`output.file` with some encoders produces paddings

[vitoyucepi]

Describe the bug Output to file with encoders %mp3, %shine and $ffmpeg(mp3) produces padding at the start and the end.

To Reproduce

def o(codec, file)
    output.file(
        reopen_delay=2.0,
        reopen_when={true},
        codec,
        file,
        sine(amplitude=0.5, 10000.)
    )
end

p='/tmp/'
s='%H_%M_%S'
o(%shine(samplerate=48000, bitrate=320), '#{p}shine_#{s}.mp3')
o(%mp3(samplerate=48000, bitrate=320), '#{p}mp3_#{s}.mp3')
o(%opus(samplerate=48000, bitrate=320), '#{p}opus_#{s}.opus')
o(%vorbis.cbr(samplerate=48000, bitrate=320), '#{p}vorbis_#{s}.ogg')
o(%ffmpeg(format="mp3", %audio(codec="libmp3lame", samplerate=48000, b="320k")), '#{p}ffmpeg_mp3_#{s}.mp3')
o(%ffmpeg(format="opus", %audio(codec="libopus", samplerate=48000, b="320k")), '#{p}ffmpeg_opus_#{s}.opus')
o(%ffmpeg(format="ogg", %audio(codec="libvorbis", samplerate=48000, b="320k")), '#{p}ffmpeg_vorbis_#{s}.ogg')

Screenshots from audacity

• ffmpeg+mp3
• ffmpeg+opus
• ffmpeg+vorbis
• mp3
• opus
• shine
• vorbis

Expected behavior %mp3, %shine and $ffmpeg(mp3) encoders should produce files without paddings.

Version details

• OS: ubuntu:22.04 in docker
• Version: 2.1.3

Install method Deb package from liquidsoap releases at github

Common issues https://github.com/savonet/liquidsoap/discussions/2838#discussioncomment-4645835

2726

Additional I've found some oddities in %vorbis encoder.

• Odd vorbis at 10kHz
• Odd vorbis at 4800 Hz

[vitoyucepi]

Paddings in %mp3 and %shine still exist in 2.2.4-1. It seems that some encoders can loose/duplicate data when liquidsoap reopens files.

[toots]

The missing data was most likely addressed with the fix for https://github.com/savonet/liquidsoap/issues/3675

[vitoyucepi]

I'm not sure if this is a bug or intended behavior.