Bug#734100: vlc: Video stuttering with ALSA output

[Vitaliy Filippov]

Package: vlc
Version: 2.1.2-2
Severity: important

Hi!

Starting somewhere around VLC 2.x, I experience "video stuttering" problems on many files, mostly >= 720P, MKV/H.264+AC3 (almost all such files), but not only them - for example I also experience it on some MPEG2 720x576 files (mpeg container, mpeg2 video and audio codecs). HW acceleration is disabled, the problem always reproduces at least on 2 different Debian machines (laptop and PC, both 32-bit and both with snd-hda-intel kernel module), and on both debian-multimedia and normal VLC/libav* packages. The same files play without problem in mplayer/mplayer2/mpv.

vlc -vvv output shows many "ES_OUT_SET_(GROUP_)PCR  is called too late" errors; on each error the video playback temporarily stops ("stutters").

...
[0x87a0a30] main audio output warning: playback way too early (-563272): playing silence
[0x87a0a30] main audio output debug: inserting 27037 zeroes
[0xf4c11150] main input error: ES_OUT_SET_(GROUP_)PCR  is called too late (pts_delay increased to 300 ms)
[0xf4c11150] main input error: ES_OUT_RESET_PCR called
[0xf4c11150] main input debug: Buffering 0%
...
[0xf0c45bc0] main decoder debug: End of audio preroll
...
[0xf4c11150] main input debug: Stream buffering done (334 ms in 3 ms)
[0xf4c11150] main input debug: Decoder buffering done in 0 ms
[0x87a0a30] main audio output debug: inserting 9553 zeroes
[0xebc00c58] main vout display debug: auto hiding mouse cursor
[0xf0c36aa8] main decoder debug: End of video preroll
[0xf4c11150] main input error: ES_OUT_SET_(GROUP_)PCR  is called too late (pts_delay increased to 320 ms)
[0xf4c11150] main input error: ES_OUT_RESET_PCR called
...

The key point is, first I've thought it's some video decoder problem, but I was wrong!

I've tried different setups and discovered that the problem is in _direct_ ALSA sound output - i.e. it works all good with PulseAudio! (direct PA; didn't check alsa piped to PA). Also it works with sound disabled or if the "discard all samples" audio device is selected (so it's not an audio decoder problem).

I don't want to have PulseAudio installed, just because for me it's just a useless wrapper for ALSA (everything always worked fine without it) and because I don't like Lennart's creations. :-)

In any case I think it's a bug if ALSA output doesn't work in VLC...

Is it a known problem? Do you have any ideas of fixing it? I've found many "stuttering" problems in VLC bug database, but it seems nobody tried to check for audio output problems...

-- System Information:
Debian Release: jessie/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: i386 (x86_64)
Foreign Architectures: amd64

Kernel: Linux 3.12-trunk-amd64 (SMP w/8 CPU cores)
Locale: LANG=ru_RU.UTF-8, LC_CTYPE=ru_RU.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to ru_RU.UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages vlc depends on:
ii  dpkg                      1.17.1
ii  fonts-freefont-ttf        20120503-1
ii  libaa1                    1.4p5-41
ii  libavcodec54              10:1.2.4-dmo2
ii  libavutil52               10:2.1.1-dmo2
ii  libc6                     2.17-97
ii  libcaca0                  0.99.beta18-1
ii  libfreetype6              2.4.9-1.1
ii  libfribidi0               0.19.5-2
ii  libgcc1                   1:4.8.2-8
ii  libgl1-mesa-glx [libgl1]  10.1~git1312192008.22bf0f~gd~s
ii  libice6                   2:1.0.8-2
ii  libqtcore4                4:4.8.5+git121-g2a9ea11+dfsg-1
ii  libqtgui4                 4:4.8.5+git121-g2a9ea11+dfsg-1
ii  libsdl-image1.2           1.2.12-5
ii  libsdl1.2debian           1.2.15-7
ii  libsm6                    2:1.2.1-2
ii  libstdc++6                4.8.2-8
ii  libtar0                   1.2.19-1
ii  libva-x11-1               1.2.1-2
ii  libva1                    1.2.1-2
ii  libvlccore7               1:2.1.2-dmo1
ii  libx11-6                  2:1.6.2-1
ii  libxcb-composite0         1.9.1-3
ii  libxcb-keysyms1           0.3.9-1
ii  libxcb-randr0             1.9.1-3
ii  libxcb-render0            1.9.1-3
ii  libxcb-shape0             1.9.1-3
ii  libxcb-shm0               1.9.1-3
ii  libxcb-xfixes0            1.9.1-3
ii  libxcb-xv0                1.9.1-3
ii  libxcb1                   1.9.1-3
ii  libxext6                  2:1.3.2-1
ii  libxinerama1              2:1.1.3-1
ii  libxpm4                   1:3.5.10-1
ii  vlc-nox                   2.1.2-2
ii  zlib1g                    1:1.2.8.dfsg-1

Versions of packages vlc recommends:
pn  vlc-plugin-notify  <none>
pn  vlc-plugin-pulse   <none>
ii  xdg-utils          1.1.0~rc1+git20111210-7

Versions of packages vlc suggests:
pn  videolan-doc  <none>

-- no debconf information