Whether you’re launching a new campaign or just looking to express yourself creatively, all video-makers have to dance within the world of file formats.

In order to deliver the correct file to your client, team, or collaborator, you’ll need to check certain boxes and click a few buttons when exporting from your editing program. Don’t know what .mp4 or .mov really means? You’ve heard of a codec — but what is it, really?

We’re breaking down some common questions, so you can go into post-production with a solid sense of video file formats. Read on for a breakdown of different file formats, and why your computer might happily decode some while the struggle is real for others!

Everything is in the container

A container includes all of your video file’s important information. This includes your video and audio, as well metadata: Video title, description, thumbnail, or captions and subtitles.

To determine your container’s format, simply look at its file extension. For example, an MPEG-4 Part 14 container will show up as an .mp4, while a Quicktime container will format as .mov. There are other containers specific to broadcasting or archiving, but for online video streaming and distribution, .mp4 and .mov are the most compatible, and thus, most frequently used.

How about a codec?

A codec is short for compressor-decompressor (hence the name codec), and it implements the specific algorithm for compressing video and audio data — and also for de-compressing that same data when you are watching the video file on your computer. Your operating system may already come with everything it needs to playback some codecs. However, if it doesn’t, there are additional programs you can install to enable you to view a wider variety of videos, like VLC.

Common codecs

There is a huge variety of video codecs, but the two below are the ones you’ll encounter the most.

H.264/AVC: This is an international ISO/ITU standard, and the most used codec for distributing HD video. Vimeo encodes all of our videos to H.264 for playback, which is why we recommend using this codec in our Compression Guidelines.

Apple ProRes: This is a close second in popularity because a lot of post-production happens on Apple products.

Note: Audio and video codecs are separate entities. A container interweaves your audio and video into a single stream. AAC is an ISO standard audio codec, so we recommend using AAC-LC (low complexity) for your video’s audio codec.

How are videos compressed?

Compression can be lossy or lossless. Here’s what that means.

Lossy files are smaller and easier for digital delivery, and they are compressed in such a way that the data loss is imperceptible to humans. This is the more logical choice for online video playback. Large video files take up more storage space and might cause playback issues for viewers with a slower internet connection.

Lossless files are compressed so that all original data is there, but the file size is significantly larger and, in this case, impractical. Because of this, lossless files are never used on the web, but are used in production and for archiving.

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