Skip to content
Snippets Groups Projects
Forked from VideoLAN / VLC
133 commits behind the upstream repository.
Alexandre Janniaux's avatar
Alexandre Janniaux authored
This patch adds a new metric to track and understand the behaviour of
the input pacing done from the input buffering values. The behaviour is
showing correct properties currently, but as will be shown later in this
commit message, this metric helps debugging pacing issues leading to
screen freeze.

In the work for making clock-start distributed across every clock
tracker, and because of a change removing the call to the function
input_clock_ChangeSystemOrigin, the input clock wake-up delay was not
computed correctly. Specifically, a huge delay of multiple hundred of
millisecond was appearing at the startup of the playback for file://
media, leading to a huge gap in playback.

The problem can be revealed when tracing the input_clock_GetWakeup
values. Those values are used to pace the input, and they are dates
matching with up until when the input is allowed to sleep, or 0 to
disable sleeping altogether. The value returned is valid up until
vlc_tick_now() is bigger or a new input_clock_Update() is made.

By substracting vlc_tick_now() to this date when the value is not 0, we
can get the time the input is supposed to wait before doing anything
else. The graph would typically look like this when the freeze was
happening at the beginning of the playback

       Input clock
         wake up
           ^
    330ms -|             +----+
           |             |    |
           |             |    |
        0 -| ------------+    +--------..
           +----------------------------->t

In the current state or after proper fixes for the input pacing were
done, it would display the following graph:

        Input clock
          wake up
            ^
            |
            +----------------------------->t
         0 -| ------------++--------------
            |             ||
            |             || 
    -550ms -|             ++

As such, a very high value looks suspiciously wrong, and improvement
could be made later to start the wake-up delay at -pts_delay immediately
instead of returning 0 as long as the reference point is not registered
yet in the input clock buffering subsystem.

This metric also catches additional artifacts that are generated by the
input decoder waits right at the end of buffering, which might be
interesting to investigate later.
5f6060a4

VLC media player

VLC is a libre and open source media player and multimedia engine, focused on playing everything, and running everywhere.

VLC can play most multimedia files, discs, streams, devices and is also able to convert, encode, stream and manipulate streams into numerous formats.

VLC is used by many over the world, on numerous platforms, for very different use cases.

The engine of VLC can be embedded into 3rd party applications, and is called libVLC.

VLC is part of the VideoLAN project and is developed and supported by a community of volunteers.

The VideoLAN project was started at the university École Centrale Paris who relicensed VLC under the GPLv2 license in February 2001. Since then, VLC has been downloaded billions of times.

License

VLC is released under the GPLv2 (or later) license. On some platforms, it is de facto GPLv3, because of the licenses of dependencies.

libVLC, the engine is released under the LGPLv2 (or later) license.
This allows embedding the engine in 3rd party applications, while letting them to be licensed under other licenses.

Platforms

VLC is available for the following platforms:

  • Windows (from 7 and later, including UWP platforms and all versions of Windows 10)
  • macOS (10.10 and later)
  • GNU/Linux and affiliated
  • BSD and affiliated
  • Android (4.2 and later), including Android TV and Android Auto
  • iOS (9 and later), including AppleTV and iPadOS
  • Haiku, OS/2 and a few others.

Not all platforms receive the same amount of care, due to our limited resources.

Nota Bene: The Android app and the iOS app are located in different repositories than the main one.

Contributing & Community

VLC is maintained by a community of people, and VideoLAN is not paying any of them.
The community is composed of developers, helpers, maintainers, designers and writers that want this open source project to thrive.

The main development of VLC is done in the C language, but this repository also contains plenty of C++, Obj-C, asm and Rust.

Other repositories linked to vlc are done in languages including Kotlin/Java (Android), Swift (iOS), and C# (libVLCSharp).

We need help with the following tasks:

  • Coding
  • Packaging for Windows, macOS and Linux distributions
  • Technical writing for the documentation
  • Design
  • Support
  • Community management and communication.

Please contribute :)

We are on IRC. You can find us on the #videolan channel on Libera.chat.

Contributions

Contributions are now done through Merge Requests on our GitLab repository.

CI and discussions should be resolved before a Merge Request can be merged.

libVLC

libVLC is an embeddable engine for 3rd party applications and frameworks.

It runs on the same platforms as VLC (and sometimes on more) and can provide playback, streaming and conversion of multimedia files and streams.

libVLC has numerous bindings for other languages, such as C++, Python and C#.

Support

Links

Some useful links that might help you:

Source Code sitemap

ABOUT-NLS          - Notes on the Free Translation Project.
AUTHORS            - VLC authors.
COPYING            - The GPL license.
COPYING.LIB        - The LGPL license.
INSTALL            - Installation and building instructions.
NEWS               - Important modifications between the releases.
README             - Project summary.
THANKS             - VLC contributors.

bin/               - VLC binaries.
bindings/          - libVLC bindings to other languages.
compat/            - compatibility library for operating systems missing
                     essential functionalities.
contrib/           - Facilities for retrieving external libraries and building
                     them for systems that don't have the right versions.
doc/               - Miscellaneous documentation.
extras/analyser    - Code analyser and editor specific files.
extras/buildsystem - Different build system specific files.
extras/misc        - Files that don't fit in the other extras/ categories.
extras/package     - VLC packaging specific files such as spec files.
extras/tools/      - Facilities for retrieving external building tools needed
                     for systems that don't have the right versions.
include/           - Header files.
lib/               - libVLC source code.
modules/           - VLC plugins and modules. Most of the code is here.
po/                - VLC translations.
share/             - Common resource files.
src/               - libvlccore source code.
test/              - Testing system.