Encoding and transcoding: what's the difference?

Encoding and transcoding are often used interchangeably but they have slightly different definitions. Encoding is the initial process of converting raw video files into a specific digital format or codec. It involves compressing and packaging the video data, often to reduce file size while maintaining acceptable quality. Encoding prepares the video for storage, transmission, or playback.

 

Transcoding, on the other hand, involves converting a video from one digital format or codec to another. This is typically done to optimize the video for different devices or platforms, adapt to varying network conditions, or ensure compatibility with specific playback requirements. Transcoding occurs after encoding and often involves changing resolution, bitrates, or formats without altering the content itself.

What goes on behind encoding a video?

It's easy to say that encoding is when you go from an uncompressed source to a compressed source, but you may ask, what exactly do compressed and uncompressed sources mean?

 

Uncompressed sources are video files that contain data that comes directly from a camera sensor vs. encoded video. In the digital space, it's SDI (Serial Digital Interface) or HDMI (High Definition Multimedia Interface). Both of them are popular standards. You'll find HDMI in places like your GoPro camera, or a mini camcorder. These days, you might also find HDMI in professional settings, but SDI is more common due to its reliability. Another example of an uncompressed source would be something analog, for instance, VHS tapes.

 

A compressed sources, on the other hand, are video files that have undergone compression during the encoding process. Compression involves reducing the file size by removing unnecessary information or encoding the data in a more efficient format. This process results in a smaller file size, making it more manageable for storage, transmission, and playback.

What are the types of transcoding methods?

There are three types of transcoding, depending on what you are trying to do to get a video to suit a particular browser, player, or platform:

• Lossless-to-lossless - This type of transcoding maintains the quality of your video across formats but allows you to take advantage of better hardware or compression algorithms.
• Lossless-to-lossy - This type of transcoding will decrease your video in quality, but it will benefit you in ways such as – you will get a smaller and/or faster playing file, or a file that is compatible with the requirements of a particular platform, player, or browser.
• Lossy-to-lossless - Sometimes people think this means they are regaining quality. This isn't the case in this type of transcoding. If you transcode from a lossy format to a lossless format, all that it means is that you will not lose additional quality in the conversion process. You will not regain data you already lost through compression.

Codecs for encoding and transcoding

For both encoding and transcoding, you will need to make use of codecs. A codec's job is to compress and decompress video files. It's right there in the name - compress decompress or encode decode. So basically, codec is an algorithm that takes the video and shrinks it or changes it into a format that makes it compatible with the requirements of wherever you want the video to play. There are many codecs because there are many ways to compress a video or livestream for playback.

What is transmuxing?

Now that you know the difference between encoding and transcoding, let's throw one more term in there - transmuxing. Transmuxing is when you change the container for a video instead of the format. It's a way of repackaging a video to make it compatible somewhere without changing what's in the file.

 

This process is faster than encoding or transcoding and takes less computing power because you only change the container, not the file. It's great when you need to quickly make something available, but the downside is that it doesn't handle things like making multiple video resolutions available. If you choose a container type that's incompatible with your video file, you may also cause compatibility issues, resulting in not being able to play the video.

In closing

• Encoding - Encoding happens when you compress a raw data file from a video camera sensor or an analog source like a VHS tape.
• Transcoding - Transcoding happens when you take an already compressed video file and change it to another format.
• Transmuxing - Transmuxing happens when you change the container of a video file but leave the video file untouched.

We hope that explains the difference between encoding and transcoding clearly.

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