This format is a big one in the video camp, and it is also the most common video format we usually see. There are many derived formats, including video files with suffixes of mpg, mpe, mpa, m 15, m 1v, mp2, etc. , all from this family. MPEG format includes three parts: MPEG video, MPEG audio and MPEG system (video and audio synchronization). MP3(MPEG-3) audio file is a typical application of MPEG audio. Video includes MPEG- 1, MPEG-2 and MPEG-4.
MPEG- 1 is widely used to make VCDs and download some video clips, among which VCDs are the most-almost all VCDs are compressed in Mpge- 1 format (the file is *. Dat format). The compression algorithm of MPEG- 1 can compress a movie (original video file) with the length of 120 minutes to the size of 1.2 GB.
MPEG-2 is suitable for DVD production (the file format is *. Vob format), as well as some HDTV high-definition TV broadcasts) and some demanding video editing processing. Using the compression algorithm of MPEG-2, the size of a 120-minute movie (original video file) is about 4GB to 8GB. Of course, its picture quality index is incomparable with MPEG- 1.
MPEG-4 is a new compression algorithm. The ASF format file (which will be introduced next) using this algorithm can make a movie (original video file) with a length of 120 minutes "slim down" to about 300MB. Because it is small and easy to spread, it has become one of the main ways to watch online. This algorithm is said to be a coding technology prohibited from export in the United States. In addition, the source file can be compressed to about 600MB by using DivX format, but its image quality is much higher than ASF. Because of its high efficiency, there are rumors that the US government prohibits the export of this technology.
By the way, I also want to introduce the DivX format. The most incisive word to summarize DivX format is: DVD killer. DivX video coding technology can be said to be born for DVD and developed to break the shackles of ASF. As mentioned above, it uses MPEG-4 algorithm, so only two VCDs are needed to compress a DVD! This not only means that you can get almost the same video quality without buying DVD-ROM, but also has low requirements for the machine to play this code: as long as the CPU is above 300 MHz, 64MB of memory and 4MB of graphics card (I believe most machines meet the requirements now), it can play smoothly.
In addition, it is worth mentioning that MPEG- 1 and MPEG-2 have their own special resolution standards when they are made into VCD and DVD respectively. The resolution of MPEG- 1 compressed image is 352×240 when using NTSC format, 352×288 when using PAL format, and DVD is used. If you plan to make CDs for DVD/VCD players, you need to pay special attention to the formats used by various video recorders when making video files.