Docker container for LosslessCut

This is a Docker container for LosslessCut.

The GUI of the application is accessed through a modern web browser (no installation or configuration needed on the client side) or via any VNC client.

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LosslessCut
The swiss army knife of lossless video/audio editing

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Table of Content

• Quick Start
• Usage
  • Environment Variables
  • Data Volumes
  • Ports
  • Audio playback
  • Changing Parameters of a Running Container
• Docker Compose File
• Docker Image Versioning
• User/Group IDs
• Accessing the GUI
• Security
  • Certificates
  • VNC Password
• Shell Access
• Support or Contact

Quick Start

Launch the LosslessCut docker container with the following command:

docker run --rm -d \
    --name=losslesscut \
    -p 5800:5800 \
    -v /path/to/data/losslesscut:/config:rw \
    -v $HOME:/storage:rw \
    outlyernet/losslesscut

Where:

• /path/to/data/losslesscut: Where the application stores any persistent data.
• $HOME: This location contains files from your host that need to be accessible to the application.

Browse to http://your-host-ip:5800 to access the LosslessCut GUI. Files from the host appear under the /storage folder in the container.

Notes:

• This Docker command is given as an example and parameters should be adjusted to your needs.
• The image is available in both Docker Hub as outlyernet/losslesscut and the GitHub Container Registry as ghcr.io/outlyer-net/docker-losslesscut
• For additional documentation see the base image.

Usage

docker run [--rm] [-d] \
    [--name=losslesscut] \
    [-e <VARIABLE_NAME>=<VALUE>]... \
    [-v <HOST_DIR>:<CONTAINER_DIR>[:PERMISSIONS]]... \
    [-p <HOST_PORT>:<CONTAINER_PORT>]... \
    outlyernet/losslesscut

Parameter	Description
--rm	Destroy the container once it stops.
-d	Run the container in the background. If not set, the container runs in the foreground.
-e	Pass an environment variable to the container. See the Environment Variables section for more details.
-v	Set a volume mapping (allows to share a folder/file between the host and the container). See the Data Volumes section for more details.
-p	Set a network port mapping (exposes an internal container port to the host). See the Ports section for more details.
--name	Assign a name to the container

Environment Variables

To customize some properties of the container, the following environment variables can be passed via the -e parameter (one for each variable).
Values of this parameter has the format <VARIABLE_NAME>=<VALUE>.

Variable	Description	Default
USER_ID	ID of the user the application runs as. See User/Group IDs to better understand when this should be set.	1000
GROUP_ID	ID of the group the application runs as. See User/Group IDs to better understand when this should be set.	1000
SUP_GROUP_IDS	Comma-separated list of supplementary group IDs of the application.	""
UMASK	Mask that controls how file permissions are set for newly created files. The value of the mask is in octal notation. By default, the default umask value is 0022, meaning that newly created files are readable by everyone, but only writable by the owner. See the online umask calculator at http://wintelguy.com/umask-calc.pl.	0022
LANG	Set the locale, which defines the application's language, if supported. Format of the locale is language[_territory][.codeset], where language is an ISO 639 language code, territory is an ISO 3166 country code and codeset is a character set, like UTF-8. For example, Australian English using the UTF-8 encoding is en_AU.UTF-8.	en_US.UTF-8
TZ	TimeZone used by the container. Timezone can also be set by mapping /etc/localtime between the host and the container.	Etc/UTC
KEEP_APP_RUNNING	When set to 1, the application will be automatically restarted when it crashes or terminates.	0
APP_NICENESS	Priority at which the application should run. A niceness value of -20 is the highest priority and 19 is the lowest priority. The default niceness value is 0. NOTE: A negative niceness (priority increase) requires additional permissions. In this case, the container should be run with the docker option --cap-add=SYS_NICE.	0
INSTALL_PACKAGES	Space-separated list of packages to install during the startup of the container. Packages are installed from the repository of the Linux distribution this container is based on. ATTENTION: Container functionality can be affected when installing a package that overrides existing container files (e.g. binaries).	""
CONTAINER_DEBUG	Set to 1 to enable debug logging.	0
DISPLAY_WIDTH	Width (in pixels) of the application's window.	1920
DISPLAY_HEIGHT	Height (in pixels) of the application's window.	1080
DARK_MODE	When set to 1, dark mode is enabled for the application.	0
WEB_AUDIO	When set to 1, audio support is enabled, meaning that any audio produced by the application is played through the browser. Note that audio is not supported for VNC clients.	0
SECURE_CONNECTION	When set to 1, an encrypted connection is used to access the application's GUI (either via a web browser or VNC client). See the Security section for more details.	0
SECURE_CONNECTION_VNC_METHOD	Method used to perform the secure VNC connection. Possible values are SSL or TLS. See the Security section for more details.	SSL
SECURE_CONNECTION_CERTS_CHECK_INTERVAL	Interval, in seconds, at which the system verifies if web or VNC certificates have changed. When a change is detected, the affected services are automatically restarted. A value of 0 disables the check.	60
WEB_LISTENING_PORT	Port used by the web server to serve the UI of the application. This port is used internally by the container and it is usually not required to be changed. By default, a container is created with the default bridge network, meaning that, to be accessible, each internal container port must be mapped to an external port (using the -p or --publish argument). However, if the container is created with another network type, changing the port used by the container might be useful to prevent conflict with other services/containers. NOTE: a value of -1 disables listening, meaning that the application's UI won't be accessible over HTTP/HTTPs.	5800
VNC_LISTENING_PORT	Port used by the VNC server to serve the UI of the application. This port is used internally by the container and it is usually not required to be changed. By default, a container is created with the default bridge network, meaning that, to be accessible, each internal container port must be mapped to an external port (using the -p or --publish argument). However, if the container is created with another network type, changing the port used by the container might be useful to prevent conflict with other services/containers. NOTE: a value of -1 disables listening, meaning that the application's UI won't be accessible over VNC.	5900
VNC_PASSWORD	Password needed to connect to the application's GUI. See the VNC Password section for more details.	""
ENABLE_CJK_FONT	When set to 1, open-source computer font WenQuanYi Zen Hei is installed. This font contains a large range of Chinese/Japanese/Korean characters.	0

Data Volumes

The following table describes data volumes used by the container.
The mappings are set via the -v parameter.
Each mapping is specified with the following format:
<HOST_DIR>:<CONTAINER_DIR>[:PERMISSIONS].

Container path	Permissions	Description
/config	rw	This is where the application stores its configuration, states, log and any files needing persistency.
/storage	rw	This location contains files from your host that need to be accessible to the application.

Ports

Here is the list of ports used by the container. They can be mapped to the host via the -p parameter (one per port mapping). Each mapping is defined in the following format: <HOST_PORT>:<CONTAINER_PORT>. The port number inside the container cannot be changed, but you are free to use any port on the host side.

Port	Mapping to host	Description
5800	Optional	Port to access the application's GUI via the web interface. Mapping to the host is optional if access through the web interface is not wanted. For a container not using the default bridge network, the port can be changed with the WEB_LISTENING_PORT environment variable.
5900	Optional	Port to access the application's GUI via the VNC protocol. Mapping to the host is optional if access through the VNC protocol is not wanted. For a container not using the default bridge network, the port can be changed with the VNC_LISTENING_PORT environment variable.

Audio playback

Audio can be played when accessed via web browser.

To enable it set the environment variable WEB_AUDIO to 1.

You'll also need to enable audio from within the browser via the three-dots menu overlaid on the left hand of the window.

See the Environment Variables section

Changing Parameters of a Running Container

As can be seen, environment variables, volume and port mappings are all specified while creating the container.

The following steps describe the method used to add, remove or update parameter(s) of an existing container. The general idea is to destroy and re-create the container:

1. Stop the container (if it is running):

docker stop losslesscut

2. Remove the container:

docker rm losslesscut

3. Create/start the container using the docker run command, by adjusting parameters as needed.

NOTE: Since all application's data is saved under the /config container folder, destroying and re-creating a container is not a problem: nothing is lost and the application comes back with the same state (as long as the mapping of the /config folder remains the same).

Docker Compose File

An example docker-compose.yaml file is provided for use with Docker Compose.

Make sure to adjust according to your needs. Note that only mandatory network ports are part of the example.

Docker Image Versioning

Each release of a Docker image is versioned using semantic versioning matching the version of the bundled LosslessCut.
Additional tags for major and major.minor versions are also provided.
In case the image is updated it will have an additional -v<NUMBER> indicating the new version.

Example tags:

Tag	Interpret as
:latest	Always points to the most up to date image
:3.47.1	LosslessCut v3.47.1
:3.47	Latest image built with LosslessCut v3.47.x
:3	Latest image built with LosslessCut v3.x.y
:3.47-v1	First image built with LosslessCut v3.47.x

User/Group IDs

When using data volumes (-v flags), permissions issues can occur between the host and the container.
For example, the user within the container may not exist on the host.
This could prevent the host from properly accessing files and folders on the shared volume.

To avoid any problem, you can specify the user the application should run as.

This is done by passing the user ID and group ID to the container via the USER_ID and GROUP_ID environment variables.

To find the right IDs to use, issue the following command on the host, with the user owning the data volume on the host:

$ id <username>

Which gives an output like this one:

uid=1000(myuser) gid=1000(myuser) groups=1000(myuser),4(adm),24(cdrom),27(sudo),46(plugdev),113(lpadmin)

The value of uid (user ID) and gid (group ID) are the ones that you should be given the container.

Accessing the GUI

Assuming that container's ports are mapped to the same host's ports, the graphical interface of the application can be accessed via:

• A web browser:

http://<HOST IP ADDR>:5800

• Any VNC client:

<HOST IP ADDR>:5900

Security

By default, access to the application's GUI is done over an unencrypted connection (HTTP or VNC).

Secure connection can be enabled via the SECURE_CONNECTION environment variable.
See the Environment Variables section for more details on how to set an environment variable.

When enabled, application's GUI is performed over an HTTPs connection when accessed with a browser.
All HTTP accesses are automatically redirected to HTTPs.

When using a VNC client, the VNC connection is performed over SSL.
Note that few VNC clients support this method. SSVNC is one of them.

Certificates

Here are the encryption certificate files needed by the container.
By default, when they are missing, self-signed certificates are generated and used.
All files have PEM encoded, x509 certificates.

Container Path	Purpose	Content
/config/certs/vnc-server.pem	VNC connection encryption.	VNC server's private key and certificate, bundled with any root and intermediate certificates.
/config/certs/web-privkey.pem	HTTPs connection encryption.	Web server's private key.
/config/certs/web-fullchain.pem	HTTPs connection encryption.	Web server's certificate, bundled with any root and intermediate certificates.

NOTE: To prevent any certificate validity warnings/errors from the browser or VNC client, make sure to supply your own valid certificates.

NOTE: Certificate files are monitored and relevant daemons are automatically restarted when changes are detected.

VNC Password

To restrict access to your application, a password can be specified. This can be done via two methods:

• By using the VNC_PASSWORD environment variable.
• By creating a .vncpass_clear file at the root of the /config volume. This file should contain the password in clear-text. During the container startup, content of the file is obfuscated and moved to .vncpass.

The level of security provided by the VNC password depends on two things:

• The type of communication channel (encrypted/unencrypted).
• How secure the access to the host is.

When using a VNC password, it is highly desirable to enable the secure connection to prevent sending the password in clear over an unencrypted channel.

ATTENTION: Password is limited to 8 characters. This limitation comes from the Remote Framebuffer Protocol RFC (see section 7.2.2). Any characters beyond the limit are ignored.

Shell Access

To get shell access to the running container, execute the following command:

docker exec -ti CONTAINER sh

Where CONTAINER is the ID or the name of the container used during its creation (e.g. losslesscut).

Support or Contact

Having troubles with the container or have questions? Please create a new issue.

For other great Dockerized applications by jlesage, see https://jlesage.github.io/docker-apps.