What is MPG
MPG, namely MPEG-1, is a world-famous 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 without excessive quality loss, making video CDs, digital cable/satellite TV and digital audio broadcasting (DAB) possible. Today, MPEG-1 has become the most widely compatible lossy audio/video format in the world, and is widely used in a large number of products and technologies. Perhaps the best-known part of the MPEG-1 standard is the MP3 audio format it introduced.
The MPEG-1 standard is published as ISO/IEC 11172 – Information technology—coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbit/s. The standard consists of the following five parts:
- Systems (storage and synchronization of video, audio, and other data together)
- Video (compressed video content)
- Audio (compressed audio content)
- Conformance testing (testing the correctness of implementations of the standard)
- Reference software (example software showing how to encode and decode according to the standard)
.mpg is one of a number of file extensions for MPEG-1 or MPEG-2 audio and video compression. .mp3 is the most common extension for files containing MPEG-1 Layer 3 audio. An MP3 file is typically an uncontained stream of raw audio; the conventional way to tag MP3 files is by writing data to “garbage” segments of each frame, which preserve the media information but are discarded by the player.
MPEG-1 supports resolutions up to 4095×4095 (12-bits), and bitrates up to 100 Mbit/s. MPEG-1 videos are most commonly seen using Source Input Format (SIF) resolution: 352×240, 352×288, or 320×240. These low resolutions, combined with a bitrate less than 1.5 Mbit/s, make up what is known as a constrained parameters bitstream (CPB), later renamed the “Low Level” (LL) profile in MPEG-2. This is the minimum video specifications any decoder should be able to handle, to be considered MPEG-1 compliant. This was selected to provide a good balance between quality and performance, allowing the use of reasonably inexpensive hardware of the time.
- Most popular software for video playback includes MPEG-1 decoding, in addition to any other supported formats.
- The popularity of MP3 audio has established a massive installed base of hardware that can play back MPEG-1 Audio (all three layers).
- “Virtually all digital audio devices” can play back MPEG-1 Audio. Many millions have been sold to-date.
- MPEG-1 is the exclusive video and audio format used on Green Book CD-i, the first consumer digital video format, and on Video CD (VCD), still a very popular format around the world.
- The DVD-Video standard originally required MPEG-1 Layer II audio for PAL countries, but was changed to allow AC-3/Dolby Digital-only discs. MPEG-1 Layer II audio is still allowed on DVDs, although newer extensions to the format, like MPEG Multichannel, are rarely supported.
- Most DVD players also support Video CD and MP3 CD playback, which use MPEG-1.
- The international Digital Video Broadcasting (DVB) standard primarily uses MPEG-1 Layer II audio, and MPEG-2 video.
- The international Digital Audio Broadcasting (DAB) standard uses MPEG-1 Layer II audio exclusively, due to MP2′s especially high quality, modest decoder performance requirements, and tolerance of errors.
Related Guides and Tutorials for MPG Format
MPG to AVI – convert MPG videos to AVI on Win/Mac with high quality
MPG to DVD – convert and burn MPG video files to DVD easily and quickly