CODECS & COMPRESSION
These may sound like something from a wizard’s spell book, but I assure you they have a very real impact on your images, for better or worse. Let’s start with what a codec is. There are many, many, many codecs out there. A codec takes a stream of data and encodes it into a specific format that you can view and edit. Here are some of the more popular formats you will come across:
Now that your eyeballs are glossed over, let’s try to break these down into English! Generally, your camera will only have one or two codec options. You will need to research your camera to find out what those might be. What do codecs translate to in the real world? The video signal coming from the camera sensor contains a massive amount of data. To be able to record this data in an efficient way, the codec in your camera uses compression to create smaller file sizes. Compression is exactly what it sounds like: shrinking your incoming data down to a smaller file size. For example, 1080p at 30 frames per second is about 9Gigs per minute if uncompressed. The camera essentially discards most of the information in order to compress the file size to about 300-400 MB per minute.
Sounds great, right? Smaller file sizes – yay! Before you get too excited, let’s stop and think about this for a minute. Compression helps us avoid using massive amounts of hard drive space, which is definitely a good thing. However, it also limits us because we now have less information in the video files that we want to edit and manipulate. For example, if we want to really go wild on a color grade, a more compressed file will start to look bad much more quickly when adding effects. Now before you throw your camera off a cliff for shooting compressed formats, though, all is not lost. For the majority of what filmmakers do, shooting compressed formats is just fine. Encoding is getting much better, and chances are your camera will have a great internal codec already. If not... I can recommend a few high mountains.
If you still aren’t crazy about the idea of compression, never fear. Instead, you can take advantage of something called “raw recording.” Multiple formats exist for raw recording. Generally, they still involve a small amount of compression, but it’s usually not very noticeable. Often, you can change the amount of compression on your raw images when you don’t need your footage to be totally uncompressed. Before you decide that raw recording is the only way for a true filmmaker to record footage, though, remember that there are drawbacks. As mentioned previously, it takes up massive amounts of storage space. For example, if you are shooting raw footage at 4k with no compression, 1 hour of footage will take up roughly 480 gigabytes of hard drive space. That’s a lot of storage! Also, raw recording is often only available in more expensive camera platforms. These drawbacks need to be balanced with your desire for greater ability to manipulate the color and exposure in the video. One time when greater control may outweigh practicality is if you are shooting green screen footage. Also, you may need the additional editing flexibility if you are creating visual effects.
In summary, then, compressed footage is a smaller file with less information, often able to be edited right away with little set up time while uncompressed footage contains more information in a much larger file often with a more complex workflow inside your editing system. A codec is what the compressed/uncompressed footage is turned into so that you are able to view and edit your files on a computer. Most editing systems will allow you to simply drag and drop your footage in and start editing. Some codecs may need to be encoded into a more edit-friendly format or to be run through external applications such as Divinci Resolve. Hopefully, I have adequately compressed all that information down so that you can retain it more easily! If not, don’t worry too much. Codecs and compression is a pretty technical and advanced subject. Generally, you won’t pay much attention to these elements of film until you have more experience.
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