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Decoding of different audio files on PMPs

post #1 of 3
2/18/12 at 6:49pm
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I have a iPod Touch 2G and it is running stock firmware. original firmware. i downgraded for max performance boost. Now I use ALAC's on it. 90% of the songs on there are CD ripped into ALAC. so generally 800-1000kbps. My ipod freezes and lags every now and then. as in when switching songs and going out, it has this laggy thing to it. and then music would sometimes cut and have that garbled sound for a bit when i switch on the ipod. and then the music app would crash

 

i have deduced a while ago that the decoding of MPEG 4 wrapped ALAC at such a bit rate takes more effort for the DAC and CPU(mainly CPU) of the ipod, and thus crashes it sometimes. is this true? The ARM cPU used in this is of course old and slow. and despite what regular people think..the older the deivce is doesn't make it slower. i've done a full restore of it to factory firmware. it should be running like the day i got it. it doesn't when the music app is open.

 

just getting some opinions out there.


Edited by bowei006 - 2/18/12 at 6:53pm
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post #2 of 3
2/19/12 at 2:49am

The music app itself takes up CPU on top of the playing, which on the 2g is probably bound to have problems that you have mentioned. I don't know what the algorithm for apple Ipods use but ALAC in mp4 container(assuming no video) should not take up more processor as bit rate will still be the same.

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post #3 of 3
2/19/12 at 9:28am
Thread Starter 
Quote:
Originally Posted by firev1 View Post

The music app itself takes up CPU on top of the playing, which on the 2g is probably bound to have problems that you have mentioned. I don't know what the algorithm for apple Ipods use but ALAC in mp4 container(assuming no video) should not take up more processor as bit rate will still be the same.



the app of course takes up a couple cycles. now i've also thought about how ALAC and MP3's and others might take up the same cycles. but how is the bit rate the same in your opinion? an MP3 is encoded lossy and has a at most 128kbps per channel for a total 320 stereo kbps. ALAC is encoded and feautres compression from the original 1411.2kbps(if it's 16 bit at 44.1KHz) so it's uaually 800-1000kbps for me. anything im missing here? great opinion but i already knew what you posted already.

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