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Summary:

How live is live? That’s a question that soccer fans have been asking themselves when confronted with significantly-delayed World Cup streams.

The 2014 World Cup has broken records as the largest live event on the internet. However, this also means that countless viewers have been waking up to a painful reality of internet TV: Sometimes you just have to wait a few extra seconds to see that deciding goal, and that can be especially frustrating if your cable-watching neighbor is already loudly cheering. Or if you’re watching games with one eye on your Twitter feed, for that matter.

Throughout the Cup, there have been numerous reports on Twitter and elsewhere from soccer fans who had to deal with delays ranging anywhere from a few seconds to up to two minutes. Some people reported different latencies on varying devices, while others have seen results improve by switching from one streaming service to another. And when I watched the U.S. versus Germany game at ESPN’s booth during Google I/O, the cable network had four TVs on display, all showing the game with slightly varying delays, prompting one of the attendees to ask: “Which one is more live?”

Satellite TV tends to be a few seconds behind

Latency issues during live sports games are nothing new, and not by any means exclusive to online video. Even regular live TV feeds face different types of latencies when distributed via cable, broadcast, IPTV and satellite TV services. For example, satellite viewers often report that they’re around five seconds behind cable or over-the-air broadcast signals, and multi-room set-ups that relay signals from one single cable box can even lead to delays between TVs within the same household — or sports bar, for that matter.

That kind of latency doesn’t really matter for everyday TV use, but can be enough to make a dedicated sports fan close their windows if the neighbors are watching as well and happen to get their programming from a lower-latency feed. Some of these differences can be explained through the different pathways of TV signals. Sending a live feed to a satellite and back introduces half a second of delay, compression and decompression can add a few more seconds.

HLS alone can add ten extra seconds

With online video, there are a number of additional factors that can introduce latency. On-premise encoding doesn’t add too much latency, but some streaming services instead encode their signal in the cloud, which can add a few extra seconds.

Then there are the video formats used to stream World Cup games to Apple TVs, Roku boxes and other devices: Services like ESPN’s WatchESPN live streaming service tend to use HLS, a format first introduced by Apple, for these kinds of streams. However, HLS streams tend to introduce a delay of around ten seconds, according to an industry insider who didn’t want to be quoted on the matter.

After the transcoding, streams are sent to a content delivery network, which can introduce significant additional latency. And when the signal is streamed to the end-user, there are last-mile issues, and even issues with home routers, local Wi-Fi networks and playback devices that slow things down some more. All of this adds up to the point where internet live just isn’t quite the same as TV live.

Still, latency issues clearly haven’t stopped soccer fans from tuning in online. ESPN averaged 829,000 unique viewers and 36.9 million minutes per game through the end of the round of 16, and the USA vs. Germany match was viewed by 1.7 million concurrent viewers during peak times, making it the most popular live stream in the network’s history. A total of 2.1 million people tuned in during the semifinal match between Germany and Brazil.

Maybe sports fans have just learned to live with the delay and stopped looking at their Twitter feed while the action unfolded on TV.

  1. Hey Janko, if you write on tech topics, you should likely check w/ someone. For example, I work on video streams. You are very wrong. Cheers.

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    1. I don’t if his technical explanation is correct but based on my experience Janko is right about some streams being delayed compared with others. I don’t have cable and watched most of the games on Spanish language broadcast TV. I don’t understand Spanish very well so I listened to ESPN Radio’s online audio stream. The streaming content was delayed by anywhere from 30 seconds to two minutes.

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    2. Vic, if you’re going to call someone out, you have to make an argument, not just say he’s wrong.

      Thanks.

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  2. Jens Loeffler Friday, July 11, 2014

    Here is some real-world analysis – RTMP is actually a lot better than HLS, but there is a generic delay just due to broadcast workflows – http://www.overdigital.com/2012/02/07/the-mystery-behind-live-streaming-delay/

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  3. I used to live near a football stadium and the TV signal would arrive quicker than sound would travel a few blocks. That was very strange to hear the crowd cheer on TV before hearing it through the window.

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  4. Alex Zambelli Friday, July 11, 2014

    Janko is correct – HLS does indeed introduce a delay of *at least* 10 seconds. This stems from the fact that the typical duration of an HLS segment is 10 seconds, which means that an encoder can’t event publish the first frame of video until at least 10 seconds worth of content has been packaged up into a segment.

    On top of that the video encoder typically introduces at least a few seconds worth of delay (due to decode and encode buffers), and then HTTP tacks on additional latency (time it takes to upload a segment from encoder to origin server), and then the CDN introduces yet more latency when caching and distributing the segments to the end-users.

    The end-to-end latency for HLS typically falls somewhere in the 15-45 second range behind the distribution feed.

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  5. John Willkie Friday, July 11, 2014

    Funny how the hoi polloi has yet to notice that cable and satellite are at least 4 seconds behind the over the air signals of the broadcast stations they carry. This is because the cable and satellite systems have to acquire the signal and re-encode it. All emission-quality encoders worth talking about have their own 4 second (or so) encoder latency.

    The second UNSURMOUNTABLE issue: cable/satellite/broadcast all are mass mediums and are designed as such: the latency between encode and decode is essentially “fixed” in time AND the timing is “deterministic” in that you can determine the exact moment the content will enter the TV set.

    The Internet is an individual medium, not a mass medium. Timing is not deterministic and individual packets don’t necessarily travel the same path. Adding RTSP/RTMP or HLS does nothing to change these simple facts, and each of those introduce latency — variable latency.

    The quoted ABC guy is simply ignorant of the technological systems used for Watch TV. That’s inexcusable: the likelihood of a solution to this is about as likely as watching in color a TV show on a black and white TV. You are simply arguing with the laws of physics.

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  6. Jens Loeffler Friday, July 11, 2014

    The issue is that HLS was not really designed to be low latency, and the iOS buffer algorithms are very conservative, meaning it goes up to 45 seconds+. On the desktop you see often HDS, which is a bit more flexible when it comes to low latency, but CDNs then can add latency as well depending on the packaging/caching workflows.

    The argument you hear in the online video community is quality vs. latency. HTTP streaming can’t really beat RTMP – RTMP was originally a low latency protocol for real-time communication repurposed for streaming, but the industry shifted to HTTP based protocols due to (rightfully) more scalability, and the ability to e.g. use HLS for all platforms.

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  7. SATHYAMURTHY Friday, July 11, 2014

    ALL THE MATCHES i WATCHED HAD THE PROBLEM OF EITHER DELAY OR INTERRUPTION AND HAD TO SWITCH OVER TO DIFFERENT LINKS TO A GET THE TELECAST.DISGUSTING EXPERIENCE INDEED BUT WAS FORCED TO PUT UP WITH SINCE IT WAS WORLD CUP EVENT

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  8. SATHYAMURTHY Friday, July 11, 2014

    I HAD TO ENCOUNTER THE PROBLEM OF EITHER DELAY OF 30 SECONDS TO 1 MINUTE THROUGH OUT THE WORLD CUP SERIES AND IT WAS AGONIZING EXPERIENCE BUT HAD TO PUT UP WITH IT.NO OTHER GO.

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    1. why are you yelling? :p

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      1. Maybe his favorite team lost ;)

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  9. Welcome to digital!! You can’t even go into a Best Buy and have the sound up on several sets and will not sync. Nature of the Beast.

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