Streaming vs. progressive download : Understanding the difference

One of the most frequently asked questions about delivering video online is – “What’s the difference between streaming video and progressive download?” As a user clicking a video link on a website, you will not often know which delivery method is being used, unless you do some poking around. Although the end result may look the same to the end user, streaming and progressive download are very different delivery methods, each with their own strengths and weaknesses. Here we will take a look at the two delivery methods and help you to decide which will work best for you.

Delivering a file via HTTP:

• Delivery of a file over HTTP is normally referred to as ‘progressive download’ or ‘http streaming’.
•  In reality, it is not streaming at all but a very simple bulk download of a video file to the end user’s computer.
•  A temporary copy of the video file is then stored on the local computer so that the viewer can watch the file over and over without having to download the file each time.

• Let’s assume you have a video file encoded at 500kbps.
•  The server delivering the file does not know or care that your video file is encoded at 500kbps; 
• it simply pushes data to the host machine as quickly as it can. This can sometimes give the illusion that the file is being streamed because playback can start as soon as enough of the file is available on the local machine.
•  This obviously restricts the users from skipping to parts of the file that have not yet been downloaded.

If the bandwidth available to the machine downloading the file is smaller than the encoded bit-rate there may be a wait before the file will start to play. For example, on a 56kbps dial-up modem, trying to play a file that is encoded at 500kbps you may have to wait a fairly long time before enough of the file has been downloaded for it to start playing. On a 500kbps internet connect, or faster, playback should start almost immediately and the file should download faster than it will play, meaning that playback will not have to stop because not enough data has been downloaded.

HTTP(Hypertext transport protocol) operates over TCP(Transport control protocol) which controls the actual transport of the packets over the network. TCP is optimized for guarantee of delivery, regardless of file format or size. If a packet is skipped during the transfer of a file, it will request a resend of that packet. Resend requests take time and bandwidth and could increase the load on the server. TCP is not designed for efficient real time delivery or careful bandwidth control, but for accurate and reliable delivery of every bit.

Delivering from a streaming server:

Effectively, a streaming server is a piece of software which deals with video requests. Unlike a standard web server delivering a video file over HTTP (progressive download), a streaming server opens a conversation with the local machine. There are two sides to this conversation, one is for transferring the video and the other is for control messages between the media player and the server. These control messages include commands such as ‘play’, ‘pause’, ‘stop’ and ‘seek’.

If you have a 56kbps connection, you will not be able to receive a stream encoded at 500kbps; you will have to settle for a lower quality video encoded for 56kbps connections. Streaming does however have many advantages.

1. You can begin video playback at any point of the video, or skip through the video as you see fit. This is very convenient for users.

2. It makes a lot more efficient use of bandwidth as you are only using bandwidth for part of the video that are actually watched as opposed to HTTP delivery where the whole file gets delivered.

3. The video file is not stored on the viewer’s computer – the video data is played and then discarded by the media player. This lets you maintain more control over your content.

Streaming servers use a specific set of protocols to deliver streams, such as RTSP(Real time streaming protocol), RTMP(Real time messaging protocol) and MMS(Microsoft media services). These protocols are all more suited to delivering video streams because they are more focussed with continuous delivery than they are with 100% accuracy. Unlike TCP, they do not send resend requests for missing packets but instead continue with the rest of the video file. The idea is that it is better to have a momentary glitch in audio or video than for the playback to stop altogether and wait for the missing data.

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6 Ways to Make Your Computer Run Faster

This holiday season, the lines at Apple will flood out the door as people wait in line to upgrade their computers. However, if you’re experiencing problems with your computer it is most likely not because it’s too old or too worn down. If your computer is slow or is constantly freezing, you don’t need to run out to the store to purchase a new one. Here are 6 ways that you can save yourself the costly purchase of a new laptop or PC, and get your computer running faster:

Uninstall programs you don’t use: 

New computers come with a long list of programs, many of which you will never use, and most likely don’t even know exist. If you’ve never used a program and don’t foresee using it in the near future, get rid of it. Open the Control Panel, go into programs and features, and browse through the list of installed software. Uninstall everything that you don’t need. If you’re worried about deleting a program your computer’s hardware needs, you can use a program like PC Decrapifier which will select the programs you don’t need for you.

Run a disk de-fragment:

Maximize the efficiency of your computer by running a disk de-fragment and re-configuring how your hard drive stores information. In order to do this, open “my computer”, right-click on the hard drive and select “properties” from the drop down menu. Under the “Tools” tab click the option “Defragment now”.

Run a disk clean up:

You can also de-clutter your computer if you have windows with a built-in tool called Disk Cleanup. Disk Cleanup searches through your system for any unnecessary files that take up a lot of memory, like program installers, or temporary internet files. All you have to do to run the program is click “start”>”All Programs”> “Accessories”>”System Tools”> “Disk Cleanup”. The program does all the work for you.

Delete Temporary Files:

The every day tasks you perform on your computer cause temporary files to accumulate on your computer. These files remain on your hard disk, and slow your computer down. Remove the files to free up more hard disk space, speeding up your computer at the same time. This involves mainly deleting your internet history and cookies. In order to do this go to “My Computer”>”Local Hard Drive” (It will usually be C:\)>”Windows”>”Temp”. Right-click on “Temp”, hold your mouse over “View” in the drop down menu, and choose “Details”. Then, select the files that are older than the current date and press delete. If you want to delete cookies and web history from a laptop, open up your internet browser, choose “History” and then “clear browsing history”. Once you’ve finished these steps, make sure to empty your computer’s recycle bin.

Get A Bigger Hard Drive:

Even if you delete temporary files on a regular basis, if your hard drive is not big enough for you, your computer will slow down. When your hard drive becomes 85% full, your computer is sure to slow down. If you’re someone who uses the computer mainly for checking e-mail and moderate internet browsing, you most likely will not need a very large hard drive. However, if you regularly download television shows or other large files, you will need a large hard drive, one that’s more than 1TB in size. Head over to your nearest computer supply store in order to purchase a new one. The installation process is not difficult, and there are plenty of Youtube videos that can help you along the way. If you’re not comfortable doing it yourself, have them install the new hard drive for you at the store.

Remove Dust:

Dust can actually cause huge problems for your computer. Dust can obstruct your computer’s airflow which is necessary in order to keep it’s temperature down and keep it from over-heating. When your computer over-heats, it slows down in order to cope. In order to remove dust, simply take off the computer’s exterior and use a vacuum with a nozzle attachment at a very low power setting in order to remove some dust without damaging your computer. Make sure your computer is off before you start to clean. You can also reverse the setting if you encounter stubborn dust, and have the vacuum blow air out in order to blow the dust out.
Follow these steps, and your computer will be running as fast as it did when you ripped it out of it’s brand new box.

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