**Describe the bug**
Though it ideally should never happen, clipping is sometimes unavoidable.
However, unlike other encoders which let the signal "stay" at the clipping
boundary while it clips, the FLAC encoder does weird things.
When I produce FLAC contained in OGG, the signal overflows or underflows. At
least when I run it through a conversion using http://soundconverter.org/
(which uses GStreamer under the hood) and import it into Audacity. See the
visualization below.
When I produce raw FLAC files, the signal seems to go out of the boundaries
(beyond what Audacity displays). But after 186ms the signal is at max, later
it's back to how it first was, then it produces garbage, then it's at min,
before returning to how it first was after a total of 650ms. The cycle then
continues. See the visualization below.
I have seen the comments around here about how the FLAC encoder is not really
fit for the purpose of streaming, and that it is pretty experimental. We are
therefore transitioning to high-quality Ogg Vorbis instead. But I thought you
might want to know about this problem either way.
**To Reproduce**
```liquidsoap
set("log.file", false)
set("log.stdout", true)
sound = sine(amplitude=1.2)
output.file(
%flac(samplerate=44100, channels=1, compression=5, bits_per_sample=16),
"clipping.flac",
sound
)
output.file(
%ogg(%flac(samplerate=44100, channels=1, compression=5,
bits_per_sample=16)),
"clipping.flac.ogg",
sound
)
```
Hit CTRL-C when a couple seconds have passed. This probably goes without
saying, but don't ever listen to files produced. To check how it looked, I used
Audacity. To open the FLAC contained in OGG file, I had to convert it to
another format first (in my case Ogg Vorbis, using GStreamer/SoundConverter)
before opening it in Audacity.
**Expected behavior**
I expect the signal to stay at the clipping boundary while it clips, discarding
information about what value it has beyond the boundary. See the visualization
below of how the Ogg Vorbis encoder handles this:
**Version details**
- OS: Ubuntu 18.04.1
- Version: `1.3.6`, but we have also encountered this in earlier versions.
**Install method**
Installed from sources
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