If one of your neighbors has ever “spoiled” a goal by yelling at a football match a few seconds before the images arrive on your television, you have probably already wondered where this delay came from. This latency, which can sometimes literally ruin your evenings with friends, has different origins and depends on many factors, the main ones being the source chosen (TNT, Box, mobile applications, etc.) and the quality of the video stream. We decided to explore this phenomenon in order to better understand it and above all to allow you to obtain the lowest possible latency.
TNT VS Box VS Internet and applications
We started by comparing the lag between the main sources, taking the TF1 channel as a reference. Of course, the classification that you are going to see is not exhaustive but know that we will regularly expand it with new sources.
As much to say it at the outset, DTT is the source that will induce the least latency but you should know that it does not correspond to real direct. There is actually a small lag of up to 2 seconds between the real action and the reception of images in the channels’ control rooms. Then adds new latency on the rest of the way to your TV depending on the chosen broadcast channel. It is the latter that we are measuring here, taking DTT as a reference, since it currently remains the fastest source.
|TF1 via TNT||Reference|
|TF1 via Freebox Mini 4K (fiber)||+2 seconds|
|TF1 via Livebox Orange (ADSL)||+2 seconds|
|TF1 via SFR Box 7 (fiber)||+3 seconds|
|TF1 4K via Bbox Must (fiber)||+10 seconds|
|TF1 via Bbox Must (fiber)||+11 seconds|
|TF1 via MyTF1 (PC)||+23 seconds|
|TF1 via MyTF1 (smartphone)||+26 seconds|
|TF1 via Mycanal (smartphone)||+26 seconds|
|TF1 via Molotov TV (all devices)||+44 seconds|
|TF1 via Salto (PC)||+49 seconds|
Note that the latency can vary significantly at home depending on a multitude of criteria such as the quality of your antenna, your Internet connection or the definition of the stream (SD, HD, 4K). Indeed, a 4K stream requires longer encoding.
Each operator also re-encodes the video signal with its own technology in order to adapt the stream to its broadcasting platform. This processing will induce more or less latency depending on the parameters chosen by the operator, which explains why you do not necessarily obtain the same result with an SFR, Orange, Bouygues box or with a Freebox Mini 4K.
Moreover, the result can also vary with the same Internet box depending on the time of day, we saw this during our measurements of the Bbox Must for example, which proved to be quite random. It seems to depend on how busy the network is. In any case think about it on the days of important matches when there will probably be more people in front of the television than usual.
From the stadium to your TV
In order to better understand the origins of the delay between the real action of the match and its arrival on your television, it is important to know the path traveled by the images since the video capture at the stadium.
Let’s take the example of Euro 2021 football which took place in June in different countries to celebrate the 60th anniversary of the competition. The images captured in the stadiums by the UEFA cameras were all sent by optical fiber to the Netherlands, to an IBC (International Broadcast Center), a center not far from Amsterdam which was then responsible for distributing the video streams to various European TV channels.
In the case of TF1, Yves Davot, Head of Advanced TV Technologies and Sports Operations for the channel, explained to us at the time that the procedure was “less than 1/2 second, the exact value depending on the distance, the number network interconnections on the course and the intrinsic security of UEFA’s production”.
Indeed, to guarantee good signal transmission, UEFA had to, in addition to fiber, provide “one or more satellite transmissions, which could accumulate a delay of up to around 2 seconds. Depending on the level of security desired, each chain [pouvait] make the choice to align its reception on the most delayed signal”. This explains the differences between the TV channels.
Towards a revenge of the web?
On its way to your television, the video signal thus undergoes several treatments which delay it. Depending on the channels, the operators, the broadcasting mode and the image quality, the time lag turns out to be very different, giving DTT the advantage for the moment.
But new technologies may reshuffle the cards in the future. Apple, for example, has developed Low-Latency HLS technology, announced at its WWDC 2019 conference. According to the firm, this evolution of the HTTP Live Streaming protocol would reduce the gap between reality and live streaming via web services (such as MyTF1 or Molotov, mentioned above) to only 2 seconds against several dozen today. In theory, this technology could then prove to be more efficient than DTT. Note that on Android low latency streaming will go through Dash technology.
At the start of 2022, Canal+, a pioneer of HLS, became one of the first broadcasters in the world (and the first in France) to deploy low-latency streaming via its myCanal application. An evolution made possible by the collaboration between the channel and the company Ateme, which offers a solution called Just-In-Time NEA. With HLS and Dash, according to the company, this would reduce latency for end users from 40 to just 5 seconds while improving image quality.
However, this feature is currently restricted to Apple devices (Apple TV 4K, iPhone, iPad, and Mac) and certain sporting events. You can still try it if you have a compatible terminal by activating it from the settings of your myCanal application. For our part, we will measure the latency of this technology very soon in order to integrate it into our comparative table in a future update of this article.
While waiting for the Web to take its revenge, we still advise you to connect to your antenna socket if you have poor insulation and a noisy neighbor.