Bug#697119: pulseaudio: the default global volum control: sudden very loud sound to cause hearing demage

[fermat]

Package: pulseaudio
Version: 2.0-6
Severity: important

Dear Maintainer,

I use a little ear-phone on my computer, and adjust the system volume to about
20%, which is comfortable. I open the VLC player and want to adjust the volume
a little higher. VLC displays the current volume is 100%, so I adjust it to
147%, and I heared a very loud sound I have never imaged. It turned out that
VLC adjust the system volume from 20% to 147%, while the volume 100% it
displays is entirely false and misleading. I think my hearing is hurt since my
ear is rather uncomfortable since then.

I think this is bug both of pulse audio and vlc, so I report bug on both
pulseaudio and vlc.

It is a bug of pulseaudio because it use a default setting that applications
don't have independent volume control. otherwise the volume whill not grow to
147% but rather 20%*147% = 29.4%.

It is apperently a bug of vlc because it displays a very misleading current
volume 100% rather of 20%. Even if some adjust to the volume from 100% to 95%,
it will cause the volume suddenly jumps from 20% to 95%.



-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.2.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=zh_CN.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages pulseaudio depends on:
ii  adduser                       3.113+nmu3
ii  consolekit                    0.4.5-3.1
ii  libasound2                    1.0.25-4
ii  libasound2-plugins            1.0.25-2
ii  libc6                         2.13-37
ii  libcap2                       1:2.22-1.2
ii  libdbus-1-3                   1.6.8-1
ii  libfftw3-3                    3.3.2-3.1
ii  libgcc1                       1:4.7.2-4
ii  libice6                       2:1.0.8-2
ii  libltdl7                      2.4.2-1.1
ii  liborc-0.4-0                  1:0.4.16-2
ii  libpulse0                     2.0-6
ii  libsamplerate0                0.1.8-5
ii  libsm6                        2:1.2.1-2
ii  libsndfile1                   1.0.25-5
ii  libspeexdsp1                  1.2~rc1-7
ii  libstdc++6                    4.7.2-4
ii  libsystemd-daemon0            44-5
ii  libsystemd-login0             44-5
ii  libtdb1                       1.2.10-2
ii  libudev0                      175-7
ii  libwebrtc-audio-processing-0  0.1-2
ii  libx11-6                      2:1.5.0-1
ii  libx11-xcb1                   2:1.5.0-1
ii  libxcb1                       1.8.1-2
ii  libxtst6                      2:1.2.1-1
ii  lsb-base                      4.1+Debian8
ii  udev                          175-7

Versions of packages pulseaudio recommends:
ii  gstreamer0.10-pulseaudio  0.10.31-3+nmu1
pn  pulseaudio-module-x11     <none>
pn  rtkit                     <none>

Versions of packages pulseaudio suggests:
pn  paman             <none>
pn  paprefs           <none>
pn  pavucontrol       <none>
pn  pavumeter         <none>
pn  pulseaudio-utils  <none>

-- Configuration Files:
/etc/pulse/daemon.conf changed:
; daemonize = no
; fail = yes
; allow-module-loading = yes
; allow-exit = yes
; use-pid-file = yes
; system-instance = no
; local-server-type = user
; enable-shm = yes
; shm-size-bytes = 0 # setting this 0 will use the system-default, usually 64 MiB
; lock-memory = no
; cpu-limit = no
flat-volumes = no
; high-priority = yes
; nice-level = -11
; realtime-scheduling = yes
; realtime-priority = 5
; exit-idle-time = 20
; scache-idle-time = 20
; dl-search-path = (depends on architecture)
; load-default-script-file = yes
; default-script-file = /etc/pulse/default.pa
; log-target = auto
; log-level = notice
; log-meta = no
; log-time = no
; log-backtrace = 0
; resample-method = speex-float-3
; enable-remixing = yes
; enable-lfe-remixing = no
; flat-volumes = yes
; rlimit-fsize = -1
; rlimit-data = -1
; rlimit-stack = -1
; rlimit-core = -1
; rlimit-as = -1
; rlimit-rss = -1
; rlimit-nproc = -1
; rlimit-nofile = 256
; rlimit-memlock = -1
; rlimit-locks = -1
; rlimit-sigpending = -1
; rlimit-msgqueue = -1
; rlimit-nice = 31
; rlimit-rtprio = 9
; rlimit-rttime = 1000000
; default-sample-format = s16le
; default-sample-rate = 44100
; alternate-sample-rate = 48000
; default-sample-channels = 2
; default-channel-map = front-left,front-right
; default-fragments = 4
; default-fragment-size-msec = 25
; enable-deferred-volume = yes
; deferred-volume-safety-margin-usec = 8000
; deferred-volume-extra-delay-usec = 0


-- no debconf information