High-quality and interference-free transmission of live streams
Video livestreams are a trend across all industries.
In the professional environment, they have long been used not only by media companies to broadcast their content on the Internet. Many companies from other industries are also increasingly working on using video as a channel for their own topics and target groups.
The importance of this communication channel can be easily seen in the increased user numbers. The number of consumers of livestreams has risen continuously in recent years.
While in 2013 there were still around 15 million users who used livestreaming offers in Germany, the number already rose to around 24.3 million in 2017 and is expected to exceed the 30 million mark in 2020.
Success of Live Streaming
The great success of livestreaming for companies is also related to the fact that publishing streams has become easier and also more affordable today.
Anyone who runs a website, blog or app can now quickly and easily integrate livestreams into their web offering or into high-reach social media platforms such as Facebook. In our opinion, it doesn’t matter whether you want to broadcast a soccer match or the annual general meeting, for example, in times of Netflix and Co, the viewer expects a qualitatively appealing and interference-free broadcast.
In order to make the best use of the medium, it is important not only to produce attractive content, but also to take a look at the technical requirements for high-quality broadcasting. Therefore, one should pay attention to the following five basics for an appealing livestream.
The starting point is usually a finished AV signal that is to be transmitted to the Internet or, for example, to a company network with the help of an encoder.
1. Choosing the right encoder, transmission protocol and settings
To send the live signal from the transmission location to the streaming platform, a software or hardware encoder is required. Basically, we recommend the use of hardware encoders.
If you want to add overlays to the video signal, for example, and you don’t have a video mixer, you can do this with a software encoder. Wirecast is a good solution here. But there are also free alternatives like OBS Studio.
Each device or software works slightly differently. Basically you have to pay attention to the following settings and requirements, and test them extensively before the main transmission.
Encoder settings for optimal transmission quality:
- Protocol: SRT or RTMP
- Codec: H.264, HEVC
- Profiles: High 3.2 and higher
- Resolution/bitrate: 720p 4 Mbit/s and higher
- Frames per second: 25, 30, 50 or 60
- Keyframes: Every 2 seconds
- Audio Codec: AAC 128k and higher
2. Upstream or bandwidth available for signal delivery
Of course, it is important to provide sufficient bandwidth for the transmission. As a rule, you should estimate a maximum of 2/3 of the available bandwidth for the stream and leave about 1/3 of the total width as a reserve. This means that if you want to send a signal in full HD (1080p25, or e.g. 1080p60), we would estimate about 8 – 10 Mbit/s for a transmission with relatively little movement in the image. Thus, an Internet connection with a total bandwidth of at least 15 Mbit/s should be available.
It should also be noted that this connection should be available exclusively for your livestream or that the required bandwidth is permanently available (QoS/QoE). Often enough, we have experienced that bandwidth was available, but the line was not stable. In addition, the route to the Internet connection should ideally be available via cable – not wireless.
3. Backup/failover concept
If the signal is sent over public networks like the Internet, you should have a backup concept for every live transmission. It can happen at any time that the connection is interrupted by disturbances in the network.
It is true that the SRT protocol, for example, can compensate for strong fluctuations or disturbances. Nevertheless, you should operate a second upstream and encoder for the live transmission in parallel. If the primary encoder fails, it is possible to switch seamlessly to the backup in the event of a disruption without the user noticing.
To make the livestream accessible to all users, the signal you send is still converted into the appropriate formats and resolutions for adaptive streaming. The created formats are then provided as an adaptive multi-bitrate stream in the streaming methods HLS and MPEG-DASH.
The following graphic shows the technical flow of a live stream. The signal is first transmitted to the streaming platform and, if necessary, transferred to third-party platforms. In parallel, this is converted into different quality levels and then displayed on the company’s own portal using a video player.
5. Delivery and integration
Once the complete setup is in place, the video player must be embedded on the desired websites. It is important here that the website/webserver is also set up redundantly and with high performance, just like the livestream. If you expect large numbers of viewers, your website must also be able to handle these high access numbers. If the video player cannot be initialized, your users will not be able to watch the livestream.
If you keep these five points in mind, your viewers will greatly appreciate the quality of the broadcast.