| AVI Format | | | | |
| | | | RM Format |
| The AVI format whose full name is "Audio | | | | |
| Video Interleaved" is very familiar to | | | | RM format developed by RealNetworks |
| peoples. This format is widely used in daily | | | | Corporation is a video format for stream |
| life, and its video quality is superior, | | | | media. It includes RealAudio, RealVideo and |
| while there are also many defects such as its | | | | RealFlash. To transmit and play real-time |
| large size, which takes too much hard-disk to | | | | video files in narrow-bandwidth Internet, |
| store. | | | | Real Media adopts distinct compress rate |
| | | | according to the bandwidth. RealVideo is used |
| In 1992, Microsoft corporation developed the | | | | to transmit video data. Except being played |
| AVI video format, which is known by people | | | | as a normal video file, it also can be used |
| with Windows3.1. Namely "Audio Video | | | | together with RealServer. RealEncoder |
| Interleaved", the AVI file interleaves video | | | | converts real-time video to RealMedia Format, |
| and audio data and play them together. One of | | | | which is broadcasted by RealServer. You can |
| the advantage of AVI file is it can be used | | | | enjoy the video when you are downloading it. |
| and played in different platforms. In another | | | | Not like many other video format, it is not |
| hand, to achieve the good quality, its file | | | | necessary for RM format to download the whole |
| size is too large. Even worse, there are many | | | | video file before it can be played. |
| different compression standards so that some | | | | |
| AVI files can not be played if the system | | | | Currently, many websites provide RealVideo |
| does not contain a proper codec. In order to | | | | files. You can use RealPlayer or RealOne |
| play a AVI, sometimes, you have to download | | | | Player to play videos compressed by RealMedia |
| newer codec updates and that is very | | | | technology. Another important feature of the |
| inconvenient. | | | | format is video files can be played without |
| | | | downloading, if you use RealPlayer or RealOne |
| MPEG Format | | | | Player. |
| | | | |
| The full name of MPEG is ?Moving Picture | | | | RMVB Format |
| Expert Group?, which is an international | | | | |
| compression standard designed for moving | | | | As the heir of RM format, RMVB format is |
| images. MPEG algorithms compress data to form | | | | developed based on RM format. The advantage |
| small bits that can be easily transmitted and | | | | is RMVB format abandons Average Bit Rate and |
| then decompressed. Redundancy between | | | | use Variable Bit Rate to compress video data. |
| subsequent images and previous images is | | | | By Variable Bit Rate technology, quality of |
| removed while most similar parts are | | | | video files is greatly improved while file |
| preserved to cut down the file size. Its | | | | size of them is acceptable. |
| compression rate can reach 50:1 and it is a | | | | |
| video standard of good compatible. Currently, | | | | DivX Technology |
| MPEG includes three compression standards: | | | | |
| MPEG-1, MPEG-2 and MPEG-4. Additional, MPEG-7 | | | | DivX developed by DivX, Inc. is a popular new |
| and MPEG-21 are being developed. | | | | video compression technology, which enables |
| | | | users to create and play high-quality videos |
| MPEG-4 Format | | | | in a fast and convenient way. For its |
| | | | outstanding quality, the DivX codec is one of |
| MPEG-4 (MP4) is a moving picture compression | | | | the most popular MPEG-4 based codec. It |
| standard which is used for Internet, | | | | integrates MPEG-4 and MP3 technology, namely |
| broadcast, and on storage media. Relative to | | | | it adopts DivX technology to compress DVD |
| MPEG-2, MPEG-4 provides improved quality at a | | | | video data, while MP3 or AC3 is used to |
| small size. Not only can it be used in narrow | | | | compress Audio. The quality is so superb that |
| bandwidth but also in wide bandwidth. | | | | there is only a little disparity between DivX |
| Currently, the most compression technology of | | | | videos and DVDs. Another remarkable advantage |
| MPEG4 are DivX and XviD. Videos processed by | | | | is compared to DVDs, DivX videos provide the |
| DivX or XviD lose a little quality but the | | | | same image quality at only 1/10 the size. |
| size will be reduced greatly. It provides | | | | Especially, it is suitable for movie |
| users a convenient way to store a movie in a | | | | downloads. In a word, this video format is |
| common CD-Rom disc, while the quality is | | | | very popular and liked by many movie fans. |
| better than VCD obviously. | | | | |