[linux-audio-user] [ANN] Aqualung 0.9beta5 released

Mark Knecht markknecht at gmail.com
Sat Jul 8 19:22:25 EDT 2006

On 7/8/06, Cesare Marilungo <cesare at poeticstudios.com> wrote:
> > I agree Lee.
> >
> > In fact there is an old Quicksilver Album (Happy Trials I think) where
> > the vinyl had no gaps in a 25 minute song. When a CD for it came out
> > it played on my hardware CD player as one long song. If I played this
> > on any Linux player other than Aqualung it put gaps in. This was not
> > good. Aqualung was the only player I found that played the music
> > correctly, as the original.
> >
> > I like the way Aqualung does this today.
> >
> > - Mark
> But shouldn't the mp3 be encoded in a particular way to make gapless
> playback work?

Certainly. And as far as I can tell Sound Juicer, which calls the ogg
encoder or the flac encoder - the two formats I use - can as the files
are built correctly.

Note that earlier I said my hardware CD player - a Marantz or Sony or
the one in my car - plays these CD correctly. The other Linux players
I had tried - mplayer and alsaplayer - did not even play the the CDs
correctly. Back in those days I didn't rip much so I don't know what
other rippers might have done. However, I think there are two issues
in making this work:

1) The encoded file - be it mp3, flac or whatever, must be encoded
with no extra silence.

2) The player must get the second file ready to play before the first
one has finished so that if there is not supposed ot be a gap there
will not be a gap.

I am guessing that it's #2 that causes most players problems.

Aqualung has taken this all a step further by making the playback
insensitive to file type, encoding frequency, storage location, etc.

- Mark

> AFAIK, the mp3 format has a fixed frame size, the last frame is always
> only partially filled and so any mp3 track contains some silence at the end.
> And how does Aqualung know if two tracks were meant to be played without
> any gap?
> In theory, the cleanest solution could be to use a CD ripper that writes
> some sort of playlist file that the player can read to know which tracks
> should be played without gaps and which is the duration of the gap when
> it is meant to be there (gaps between tracks on a cd can be != 2secs).
> c.
> --
> www.cesaremarilungo.com

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