Streaming Video

[urgeok2]

This is NOT a discussion on video piracy.


this is just answering a question about video streaming :


Streaming vs. Downloading Video: Understanding The Differences



by Larry Bouthillier
July 22, 2003





Delivering From a Streaming Server
A streaming media server is a specialized piece of software that accepts requests for video files, knows about the format, bandwidth, and structure of those files, and in many cases, pays attention to the performance of the player that's receiving the video. Streaming servers deliver just the amount of data necessary to play the video, at precisely the rate needed to play it.

Unlike the web server, which simply starts dumping as much video data onto the network as it can, the streaming server opens a conversation with the media player. There are two sides to this conversation – one to transfer the video and one for control messages between the player and the server. Because they continue to exchange these control messages with the player, streaming servers can adjust to changing network conditions as the video plays, improving the viewing experience. The control messages also include user actions like play, pause, stop, and seeking to a particular part of the file. Since the server sends video data only as it's needed and at just the rate it's needed, it also allows you to have precise control over the number of streams you serve and the maximum bandwidth you consume.

If you've got a 56kbps connection to the network, you won't be able to receive that 200kbps video. You'll have to settle for a lower-quality version that's encoded for 56kbps connections. But streaming delivery of video data does have some advantages:

- You can skip ahead in a video, or begin playback at a point somewhere in the middle. This is a convenience to users, but also a boon to you as a provider. It enables interactive applications like video search and personalized playlists.

- It lets you monitor exactly what people are watching and for how long they are watching it.

- It makes more efficient use of bandwidth since only the part of the file that's watched gets transferred.

- The video file is not stored on the viewer's computer. The video data is played and then discarded by the media player, so you maintain more control over your content.

In a pinch, streaming servers can use HTTP and TCP to deliver video streams, but by default they use protocols more suited to streaming, such as RTSP (Real Time Streaming Protocol) and UDP (User Datagram Protocol). RTSP provides built-in support for the control messages and other features of streaming servers. UDP is a lightweight protocol that saves bandwidth by introducing less overhead than other protocols. It's more concerned with continuous delivery than with being 100% accurate – a feature that makes it well-suited to real time operations like streaming. Unlike TCP, it doesn't request resends of missing packets. With UDP, if a packet gets dropped on the way from the server to the player, the server just keeps sending data. The idea behind UDP is that it's better to have a momentary glitch in the audio or video than to stop everything and wait for the missing data to arrive.

Finally, a streaming server is necessary to deliver live webcasts and to use multicast. For networks that support it, multicast allows more than one client to tune in to a single stream, saving bandwidth at every part of the delivery chain.

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the complete article is here :

http://www.streamingmedia.com/articl...id=8456&page=1

[Ferox13]

The video file is not stored on the viewer's computer. The video data is played and then discarded by the media player, so you maintain more control over your content.

I was wrong about the process then - i thought the media was downloaded in small chunks (as a buffer) and then erased as the player got through them then.

[neverending]

It is- nothing in that article says otherwise. In fact, the section in red confirms it.

[urgeok2]

well - yeah - which means you never have anything left thats playable at any time residing on your PC. temp files or not.

[Ferox13]

I imagine 'legally' it could be proved as downloading then,

[ManchestrMorgue]

Watching streaming video is downloading, but it's not the type of downloading that leaves you with a file that you can play again offline.

To see anything that is on the internet, you need to download it.

When you type a website's name into the url box at the top of the browser, this gets sent to a dns server that looks up the ip address of the said site. For example, if you type "www.horror.com", this is looked up by a dns server and the dns server says "OK, www.horror.com is at xxx.xxx.xxx.xxx" and directs you as such. (sort of like looking up someone's number or address in the phone book when you know their name).

So, basically then a request is sent for the page that you surfed to be downloaded to your computer. In the process, you have uploaded some data to the internet (ie you have sent a request from your computer to the website that you want to view, which is a small upload of data).

The information that you request is downloaded so that you can view it. It may not be stored in a way that has much permanency (eg it may go to a temp folder that is deleted after the session or at some other time).

Similarly, if you wish to watch a youtube video, you have to download the data that the video is comprised of. Because it is a streaming video, you will view it whilst it is still downloading. If you connection isn't fast enough, it may pause or stutter, whilst it is "buffering" more data. Again, this downloaded data won't be stored in a way that you can watch it again offline later. But it is certainly downloaded.

If you live in a country like Australia where we have quotas on monthly downloads, your ISP will probably offer an online usage monitor (so you can see how much you have left for the month). Watching youtube or other streaming video certainly uses up your quota, as the data that comprises the stream has to be downloaded to be viewed. (Surfing to websites and reading email also uses quota as these are also downloads, but usually small compared to streaming video).

So, basically everything you view on the net requires a download (and a - usually - much smaller upload to request the info in the first place).

One obvious difference between a streaming video and a video file that can be played offline is the temporary nature of the storage of the first set of data vs the persistent nature of the storage of the latter. But they are both equally a "download"