Almost the same age
This definition is similar to DVD format.
But the most clear point is that it should be a video in AVI format.
It belongs to the ultra-clear version, but the file is super large.
ASF stands for Advanced Streaming Format, which is a streaming multimedia file format developed by Microsoft for Windows 98. The term is currently interchangeable with WMA and WMV.
ASF is an open standard, which can rely on various protocols to support data transmission in various network environments. Like JPG and MPG files, ASF file is a file type, but it is specially designed for transmitting multimedia data with synchronous relationship on ip network, so ASF format information is especially suitable for transmitting on IP network. The content of ASF file can be a familiar common file or a continuous data stream generated by coding equipment in real time, so ASF can transmit both pre-recorded programs and real-time generated programs.
ASF is used to arrange, organize and synchronize multimedia data for transmission through the network. ASF is a data format and can also be used to specify live demonstrations. ASF is most suitable for sending multimedia streams through the network and playing them locally. Any compression/decompression algorithm (codec) can be used to encode ASF streams.
The core of Windows Media Service is ASF. ASF is a data format, through which multimedia information such as audio, video, images, control command scripts and so on are transmitted in the form of network packets, thus realizing the publishing of streaming media content. Among them, the content transmitted on the network is called ASF stream. ASF supports any compression/decompression coding method and can use any underlying network transmission protocol, which has great flexibility.
Microsoft Media Player is a player that can play almost all multimedia files. It supports the streaming file format of ASF on the Internet. You can download and play in real time, and you don't have to listen after downloading.
WMV is a streaming media format introduced by Microsoft, which is an upgrade and extension of ASF (Advanced Streaming Format) format. Under the same video quality, WMV format is very small, which is very suitable for playing and transmitting on the Internet. AVI file encapsulates video and audio in one file, and allows audio and video playback to be synchronized. Similar to DVD video format, AVI files support multiple video streams and audio streams.
WMV is not only developed based on Microsoft's own technology. Since the seventh edition (WMV 1), Microsoft has started to use its own non-standard MPEG-4 Part 2. However, since the ninth edition of WMV is an independent standard of SMPTE (42 1M, also called VC- 1), it is reasonable to believe that the development of WMV does not have its own proprietary encoding and decoding technology like MPEG-4. At present, there are 16 companies enjoying the patent of VC-1(April 2006), and Microsoft is also one of the companies enjoying the patent of MPEG-4 AVC/H.264.
Microsoft's WMV is still very influential. However, due to Microsoft's own limitations, its WMV application development is not smooth. First, WM9 is a product of Microsoft and must rely on Windows. Windows means that the decoding part should also have a PC, at least the motherboard of the PC. This greatly increases the cost of set-top boxes, thus affecting the popularity of video on demand. Secondly, the video transmission delay of WMV technology is very large, usually 10 second. Because of this restriction, WMV can only browse WM9 video files on the computer at present.
Wmv-HD is a video compression format created by Microsoft, a software giant, and is generally adopted. WMV as a file suffix. Its compression ratio is even higher than MPEG-2 standard, and it is also a 2-hour HDTV program. If MPEG-2 is used, it can only be compressed to 30GB at most, while if a high compression rate encoder such as WMV-HD is used, it can be compressed to less than 15GB, and the image quality is not degraded.
Based on WMV9 standard, WMV-HD is the latest version of video compression technology series developed by Microsoft. Although WMV-HD is a unique standard of Microsoft, it is rapidly popularized in desktop systems because it strongly supports WMV series versions in the operating system. In terms of performance, the data compression ratio of WMV-HD is the same as that of H.264, and its application fields are also very similar. Therefore, in the struggle for the dominance of the new generation of mainstream video coding standards, the two sides launched a tit-for-tat struggle, focusing on the next generation of optical disc specification "HD DVD" and digital microwave broadcasting and television.
Generally speaking, HDTV files use. The wmv suffix is compressed by WMV-HD.
At present, the DVD Forum has preliminarily approved Microsoft's MPEG-2, H.264 and WMA-HD as the mandatory standards of the next generation DVD, namely HD-DVD technology.
The audio and video compression standard developed by RealNetworks Company is called RealMedia. Users can use RealPlayer or RealOnePlayer to play network audio and video resources that meet the technical specifications of RealMedia. RealMedia can set different compression ratios according to different network transmission rates, so as to realize real-time transmission and playback of image data on low-rate networks. Another feature of this format is that users can use RealPlayer or RealOnePlayer to realize play online without downloading audio/video content. In addition, RM, as the mainstream network video format at present, can also convert videos in other formats into RM videos through its RealServer server, which is responsible for publishing and playing. RM and ASF formats can be said to have their own advantages. Generally, RM video is soft, while ASF video is relatively clear.
RM format has been positioned in the application of video streaming from the beginning, and it can also be said that it is the originator of video streaming technology. It can realize uninterrupted video playback under the condition of using 56K modem to dial up the Internet. Of course, its image quality has a certain gap compared with MPEG2-2 and DIVX. After all, it takes a lot of bandwidth to realize uninterrupted video transmission on the Internet.
RM format is a great contribution of Real Company to the multimedia world and also to the promotion of online movies. Its birth also makes streaming files known to more people. This kind of file can be played in real time, that is, some video files are downloaded from the server to form a video stream buffer and then played in real time, and at the same time, the download is continued to prepare for the next play. This way of "broadcasting while transmitting" avoids the disadvantage that users have to wait for the whole file to be downloaded from the Internet before they can watch it, so it is especially suitable for watching movies online. RM is mainly used for real-time transmission of compressed video on low-speed networks, and also has the characteristics of small size and clarity. The size of RM file depends entirely on the compression ratio chosen when making it, which is why sometimes we see that the image of 1 hour is only 200MB, while others are 500MB.
The difference between RM format and RMVB format
The common rm format is real8.0 format, which adopts fixed rate coding. Many of them are Vcd-R M, which have been popular for a while. However, due to the congenital deficiency and lack of clarity of VCD film source, the rm pressed out will not be clear. Especially the standard online code rate of 225kbps, the definition is simply terrible.
RMVB has one more VB than RM, and VB means variable bit, that is, dynamic code rate! It is the new coding format 9.0 format of the real company. Rmvb(real9.0) and rm(real8.0) still use 8.0 format in audio coding. We use at least 32kbps sterero music when tabletting, usually 44K, and 96K for MTV. If it is higher, there is no need to compress it!
Now, for example:
If they are all 450K, the code rate is 450K for RM and 450 ~ 900 K for RMVB (double by default) according to the intensity of the picture. Finally, you will get an average code rate, such as 460.8K The following is a detailed explanation:
Because of the large amount of data and clear image quality, DVDRIP will get a clear effect when compressed into rmvb (of course, the code rate we use when compressing is also large). If you press rm format, that is, 8.0 format will be clearer, but not as good as rmvb. However, rm format has good compatibility and low requirements for cpu, so rmvb needs to be played on a high-profile machine to be smooth.
If the VCD is also in rmvb format, it is unnecessary, because rmvb does not mean that the file must be clear, but depends on the original movie file. If you want to get a clear rm/rmvb, you need high-definition original files, such as DVDRIP. VCD format, that is, the bit rate of 1M, the picture quality effect is almost the same as Wish VCD at best.
This is the difference between the two. Here is just to remind everyone not to ignore rm because of rmvb. If VCD is pressed into real format, you should use real8.0 format, that is, rm, instead of rmvb of real9.0. For some DVDs such as life dramas and comics, you can use rm format of real8.0 instead of VBR encoding. This is a misunderstanding!