What is a new streaming video file format developed by realnetworks

A new streaming video file format developed by realnetworks company is "RealVideo", including four video formats with the suffixes "RA", "RM", "RAM" and "RMVB"; it mainly It is used to transmit moving video images in real time over low-speed wide area networks. Different compression ratios can be used according to different network data transmission rates, thereby realizing real-time transmission and real-time playback of image data.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

A new streaming video file format developed by realnetworks company is "RealVideo".

RealVideo format files include four video formats with suffixes of RA, RM, RAM, and RMVB.

RealVideo is included in RealMedia, the audio and video compression specification developed by RealNetworks. It is mainly used to transmit moving video images in real time over low-speed wide area networks. Different compression ratios can be used according to different network data transmission rates. , thereby realizing real-time transmission and real-time playback of image data.

In addition to playing in the form of ordinary video files, RealVideo can also cooperate with the RealServer server to play video images while downloading during the data transmission process. It does not have to be downloaded first like most video files. Download and then play. Currently, many websites on the Internet use RealVideo technology to broadcast live broadcasts of major events.

Real Video is a high compression ratio video format. RealVideo files can be created using any method commonly used for multimedia and video production on the Web. For example, Premiere, VideoShop and AfterEffects, etc., realplayer and Baofengyingyin can be used to play files.

RMVB video format has the word VB more than the original RM. Here VB is the abbreviation of VBR (Variable Bit Rate--variable bit rate). On the basis of ensuring the average sampling rate, the maximum sampling rate value is generally set to twice the average sampling rate. It can also obtain relatively good results when processing more complex dynamic images, and is flexible when processing general still images. Converting to a lower sampling rate effectively reduces the file size!

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RealVideo format RA

ra format is developed by RealNetworks company A new streaming audio RealAudio file format. The .rm format is a streaming video RealVedio file format. It is mainly used to transmit moving video images in real time on low-speed networks. Different compression ratios can be used according to different network data transmission rates, and it can be downloaded during the data transmission process. Play video images to achieve real-time transmission and playback of image data. The client plays through the RealPlayer player. (Streaming media) audio files in ra format require realplayer to play, but due to their small size and popularity on the Internet, they are collected by users in large quantities on their computers. Unfortunately, many MP3 players cannot support this format. As a result, it cannot be played directly. To solve this problem, we found a free conversion method. First download WindowsMediaEncoderV9.0 and its "real decoder". After installation, use the renaming software to change the suffix ra to wav or other formats that MediaEncoder can "recognize". Open the command line window again and enter the MediaEncoder directory. (The default location may be "c:ProgramFilesWindowsMediaComponentsEncoder") Enter cscriptwmcmd.vbs -input "input folder" -output "output folder" -profilea20_2. Compared with software such as RealProducter, the biggest advantage of this move is that it is free.

RM of RealVideo format

The audio and video compression specification formulated by RealNetworks is called RealMedia. Users can use RealPlayer or RealOnePlayer to compress network audio/video that complies with RealMedia technical specifications. Video resources are broadcast live and RealMedia can develop different compression ratios according to different network transmission rates, thereby realizing real-time transmission and playback of image data on low-speed networks. Another feature of this format is that users can use RealPlayer or RealOnePlayer to play online without downloading audio/video content. In addition, as the current mainstream network video format, RM can also convert videos in other formats into RM videos through its RealServer server, and the RealServer server is responsible for external publishing and playback. It can be said that the RM and ASF formats have their own merits. Generally, RM videos are softer, while ASF videos are relatively clear.

The RM format has been positioned in video streaming applications from the beginning, and can also be said to be the originator of video streaming technology. It can achieve uninterrupted video playback under the condition of dial-up Internet access using 56K Modem. Of course, its image quality is lagging behind MPEG2, DIVX, etc. After all, it requires a lot of bandwidth to transmit uninterrupted video on the Internet. .

The RM format is Real’s major contribution to the multimedia world and its contribution to online film and television promotion. Its birth also made streaming files known to more people. This type of file can be played immediately, that is, a part of the video file is downloaded from the server first, a video stream buffer is formed, and then played in real time, while the download continues to prepare for the next playback. This "broadcast while broadcasting" method avoids the disadvantage that users have to wait for the entire file to be downloaded from the Internet before watching it, so it is particularly suitable for watching movies and TV shows online. RM is mainly used as a compression format for real-time transmission of video on low-speed networks. It also has the characteristics of small size and relatively clear. The size of the RM file depends entirely on the compression rate selected during production, which is why sometimes we see 1 hour of images only 200MB, while others are as much as 500MB.

RealVideo Format RAM

RAM format file, Real Company’s improved version of RM/RA format, improves support for streaming media protocols, but the image quality is relatively reduced . Mostly used for network video transmission.

RMVB of RealVideo format

RMVB is a multimedia video file format. The vb in rmvb refers to Variable Bit Rate (changeable bit rate). Compared with the previous generation The rm format picture is much clearer, because the bit rate of the static picture is reduced, and it can be played with the RealOne Player multimedia player.

The ordinary rm format is real8.0 format, which uses fixed bit rate encoding. Many pieces are on VCD-rm, which has been popular for some time. However, due to the inherent shortcomings of the VCD source, it is not clear enough, so the pressed rm will not be clear either. Especially at the standard online bit rate of 225kbps, the clarity is simply appalling.

RMVB has one more VB than RM. VB refers to variable bit, which means dynamic bit rate! It is the new encoding format 9.0 format of real company. Both rmvb (real9.0) and rm (real8.0) still use the 8.0 format for audio encoding. We use at least 32kbps stereo music when compressing, usually 44K, and 96K for MTV, no matter how high it is. Need to compress!

Now give an example:

If both are 450K, for RM the fixed code rate is 450K, for RMVB it is between 450~900K (the default is doubled) according to the screen intensity was coded. You will eventually get an average bitrate, such as 460.8K. There are detailed instructions below:

Because DVDRIP has a large amount of data and clear image quality, compressing it into rmvb will achieve clear results (of course the bitrate we use when compressing is also high). If compressed into rm format, that is, 8.0 format, it will be clear, but the effect will not be as good as rmvb. However, the rm format has good compatibility and the playback requirements are not high on the CPU. rmvb needs to be played on a high-configuration machine to play smoothly.

If you compress the VCD into rmvb format, it is not necessary, because rmvb is not meant to make the file clear, but to see the original movie file. To obtain clear rm/rmvb, you need high-definition original files, such as DVDRIP. In VCD format, using a coding rate of 1M, the picture quality effect is at best similar to that of VCD.

This is the difference between the two. This is just a reminder not to ignore rm because of rmvb. If the VCD is compressed into real format, you should use real8.0 format, that is, rm, instead of real9.0's rmvb. For some life dramas, cartoons and other DVDRIPs, you can use real8.0's rm format to compress them, and you don't have to use VBR encoding uniformly. This is a misunderstanding!

The so-called RMVB format is an upgrade and extension of the RM video format of streaming media. VB is VBR, which is the English abbreviation of Variable Bit Rate (changeable bit rate). When we play the common RM format movies in the past, we can see the words 225Kbps in the lower left corner of the player, which is the bit rate. Still images and moving images in a movie have different compression sampling rate requirements. If the bit rate is always maintained at a fixed bit rate, the quality of the movie will be wasted.

RMVB breaks the average compression sampling method of the original RM format. On the basis of ensuring the average compression ratio, it sets a maximum sampling rate value that is generally twice the average sampling rate. Use higher bit rates for complex dynamic images (singing and dancing, speeding cars, wars, etc.), and flexibly switch to lower sampling rates for static images, making reasonable use of bit rate resources, allowing RMVB to sacrifice less The size of the video is compressed to the maximum extent while the quality of the video is not noticeable to you, and finally it has an almost perfect audio-visual effect close to DVD quality. It can be said that it has the best of both worlds in terms of size and clarity, and its development prospects cannot be underestimated.

Compared with DVDrip, the advantages of RMVB are self-evident. First of all, under the premise of ensuring the overall audio-visual effect of the film, the size of RMVB is only about 300~450MB (calculated based on a standard 90-minute movie), while DVDrip requires 700MB or more; secondly, the subtitles of RMVB are embedded subtitles, unlike DVDrip In this way, you need to install and debug subtitle plug-in software, and sometimes garbled characters will appear; more importantly, for RMVB audio and video playback, you only need to install the decoder once, and there is no need to debug the video or sound effects in the future. DVDrip, on the other hand, requires a lot of video and audio decoding. Improper settings can cause problems such as out-of-sync audio and video, blurry screen, and loss of sound.

The difference between RM and RMVB

The ordinary rm format is real8.0 format, which uses fixed bit rate encoding. Many pieces are on VCD-rm, which has been popular for some time. However, due to the inherent shortcomings of the VCD source, it is not clear enough, so the pressed rm will not be clear either. Especially at the standard online bit rate of 225kbps, the clarity is simply appalling.

RMVB has one more VB than RM. VB refers to variable bit, which means dynamic bit rate! It is the new encoding format 9.0 format of real company. Both rmvb (real9.0) and rm (real8.0) still use the 8.0 format for audio encoding. We use at least 32kbps stereo music when compressing, usually 44K, and 96K for MTV, no matter how high it is. Need to compress!

Now give an example:

If both are 450K, for RM the fixed code rate is 450K, for RMVB it is between 450~900K (the default is doubled) according to the screen intensity was coded. You will eventually get an average bitrate, such as 460.8K. There are detailed instructions below:

Because DVDRIP has a large amount of data and clear image quality, compressing it into rmvb will achieve clear results (of course the bitrate we use when compressing is also high). If compressed into rm format, that is, 8.0 format, it will be clear, but the effect will not be as good as rmvb. However, the rm format has good compatibility and the playback requirements are not high on the CPU. rmvb needs to be played on a high-configuration machine to play smoothly.

If you compress the VCD into rmvb format, it is not necessary, because rmvb is not meant to make the file clear, but to see the original movie file. To obtain clear rm/rmvb, you need high-definition original files, such as DVDRIP. In VCD format, using a coding rate of 1M, the picture quality effect is at best similar to that of VCD.

This is the difference between the two. This is just a reminder not to ignore rm because of rmvb. If the VCD is compressed into real format, you should use real8.0 format, that is, rm, instead of real9.0's rmvb. For some life dramas, cartoons and other DVDRIPs, you can use real8.0's rm format to compress them, and you don't have to use VBR encoding uniformly. This is a misunderstanding!

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