Inferior sound quality for PCM/ulaw when compared to MPlayer

[sampsa]

Hello,

I am streaming PCM/ulaw audio from a webcam using both VLC and MPlayer.

vlc rtsp://admin:12345@192.168.1.30

mplayer rtsp://admin:12345@192.168.1.30

VLC has inferior sound quality, with a "robotic"/"metallic" sound

VLC output tells me that:

[0x7ff908002f78] main audio resampler debug: looking for audio resampler module matching "any": 3 candidates
[0x7ff908002f78] main audio resampler debug: using audio resampler module "ugly_resampler"

After some googling it turns out that this is an old bug of VLC 2.1.4

https://bugs.archlinux.org/task/41414
https://bbs.archlinux.org/viewtopic.php?pid=1442284

A work-around would be to use the speex resampler, but that doesn't work either..

vlc --audio-resampler speex ..
vlc --audio-resampler Speex" ..
vlc --audio-resampler "speex" ..
vlc --audio-resampler "Speex" ..

Now VLC output tells me that ..

main debug: looking for audio resampler module matching "Speex": 3 candidates
pulse debug: changing sink 0: alsa_output.pci-0000_00_1b.0.analog-stereo (Built-in Audio Analog Stereo)
main debug: using audio resampler module "ugly_resampler"
main debug: End of audio preroll

I need to give the audio-resampler option from the command line, as I am using the VLC python plugins.

Any solution/fix appreciated!

Regards,

Sampsa

[Rémi Denis-Courmont]

That's a bug in Arch Linux, not in VLC. We cannot help you here.

[sampsa]

I am using ubuntu 14.04, so the bug seems to be there too ..!

What's is the switch for turning on speex resampler (the quick fix) ?

[Rémi Denis-Courmont]

Speex is known buggy and broken. It is no accident that it is disabled by default. For good resampling, you want to use SRC (samplerate), which is the default where available.

If you distro returns ugly rather than samplerate, then it is a distro issue.

[sampsa]

Dear Remi,

If the same problem occurs in ubuntu, linux mint, arch linux and gentoo (I have tried by explicitly testing with ubuntu and mint, others were confirmed by google), I can safely assume that the problem occurs in ALL linux distros, so then I can't agree that it is a distro problem..! If those distros install the libsamplerate as they should and VLC is unable to find it - then it is a VLC problem.

.. and how about your own linux distro - whichever you are using - do you get the problem yourself?

Regards,

Sampsa

P. S.

Here is the original bug report discarded by VLC devs:

https://trac.videolan.org/vlc/ticket/11844#comment:2

.. which leads to this link .. people seem quite desperate, trying to do fixes that result in even more VLC bugs:

https://bugs.archlinux.org/task/39676

[sampsa]

Some more info..

vlc -vvv

reports the following:

configured with ./configure '--includedir=${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=${prefix}/share/info' '--localstatedir=/var' '--libdir=${prefix}/lib/x86_64-linux-gnu' '--libexecdir=${prefix}/lib/x86_64-linux-gnu' '--disable-dependency-tracking' '--build=x86_64-linux-gnu' ....... '--enable-samplerate' ...... --param=ssp-buffer-size=4 -Wformat -Werror=format-security' 'build_alias=x86_64-linux-gnu'

Libsamplerate is installed OK:

sampsa@sampsa-xps13:~$ sudo dpkg -L libsamplerate0
/.
/usr
/usr/share
/usr/share/doc
/usr/share/doc/libsamplerate0
/usr/share/doc/libsamplerate0/changelog.Debian.gz
/usr/share/doc/libsamplerate0/copyright
/usr/lib
/usr/lib/x86_64-linux-gnu
/usr/lib/x86_64-linux-gnu/libsamplerate.so.0.1.8
/usr/lib/x86_64-linux-gnu/libsamplerate.so.0

sampsa@sampsa-xps13:/usr/lib/x86_64-linux-gnu$ ls libsamplerate.*
libsamplerate.a libsamplerate.so libsamplerate.so.0 libsamplerate.so.0.1.8
sampsa@sampsa-xps13:/usr/lib/x86_64-linux-gnu$ ls -l libsamplerate.so
lrwxrwxrwx 1 root root 22 helmi 4 2014 libsamplerate.so -> libsamplerate.so.0.1.8
sampsa@sampsa-xps13:/usr/lib/x86_64-linux-gnu$ ls -l libsamplerate.so.0
lrwxrwxrwx 1 root root 22 elo 26 21:30 libsamplerate.so.0 -> libsamplerate.so.0.1.8

Regards,

Sampsa