MPEG-1 is 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 (26:1 and 6:1 compression ratios respectively) 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 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)
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.
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MPEG-1 – MPEG1 is 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 (26:1 and 6:1 compression ratios respectively) without excessive quality loss..