Smooth Streaming techniques

Smooth Streaming techniques

In the last video I explained the
difference between broadcasting… ..and internet streaming. And I promised to explain later on the techniques that… ..make internet streaming work more smoothly. The first technique is “buffering”. The principal of buffering can be
explained by a water tank like this. It has an outlet right at the bottom. I can fill this up irratically with water and you’ll see that… ..the rate from the bottom is always constant. I ‘ll add some water… So you see the water rate from the outlet is constant. And it is exactly the same with internet television. It buffers the incoming videostream, so
you can watch the programmes smoothly. This works, as long as… ..the incoming rate is not too different from the rate you want to see. If it is, we need another trick. That is called adaptive streaming. In this case the programme is provided in a number of different streams at the same time. These are in different qualities, with different bitrates. For example high quality, medium quality and low quality. What your receiver has to do… to move its buffer, to capture the stream that provides smooth pictures. This may be high quality, … might be medium quality, … ..or low quality. At any moment the receiver can choose the quality. Remember a smooth flow is more important than smooth quality. We can tolerate some changes in picture quality, … ..but we cannot tolerate jerkiness or no pictures at all. So it’s thanks to these two techniques: buffering and adaptive streaming… ..that we are able to watch internet programmes smoothly. Next time we will look at ways in which we can combine broadcasting and the internet. Using a device such as a tablet And I promise there’ll be no water
involved then…


    The analogy is very confusing for those who don't already understand the concepts. The 'high quality, high bitrate' stream is filling up the 'buffer' faster, meaning the outlet is less likely to be stopped. The 'low quality, low bitrate' stream is not filling up the 'buffer' nearly as fast, and it is natural to assume therefore the outlet will be stopped if the outlet's rate of flow is greater than that of the input low quality stream.

    The viewer therefore comes to the conclusion that for uninterrupted viewing, they should choose the 'high quality, high bitrate' stream, when we know the opposite may be true.

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