Killerbee
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MPEG-2 license also for mp3?

Sat Aug 25, 2012 1:41 pm

Call me stupid but does the MPEG-2 licence also bring hardware mp3 decoding?
Probably not :? or?

dom
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Re: MPEG-2 license also for mp3?

Sat Aug 25, 2012 1:49 pm

Killerbee wrote:Call me stupid but does the MPEG-2 licence also bring hardware mp3 decoding?
Probably not :? or?
No

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mahjongg
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Re: MPEG-2 license also for mp3?

Sat Aug 25, 2012 1:50 pm

Not so stupid a question, you can read some about it here http://en.wikipedia.org/wiki/MPEG-2#Audio

I believe however that the PI is capable of software decoding of MP3, in fact I believe that for H.264 decoding the audio was also done in software, not by the GPU.

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liz
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Re: MPEG-2 license also for mp3?

Sat Aug 25, 2012 1:50 pm

...But you already had software decode anyway. :)
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Killerbee
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Re: MPEG-2 license also for mp3?

Sat Aug 25, 2012 3:43 pm

So MPEG-2 is Video only?

ghans
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Re: MPEG-2 license also for mp3?

Sat Aug 25, 2012 3:50 pm

Yes.
AFAIK the Pi can cope with software decoding MP3 while playing video.
It plays MP3 by itself quite nicely.
Only some digital surround sound thingies make problems.

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toxibunny
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Re: MPEG-2 license also for mp3?

Sat Aug 25, 2012 4:29 pm

would it cost money for hardware mp3 decode?
note: I may or may not know what I'm talking about...

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jackokring
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Re: MPEG-2 license also for mp3?

Sat Aug 25, 2012 4:34 pm

Killerbee wrote:Call me stupid but does the MPEG-2 licence also bring hardware mp3 decoding?
Probably not :? or?
MP3 decode only takes about 300MHz processor or less, while running a graphic EQ too. I'm sure WinAmp on an old pentium III did it fine.
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robwriter
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Re: MPEG-2 license also for mp3?

Sat Aug 25, 2012 5:04 pm

I think the point being made is not that MP3 can't be decoded, but that it takes resource that would be freed if the hardware decode was available. That said, with the MPEG-2 license now available, I can't see any scenarios where this matters, whilst when trying to do software MPEG-2, having to decode MP3 as well was trickier.

recliq
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Re: MPEG-2 license also for mp3?

Mon Aug 27, 2012 3:04 pm

Just make this clear, MP3 has nothing to do with MPEG-2.
MP3 is in fact MPEG-1 Audio Layer III, it's a different codec.

MPEG-1 != (not euqal, different) MPEG-2

yeahbox
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Re: MPEG-2 license also for mp3?

Mon Aug 27, 2012 3:36 pm

recliq wrote:Just make this clear, MP3 has nothing to do with MPEG-2.
Well, that's stretching it. MPEG-2 also defines audiolayer 1, 2 and 3, so you do have a layer 3 structure in MPEG-2 The difference is the samplerates (and some additional bitrates), where MPEG-1 layer 3 is 32kHz, 44.1kHz and 48kHz but MPEG-2 layer 3 is half of the previous, i.e 16kHz, 22.05kHz and 24kHz

So if you by mp3 mean a layer 3 decoder then yes, MPEG-2 falls into that category. But the real problem is that at home the majority of music is stored at 44.1 kHz (CD standard) which made MPEG-1 layer 3 the perfect choice for your music collection back in the days.

recliq
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Re: MPEG-2 license also for mp3?

Mon Aug 27, 2012 4:37 pm

Yes, you are right, MP3 specifies Layer 3 of either MPEG-1 or MPEG-2. :oops:
(But 48kHz sampling frequency is also defined for MPEG-1 Layer 3...)

The reason why I wrote the above is that *most* (if not all) .mp3 files I have encountered so far are MPEG-1 Layer 3.
Eg. most personal use encoders produce MPEG-1 Layer 3, also LAME produces MPEG-1 Layer 3 (IIRC). :mrgreen:

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