Monday, 7 November 2022

Explain MPEG? || MPEG || What is Mpeg?

MPEG (Moving picture expert group):

It is moving  picture expert group.It develops audio video file formats, which are known as MPEG. This group has been formed by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). It has released different versions of files (standards) namely MPEG-1, MPEG-2, MPEG-3, MPEG-4, MPEG-7, MPEG-21 etc.

MPEG standards are a set of specifications for compressed audio and video files. It is designed for storing video on digital audio tapes (DAT) and audio files on standard audio compact discs (CDs), MPEG files have ".mpeg" as the file extension.
1. The MPEG standard specify coding of video and audio streams, and how synchronization between them is supported to be done.

2. The MPEG has been creating standards that control the development of audio and video digital compression format.

MPEG algorithm compresses the data to smaller bits. These bits can be simply transmitted and decomposed, and the video is then encoded through a technique called Discrete Cosine Transform (DCT). MPEG has a very high compression rate because it stores only the changes that occur from one frame to the next. It does not store full frames which allows it to reduce the overall file size

3. MPEG defines three different types of frames: 

(a). I-frames (Intraframe).

(b). P-frames (Predicted frame).

(c). B-frames (Bidirectional predicted frame). 

4. Intraframes, defines the start of a group of frames. I-frames are coded as standalone images; they can be reconstructed without any reference to other frames.

5. The P-frames are forward predicted from the last I-frame or P-frame, i.e it is impossible to reconstruct them without the data of another frame (I or P).

6. The B-frames are both, forward predicted and backward predicted from the last / next I-frame or P-frame. 

7. P-frames and B-frames are referred to as inter coded frames. it one of the most popular and widely compatible video/audio formats in the world. Video data for MPEG-1 is normally 30 fps (frames per second), with a resolution.

8. The motion vector is part of the MPEG stream and it is divided in a horizontal and a vertical part. These parts can be positive or negative. A positive value means motion to the right or motion downwards respectively. A negative value means motion to the left or motion upwards respectively.

9. The part of the motion vector are in a range of -64 +63. So the referred area can be up to 64x64 pixels away.

its identity of any program is its extension, that is, if we have to open an extension file named .doc, then it is necessary to have a software named MS Word in your computer, similarly if you have an extension named .pdf If you want to open the file, then it is necessary to have a software named Pdf reader in your computer, in the same way all the extensions present in the computer or mobile open with the help of some software

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