters files that control the blobs set x-maemo.stereo-widening = "false" which I assume means "turn it off". If its in fact not used that means we can ignore it (it would also explain why its not even compiled in for Meego)
nb_eeq is "narrowband ear equalizer" nb_meq is "narrowband mic equalizer" wb_eeq is "wideband ear equalizer" wb_meq is "wideband mic equalizer" What is the difference between "narrowband" and "wideband" here? What is xprot displacement?
Can you tell me which of these sets of parameters will be tied to the specific details of the microphone in the N900 or of the FMTX in the N900? (bluetooth is digital so changing bluetooth chips shouldn't change the way the audio needs to be processed and we are using the same earpiece, speakers, headphone, lineout and tvout setup so those wont change)
aep
nb_eeq
nb_meq
wb_eeq
wb_meq
mumdrc.ul
mumdrc.dl
limiter.ul
limiter.dl
xprot
That will tell us which bits we need to dig deep into and retune/replace for our needs
retune/replace
oh and one more thing, if you know anything at all about alsaped, alsaped.conf or alsa-policy-enforcement, feel free to share :)