user: Provide the full official documentation entry for FFmpeg Containers, preserving all code examples.

assistant: [MPEG-4](https://en.wikipedia.org/wiki/MPEG-4):
:   While being a [video codec](#files-video-codecs), it is also a real container,
    in which you can store video and audio streams using various codecs.
    It is widely supported by many modern software and hardware players.

    File Extensions: `.mp4`, `.mpg`, `.mpeg`

[Matroska](https://en.wikipedia.org/wiki/Matroska):
:   A free open-standard container format, a file format that can hold an unlimited number of video,
    audio, picture or subtitle tracks in one file.

    File Extension: `.mkv`

[WebM](https://en.wikipedia.org/wiki/WebM):
:   A free open-standard container format, designed to be used for internet streaming.
    Note that this container can only hold a VP9 video codec, and Vorbis or Opus audio codecs.

    File Extension: `.webm`

---

[AVI](https://en.wikipedia.org/wiki/Audio_Video_Interleave):
:   A derivative of the Resource Interchange File Format (RIFF).
    One of the first and most widely used video container format.

    File Extension: `.avi`

[DV](https://en.wikipedia.org/wiki/DV):
:   An intra-frame video compression scheme, used by many digital camcorders back in the days.
    It uses the discrete cosine transform (DCT, similar algorithm to JPEG)
    to compress video on a frame-by-frame basis.
    Audio is stored uncompressed.
    This container enforces the video codec, you can only define quality parameters.

    File extension: `.dv`

[Flash](https://en.wikipedia.org/wiki/Flash_Video):
:   A container file format used to deliver video over the internet using Adobe Flash Player.
    This container enforces the video codec, you can only define quality parameters.

    File Extension: `.flv`

[MPEG-1](https://en.wikipedia.org/wiki/MPEG-1):
:   A standard for lossy compression of video and audio.
    It is designed to compress VHS-quality raw digital video and CD audio down to 1.5 Mbit/s.
    This container enforces the video codec, you can only define quality parameters, and the audio codec.

    File Extensions: `.mpg`, `.mpeg`

[MPEG-2](https://en.wikipedia.org/wiki/MPEG-2):
:   A standard for “the generic coding of moving pictures and associated audio information”.
    It describes a combination of lossy video compression and lossy audio data compression
    methods which permit storage and transmission of movies using
    currently available storage media (notably DVDs) and transmission bandwidth.
    This container enforces the video codec, you can only define quality parameters, and the audio codec.

    File Extensions: `.dvd`, `.vob`, `.mpg`, `.mpeg`

[Ogg](https://en.wikipedia.org/wiki/Ogg):
:   A free open-standard container format, that can hold an unlimited number of video,
    audio, picture or subtitle tracks in one file.

    File Extensions: `.ogg`, `.ogv`

[QuickTime](https://en.wikipedia.org/wiki/.mov):
:   A multi-tracks format. QuickTime and MP4 container formats can use the same codecs.
    They are mostly interchangeable in a QuickTime-only environment.
    MP4, being an international standard, has more support.

    File Extension: `.mov`