DVB-MABR-Tool

Welcome to the DVB-MABR Validation Tool.

The repository contains a Python script (app.py), a configuration file (config.ini), and three scripts for launching the application in the different modes described in the DVB's RfP a/o the V2V (Verification and Validation) document.

Description

The Python script app.py is designed to configure and run a media processing application using the GPAC library. It loads configurations from the provided config.ini file and/or from the command-line, processes command-line arguments, and initiates the media processing session accordingly. The application can run in two modes: server or gateway.

Requirements

• Python 3.x
• GPAC library (libgpac.so/.dll/.dylib):
  1. installed with a prefix detected by pkg-config and
  2. accessible from your shell (Windows: export PATH= ; Linux: export LD_LIBRARY_PATH= ; MacOS: export DYLD_LIBRARY_PATH=)
• A MPEG-DASH player (GPAC (gpac -play http://127.0.0.1:8080/Manifest.mpd)), dash.js, Theoplayer, ...) for viewing the stream (optional)

Usage

1. Configuration Setup:

   • If necessary modify the config.ini file to customize settings according to your requirements. Ensure that all necessary parameters are correctly set for the chosen mode (server or gateway).

2. Running Examples:

   • The repository provides a script (run_servers.sh) using the TAD streaming content to demonstrate the sequential execution of server and gateway modes. This script can be executed to automatically run the servers.

   • Example usage:

     ./run_servers.sh

     Then choose which TAD stream to execute:

     Choose a stream source:
     A: Live segment template without manifest updates
     B: Live segment template with manifest updates every 30s
     C: Live segment timeline with manifest updates every 30s
     D: Multi-period, 1 period per minute
     E: low-latency single rate
     F: low-latency multi rate

     then run this command

      ./scripts/launch_gateway.sh 

     to launch the gateway with default configuration.

3. Viewing the Stream:

   • After launching the application, you can use dash.js or the GPAC player (gpac -play http://127.0.0.1:8080/Manifest.mpd) to view the stream. The playback link will be provided in the terminal output for gateway mode.
   • The default playback URL is http://127.0.0.1:8080/Manifest.mpd.
   • When using dash.js you may need to install a CORS extension for your browser.

4. Advanced mode: manual launch of the Application:

   • Execute the appropriate launch script based on the desired mode:
     • For running in server mode with default multicast adreeses/options, execute python3 app.py config.ini mode=server stream_src="http_source_link" .
     • For running in gateway mode, execute with default multicast adreeses/optionspython3 app.py config.ini mode=gateway .
   • Example usage:

     ./scripts/launch_server.sh
     ./scripts/launch_gateway.sh

   • Notes on configurable options:
     • To select how the URI of objects delived should be constructed use the option: "fdt_absolute_url" in the global configuration file.
     • To select how the manifests and init segments are delivered use the option: "use_inband_transport" in the global configuration file.

Note

Troubleshoot:

• Error or warning messages should be processed by order of appearance. There is a butterfly effect in errors so try to identify the root error.
• Ensure that the GPAC library is properly installed on your system.
• Additional parameters and configurations can be added to the config.ini file as needed.
• The GPAC Python bindings use ctypes for interfacing with libgpac filter session, while providing an object-oriented wrapper hiding all ctypes internals and GPAC C design.
• The timeout of the repair mode depends on this patch which is not yet in GPAC master.
• In case of gateway errors, one can check the state of the HTTP cache by replace the gmem value of rdirs = gmem by any valid folder. Then inspect this cache folder.

You must:

• Use the bindings which come along with your GPAC installation, otherwise ABI/API might mismatch, resulting in crashes.
• Use a regular GPAC build, not a static library version (so python bindings are not compatible with static or mp4box-only build).
• Make sure the libgpac shared library is known to your dynamic library loader.

The binding is called libgpac.py, and is by default available in GPAC share folder, for example /usr/local/share/gpac/python. It is hosted in GPAC source tree under share/python.

The Python module handler is furthermore very likely not configured to look at this directory, in app.py we have to indicate where to look: sys.path.append('/usr/local/share/gpac/python')

Alternatively you can use pip to install the binding.

For more information on this visit:

• the wiki page: wiki
• or this post: github discussion