VLC does not resample correctly with JACK

[Walter Oesch]

When using the Jack output module audio gets distorted or does not play at all when playing a track with a samplerate other than the one specified in jack.

the (i hope) relevant part of VLC debug messages when starting playback is:

jack debug: JACK audio output initialized (6 channels, rate=48000)
main debug: using audio output module "jack"
main debug: TIMER module_need() : 207.535 ms - Total 207.535 ms / 1 intvls (Avg 207.535 ms)
main debug: output 'f32l' 48000 Hz 3F2R/LFE frame=1 samples/24 bytes
main debug: mixer 'f32l' 48000 Hz 3F2R/LFE frame=1 samples/24 bytes
main debug: filter(s) 'f32l'->'f32l' 48000 Hz->48000 Hz 3F2R/LFE->3F2R/LFE
main debug: conversion pipeline completed
main debug: looking for audio mixer module: 2 candidates
main debug: using audio mixer module "float32_mixer"
main debug: TIMER module_need() : 0.170 ms - Total 0.170 ms / 1 intvls (Avg 0.170 ms)
main debug: input 's24l' 96000 Hz 3F2R/LFE frame=1 samples/18 bytes
main debug: looking for audio filter module: 1 candidate
scaletempo debug: format: 96000 rate, 6 nch, 4 bps, fl32
scaletempo debug: params: 30 stride, 0.200 overlap, 14 search
scaletempo debug: 1.000 scale, 2880.000 stride_in, 2880 stride_out, 2304 standing, 576 overlap, 1344 search, 4800 queue, fl32 mode
main debug: using audio filter module "scaletempo"
main debug: TIMER module_need() : 0.208 ms - Total 0.208 ms / 1 intvls (Avg 0.208 ms)
main debug: filter(s) 's24l'->'f32l' 96000 Hz->96000 Hz 3F2R/LFE->3F2R/LFE
main debug: looking for audio filter module: 14 candidates
jack debug: JACK graph reordered. Our maximum latency=0.
audio_format debug: s24l->f32l, bits per sample: 24->32
main debug: using audio filter module "audio_format"
main debug: TIMER module_need() : 5.259 ms - Total 5.259 ms / 1 intvls (Avg 5.259 ms)
main debug: conversion pipeline completed
main debug: filter(s) 'f32l'->'f32l' 96000 Hz->96000 Hz 3F2R/LFE->3F2R/LFE
main debug: conversion pipeline completed
main debug: filter(s) 'f32l'->'f32l' 105600 Hz->48000 Hz 3F2R/LFE->3F2R/LFE
main debug: looking for audio filter module: 14 candidates
main debug: using audio filter module "samplerate"
main debug: TIMER module_need() : 0.567 ms - Total 0.567 ms / 1 intvls (Avg 0.567 ms)
main debug: conversion pipeline completed
main debug: End of audio preroll
main debug: Decoder buffering done in 214 ms
main warning: PTS is out of range (-7893), dropping buffer
main warning: audio output out of sync, adjusting dates (73547 us)
main warning: not synchronized (73548 us), resampling
main warning: buffer too late (73130), up-sampling
main warning: audio output out of sync, adjusting dates (64012 us)
main warning: not synchronized (64014 us), resampling
main warning: timing screwed, stopping resampling
main warning: buffer too late (137124), up-sampling
main warning: audio output out of sync, adjusting dates (63978 us)
main warning: not synchronized (63980 us), resampling
main warning: buffer way too late (201083), dropping buffer
main warning: audio output out of sync, adjusting dates (64026 us)
main warning: not synchronized (64028 us), resampling
main warning: buffer way too late (222444), dropping buffer
main warning: audio output out of sync, adjusting dates (64113 us)
main warning: not synchronized (64115 us), resampling
main warning: buffer way too late (243892), dropping buffer
main warning: buffer way too late (201226), dropping buffer
main warning: audio output out of sync, adjusting dates (63992 us)
main warning: not synchronized (63994 us), resampling
main warning: buffer way too late (222532), dropping buffer
main warning: audio output out of sync, adjusting dates (63984 us)
main warning: not synchronized (63986 us), resampling
main warning: buffer way too late (243851), dropping buffer
main warning: buffer way too late (201185), dropping buffer
main warning: audio output out of sync, adjusting dates (64004 us)
main warning: not synchronized (64005 us), resampling
main warning: buffer way too late (222502), dropping buffer
main warning: audio output out of sync, adjusting dates (63904 us)
main warning: not synchronized (63905 us), resampling
main warning: buffer way too late (243720), dropping buffer
main warning: buffer way too late (201054), dropping buffer
main warning: audio output out of sync, adjusting dates (106827 us)
main warning: not synchronized (106829 us), resampling
main warning: buffer way too late (265195), dropping buffer
main warning: buffer way too late (222528), dropping buffer
main warning: audio output out of sync, adjusting dates (127947 us)
main warning: not synchronized (127949 us), resampling
main warning: buffer way too late (307790), dropping buffer
main warning: buffer way too late (265123), dropping buffer
main warning: buffer way too late (222457), dropping buffer
main debug: audio output is too slow (21186 us): trashing 10667 us
main debug: audio output is too slow (10519 us): trashing 10666 us
....

When playing a track with higher samplerate the VLC output is flooded with:

main debug: audio output is too slow (1824148 us): trashing 10667 us
main debug: audio output is too slow (1856244 us): trashing 10666 us
main debug: audio output is too slow (1845578 us): trashing 10667 us
...

when playing a track with lower samplerate:

main debug: audio output is starving (-24525), playing silence
main debug: audio output is starving (-24066), playing silence
main debug: audio output is starving (-23354), playing silence
...

I made tests with different settings of samplerate and periode for jack but the result is always the same.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: vlc-plugin-jack 2.0.1-4
ProcVersionSignature: Ubuntu 3.2.0-23.31-lowlatency 3.2.14
Uname: Linux 3.2.0-23-lowlatency i686
ApportVersion: 2.0.1-0ubuntu5
Architecture: i386
Date: Mon Apr 23 12:44:29 2012
InstallationMedia: Xubuntu 11.04 "Natty Narwhal" - Release i386 (20110426.1)
ProcEnviron:
 LANGUAGE=en_US:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: vlc
UpgradeStatus: Upgraded to precise on 2012-04-10 (13 days ago)

[Rémi Denis-Courmont (rdenis)]

Can you please retry with audio time stretching disabled in the preferences?

[Walter Oesch (walteroesch)]

I disabled audio time stretching but nothing changed.

[Rémi Denis-Courmont (rdenis)]

Does the problem happen if you delete /usr/lib/vlc/plugins/audio_filter/libsamplerate_plugin.so then restart VLC ? and /usr/lib/vlc/plugins/audio_filter/libspeex_resampler_plugin.so ?

(You can restore them afterward with the command 'apt-get install --reinstall vlc-nox')

What if you use the ALSA output directly, also at 96 kHz ?

[Walter Oesch (walteroesch)]

I tested removing libsamplerate_plugin.so or libspeex_resampler_plugin.so or both and none of it changed anything.

However playback directly to ALSA workes fine. I made test with various combinations of sample rates for my USB sound interface and the audio track and all of them worked flawlessly.

[Walter Oesch (walteroesch)]

I also checked that ALSA is really running on the sample rate specified on the audio interface with:
cat /proc/asound/card1/pcm0p/sub0/hw_params

[Rémi Denis-Courmont (rdenis)]

That was with scaletempo (time stretching) disabled?

I guess the JACK output is broken. It has not had a maintainer in some years.

[Walter Oesch (walteroesch)]

I took a look at the code of the Jack output module and with some debugging and some luck i found the problem:

in modules/audio_output/jack.c on line 139:

aout_PacketInit is called with p_aout and this p_aout contains the wrong sample rate, because it is set later, on line 146. Moving line 146 up before the call to aout_PacketInit solved the problem.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Launchpad Janitor (janitor)]

This bug was fixed in the package vlc - 2.0.2-1

---------------
vlc (2.0.2-1) unstable; urgency=medium

  [ Edward Wang ]
  * New upstream release (Closes: #679625, #664279, LP: #689122, #936488,
    #942126, #971106, #972615, #973051, #987231, #995003, #998538).
    - Fix Ogg Heap buffer overflow. Thanks to Hugo Beauzée-Luyssen
  * Add the crystalhd plugin to the vlc distribution.
  * libcaca_plugin.so now depends on X11 in this release, so it must
    be installed under vlc (versus vlc-nox).

  [ Reinhard Tartler ]
  * Urgency set to medium because a security issue is fixed in this release

  [ Benjamin Drung ]
  * Add new plugins to vlc-nox:
    - crystalhd (Linux amd64 and i386 only)
    - directfb
    - fbosd (Linux only)
    - omxil (Linux only)
  * Add build dependencies for new plugins.
  * Add new symbols to libvlccore5.
  * Switch to debhelper 8.

 -- Benjamin Drung <email address hidden> Sat, 30 Jun 2012 18:39:41 +0200

[Brian Murray (brian-murray)]

The verification of this Stable Release Update has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.