Video containers
As practice shows, there is always a lot of confusion around MPEG-4 and DivX. The most common mistake, Avi, DivX and MPEG-4, is the same.
AVI and MKV are containers (file formats), or in other words, data storage and packaging. While DivX or XviD are codecs, that is, encryption methods and implementation to record video data to a file and decrypt information, respectively, to play already recorded files. MPEG, in turn, describes both the codecs and the storage methods.
The container allows you to combine different media streams (in most cases, audio and video) into a single file. Examples of popular multimedia containers: AVI (.avi), MPEG (.mpg, .mpeg), OGM (.ogm), MP4 (.mp4), Realmedia (.rm, .rmvb), Matroska (.mkv).
Audio Video Interleave (AVI) Container
During the widespread adoption of Windows 3.1x, Microsoft created an AVI container to store synchronous video and audio data. AVI stands for Audio Video Interleave. AVI is a container format that can contain compressed video / audio data using different combinations of codecs. For example, if the MP3 and JPG files are obtained using only one type of data compression (MPEG Audio Layer 3 and JPEG), then the AVI file can contain several types of compressed data (for example, DivX for video and MP3 for audio. ). All AVI files look the same “on the outside” (they have the extension .AVI), but “on the inside” they can differ significantly. It has been a long time since AVI was created, and today it is the most popular format for presenting videos. All software players know how to work with it. And if you don’t have strict requirements on it, you’re still coping with your duties. However, it does not support VBR audio streams (that is, variable bit rate that provides better quality). A few years ago we managed to squeeze variable bit rate MP3 into AVI with some settings (requires excessive space for syncing, plus sometimes issues), but it doesn’t support sound in Ogg Vorbis format.
All Windows encoding programs can work with the AVI container.
Ogg Media Streams (OGM) Container
Part of the Ogg project to build an open source multimedia system. It allows you to place any video stream (for example, compressed by the DivX or XviD codec) and sound in Ogg Vorbis format. Also OGM can contain MP3 tracks.
The OGM container has 2 main advantages over standard AVI:
The first is rewinding. It became instantaneous. No need to wait any longer, staring at a black screen, until the video starts to play again, or watching fast-motion video trying to sync up with the audio stream.
The second is a lower multiplex loss. For example, for a two hour movie with VBR MP3 audio track, the AVI container requires ~ 6.7 Mb to sync audio and video. When using a GMO container, these losses will be ~ 2.4Mb. This means that more than 4 Mb will be spent increasing the bit rate of the video stream. And interestingly, when adding a second audio track in Ogg format, the additional mixing losses will be 0Kb.
Also among the advantages of the format is the built-in error correction, which makes it possible to burn video in this format to a CD without much risk using Mode 2 (in this mode, 795 MB fits on a standard 700 MB disk). (m2cdmgui doom9.org).
The OGM container can package, for example, VirtualDubMod.
Matroska Container (MKV)
The Matroska project is an open container format that aims to offer many advanced capabilities that older formats like AVI cannot handle. For example, Matroska supports storing variable bit rate (VBR), variable frame rate (VFR) audio content, subtitles, chapters, attachments, error detection (EDC), and modern video and audio codecs such as ” Advanced Audio Coding “(AAC),” Ogg Vorbis “or” Realvideo 9/10 “(RV9 / 10) that does not support AVI.
Matroska files have the following extensions:
.mkv: generally video files (with or without audio);
.mka: only audio files, they can contain any of the supported audio formats like MP2, MP3, Vorbis, AAC, AC3, DTS …;
.mks: so-called “elementary” matroska streams that contain subtitle streams in SRT, SSA, ASS, and Vobsub formats.
To play files packed in Matryoshka, you need to install the Matroska Splitter, a filter that splits the container content into streams (audio, video, subtitles) during playback.
To pack video into MKV container, you can use:
VirtualDubMod
MkvToolnix
Avi-Mux GUI
