Trying to watch the Olympics on my computer and it's some awful coverage.....really hard to watch with all this buffering
— Haley Wilson (@flipnhaley) July 28, 2012
Buffering is caused by the amount of data coming into your computer being too slow.
When you're watching something like YouTube, you don't notice most of the time, because you're watching pre-recorded content; so your computer will download the video as quickly as possible and store it temporarily on your computer. If the video needs 1Mb/s to show properly, but your connection is 2Mb/s, then your video will download twice as quickly as it'll take to watch. This process is called caching.
Caching fixes most problems with streaming media over the internet. Once you've started watching the programme, it doesn't matter whether your broadband connection runs slightly slow every now and again: as long as, on average, your connection is fast enough for the connection, it's fine.
But with live video, the opportunity to cache is very low: because you're watching a live stream that is being encoded at the same speed as your computer decodes it. There's no way for your computer to download ahead; because there's nothing more to download. A live stream is difficult to cache.
Some devices and players will deliberately cache a few seconds ahead, to keep any re-buffering low. They'll store two seconds, say, of the video before beginning to play it to you. This has the effect of delaying playback (since you need to wait a few seconds for it to cache first); and also the effect of making any re-buffering take at least two seconds as well. In some players, you'll see settings to adjust this buffering time. The Android version of TuneIn Radio, for example, lets you adjust a setting marked "Buffer before play".
So, even if on-demand video works well for you, live video is always more difficult to get online without buffering.
BBC player for the olympics is crap. I have a 20meg pipe into my house so there should be no buffering. it's so frustrating having to reload
— Neil Andrew Eyre (@nevmech) July 28, 2012
The problem isn't necessarily the BBC's here; and nor is it just down to how fast your connection is.
All network connections use a concept of a "packet" of information: and sometimes these packets are delayed.
Imagine your Aunt Flo is sending you a book. She knows you only have a small letterbox, though, so she's sending you ten pages at a time, so that the postman can fit it through the box. She sends you ten pages, and you then write back and say "thanks for the ten pages, Flo, I've read those, can I have the next ten pages?". She then sends you the next ten pages; and you write back telling her you've read them. And so on.
Sometimes, her post will get delayed in the mail. So you have to wait for the next instalment. Sometimes, your letter back to her will, similarly, be delayed; which means you'll have to wait, too. It's nothing to do with your postman, or hers: but to do with the complicated mail system in the middle: which you've no control over, and nor has your aunt.
This is just like the internet. Your computer get sent packets of information, which it reassembles and makes into a video. The BBC's connection to the internet is nice and fast; and your connection might also be nice and fast: but you don't have a direct connection to the BBC's computers - just as your postman hasn't driven all the way from Aunt Flo's house. There's lots of other connections in the middle: connections that neither the BBC or you control.
Occasionally, your book takes even longer to come. After a week or so, you call Aunt Flo. "What happened to my latest ten pages?", you ask. "Oh, I never got a letter from you saying you'd read the last lot," she replies. "But I sent you a letter!", you protest. But she never got it. It got lost in the mail somewhere. "I'll send you another letter", you say.
And, again, that's just like the internet, too. Sometimes, packets get lost completely; so your computer asks for them again. All of this takes time, too: which can cause buffering.
This might even happen within your home: wifi connections aren't always perfect, and are just as susceptible to interference as your radio is.
dear dog, the BBC internet streaming of #olympics is shite. Buffering issues on all 4 tennis feeds. Giving up in disgust.
— Louise Bolotin (@louisebolotin) July 28, 2012
Another problem is that your broadband connection isn't actually your own.
For a start, your broadband connection is shared by everything in your house, of course. The use of BitTorrent and other downloading systems, or automatic backups and upgrades, can slow your entire internet connection down. The latest generation of computers can even access the internet when they're turned off.
Also; most broadband connections are contended - which means to say, you share your connection with other people in the same street. Your street might have 200Mb/s available, but that means that if you all use it at the same time, you'll not have access to that 200Mb/s. That's why internet seems faster overnight, or during the day, than in the evening.
Since the BBC has publicised its 24-screen Olympics coverage highly, more people than ever are using it. It's designed, too, to give you excellent picture quality; their player will specifically use as much bandwidth as it has access to, to ensure that the quality is as high as possible. With popularity comes increased usage; and particularly at a time when everyone is likely to be at home - on a Saturday afternoon, for example - it's certainly possible that you'll have increased issues.
And no, it's not just the BBC, either. It's a problem with the Americans...
This watch-the-Olympics-online thing would be great if NBC's feed wasn't CONSTANTLY buffering, ugh.
— Mark Haines (@lilserf) July 28, 2012
... and also a problem with those in Canada.
The CTV live stream is buffering like nobody's business. #London2012 #Olympics
— Khoa Nguyen (@khoaski) July 27, 2012
Here are some tips on how to get better quality for the Olympics:
1. Always use a wired connection where you can. Most laptops have a wired connection, and it can have a surprising effect on connections - you'll see increased reliability for things like Skype as well as iPlayer, for example.
2. Make sure there's nothing else in the house using broadband: even your iPad.
3. Check your connection speed directly to the BBC iPlayer by using the BBC iPlayer Connection Speed Checker. Do it particularly at a time when you're having problems. The bank of tests it runs are automatically fed back to the BBC to help them.
4. Chat to neighbours to find out if they have the same problem. It could be that your street's internet connections are simply being swamped.
5. Try TVCatchup or Eurovision for alternative streaming links.
Alternatively, you'll find all streams are also available on satellite television (Sky or Freesat), or on Virgin Media.
Post your experiences
Is the BBC's coverage buffering for you? Do you know any other tips? Help others by posting your comments below.