audio video formats explained Archives

Advantages and disadvantages of the main formats

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Formats

The MP4 file format

The MP4 file format has long been one of the most popular video formats on the web. Thanks to good compression coupled with good video file quality, excellent compromises can be achieved. The codecs used for MP4 are mainly H.264 or H.265.

Advantage

The format offers a good compromise between image quality and compression and is particularly compelling due to the simple ability to bundle multiple audio tracks and additional elements into a single format.

Disadvantages

MP4 files are often heavily compressed using standard codecs, making processing and creation difficult.

The AVI file format

The abbreviation AVI stands for Audio Video Interleave and means that in this format the video and audio tracks are directly linked to each other. The format is widespread, but technically obsolete.

Advantage

This format is mainly characterized by a very high level of acceptance. There is hardly any player and hardly any browser that does not support AVI files.

Disadvantages

The technical limitations of the file format and, above all, the lack of ability to use multiple audio tracks mean that fewer and fewer users are using the AVI file format.

The MKV file format

The MKV format is currently one of the most popular video formats on the net. It is a powerful container format that can integrate not only video files but also audio tracks, menus, and many other functions.

Advantage

The MKV format is particularly compelling due to the high quality of video files and the wide range of functions in which the format can be used. The format can only be used with the appropriate codec, but it is freely available on the net.

Disadvantages

The disadvantages of the format are mainly the low compression properties, so it is not possible to create very compact files.

The MOV file format

This video format was developed by Apple and is designed primarily for use with Quicktime. However, the format is no longer up to date and is therefore rarely used for network applications.

Advantage

The advantages of the format are mainly the ease of use in an Apple environment and the very high compression, which allows to obtain small files.

Disadvantages

Due to the very high compression of video files, there is a consequent loss of images and information. While relatively small and compact files can be created, in most cases the result is not as convincing.

The OGG file format

The OGG video file format was developed, among other things, to bring more flexibility to the market structure, which is often controlled by the rights holders. The OGG format was one of the first formats to be used in a widespread environment such as Linux, and thus it was able to establish itself in the market very quickly.

Advantage

The OGG file format has the advantage of being very widespread and not having authorization keys. Therefore, most browsers can extract it and use it natively. As a result, this video file format is often used to embed video files on your website.

Disadvantages

Despite the wide distribution, there are also downsides. Both the Safari browser and the older Internet Explorer only partially support the format, which can lead to display issues.

The VOB file format

The VOB video file format was established relatively early as the standard for DVD and was therefore developed primarily for these media. The format is not suitable for network use due to lack of licenses and low compression.

Advantage

The format can be easily read by any DVD player and also offers the advantage of low compression. It also allows you to merge different audio tracks.

Disadvantages

The VOB format is not suitable for network use as it cannot be uploaded on various platforms or on your own website. To play the format, you need your own codec, which is not freely available.

The WMV file format

The WMV format was developed by Microsoft and is still widely used today. Since this format supports digital rights management (DRM), it is generally used whenever the copyright of the video file is required.

Advantage

The format is recognized as reliable on all common devices with the Microsoft operating system and can be used without problems.

Disadvantages

As the format is older, very large video files are only partially supported. There are also limitations on file size and video quality.

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What are the digital audio formats?

PCM, Wav, Aiff. Compression. Mp3, Ogg, Wma.

Working with digital audio is almost a chore for puzzle specialists. Since audio is saved on the computer and all computer files have extensions, we have to interpret each acronym and abbreviation.

The extension is the end of the file after the name and period. It is used to know what type of file it is, whether it is a text, a video or an audio. There are many extensions and they are all sure to sound familiar to you: WAV, RM, MP3, WMA, OGG … Let’s play, then, to decipher puzzles and see what each of these acronyms means.

UNCOMPRESSED DIGITAL AUDIO FILES

.PCM

It is not a file type or format, but a technique of transforming analog to digital audio without any compression. (1) Therefore, we do not see audios with the pcm extension. We work with PCM when digitizing, but we always keep files with one of these extensions:

.WAV: (Wave, wave in English)

It is the most widely used uncompressed digital audio format. It belongs to Microsoft / IBM.

.AIFF: (Audio Interchange File Format)

It is similar to WAV but for Apple Macintosh or MAC computers.

.CDA

: These are the audio tracks recorded on Compact Disc that also use the PCM system.

All uncompressed files are large. Approximately 10 megabytes for every minute of audio. These are the formats used to store audio at a professional level since the quality is very good. But when we don’t need that much quality and we’re short on space, it’s time to use file compression.

AUDIO COMPRESSION

Compressing is reducing and whenever we reduce we lose something. The same is true for digital audio. The latest advances have allowed compression to be done with the least possible loss of quality, but there always are. Against that, much has been gained in reducing the size of the files.

While a 4-minute audio in WAV format takes approximately 40 megabytes, that same audio, compressed to MP3, can reduce its weight to 4 megabytes, 10 times less. And apparently, they sound the same. (2)

SAVE WITHOUT COMPRESSING

When working in production, it is always recorded in WAV, without compression. In that same way it is edited and mixed. If the final result of the edition is an audio to be uploaded on the Web or saved on the hard drive of a computer, we can compress it to mp3 but with a quality of no less than 160 kbps.

If, on the contrary, the production has as its final destination to be recorded on a CD, never compress, always leave the audio in WAV and burn it that way on the CD.

1. How does compression work?

It is not about wrinkling or crushing the audio. Most audio compression systems take advantage of a “defect” in our ears to reduce file size. It is called masking.

Masking is a property of the human ear that prevents it from distinguishing two frequencies close together within the same range, one masking the other. For example, if a sound with a frequency of 12 Khz and another of 12.2 Khz sounds at the same time in a song, we could remove one of the two without being noticed when listening to it.

In this way, the compressor “subtracts” the masked frequencies, which reduces the number of bytes. And fewer bytes in computing translates into smaller files, but not shorter. The song, when compressed, lasts as long as it is uncompressed.

2. Quality of compressed files

We saw in the previous question that digital audio has two parameters: the sampling frequency (the optimum is 44.1 Khz.) And the resolution or size of each sample (8 or 16 bits). By compressing, we add a third parameter to these two, the bitrate. It is the amount of kilobytes per second (kbps) and refers to the quality of the compression.

• A lower number of Kbps, more compression, smaller file size, but lower quality.

• A higher number of Kbps, less compression, larger file size and more quality.

A compressed audio at 128 Kbps has a higher compression level than a 256 Kbps one. That means that 128 is a smaller file and less quality than 256. Although you must have a cat’s ear to distinguish between both!

VARIABLE OR CONSTANT BIT

Some files have a constant bit rate per second (CBR Constant Bit Rate) and others have a variable one (VBR Variable Bit Rate). The constant is always the same for all audio, for example 128 kilobytes per second. In the variable method, what the compressor does is use more bits when there are parts of the audio where there are more frequencies and it cannot mask all of them.

COMPRESSED FILE FORMATS

Mp3 (MPEG-1 Audio Layer 3)

It achieves high compressions without much loss, although it all depends on the quality of the compression we use. 128 Kbps and below is not recommended.

Although mp3 is the most widely used compression standard, especially for audio on Web pages, the great drawback is its patent. So any player or editing software that wants to use it has to pay for it.

.OGG (Vorbis)

As a result of this patent, the Xiph.org Foundation developed in 2002 a completely free codec (5) for audio compression. Similar in characteristics to mp3, it is beginning to be used a lot on the Web and in some players since manufacturers do not have to pay the costs of the patent. At this point, it is difficult to completely replace the mp3 but it is eating up a lot of ground.

.AAC (Advanced Audio Coding)

The compression level is higher than mp3 (MPEG-1) without major loss of quality. AAC is one of the codecs used in the new MPEG-4 compression standard. This audio format is used in players like the iPod and in some of the new digital radio systems. AAC is shaping up to be the successor to the mp3.

.RAM (also RM or RA)

They are the files of the Real Network company for audio. The problem is that its reproduction and edition is very limited to software from the same company and few others.

.WMA (Windows Media Audio)

It is Windows’ bet on compressed formats. It is like a WAV, but smaller and less quality. While mp3 and ogg files are played by almost all players and editors, the same is not the case with wma files, so it is rarely used.

. AA3 (ATRAC – Adaptive Transform Acoustic Coding)

Format invented by Sony. It is the one used by minidisc recorder-players.

What audio and video formats exist?

When we talk about the quality of videos or audio, many doubts arise in people’s minds, as there are many terms that are very confusing for the user. For example, people talk about kbs, people talk about bitrate, the sample rate and many other terms that are not clear in people’s mentality are mentioned.

But in the end the question is always the same, what is it that is truly decisive to have a better video quality or better audio quality? The answer can be simple if we summarize it: because the difference in quality will depend on the amount of information that is stored, because the more we will have more detail.

When we talk about video formats within the different types that are applied to digital video and that there are three important parts to distinguish in them on the Internet or on a DVD:

The video and its codec (When the video is so heavy, it must always be encoded and subsequently decoded). They are simply mathematical algorithms to compress and decompress the video file.
The audio and its different formats or containers.
The file that contains the audio and video. The container
Let’s see which are the most popular and try to explain them:

Digital Video Formats

MPEG: Moving Pictures Expert Group (Mpeg1, Mpeg2, Mp4 or Mpeg4)
AVI: It is the standard format but the one with the most weight. (Xvid or Divx)
WINDOWS MEDIA: Format developed by Microsoft. (. Mp4 or .asf)
MOV: Format developed by Apple. Quicktime needed to read it. Low weight.Ideal for Web (.m4v or .mov)
FLV: Adobe Flash format. Use Sorensen Spark codec. (.flv)
Digital Audio Formats

Mp3 or MPEG-1 Audio Layer 3: Tablet with imperceptible signal loss for humans. (1Mb / Min)
Aiff: Audio Interchange File Format. It has no compression and uses PCM modulation so they are very heavy (10 Mb / Min.)
AAC: Advanced Audio Coding. Mpeg-2 compression. Suitable for surround or surround sounds
Windows Media Audio: The worst quality of all the above, is the Windows format.
Formats of Digital Audio and Video Containers

.mp4
.mov
.avi
.mkv
.flv
.swf
.m4v
The truth is that it is a world and more when the big companies live thinking only of leading their own markets and not from the point of view of the user they have had abandoned for years. Obviously these are not all there are but if I wanted to include the best known.

But if we are talking about a file or files that any DVD or download from the Internet can have in any format or container type Mp4, mkv, avi with greater quality, we must remember that the important thing is the amount of information that they carry inside, it is say the Mbs to which this video is exported.

It is as if we have a 16-ton truck and we put a box of oranges inside when it can carry 1000 boxes of oranges. What we are going to see is oranges but with a very low quality.

I hope I have shed some light on this world of digital video and how the next time you face a file of this type you will be able to understand what each of the things that are attached to it means. I must admit that it is not easy but that with that global vision and knowing what each one means you feel better when facing him.

And you know some kind of format that you are using and do you think it is missing here? This is a live article to be developed among all and thus clarify all more.