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Subject: RE: gapless mp3 playback with rockbox

RE: gapless mp3 playback with rockbox

From: Christopher Woods <christof_at_infinitus.co.uk>
Date: 2005-12-16

It's not _truly_ gapless, it merely tells the decoder to seek ahead whilst
playing the current track - <pedant mode on> there is an ever-so-slight gap
whilst the decoder threads switch over, even if you tweak the buffer
settings as much as possible to eliminate most of the lag. </pedant mode
off>I long ago gave up trying any one of the 'gapless' plugins for Winamp,
and now have a customised implementation of the Nullsoft cross-fading
DirectSound plugin happily playing my music back to me - which I think is a
better way of doing it too, because DirectSound also allows multiple
simultaneous buffers. Afaik, none of the platforms Rockbox run on are
capable of multi-threaded decoding of more than one file at once, this is
one of the few things the Rio Karma was good at because it had multiple
hardware decoders, enabling true gapless playback, whereas (again, as far as
I know) the Archos, iRiver et al. only have one hardware decoder. Because
the decoding is done in hardware, and due to the coding optimisations for
the much slower CPUs, it would be in my opinion pretty unfeasible,
unfortunately, to have multithreaded decoding of files to enable true
gapless.
 
I'm not intimately familiar with the Rockbox code, but I assume that it
reads the file, buffers and then begins to play, buffering more as it goes
(that's how I figure it works, anyway, and it'd be the most logical method
of implementation) - it's probably doable to implement a routine which would
cache the forthcoming file quicker (the iRiver seems to do this at least
with its default firmware, after you've been playing files sequentially for
a while the gap inbetween them is less, almost like the playing is cacheing
the next track slightly quicker than the first selection you make from the
playlist). However, this still isn't gapless, as you can hear the silence,
and I have to take a rather pessimistic view towards any of these players
being able to truly play back gaplessly, purely due to the restrictions of
their respective hardware implementations.
 
Correct me if I'm wrong anyone? (heh, I can see this becoming my signoff)
Christopher

  _____

From: alex wallis [mailto:wallis@andrelouis.com]
Sent: 16 December 2005 08:57
To: rockbox@cool.haxx.se
Subject: gapless mp3 playback with rockbox

Hi list.
I have just discovered how to enable gapless playback underwinamp without
acception this has worked with all mp3s i have tried it on so it sounds
exactly like your listening to an orriginal cd.
hear is how you do it
To enable gapless MP3 playback, open the Preferences dialog box (click the
 
upper left of Winamp to drop the main menu, click Options, and then
click Preferences).
highlight Output under Plug-ins, highlight DirectSound Output, and click
 
Configure.
Click the Buffering tab and move the Buffer-Ahead On Track Change slider to
 
somewhere between 300 and 1,200ms. Switch to the Other tab and enable the
 
Remove
Silence At The Beginning/End Of Track option.
so was wondering is it possible to do something similar in rockbox or to
create such a feature? as the above method works with all mp3s and ogg files
i have tried it with.
Received on Fri Dec 16 10:55:15 2005


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