Difference between revisions of "MPEG"

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=== Muxers ===
 
=== Muxers ===
 
MPEG-2 specified 2 [[container]] formats, ts and ps. Containers hold video and audioinformation in them, and package them up so it can be sent over a network or stored on disk.
 
MPEG-2 specified 2 [[container]] formats, ts and ps. Containers hold video and audioinformation in them, and package them up so it can be sent over a network or stored on disk.
* '''ts''' should be used to store or send data where data loss will probably occur, such as over a network.
+
* '''ts''' (Transport Stream) should be used to store or send data where data loss will probably occur, such as over a network.
* '''ps''' should be used to store or send data where data loss is not likely, such as on a DVD.
+
* '''ps''' (Program Stream) should be used to store or send data where data loss is not likely, such as on a DVD.
  
 
Both ps and ts can transport MPEG-4 Video, but only ts can send MPEG-4 Audio. In addition, MPEG-4 specifies it's own muxer, '''mp4''' (see [[#MPEG-4|below]])
 
Both ps and ts can transport MPEG-4 Video, but only ts can send MPEG-4 Audio. In addition, MPEG-4 specifies it's own muxer, '''mp4''' (see [[#MPEG-4|below]])

Revision as of 22:34, 17 January 2006

MPEG refers to a set of standards created by the Moving Picture Experts Group. MPEG refers to several video, audio and container formats.

An MPEG file is a file using an MPEG container (these are called ts and ps, and also mp4 for MPEG-4).


Creating an MPEG File with VLC

To make an MPEG file, you need to:

  • Pick a container (see below)
  • Transcode the audio and video to formats able to be held in the container: in general this is the MPEG video and audio formats only. Check the compatibility information in the official documentation.

You can do this using the Wizard, or by running vlc from a command prompt

vlc file.avi --sout='#transcode{vcodec=mp2v, acodec=mpga}:std{access=file, mux=ps,url=file.mpg}'


MPEG-1 and 2

  • Video codec: mp1v, mp2v
  • Audio codec: mpga, mp2a, mp3
  • Muxer: ts, ps

MPEG-1 is a video and audio compression format, used in Video CDs. It is compatible with a large number of software and hardware devices.

MPEG-2 is used in digital television and DVB. It is also used as the format for DVDs.

MPEG-1 Audio

MPEG-1 also contains several audio compression formats:

  • mpga is MP1 or MPEG-1 (Part 3) Layer 1
  • mp2a is MP2 or MPEG-1 (Part 3) Layer 2
  • mp3 is MP3 or MPEG-1 (Part 3) Layer 3

Muxers

MPEG-2 specified 2 container formats, ts and ps. Containers hold video and audioinformation in them, and package them up so it can be sent over a network or stored on disk.

  • ts (Transport Stream) should be used to store or send data where data loss will probably occur, such as over a network.
  • ps (Program Stream) should be used to store or send data where data loss is not likely, such as on a DVD.

Both ps and ts can transport MPEG-4 Video, but only ts can send MPEG-4 Audio. In addition, MPEG-4 specifies it's own muxer, mp4 (see below)

MPEG-3

A largely unused audio and video compression format.

  • Note that MP3 is actually MPEG-1 Layer 3.


MPEG-4

  • Video codec: mp4v (m4v)
  • Audio codec: mp4a (m4a) - this is AAC.
  • Muxer: mp4

MPEG-4 is a flexible audio and video compression format. The format describes audio and video compression, with a container format for streaming across networks and saving to disk. It also contains optional extra features, including DRM and subtitles. These extra features are only included in software if needed.