forums.ps2dev.org

[cooleyes]

as we all know, we can use sceAudioOutputBlocking to play 16bit PCM data.

but all homebrew just support 44100Hz samplerate.

I browse moonlight's "PSP PRX Libraries Documentation Project",

and find out a function "sceAudioSetFrequency" in audio.prx , sceAudio_driver lib.

it can change the audio device's Frequency.

SceInt32 sceAudioSetFrequency(SceInt32 frequency); //frequency=44100 or 48000, if success it will return 0

it can setFrequency to 44100Hz or 48000Hz

sceAudio_driver.S

[SilverSpring]

int sceClockgenAudioClkSetFreq(int freq); // freq can be 44100 or 48000

Dont know if same outcome??

EDIT:

Ok, I just checked, sceAudioSetFrequency passes freq to sceClockgenAudioClkSetFreq to set the freq, but it also passes freq to sceCodecSetFrequency as well.

[Mihawk]

Nice, could be usefull.
But is it not possible to use lower frequencies, like 22.05 or 24kHz? or are only those two (44.1 and 48kHz) valid?

[SilverSpring]

The function only accepts 44100 and 48000, gives error otherwise.

[dot_blank]

wonderful !! so 48kHz OGG playback is now possible :)
thanx to you cooleyes keep it up !
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[Raphael]

Smaller frequencys can easily be done by simple sample doubling/quadrupling.
Nice find there cooleyes :)
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Alexander Berl

[J.F.]

There are plenty of rate resamplers out there. The trick is making it sound as good as possible without using too much CPU time. The code can be found everywhere because the vast majority of PC sound cards use fix rate playback (the most common being 48KHz).

[Raphael]

But you don't need any heavy math for getting 22.050/11.025 or 24.000/12.000Hz when you can playback 44100 and 48000 on hardware.
You just need to double/quadruple every single sample and you're done.
The big problem with playing 48000 or multiples Hz data, requiring fancy sample rate converting was only until now.
_________________
<Don't push the river, it flows.>
http://wordpress.fx-world.org - my devblog
http://wiki.fx-world.org - VFPU documentation wiki
Alexander Berl

[jimparis]

[Cpasjuste]

Hi, does someone know the correct nid for the 3.90 firmware?

I think it might be one of this (return 0), but i can't play a custom 48khz mp3 :

//IMPORT_FUNC "sceAudio_driver",0x2533CE02,sceAudioSetFrequency // Do not seems
//IMPORT_FUNC "sceAudio_driver",0x9A34BC0D,sceAudioSetFrequency
//IMPORT_FUNC "sceAudio_driver",0xA1B19554,sceAudioSetFrequency
//IMPORT_FUNC "sceAudio_driver",0xA8B12BF0,sceAudioSetFrequency
//IMPORT_FUNC "sceAudio_driver",0xD5CE71B8,sceAudioSetFrequency // Do not seems

[cooleyes]

[J.F.]

You should probably use the old value and rely on the NID resolver. Remember that this is a kernel-level call and should be put into an external kernel-mode prx to be called from the user app. There's a thread on doing stuff like that, or you can look at the code for PMP Player Advance.

Don't forget that your user-mode app must also be a PRX (set BUILD_PRX in the makefile) to load a kernel-mode external prx lib.