数字(Digital)视频无处不在。无论是光盘、流媒体服务还是计算机上的文件，每个视频都有特定的格式。了解常见的视频格式对于制作视频的人和只想观看视频的人来说都是必不可少的。
否则，您可能会发布质量较差的内容，或者只是不知道为什么给定的视频不会为您播放。在本文中，我们将解释什么是视频格式以及每个人都应该知道的最常见的格式。
格式(Format)、容器(Container)和编解码器(Codec)：解释关键概念
当应用于视频时，“格式”这个词需要一些解包。在任何媒体中，格式都是其标准化形式。VHS和Betamax是家庭录像带的格式。虽然两者都使用相同的基本技术（电视信号记录在磁带上），但两者的确切方法和设计不同。
最终结果是VHS磁带无法在(VHS)Betamax机器中工作（甚至不适合），反之亦然。数字(Digital)视频也不例外。将视频和音频编码为数字数据的方法有很多种。因此，播放器无法理解或播放它不适合的格式。
对于数字视频，格式是指最终视频文件中所有点点滴滴的总和。您将看到的第一件事是容器。即文件是否为.AVI。.MOV、.MP4等。容器将视频的所有不同元素包装到一个文件中。
但是，仅仅因为两个视频文件具有相同的容器，并不意味着它们的格式完全相同！在容器中，有实际的视频数据、音频数据，有时还有字幕等附加信息。
它们中的每一个都有自己独特的格式。视频和音频流都有自己独特的格式，称为它们的“编解码器(codecs)”。
术语编解码器是“编码器/解码器”的缩写。它准确地描述了视频或音频是如何从其原始的、未压缩的形式转换为更可口的大小的。
常见的视频格式MP3是音频编解码器的一个示例。它可以将高质量的 CD 音频压缩到原始大小的十分之一以下，而不会损失太多主观质量。说到损失，现在是解释“有损”编解码器的好时机。
“有损”与“无损”格式
视频(Video)包含大量数据。模拟(Analogue)胶片库存，例如在其历史上大部分时间都在胶片上制作的电影，包含大量的细节。这就是为什么可以发布老电影的高清、4K和 8K 重制版的原因。您所要做的就是返回并以更高分辨率扫描胶片帧。细节在那里，仅受扫描设备的分辨率和胶片颗粒本身的质量限制。
对于给定的图像分辨率，有大量信息。单帧4K视频相当于一张3840×2160的照片！压缩(Compression)技术使用各种奇特的数学方法来减少在屏幕上重建图像所需的信息量。
这些压缩技术中的大多数都是“有损”的。也就是说，他们丢弃了一些视觉信息以减少视频数据的大小。但是，损失通常非常小，非常值得大规模减小尺寸。您观看的任何流式视频、DVD或蓝光(BluRay)内容都使用有损压缩。
视频的无损(Lossless)压缩通常只在大预算电影项目的主数字录音或电影档案中找到。
重要的通用编解码器
有数百种不同的编解码器，在过去，安装播放视频可能需要的所有不同编解码器简直是一场噩梦。
更糟糕的是，机顶盒播放器通常只支持少量编解码器，因此您需要一台计算机将视频转换为这些机器可以理解的内容。如今，几乎所有视频都使用少数编解码器之一进行编码。
H.264 – 高级视频编码
在撰写本文时， H.264(H.264)是迄今为止最流行的视频编解码器。90% 以上的视频都是以这种常见的视频格式提供的。由于H.264如此流行，大多数设备（如智能手机和智能电视(TVs)）都内置了特殊硬件来解码H.264视频，而不会对设备的主处理器造成任何压力。这(Which)就是为什么即使是低端智能手机(smartphones)也可以毫不费力地播放高清视频。
H.265 –高效视频编码(Efficiency Video Coding)
视频压缩的高效视频编码(High Efficiency Video Coding)( HEVC ) 格式彻底改变了视频流，因为它可以显着减少您需要的带宽。它被设计为H.264的继任者，通常使用少 25% 到 50% 的带宽来在相同的带宽水平下提供相同的质量或更好的质量。
H.264在流媒体领域取得了巨大成功，但与H.264不同的是，没有多少设备具有此编解码器的特殊硬件解码组件。因此，虽然它会节省大量带宽和硬盘空间，但它会给目标设备带来真正的锻炼。与H.264一样，这可能会随着时间的推移而改变，但现在您应该在选择使用它之前记住它的有限支持。
MPEG-4
MPEG-4可能有点复杂。它也是一种非常常见的视频编解码器，但MPEG 4 Part 10实际上与H.264相同。MPEG-4的早期版本（例如第 2 部分(Part 2)）使用较旧的算法，这些算法在相同质量水平的空间方面效率较低。H.264实质上已经用新的命名约定取代了MPEG-4 。
MP3 – MPEG 音频第 3 层
几乎每个人都知道MP3是什么，因为这是颠覆唱片业的音乐格式，并最终导致了我们今天都知道的数字流媒体音乐和下载模式。您可能不知道MP3音频在视频中也很常见。
由于这种格式可以在不损失太多保真度的情况下将CD 质量的音频压缩到大约十分之一的大小，因此多年来它一直是数字音频的中流砥柱。(CD-quality)无论(Regardless)给定视频容器使用哪种视频编解码器，音频本身很有可能是MP3格式。它(Which)也有不同级别的质量，快乐媒体通常在 128 到 196 Kbps左右。
WAV – 波形音频格式
“波形”格式已经存在了很长时间，并且（通常）是一种未压缩的数字音频文件，可以精确地代表原始录音波形。因此，正如您所料，它占用了大量空间。在与 CD 音频相同的质量设置下，WAV文件应该占用与 CD 一样多的空间。虽然它不是特别常见，但视频也可以包含WAV音频。
常见的视频容器格式
最后一块拼图是常见的容器格式。这就是您实际看到的视频文件格式。也就是说，你看到的文件扩展名是属于容器的。让我们看看最常见的。
MP4
几乎所有设备都支持MP4容器格式。它可以包含任何MPEG-4格式版本和H.264。YouTube视频通常采用这种常见的视频格式。
AVI – 音频视频交错
这是最古老的视频容器之一，它不再经常使用，但它仍然受到广泛支持，并且许多现有内容都在AVI中。可以在AVI容器中使用的编解码器的数量是巨大的，这也是您在数字视频的古老狂野西部时代试图让(AVI)AVI文件播放时冒冷汗的另一个原因。
移动
MOV容器与Apple QuickTime Player相关联，并且是其内部格式。在MOV文件中，您最有可能找到 MPEG-4 视频数据。这(Which)就是为什么在大多数情况下，您可以将MOV文件重命名为MP4文件并且它的工作方式相同。
MOV和MP4文件之间的主要区别在于MOV文件有时具有复制保护。这可以防止未经授权的用户共享和播放。
视频格式兔子洞
这些常见的视频格式和容器只是冰山一角。例如，DVD(DVDs)使用MPEG-2，但现在很少用于您在商店购买的实际DVD光盘之外。(DVD)还有专业的视频格式（例如ProRes RAW）和互联网上交易的常见格式（例如MKV）。
从字面上看，这将需要一整本书来涵盖所有内容。然而，世界正在对H.264和H.265进行标准化。因此，如果您在任何时候制作视频，其中任何一个都可能是安全的选择。目前使用H.264是最安全的选择！
The Most Common Video Formats and Codecs Explained
Digital νideo is all aroυnd us. Whethеr it’ѕ a disc, a streaming service, or a file on your compυter, every video has a specific format. Understanding common video formats is essential both for people who make νideo and people who simply want to watch video.
Otherwise you might put out content with poor quality or just won’t know why a given video won’t play for you. In this article we’ll explain what video formats are as well as the most common ones everyone should know.
Format, Container And Codec: Key Concepts Explained
The word “format” when applied to videos needs a bit of unpacking. In any medium, the format is its standardized form. VHS and Betamax were formats for home video tape. While both used the same basic technology (TV signals recorded on magnetic tape), the exact method and design differed between the two.
The end result is that a VHS tape will not work (or even fit) into a Betamax machine and vice versa. Digital video is no different. There are many different ways of encoding video and audio as digital data. So a player cannot understand or play back a format it was not designed to.
For a digital video, the format refers to the sum total of all the bits and pieces that come together into the final video file. The first thing you’ll see is the container. That is, whether the file is an .AVI. .MOV, .MP4 and so on. A container wraps all the different elements of the video into a single file.
However, just because two video files have the same container, that doesn’t mean their formats are exactly the same! Within the container, there’s the actual video data, audio data and sometimes additional information such as subtitles.
Each of these have their own individual formats. The video and audio streams will each have their own unique formats, referred to as their “codecs”.
The term codec is short for “coder/decoder”. It describes exactly how video or audio is converted from its raw, uncompressed form into something of a more palatable size.
The common video format MP3 is an example of an audio codec. It’s what allows high quality CD audio to be squeezed down to less than a tenth of the original size, without losing much if any subjective quality. Speaking of loss, now’s a good time to explain “lossy” codecs.
“Lossy” Vs “Lossless” Formats
Video contains a ton of data. Analogue film stock, such as movies that have been made on film for the majority of their history, contain an incredible amount of detail. This is why it’s possible to release HD, 4K and 8K remasters of old movies. All you have to do is go back and scan the film frames at a higher resolution. The detail is there, limited only by the resolution of the scanning equipment and the quality of the film grain itself.
For a given image resolution, there’s a ton of information. A single frame of 4K video is equal to a 3840×2160 photo! Compression technology uses various fancy mathematical ways to reduce the amount of information you need to reconstruct an image on screen.
Most of these compression techniques are “lossy”. Which is to say that they throw away some visual information to reduce the size of the video data. However, the loss is usually very minor and well worth the massive reduction in size. Any streaming video, DVD or BluRay content you watch uses lossy compression.
Lossless compression for video is usually only found in the master digital recordings for big-budget film projects or in film archives.
Important Common Codecs
There are hundreds of different codecs and in the past it was an utter nightmare to install all the different codecs you might need to play back video.
Even worse, set-top players usually only supported a small number of codecs, so you would need a computer to convert video into something those machines could understand. These days, almost all video is encoded using one of a small number of codecs.
H.264 – Advanced Video Coding
H.264 is by far the most popular video codec at the time of writing. With just over 90% of all video offered in this common video format. Because H.264 is so popular, most devices (such as smartphones and smart TVs) have special hardware built in to decode H.264 video without putting any strain on the device’s main processor. Which is why even bottom-end smartphones can play HD video without breaking a sweat.
H.265 – The High Efficiency Video Coding
The High Efficiency Video Coding (HEVC) format of video compression has revolutionized video streaming, since it can significantly reduce how much bandwidth you need. It’s designed to be the successor to H.264 and in general uses 25% to 50% less bandwidth to provide the same quality or better quality at the same bandwidth levels.
H.264 is finding great success in the world of streaming, but unlike H.264 there aren’t many devices that have special hardware decoding components for this codec. So while it will save plenty of bandwidth and hard drive space, it will give the target device a real workout. As with H.264, this is likely to change over time, but for now you should keep its limited support in mind before choosing to use it.
MPEG-4
MPEG-4 can get a little complicated. It’s also a very common video codec, but MPEG 4 Part 10 is actually the same as H.264. Early versions of MPEG-4 (e.g. Part 2) use older algorithms that are much less efficient in terms of space for the same level of quality. H.264 has essentially replaced MPEG-4 with a new naming convention.
MP3 – MPEG Audio Layer-3
Just about everyone knows what an MP3 is, since this was the music format that upended the record industry and, eventually, led to the digital streaming music and download model we all know today. What you might not know is that MP3 audio is also pretty common in videos.
Since this format can squeeze CD-quality audio to roughly a tenth of its size without losing too much fidelity, it’s been a mainstay of digital audio for years. Regardless of which video codec a given video container uses, there’s a good chance the audio itself is in MP3 format. Which also has various levels of quality, with the happy medium usually falling around the 128 to 196 Kbps level.
WAV – Waveform Audio Format
The “wave” format has been around for ages and is (in general) an uncompressed digital audio file that represents the original recording waveform precisely. So, as you might expect, it takes up a huge amount of space. At the same quality settings as CD audio, a WAV file should take up roughty as much space as a CD. While it’s not particularly common, a video can contain WAV audio as well.
Common Video Container Formats
The last piece of the puzzle are common container formats. This is what you’ll actually see as the file format of the video. In other words, the file extension you see belongs to the container. Let’s look at the most common ones.
MP4
The MP4 container format is supported by just about every device. It can contain any MPEG-4 format version and H.264. YouTube videos are usually in this common video format.
AVI – Audio Video Interleave
This is one of the oldest video containers and it isn’t used very often anymore, but it’s still widely supported and a lot of existing content is in AVI. The number of codecs that can be used in the AVI container is massive, which is another reason you’d get into cold sweats trying to get an AVI file to play back in the good old wild west days of digital video.
MOV
The MOV container is associated with the Apple QuickTime Player and is its in-house format. Inside a MOV file you are most likely to find MPEG-4 video data. Which is why, in most cases, you can rename a MOV file to an MP4 file and it will work just the same.
The main difference between MOV and MP4 files is that MOV files sometimes have copy protection. This prevents sharing and playing by unauthorized users.
Down The Video Format Rabbit Hole
These common video formats and containers are but the tip of the iceberg. For example, DVDs use MPEG-2, but that’s now rarely used outside of actual DVD discs you’d buy at a store. There are also professional video formats (e.g. ProRes RAW) and common formats traded on the internet (e.g. MKV).
It would require, literally, an entire book to cover them all. However, the world is standardizing towards H.264 and H.265. So if you make videos at any point, either of those are likely to be a safe bet. With H.264 currently the safest bet of them all!
