MPG Video Format

MPEG (Moving Picture Experts Group) – a family of video compression standards that’s widely used for storing and transmitting digital video content.

History

The MPEG-1 standard was introduced in 1993, followed by MPEG-2 in 1995. The most recent version is MPEG-4 Part 10, also known as H.264 or AVC (Advanced Video Coding), which was released in 2003. The next generation of MPEG standards, including H.265/HEVC and VVC (Versatile Video Coding), are still evolving.

Key Features

Here are some key characteristics of the MPG file format:

  1. Video compression: MPEG uses lossy video compression to reduce the file size while maintaining acceptable visual quality.
  2. Standardized encoding: The MPEG standard provides a set of rules for encoding and decoding digital video, ensuring compatibility across devices and platforms.
  3. Resolution and frame rate: MPG files can store various resolutions (e.g., 480p, 720p, 1080i) and frame rates (e.g., 24fps, 30fps).
  4. Color depth: MPEG-2 supports up to 12-bit color depth, while H.264/AVC and later standards support up to 14-bit or more.
  5. Audio compression: MPG files often use audio compression algorithms like MP3 (MPEG Audio Layer 3) or AC-3.

MPEG Structure

An MPG file consists of several layers:

  1. Sequence header: The first few bytes contain metadata about the sequence, such as its resolution and frame rate.
  2. Group of Pictures (GOP): A GOP is a collection of consecutive frames that are coded together using inter-frame prediction.
  3. Picture header: Each picture has a header containing information like the type of coding used (I-, P-, or B-frames).
  4. Macroblock layer: The picture data is divided into 16×16 macroblocks, which are then compressed and encoded.

Types of MPG Files

There are several types of MPG files:

  1. MPEG-1: Used for low-resolution video, typically up to 352×288 pixels.
  2. MPEG-2: Supports higher resolutions (up to 720×480 pixels) and is used for DVD, satellite TV, and digital television.
  3. H.264/AVC: Also known as MPEG-4 Part 10, this standard offers improved compression efficiency and supports resolutions up to 1080p.

Common Uses

MPG files are widely used:

  1. DVDs and Blu-ray discs: MPG is the primary video format for these optical disc formats.
  2. Digital television: Many TV broadcasting systems use MPEG-2 or H.264/AVC for digital transmission.
  3. Web streaming: MPG files can be streamed over the internet using protocols like HLS (HTTP Live Streaming) or DASH (Dynamic Adaptive Streaming over HTTP).

Limitations

While MPG is a widely supported and versatile format, it has some limitations:

  1. Compression artifacts: The lossy compression used in MPEG can introduce visual artifacts, especially at lower bitrates.
  2. Compatibility issues: Different devices and platforms may not support all MPG file types or profiles.

Despite these limitations, the MPG file format remains a cornerstone of digital video storage and transmission due to its broad adoption and efficient compression algorithms.