As easy as it is to start or schedule a live stream through the Tradecast Video Management System (VMS), there can still be several reasons why your live broadcast does not want to start or does not start correctly. In this article, we highlight the importance of proper live stream input when creating a Basic Live stream, the starting point of any well-functioning live event.
To avoid unnecessary data consumption when testing or broadcasting a Basic Livestream, the Tradecast VMS is set up to automatically disconnect if no connection can be made to the entry point or if the input signal does not meet the minimum requirements for a quality livestream. This message is often displayed in livestream software - such as OBS, for example - with the message "Disconnect, retry in X seconds. From this you can see that the video and audio signal from the video camera to OBS are not coming in the right way, so OBS cannot forward them to your VMS in the right way either.
Above: an example of the 'disconnected' message in OBS.
Each live input stream sent to the VMS is tested against a number of criteria. If the stream does not meet these criteria, the connection is disconnected. It is therefore good to know what the minimum specifications are for an accepted (and therefore qualitative) live stream through your VMS. These are the following specifications:
Minimum livestream specifications for video:
- Frame rate: 25-30
- Width: 1280
- Height: 720
- Bitrate: 2000000 - 2500000
- Keyframe interval: 2 sec
- Profile: Main
- No B-frames and/or reference frames
Minimum livestream specifications for audio:
- Bitrate*: 63840-192000
- Sample rate: 41000-48000
- Channels: 2
- Channel layout: stereo
* The ideal bitrate for live streaming using the Tradecast VMS is 2200 Kbps. If you set the bit rate in livestream software such as OBS to 2450 Kbps, you will receive an error message. This is because in OBS 1k is counted as 1024, making 2450 Kbps 2508800 (and thus greater than 2500000).
Please note: the validation of the video and audio signal of a live stream takes place in the first ten seconds. An important rule of thumb is: if your live stream looks like it's being aborted within the first ten seconds, it's probably due to the settings used. If this is not the case, it is possibly due to a bad internet connection or busy CPU. In case of doubt or unexplained problems, the Premium Livestream variant can always help, as it is less critical of incoming signals.