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6 key terms beginners need to understand about video streaming

video streaming beginner's termsMy son has started streaming his Minecraft adventures. I set up the recording software for him, but he now knows how to edit and upload himself. One of his Minecraft buddies wanted to start streaming too, so I offered to help him get set up as well.

And that’s when I stumbled into the latest proof of the old adage, “If you want to learn something, teach it.” I sat there with the ten year old boy, so excited and anxious to make his video and watched his face contort into confusion as I spoke. There are only a few settings that need to be adjusted really, but it was hard to explain it when we had no common vocabulary.

Once I realised he wasn’t understanding (I babbled on for far too long), I backed up. I tried to start from the beginning, but then I had to go back even farther. The trouble is, that even though kids these days are so technically able, there’s so much going on behind the scenes they never even see (this is particularly true for anyone using a Mac). Many adults too, who have learned to use computers and devices don’t realise what’s going on when they do it.

But if you’re going to be streaming video with any care of what the final output looks like, there are some terms you need to know. There are many actually. But I’ve pulled out the six most basic I found myself explaining to my son’s young friend. With these terms I figured he’d have the foundation to make tweaks in the settings if need be, so I wouldn’t have to visit every other day.

File extension

Now this is really starting at the beginning. Most people realise there are different types of files: images, documents, spreadsheets, music, etc. Though the average person may not even know these are files really. They think of them in terms of a picture, a video, a Word document, and so on. But each of these, and thousands of other file types, each have a unique identifier called a file extension. You’ll find the file extension at the end of a file name like this: filename.fileextension. The dot and characters that follow the dot are the file extension. Here are some examples: .xls (Excel), .doc (Word), .jpg (JPEG image), .mp3 (audio file).

The trouble comes in because the way computer operating systems are designed now, these file extensions are hidden (though you may see a file type listed in a folder or directory). Apple computers have been hiding them for years. Windows didn’t start doing it until later, but now hides extensions of all “known” file types by default. You can change this is the settings but most people don’t know you can, or care.

So why should you care? Because when you’re managing your video streaming, you need to know you’ve got the right file in the right format. The file extension is one way you know.

Format

If you read about file extensions, this one is really easy. A format defines the type of file. There are thousands of different types of formats. Virtually every kind of software will have its own file type, unless it is designed to use one of the more standard types. But take Photoshop for example. It can use image files in virtually every format (jpeg, gif, png, – notice these are file extensions?) but will save a project in its own proprietary format with a file extension of .psd.

When you’re streaming, you’ll need certain formats in order to be compatible with different browsers or players. For example Flash format won’t work on Apple devices (natively). So if you have your video in Flash format you’ll need to convert it into another format if you want people on Apple devices to watch them. In video, formats are also called containers or container formats. You may have a video file that has an mp4 file extension. This means it’s in the MPEG-4 Part 14 container format and it likely has video and audio information (it can have others as well). Which leads to the next term you need to know in the next section.

Codecs

Back when people were first getting started creating digital media, they needed a word to describe the process of compressing and decompressing video (because uncompressed video takes up a lot of storage space). These creative people decided to smash together the words compress and decompress (or encode and decode depending who you ask) to come up with codec. It’s certainly better than saying the full words.

There are much fewer codecs than there are file formats, but sometimes they are easy to confuse with formats. It’s the codecs that actually do the work of creating video we can stream over the internet by compressing the digital data into something small enough, but  still with enough quality, that we can enjoy it on all our devices.  Why is this important? Because when you compress a video (or audio, or any file type) it loses information so it is a lower quality. That’s because most compression works by removing data, usually bits here and there you generally won’t notice if the proper settings are used. The decompression does the work of putting that data back in, or actually, recreating it according to certain rules.

A couple of the most used codecs for video are MPEG-4 and H.264. And this is why it gets confusing sometimes. Do you remember reading MPEG-4 up in the container section? Yes, you saw it there too. Sometimes the lines between container and codec do cross or disappear. But as long as you understand the codecs do the work and the container is just a way of bundling it all together so we can easily upload the files to the web for sharing, then you’re good. If you want to, you can dive in and learn all there is to know about codecs. But you don’t have to. Just focus on the few that are standard and your video will stream just fine.

FPS

This is one term the boy I mentioned in the beginning was sure he knew. But sadly, in the realm of video streaming it doesn’t mean “first person shooter”. That’s a different genre all together. What it does mean is “frames per second”. All video is really just a series of still images played back to us at a high speed. To the human eye, the images blend together and make moving pictures.

There’s a lot of history involved in trying to figure out how many frames per second you need to make video look good – meaning smooth and like watching real life. The film industry generally uses a standard of 24fps for motion pictures. There are different standards used around the world but they generally require 24, 25 or 30 frames per second. Other amounts are being used or trialled in different applications.

In video recording software, you can usually find a setting for FPS. We have an older computer and the process of recording takes a lot of resources. So for my son’s videos I dropped it down to 24fps (from the default of 48!) and it all looks much smoother. And our computer doesn’t have smoke coming out of it either.

Frame rate

No need to be confused by this one. It’s another way of referring to how many FPS you are using. My son’s videos have a frame rate of 24fps. It’s always measured in frames per second for streaming video (unless there’s some strange application I’m unaware of). This is a setting in recording software that you need to set before you start recording. If you don’t know what value to use, take a very short video and see how it looks. If there are issues during playback you may need to adjust the frame rate up or down.

So if you hear “frame rate”, think “how many frames per second” and you’ll know just what to do.

Bitrate

Once you’ve got your video recorded, you’ll need to encode it and send it out for everyone to see. A very important setting in that process is bitrate. Technically speaking, it’s how many bits are transferred per second (most commonly measured in megabits per second, or mbps). The higher the number, the more data is encoded into your video (because you told the encoder you had plenty of bandwidth available with a large bitrate).

This can be wonderful if you have a great internet connection, and the people you want to watch your video have a great internet connection. But if either one is not so great, then your video will look bad. So bitrate is one of those settings that needs to be in balance. You want it as high as possible for the best quality, but not so high that it is too large for your connection (or the viewer’s connection). Chances are the service you’re using to host, or share, your videos will have recommendations on the bitrates you should use.

The basics

These terms provide a basic vocabulary you’ll need for video streaming. There’s a lot more you can learn about each term (codecs and formats especially), but now you know enough to go and make some videos. And you’ll actually know what some of the settings are and what to do with them.

Are there any terms you’ve come across while learning about video streaming that had you stumped when you first started creating video? Share in the comments so I can get working on another blog with more terms for beginners. You could also take a look at our Glossary.

Oliver Burt

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