| Oksana | >> generally headset will consume way less power than IHF speakers << That would make looking at mediaplayer's power consumption with headset (not speakers) at minimum volume interesting. | Amp is interesting, because it's definitely a necessary part of any phone - it's active during phone calls, | 01:43 |
|---|---|---|
| Oksana | right? - and its power consumption is apparently high. | 01:43 |
| Maxdamantus | My guess is that far more power will be used in decoding the audio file than actually playing through the speakers. | 03:21 |
| Maxdamantus | You should be able to determine that just by looking at where the heat is dissipated .. is more heat dissipated by the CPU (relative to an idle system), or by the speakers/headset? | 03:22 |
| * Oksana nods... Why is decoding so difficult? Which formats/codecs are easier to decode? | 03:22 | |
| Maxdamantus | Again, I'd guess it's far more in the CPU than in speakers/headset. | 03:22 |
| Maxdamantus | WAV is the easiest to decode. | 03:23 |
| Maxdamantus | but not very space efficient .. I imagine there are other power usage considerations too though. | 03:24 |
| Oksana | There is file system, there is CPU, there is DAC (I think), there is amplifier (I think), and there is speaker. Trying to figure it out... https://wiki.maemo.org/N900_Hardware_Audio_Codec | 03:28 |
| Oksana | TLV320AIC34 is DAC (and ADC as well), and possibly an amplifier as well. The "Ultra-Low-Power Mode With Passive Analog Bypass" sounds like phone can play radio even when it's switched off? Sounds nice - for example, for "Wake Up Alarm with Radio" functionality. | 03:32 |
| DocScrutinizer05 | Oksana: what's your question regarding audio? | 21:46 |
| DocScrutinizer05 | as I hoped to have elaborated on yesterday, there's no such thing like "wake up alarm without CPU involved", and in my book it doesn't matter anyway | 21:47 |
| DocScrutinizer05 | there's a possible mode to playback FM radio without using CPU to stream PVM data. SpeedEvil and/or javispedro investigated that a lot, back in 2010/2011. It's useful for listening to FM without wasting lots of power on CPU shoveling around data that's as well available in analog form for direct processing. That's however completely unrelated to any "alarm" stuff | 21:51 |
| DocScrutinizer05 | s/PVM/PCM/ | 21:51 |
| infobot | DocScrutinizer05 meant: there's a possible mode to playback FM radio without using CPU to stream PCM data. SpeedEvil and/or javispedro investigated that a lot, back in 2010/2011. It's useful for listening to FM without wasting lots of power on CPU shoveling around data that's as... | 21:51 |
| DocScrutinizer05 | TLV320AIC34 is a complex CODEC chop that combines multiple ADC, DAC, digital filters, digital mixing and a "matrix" based analog mixer circuitry, plus a few low power audio driver amps | 21:55 |
| DocScrutinizer05 | I'm not even 100% sure if there's any digital mixing in TLV320AIC34 | 21:55 |
| DocScrutinizer05 | there's digital attenuation though, based on the DSP part | 21:55 |
| DocScrutinizer05 | iirc you can even stop the clock of all DSP/ADC/DAC in TLV320AIC34 and only use the analog matrix with its switches and gain-controlled amps | 21:56 |
| DocScrutinizer05 | but the question is: what do you want to *achieve*? (seems to be a recurring topic in here lately ;-D >>what do you want to achieve, in detail?' like, you could show a 10s video clip without comment and everybody understands what it DOES)<< No "save more power" / "streamline user experience" / "simplify contribution" abstract goals | 21:59 |
| DocScrutinizer05 | "age of XY" | 22:01 |
| DocScrutinizer05 | ~xy | 22:01 |
| infobot | well, xy is The XY problem: You want to do X, but don't know how. You think you can solve it using Y, but don't know how to do that, either. You ask about Y, which is a strange thing to want to do. Just ask about X. http://www.catb.org/~esr/faqs/smart-questions.html#goal | 22:01 |
| DocScrutinizer05 | we see a lot of XYZ lately, even | 22:02 |
| DocScrutinizer05 | colloquial we should try harder to ask the right question, rather than trying to implement what we consider was the consequence solution suggested by the implied answer to a never asked question | 22:05 |
| DocScrutinizer05 | Oksana: about your musing regarding audio amps above - yes, amps can consume a lot of power. They not always have a good efficiency, often even as low as 50%. And yet they often are supposed to deliver massive output power, like a few Watt. So a amp for e.g. the IHP speakers may consume (and drive to speakers) a very significant chunk of power, depending on audio signal and volume setting | 22:13 |
| DocScrutinizer05 | IHF* | 22:14 |
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