Grouping in the "list" command was completely broken from the start,
unlike "count group". I have no idea what I have been thinking when I
wrote commit ae178c77bd, but it didn't
make any sense.
This commit is a rewrite of the feature.
For clients to be able to detect this feature, this commit also
increments the protocol version.
So long, autotools! This is my last MPD related project to migrate
away from it. It has its strengths, but also very obvious weaknesses
and weirdnesses. Today, many of its quirks are not needed anymore,
and are cumbersome and slow. Now welcome our new Meson overlords!
Previously, there was the setting `buffered_before_play` which
specified a percentage of the audio buffer, defaulting to `10%`. That
was working well enough for quite some time, until high-quality audio
formats became common.
At 44.1 kHz, 16 bit stereo, MPD collected 2.3 seconds worth of data in
the buffer before starting playback. With the same default settings
and 192 kHz, 24 bit stereo, that was only 0.27 seconds.
Making this depend on the byte size only leads to high latency at low
quality, and too little data at high quality. The natural choice
would be to use a duration instead of a byte size, which should give
the same good experience with all audio formats.
Since the `buffered_before_play` configuration setting was not
understood well by users and caused more harm than good, this commit
deprecates it. It has now no effect.
Simplify the formula, and I guess this makes the formula more
reliable. Imagine somebody configured `buffered_before_play` larger
than 25%; then the decoder would be woken up all the time. This
doesn't seem logical. On the other hand, it's easy to understand that
the decoder should be woken up below 75% buffer fill.