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Martin Pulec edited this page Oct 15, 2024 · 5 revisions

Since UltraGrid version 1.7.2, binary builds include NDI®. NDI library is dynamically loaded, therefore you need to have the NDI runtime installed, for macOS and Windows the simplest way is to get it together with NDI tools:

After the installation system reboot is recommended for the environment values to reload.

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Firewall

If a firewall is filtering the traffic, you'll need to allow the traffic.

You'd need to allow following recv ports (assuming that outgoing traffic is not filtered) for UltraGrid to work:

  • Sender (NDI display) - TCP/5960-6000
  • Receiver (NDI capture) - UDP/5960-6000
  • (optional) for discovery (both sides) - UDP/5353 (for DNS-SD - its absence can be circumvented by using extra_ips= vidcap parameters, see extra_ips)

(The range for port numbers from 5960 is somewhat arbitrary, just few ports starting with 5960 may be sufficient for the stream but 40 port above was chosen as a margin of safety.)

(Complete listing of ports used by NDI can be found here.)

Capture

Basic usage is simply:

uv -t ndi -c <compression> [-s embedded --audio-codec <ac>] <receiver>

The above command picks first source found on a local network and sends the data to the receiver.

You may also specify name (in form "MACHINE (source)") and/or URL (either in form ip_addr or ip_addr:port, exact URL format may change with future NDI releases) to capture from, eg.:

uv -t "ndi:name=HD10 (DeckLink 4K Extreme)" -c JPEG ultragrid-receiver.example.net
uv -t "ndi:name=uv"               # source can be specified without MACHINE
uv -t "ndi:name=HD10"             # vice versa - MACHINE without explicit service
uv -t ndi:url=192.0.2.15 -c JPEG ultragrid-receiver.example.net
uv -t ndi:url=192.0.2.15:5961 -c JPEG ultragrid-receiver.example.net

Note: the apostrophes in the first command are because the resource name contains spaces

You can also let UltraGrid discover available sources on a local network:

uv -t ndi:help

(The list doesn't need to be complete - UltraGrid waits only limited amount of time to response. If DNS-SD is not operable, see extra_ips below.)

If you want to capture including alpha channel, select a mode that captures RGBA (alpha is currently stripped from YCbCr formats):

uv -t ndi:color=0          # BGRX_BGRA; 1 (UYVY_BGRA), 2 (RGBX_RGBA), 3 (UYVY_RGBA) are also ok; default is however 100 (best)

Note: Very few of compressions support alpha-channel compression, one exception is GPUJPEG.

Audio

NDI video capture is capable of capturing video alongside with audio as usual:

uv -t ndi -s embedded -c libavcodec --audio-codec OPUS ultragrid-receiver.example.net

If the NDI source is audio only, it is possible to capture the audio with the NDI vidcap module even in the absence of video signal:

uv -t ndi:name=mic -s embedded --audio-codec OPUS ultragrid-receiver.example.net   # if "mic" is audio only NDI source, no video is sent

extra_ips

If service discovery (DNS-SD) isn't working or is filtered, you'd need to use a parameter :extra_ips to explicitly specify the sender IP address(es) to be probed, examples:

uv -t ndi:extra_ips=10.0.1.24:help           # server listing running on 10.0.1.24
uv -t ndi:extra_ips=10.0.1.24,10.0.1.25:help # multiple addresses can be specified as well
uv -t ndi:extra_ips=10.0.1.24:name=uv        # capture NDI sender named "uv" send with 10.0.1.24

Note: If DNS-SD is required, in Linux Avahi is required to be run for NDI DNS-SD to work.

Display

Basic usage is quite usual:

uv -d ndi[:name=<n>] [-r embedded] <sender>

Analogically to the capture, the NDI display can also playback the audio without a video.

NDI Linux installation

This step is required to add run-time dependency, for compilation see here.

Installation steps:

  1. download and extract the installer:

    tar xaf Install_NDI_SDK_v6_Linux.tar.gz

  2. install the NDI

    ./Install_NDI_SDK_v6_Linux.sh

  3. this creates directory "NDI SDK for Linux" directory in current path

  4. make the contained library libndi.so.6 visible to UltraGrid, this can be done in two ways:

    • copy (as root) libraries to /usr/local/lib:

      cp -a NDI\ SDK\ for\ Linux/lib/x86_64-linux-gnu/lib* /usr/local/lib/
cp -a NDI\ SDK\ for\ Linux/include/* /usr/local/include/      # (headers optional, can be omitted)

    • or export path to the library before running UG (or to system environment):

      export NDI_RUNTIME_DIR_V6=<NDI_SDK_root>/lib/x86_64-linux-gnu/lib/
./UltraGrid*AppImage [...]

Footnotes

[1] NDI® is a registered trademark of NewTek, Inc.
[2] NDI® is available at http://ndi.tv/

If you have any technical or non-technical question or suggestion please feel free to contact us at

[email protected]

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