Digital video is all around us. Whether it’s a disc, streaming service, or a file on your computer, each video has a specific format. Understanding common video formats is important for both people who shoot videos and people who just want to watch videos.
Otherwise, you may post poor quality content or you simply won’t know why this video won’t play for you. In this article, we will tell you what video formats are, as well as the most common ones that everyone should know.
Format, container, and coding: Explain basic concepts
The word “format” as applied to video requires some unpacking. In any medium, a format is its standardized form. VHS and Betamax were both home videotape formats. Although both used the same basic technology (TV signals recorded on magnetic tape), the exact method and design were different.
The end result is that a VHS cassette won’t work (or even fit) in a Betamax machine and vice versa. Digital video is no different. There are many different ways to encode video and audio as digital data. Thus, the player cannot understand or reproduce a format for which it was not designed.
For digital video, format refers to the sum of all the bits and parts that are combined into the final video file. The first thing you’ll see is a container. That is, whether the file is .AVI. .MOV, .MP4 and so on. The container combines all the different elements of a video into one file.
However, just because two video files have the same container does not mean that their formats are exactly the same! The inside of the container contains actual video data, audio data, and sometimes additional information such as subtitles.
Each of them have their own individual formats. Each video and audio stream will have its own unique formats called “codecs”.
The term “codec” is an abbreviation for “encoder / decoder”. It accurately describes how video or audio is converted from a raw, uncompressed form to something more manageable.
The general video format MP3 is an example of an audio codec. This is what allows high-quality audio on a CD to be compressed to less than one tenth of its original size without much loss in subjective quality. Speaking of loss, now is the time to talk about lossy codecs
“Lossy” versus “lossy” formats
The video contains a ton of data. Analog films, such as films that have been shot on film for most of their history, contain an incredible amount of detail. This is why remasters of old movies in HD, 4K and 8K can be released. All you have to do is go back and scan the higher resolution stills of the film. There is detail here, limited only by the resolution of the scanning equipment and the quality of the film grain itself.
There is a wealth of information for a given image resolution. One frame of 4K video is equal to a 3840 × 2160 photo! Compression technology uses a variety of bizarre mathematical techniques to reduce the amount of information needed to reconstruct an image on a screen.
Most of these compression methods are lossy. That is, they discard some visual information to reduce the size of the video data. However, the losses are usually very small and worth the significant reduction in size. Any streaming video, DVD or BluRay content you watch uses lossy compression.
Lossless compression for video is typically found only in basic digital recordings for high-budget film projects or in film archives.
Important common codecs
Worse, set-top boxes usually only support a small number of codecs, so you’ll need a computer to convert the video to what these machines could understand. Almost all videos are encoded using one of a small number of codecs these days.
H.264 – Advanced Video Coding
H.264 is by far the most popular video codec at the time of writing. This general video format offers just over 90% of all video. Because H.264 is so popular, most devices (such as smartphones and smart TVs) have dedicated hardware built in to decode H.264 video without stressing the device’s main processor. This is why even inexpensive smartphones can play HD videos without worry.
H.265 – High Efficiency Video Coding
The High Efficiency Video Coding (HEVC) video compression format has revolutionized video streaming as it can drastically reduce the bandwidth required. It is designed as the successor to H.264 and typically uses 25-50% less bandwidth to provide the same or better quality at the same bandwidth levels.
H.264 has enjoyed great success in the streaming world, but unlike H.264, there are not many devices that have dedicated hardware decoding components for this codec. So while it will save a lot of bandwidth and hard drive space, it will give the target device a real workout. As with H.264, this will likely change over time, but for now you should be aware of the limited support before using it.
MPEG-4 can get a little complicated. It is also a very common video codec, but MPEG 4 Part 10 is actually the same as H.264. Earlier versions of MPEG-4 (eg Part 2) use older algorithms that are much less space efficient for the same quality level. H.264 has essentially replaced MPEG-4 with a new naming convention.
MP3 – MPEG Audio Layer-3
Pretty much everyone knows what MP3 is, as it is the music format that revolutionized the recording industry and ultimately led to the digital music streaming and download model that we all know today. You may not know that MP3 audio is also quite common in videos.
Because it can compress CD-quality audio to about one-tenth of its size without losing too much fidelity, it has been the backbone of digital audio for many years. Regardless of which video codec a given video container uses, chances are good that the audio itself is in MP3 format. Which also has various levels of quality, with the sweet spot usually being between 128 and 196 Kbps.
WAV – Waveform Audio Format
The “wave” format has been around for many years and is a (generally) uncompressed digital audio file that accurately represents the original recording waveform. So, as you might expect, it takes up a huge amount of space. With the same quality settings as an audio CD, the WAV file should take up about the same space as a CD. Although not very common, videos can also contain audio in WAV format.
Common video container formats
The last piece of the puzzle is the common container formats. This is what you will actually see as the video file format. In other words, the file extension you see belongs to the container. Let’s take a look at the most common ones.
The MP4 container format is supported by almost every device. It can contain any version of the MPEG-4 and H.264 format. YouTube videos usually have this common video format.
AVI – Audio Video Interleave
It is one of the oldest video containers and is no longer used very often, but is still widely supported, and most of the existing content is in AVI format. The number of codecs that can be used in an AVI container is overwhelming, which is another reason you will fall into a cold sweat trying to get an AVI file to play in the good old days of digital video.
The MOV container is associated with the Apple QuickTime Player and is its internal format. In the MOV file, you will most likely find MPEG-4 video data. This is why in most cases you can rename the MOV file to MP4 file and it will work exactly the same.
The main difference between MOV and MP4 files is that MOV files are sometimes copy protected. This prevents sharing and playback by unauthorized users.
Down the hole rabbit video format
These common video formats and containers are just the tip of the iceberg. For example, DVDs use MPEG-2, but nowadays it is rarely used beyond the actual DVDs you buy at the store. There are also professional video formats (such as ProRes RAW) and common formats on the Internet (such as MKV).
It would take literally an entire book to cover them all. However the world is being standardized towards H.264 and H.265. So if you are shooting videos at any given moment, any of these are likely to be a win-win. H.264 is currently the most secure option of all!