Video / audio standards -Codec / Container-
In the past, when it came to video, televisions and camcorders, and audio (music), cassette tapes and CDs didn’t require many standards.
However, now that the Internet has become mainstream, videos have also appeared that can be embedded in web pages. In addition, small portable terminals such as iPod, Walkman and PSP support music and video playback, so it is necessary to have adequate video and audio standards for each one.
As a result, there are now many video and audio standards. Since each has its own characteristics, some devices (software) can be played and some devices (software) cannot. For example, the video format that can be played on the PSP is the MP4 format, and the audio on the iPod and the Walkman is in MP3 format and WMA format.
And it can’t open files other than the supported formats.
Many people want to carry video and audio on their mobile terminals, but as mentioned above, there are various content formats, and the formats supported by the device (software) are different. It is easy for the phenomenon of “I want to play with, but I can’t, I’m in trouble” to occur.
To avoid this, please understand what file format there is in the world along with its characteristics and “convert (encode)” the file to a format that supports playback, or use software that supports playback. You will need to prepare it.
In this article, I will first focus on “containers and codecs”, which are the concepts necessary for proper playback and conversion, and “video / audio formats and characteristics”.
* Since the explanation is quite approximate, the content may be incorrect or too simple to be misleading, so if you want more information, check the specialized site.
Encode decode
Encode has the meaning of “encode”. If you handle the video and audio data as it is, it will be a large amount of data, so the computer will do a lot of calculations, encode it, and reduce the storage capacity. This work is called coding. So the word “compression” is also used.
Decode has the opposite meaning of “decoding”, “decompression” and “playback”. Encoded video and audio can be played back by decoding with a compression / decompression program called “Codec” for each encoding method.
Since playback is the main job, the words “unzip” and “unzip” that are used for archives such as zip are not used.
Container codec
Before we start talking about audio and video standards, let’s talk about “containers” and “codecs”.
Codec
Codec [Codec] refers to devices / software and algorithms that can encode (encode) and decode (decode). As I wrote earlier, it is an item related to video and audio compression / decompression.
Compression and playback methods differ by codec type, and data capacity and playback load also differ, so there are appropriate playback environments for each.
container
To be precise, it is called a “container format”.
A container is a type of file format that defines how audio and video data is stored. Simply put, it is a “box” that contains audio and video data. There are different types of containers (boxes) and the data formats that can be stored in each one are different.
If you want to store the video and audio together, you will need to store the data in this container. Since there are restrictions on the data formats (differences depending on the codec) that can be saved in the container, it is necessary to encode them carefully.
