dlna-cast

A cross-platform command-line tool that casts screen and media file to remote DLNA device.

Introduction

dlna-cast uses ffmpeg to capture screen and audio, then convert them into HLS streams which could be served by a simple HTTP server. The HLS url will be send to the selected device via uPnP protocol and the screen will be casted to the remote device (smart TV, typically).

This tool is supposed to be cross-platform but currently I don't have a Linux or MacOS device at hand so it can only run on Windows now. It won't be hard to support other platforms though, as there is no platform specific dependencies.

HLS is chosen just because it is easy to implement. But the problem of HLS is its high latency (up to 5s or more) so it's definitely not for scenarios that require low latency (presentation for example). But as a trade-off the streaming quality exceeds a lot of software-based screen-casting solutions (Lebocast for example) that have been tested by myself, which make it pretty good to stream music or video playing on your PC to the supported TV.

Install

pip install dlna-cast

Please ensure your Python is 3.7 or above.

Install ffmpeg

You can install ffmpeg by compiling from source code, or just download the prebuild binary from https://ffmpeg.org/download.html

You need to ensure the ffmpeg command can be found in the PATH environment variable, or else you need to set FFMPEG_BIN or FFMPEG_HOME to let dlna-cast know where to find the command.

dlna-cast supports reading the environment variable from .env file. You can create a .env file under the folder you are gonna run the dlna-cast command with the following content.

FFMPEG_BIN=D:\ffmpeg\ffmpeg.exe
# or
FFMPEG_HOME=D:\ffmpeg

You can also use the dotenv set command to update the .env file and use the dotenv list to check result.

dotenv set FFMPEG_HOME "D:\ffmpeg"
dotenv list

Install ScreenCapturerRecorder on Windows

Though ffmpeg is shipped with gdigrab to capture screens on Windows, its performance is terrible when frame rate is high. dlna-cast uses ScreenCapturerRecorder for the sake of performance. You need to download and install it before starting to cast.

Get Started

Before you start to stream your screen to remote devices that support DLNA protocol, you need to discover available devices in your LAN by running the following command.

dlna-cast list_dlna_devices
# You will see the output if supported devices are found
HuaweiPro
Lebocast

And now you can cast your screen to one of the found devices by running the following command.

dlna-cast screen --dlna_device HuaweiPro

Or you can also set DLNA_DEVICE in the .env file so that you can skip to set --dlna_device next time.

dotenv set DLNA_DEVICE HuaweiPro
dlna-cast screen

To stop casting just press Ctrl+C.

FAQ

Linux Limitations

The default --input_opts on Linux is -f x11grab -i $DISPLAY, which doesn't include capturing the audio. To support audio capture you may need to install loopback device first and then provide you own --input_opts, for example --input_opts='-f x11grab -i $DISPLAY -f pulse -i name_of_your_device'.

MacOS Limitations

Not provide default --input_opts on MacOS yet. You need to provide your own --input_opts, for example --input_opts='-f avfoundation -i 1:0

TODO

• Support cast media file.
• Optimize devices discover.
• Optimize latency.
• Cross platform support.