VT Receiver

A guide to receiving streams via VT Receiver.

VT Receiver is a Windows app designed to receive feeds from VT Publisher, VT Guest. VT Receiver can make feeds available as an NDI® source, play out to a hardware device (Windows Audio, ASIO, SDI) or create a virtual source in MPLink format.

Receiving feeds

1. Select one of the available sources in the "Source" tab (6).

2. Once selected, the preview of the feed will soon start to play.

3. Select desired latency in the "Buffer" tab (11).

4. Select the output method in the "Output" tab (NDI®, a hardware device, or a virtual device) and hit "Start Output" (16).

Using VT Receiver

Here's what VT Receiver looks like.

Control/Indicator	Function
1	The current version of the Video Transport software, the channels count indicator regarding your current license, its validity date, and the latest release version.
2	Current location name. Can be altered by entering a new value and clicking the "Change Location or ID" button(4)
3	The Publisher ID – your unique identifier, provides access to all feeds published under this ID.
4	Change Location or ID button. Confirms changes in respective fields.
5	Global settings menu button. See the information below.
6	Lists the streams available (published) under the current Publisher ID and license. Color indicators description: the stream is published and available (grey); the stream is being received currently (green); there is a problem with the stream (red). Click the right mouse button on the selected source and select 'Settings', to enter the Source Settings window. Read the description below.
7	Video parameters of the stream: video format, number of audio channels.
8	Current frame rate
9	Current bitrate.
10	Buffer size to configure latency. Learn more about latency configuration.
11	Current latency. If less than 350 ms, shows two values: the network latency of the stream (RTT) and real latency (Latency). Check here what is Latency(RTT) means in terms of our software.
12	Lost packets count and percentage. (audio/video/network)
13	Select the output destination: publish as NDI®, play out to a supported hardware device, or create a virtual device.
14	Stream output name. Can be altered by left-mouse click when there is no output enabled.(NDI)
15	Start and Stop receiving selected stream buttons.
16	Native VT Receiver preview viewport
17	Controls to enable full-screen preview on available monitors; mute control. To exit the Full-screen mode just click the left mouse button again.
18	Decoding and connection mode stats from left to right: Current protocol (WebRTC or VT 2.0 mode SRT), bitrate (Mbps), video codec, and GPU performance

Global settings menu

Most of the following settings require a restart of the VT Receiver application.

Global settings menu window

Parameter	Description
Language	Select the preferred interface language for the VT Receiver app. Supported Languages: English and Simplified Chinese. Default value is "English".
VT 2.0 gateways filtering (e.g. for custom routes)	Allows you to use the gateway to gateway routes. Experimental.
Show location in the channel name	Adds the VT Publisher's location name to the source name in the list. Enabled by default.
Turn on gpu_pipeline (required for 10bit feature)	Enable this switch if you want to receive a video feed in 10bit. Disabled by default.
Set the timeout for connection (in milliseconds)	Sets the maximum amount of time needed to establish a connection between your VT Receiver and a signaling server. Default value is "3000" (milliseconds).
Use Nvidia decoder	Allows you to use NVIDIA GPU for decoding the receiving feeds. Enabled by default.
Use Quicksync decoder	Allows you to use Intel Quicksync decoder for decoding the receiving feeds, Disabled by default.
Allow to output 10bit video	Enables the 10bit video output feature. Requires gpu_pipeline setting. Disabled by default.
Set the preview type	Here you can select render API for the native in-app Preview Window. Options are dx11, dx9 and dshow. Default option is is dx11.
Add RMS audio meters on the preview	Enable this to add RMS audio meters overlay on the preview to observe the sound levels. Disabled by default.
VT 2.0 P2P Connect Enabled	Enables VT 2.0 mode connection routine between VT Receiver and VT Publisher. Left for the compatibility. Enabled by default.
Split audio channels (ASIO devices only)	Split one ASIO audio device to many by the mask. Mask is applied to each device simultaneously. Format: X,X,X,.... Where X is the number of channels assigned from the physical device to split. For example, you have a device with the channels:0,1,2,3,4,5,6,7 - 7 in total. So if you set the Split audio channels=3,2,3 VT will create 3 audio devices with channels from the original device - 0,1,2; 3,4; 5,6,7

Source settings window

Selected stream settings window

Parameter	Description
Extra Audio Output	Select the extra audio output device from the present audio devices. This will output the same audio track from one additional device besides one selected for the output.
UDP/TCP Tunnel address	Sets the address for UDP/TCP tunneling feature. Check the instructions here.
Use Nvidia decoder	Enable to use NVIDIA decoder if NVIDIA GPU is present.
Use Quicksync decoder	Enable to use Quicksync decoder if Intel UHD Graphics is available.
Output Video Enabled	Enables video output Enabled by default.
Output Audio Enabled	Enables audio output. Enabled by default.
WebRTC Transport	If you enable this switch, streaming protocol for this source will be switched from SRT to WebRTC. It might be helpful to achieve stable picture in a different network conditions when SRT is not able to deliver best quality. Disabled by default.
Convert output format	Switch this on if you want to convert the output into a selected format. Disabled by default.
Output Video Format	Select the desired video format to convert on output. Note that this parameter will only apply when the 'Convert output format' switch is enabled.
Audio Channels	Here you can set the audio channels which you wish to output with the source. For example: 1,2,5,6 means that you selected channels 1,2,5,6 and only those channels will be heard in the Output.
Audio Gain	Applies custom gain to the audio tracks
SRT Passphrase	Enter the passphrase that you previously set on the Publisher side of this channel to setup secure SRT connection. Empty by default.
SRT Receiver port	Specify the custom port number that you previously set on the Publisher side of this channel. Empty by default.
SRT Receiver Buffer (min-max) in msec	Here you can set the custom buffer value. By default it displays value that is selected from the Buffer dropdown menu.

Latency configuration

There are several principal latency settings in Video Transport:

1. Real-time. In good conditions, the technology is capable of bringing latency down to 50-100 ms. When using this option, make sure your network is good and stable – network issues will cause frame drops. Use Ultra-low if you want a compromise between reliability and latency on good connections.

2. Low. If reliability is more important than latency, increase the buffer. More latency gives our protocol more time for error correction (to resend the missing frames and restore the image). Use Reliable for predictable reliability even on low-quality connections.

3. Fixed. Depending on the quality of your network, you can choose one of the fixed buffer settings. This is the recommended mode for remote multi-camera production since it allows for several sources to arrive at the same time. Also to be used in creative scenarios, such as a group of musicians jamming together).

Possible values:

Setting	Meaning
Real-time	50-150 ms
Ultra-low	150-750 ms
Low	750-2500 ms
Reliable	2500-5000 ms
Fixed 150	150 ms
Fixed 350	350 ms
Fixed 750	750 ms

What is Latency(RTT)?

As you probably already saw Latency in the VT Receiver is represented by two different values in milliseconds.

The first value called Latency is the actual time in milliseconds that is required to send the stream from the VT Publisher and receive it into the VT Receiver. This time includes network transport between locations (RTT), decoding process in the VT Receiver, and buffering process in the VT Receiver.

The second value that you can see in the round brackets is the RTT (Round-trip time). In short, RTT is the time required for a packet to travel from the VT Publisher to the VT Receiver and back again. Actually, you can measure your network quality with that value.