What is VOD Streaming?

VOD (Video On Demand) Streaming is a media distribution system that allows viewers to consume video content online. Television networks stream content continuously, so your TV shows it until you either turn the TV off or change the channel.

Unlike traditional streaming, VOD lets you choose and play specific videos. Due to flexibility and ease of use, VOD streaming is quickly replacing traditional modes of content consumption as consumers find it more convenient to watch their favorite content online.

How does VOD streaming work?

VOD streaming poses a few interesting problems. Think about how many videos are on your favorite YouTube channel. How long are those videos?

Long video files, like a 90-minute movie, can easily take up several gigabytes of storage space. As you can imagine, hosting video content requires a lot of storage space. Additionally, downloading a large video file could take quite a while on slower video connections.

To resolve this issue, VOD streams compress video files, splitting them into small segments and stitching them together as a playlist. This way, even long video files can load at the click of a button.

In order for a platform to distribute video content on demand, it needs to:

  1. Upload the raw video to cloud storage.
  2. Encode the video into a file that can easily be stored and sent. A media server compresses video, or breaks it down long videos into smaller packets.
  3. Store the video until it's requested. Usually, platforms use a Content Delivery Network to cache copies of the video closer to users.
  4. Deliver the video to end-user devices. If the video content uses any sort of digital rights management (DRM), the client uses the key included with the file to decrypt it.

This is a bit of an oversimplification, since there can be a lot of different variables in how a platform writes video content. Additionally, video content might need to be saved in different formats so it can be sent to as many devices as possible.

How is VOD streaming different than live streaming?

Live streaming specifically refers to content that is recorded and streamed in real time. You might have live streamed a concert, or a Q&A with a favorite celebrity as it was happening in real life. That's live streaming.

VOD, on the other hand, strictly describes the delivery of pre-recorded content. Whenever you watch a movie on Netflix or YouTube, you're accessing VOD content.

Live streams transcode and package content on the fly before passing it to a Content Delivery Network to distribute to end users. VOD streaming uses pre-packaged video files that are optimized and stored for consumption at any time.

Because VOD doesn't require real-time error correction or a constant connection, it's much easier to implement than live streaming. However, VOD content can't be live since the video needs to be recorded and written first.

Glossary

Encoding

The act of transferring or saving information into a usable file format.

Compression

A type of algorithm used to make files smaller.

DRM

DRM, or Digital Rights Management is a set of techniques, often used to protect copyrighted works and media.