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Subject: Re: AW: idea
From: Dave Chapman (dave_at_dchapman.com)
Date: 2002-05-13


On Monday 13 May 2002 06:25, Stefan wrote:
> Rob wrote:
> >I assume we could read the head of a file to decide if it is or isn't mp3.
> >We list it in either case, but if it is not mp3, ou can't play it. I
> >think this makes more sense then judging by the file name or extension.
>
> The Archos recorder ( maybe the player too ) is able to play mp3 _and_ mp2.
> So we should play every mpeg stream that can be decoded from the MAS...

Yes - both the MAS 3507D (Player) and MAS 3587F (Recorder) support "MPEG
1/2/2.5 Layer 2/3" audio. The recorder can encode to VBR mp3 only.

Technically, it could probably also play the audio tracks from various
formats of video files (e.g. DivX, DVDs)- if they contained mpeg audio tracks
and we can write a parser for them. The only legal mpeg audio the MAS can't
play is layer 1 - but I have never seen that in the real world.

There are also various possible formats for encapsulating mpeg streams -
elementary streams (this is the format for "mp3"), packetised elementary
streams (PES), program streams (PS - aka VOB) and transport streams (TS).
The MAS itself requires an elementary stream.

So the list of supported file types could grow and grow - making our
marketing department very happy. :-)

Going back to Rob's idea, I think this is just an implementation detail that
can be easily changed. I personally think that checking the filename (for
mp3/mp2/mpa) will be enough in the first instance, but at some point we will
need to scan the file for possible ID3 information, so we can check the
format more thoroughly then. Remember - the more disk activity, the shorter
the battery life.

Dave.



Page was last modified "Jan 10 2012" The Rockbox Crew
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