Software MP3 decoder for ATmega/ATxmega

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There are some things achieved on AVR that you would previously have said "nope, that just isn't technically possible". Then some genius goes and proves us all wrong. surprise

 

Well done!!

Last Edited: Fri. Feb 26, 2016 - 05:02 PM
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So now someone can put mp3 playback, vga graphics output, bitbanged usb and something else outrageous on a tiny85. Really unbelievable what some folks can cram into an avr.

 

Imagecraft compiler user

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the decoder requires 8 kBytes RAM, no chance to get it to run on smaller controllers.

Rats.

 

Well done, though!

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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Amazing!

If you don't know my whole story, keep your mouth shut.

If you know my whole story, you're an accomplice. Keep your mouth shut. 

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Beyond impressive ( I think this is first time anybody has EVER done this using an AVR, right ? ) ! Does this also mean an AVR can also then do the encoding, too ?
 

1) Studio 4.18 build 716 (SP3)
2) WinAvr 20100110
3) PN, all on Doze XP... For Now
A) Avr Dragon ver. 1
B) Avr MKII ISP, 2009 model
C) MKII JTAGICE ver. 1

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indianajones11 wrote:
Does this also mean an AVR can also then do the encoding, too ?
 

 

Well, I consider this a more theoretical question.

You won't see me writing "It's impossible!".

But I've definitely some doubts.

Sure, while the MP3 decoder does only makes sense if decoding is done in realtime, an encoder could be allowed to work offline, just taking the time it needs.

But even then I expect it to require more RAM, most likely only provided with devices supporting external RAM, additionally slowing down the encoding process caused by increased access time.

It might be worth a try but I'm not planning to do this. Some implementations claim to be very fast, e.g. https://github.com/toots/shine, this could be a starting point. For STM32 a library is offered, read here about the resource requirements http://www.st.com/st-web-ui/static/active/cn/resource/technical/document/data_brief/DM00024441.pdf (Page 4).

 

If your question implies realtime encoding by just feeding some audio signal into ADC, I'd say - forget it, very unlikely on 8 bit AVR.

 

Anybody out there to prove me wrong?

 

Last Edited: Wed. Mar 9, 2016 - 04:19 PM
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Yes, real-time. Thank you ( for the links, too ).

1) Studio 4.18 build 716 (SP3)
2) WinAvr 20100110
3) PN, all on Doze XP... For Now
A) Avr Dragon ver. 1
B) Avr MKII ISP, 2009 model
C) MKII JTAGICE ver. 1

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Now just wait for some so and so to start a C vs ASM war...... devil

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly