Re: Adding fade effect

[Eric Wong <e@80x24.org>]

Rene Maurer <rmnet@mailc.net> wrote:
> Eric Wong <e@80x24.org> wrote:
> 
> > command: exec sox "$INFILE" $SOXFMT - $TRIMFX fade 0 =0 5
> > 
> > I think the above fade example requires sox 14.4.x and later,
> 
> I have SoX v14.4.1 but the "=0 syntax" isn't supported.

> Surprisingly doing just
> 
> command: exec sox "$INFILE" $SOXFMT - $TRIMFX fade 0 5 5
> 
> on a playing song starts fade out immediate and does the job (fade out
> current song) as desired!

Ah, OK, I didn't realize you wanted you wanted to fade out immediately
(as opposed to fadiing out the last few seconds of every song
 as is typical for some radio stations).

> > if you're using an older version you'll probably need to calculate
> > the "=0" offset based on the length of the track itself, but
> > also need to take into account the offset set by the $TRIMFX
> > variable (if you're seeking)
> 
> This was my first idea but as already said, this seams not to be
> necessary...

OK, I thought you wanted something like a crossfade effect in MPD
where you fade out every song.  However, fade-in does not seem
to work right if seeking.

But just trying "fade 5 =0 5" seems to work right as long as you
do not seek, it just sounds horrible with a lot of silence :<

> > Again, I recommend editing the source instead of the sink as it won't
> > restart the device and for most effects, there won't be an audible
> > gap.
> 
> Done. It works well!
> 
> The documentation http://dtas.80x24.org/dtas-player_effects.txt brought
> me on the wrong way:
> 
> ,----
> | 1. source effects
> |
> |  - anything which does not change the length of the audio
> `----

Ah, a few lines below, there is:

  Effects which modify the length of the audio is not recommended here,
  as seek functionality will be impaired.

I can make the following change (wording suggestions appreciated!):

--- a/Documentation/dtas-player_effects.txt
+++ b/Documentation/dtas-player_effects.txt
@@ -10,6 +10,7 @@ They are applied in the order described.
   - ReplayGain (simple vol/gain changes)
   - anything which does not change the length of the audio:
     vol, stereo, highpass, lowpass, loudness, bass, treble, equalizer, ...
+  - ...or the fade effect for fading tracks out.
 
   Modifying source effects should introduce no extra gaps in playback.
   Effects which modify the length of the audio is not recommended here,

-- 
EW