Why 4k formats in mkv format?

Question

Video

Explain on your fingers why high-definition films are usually in mkv format. Why can't they be popular avi or mp4?

Answer 1

MKV is quite versatile. Therefore, people who rip don't bother, don't create problems for themselves, and rip in MKV.
Why not MP4? Mainly because the MKV container supports all at least some popular codecs (H.264, H.265, QuickTime...). MP4 is not. Although in this case it concerns mainly audio codecs. Because there are a lot of audio encoding options.
Why not AVI? It's too old and simple. It is impossible to put some of the necessary information in it, players sometimes have to guess the parameters themselves. As written above, for example, this is the pixel size. While I doubt any rip writers bother with pixel sizes these days, you can't do that with AVI. It is popular, for example, in archives and libraries - where you need the most simple container that does not cause any problems. By the way, I would not call him popular, his popularity remained at the beginning of the 2000s. Now we mostly have MP4, then about equally MOV and MKV.
In general, MKV is used because it is familiar and convenient. And you, as a rocker, should, in principle, not care.

Answer 2

First, AVI has a strict limitation: frames must follow a strictly defined frequency, which is written in the header. MPEG streams, in particular H264 and MPEG2, which store HD movies, generally do not meet this requirement. Each frame specifies the time at which this frame should appear, and it can be arbitrary in the general case.
There are codecs that allow you to store H264 video in an AVI container, but this is a "dirty hack" as some like to call it.
Secondly, in AVI there is no such thing as pixel aspect ratio, i. a pixel is always considered to be square. In general, this is also not the case. For example, video from an HDV camera has a frame size of 1440x1080, but it needs to be displayed as 1920x1080. In the AVI file, there is simply nowhere to register a sign that the picture needs to be stretched during playback.
And besides, are there many users who actually need 3 more languages ​​in a movie or subtitles in 5 languages?
Ask those who make these same HD rips and put several tracks into an MKV file about this. They do not ask anyone, but they believe that someone needs it. And then you ask questions about it
. The most incomprehensible thing is that there are a lot of questions on the net like "How to convert MKV to AVI"
The most incomprehensible thing is that someone needs it at all. Although you just need to install a couple of codecs and a splitter for the MKV container. People, probably, have nowhere to put their time, so they recode what has already been recoded once.
True, there is such an option: someone's computer "does not pull" a video resolution of 1920x1080. Then yes, it needs to be recoded if you don't want to upgrade your computer. But why at the same time put it in AVI, and not in the same MKV, I don’t know. It seems that VirtualDubMod allows you to save the result in MKV.
There is another option: you need to recompress the movie to a resolution of 720x576 and compress it with the DivX / XviD codec, so that later this video can be watched on a household DVD player. They only understand AVI, standard DVD, or standard definition MPEG2 (720x576/720x480), so HD video has to be recompressed. By the way, the picture still turns out to be more detailed than just a DVD disc, which was originally shot in SD resolution.
VirtualDubMod does not work normally and has been abandoned
for a long time it was originally intended to work with AVI - see above about the frame rate limit. Therefore, apparently, it is sometimes buggy if you open MKV in it.

Source: https://forum.ixbt.com/topic.cgi?id=29:29398