[vorbis-dev] ogg123 crossfade

[Paul Martin]

On Tue, Jul 30, 2002 at 11:57:08AM +1200, Ross Levis wrote:

[Please don't top post]

>  Crossfading is complicated to do it properly.  A simple time period 
> crossfade sounds horrible most of the time.

Agreed.

> You need to be testing the volume level up to at least 16 seconds in 
> advance of what is playing and bring in the next song when the finishing 
> song falls below a specific db level.

Actually, that can give bad results. What I've been trying is to sample
the perceived level of the whole song with a granularity of 200ms
(using the replaygain library), do simple stats on it, to work out a
good "fade here" dB level. Mean plus 2 SDs works pretty well.

>  There is also an advantage in 
> testing the volume of the incoming song and using that intelligently in 
> the "when to crossfade" calculations.

Agreed. I've not done any experimentation with that yet. 

> It should also be able to specify the shape of the crossfade of both the 
> outgoing & incoming songs over time.

My current crossfade shape is 1-(x^2) [x -> 0 to 1 over 2 seconds] on
the outgoing song, with the incoming song played in at full volume.

This doesn't work too well with live concert CD tracks.


-- 
Paul Martin <pm at zetnet.net> (work)
  <pm at nowster.zetnet.co.uk> (home)

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