The difference between VBR and CBR

VBR is the dynamic bit rate. CBR is the static bit rate.
        VBR (Variable Bitrate) dynamic bit rate. That is, there is no fixed bit rate, and the compression software instantly determines what bit rate to use according to the audio data during compression. This is a way of taking into account file size on the premise of quality. VBR is also called dynamic bit rate encoding. When using this method, you can select various transition stages from the worst sound quality/maximum compression ratio to the best sound quality/lowest compression ratio. When the MP3 file is encoded, the program will Try to maintain the quality of the entire selected file, and choose a bit rate suitable for different parts of the music file to encode. The main advantage is that the entire song can roughly meet our quality requirements, but the disadvantage is that the compressed file size cannot be estimated during encoding.
        CBR (Constants Bit Rate) means a fixed bit rate, which means a static (constant) bit rate. CBR is a compression method with a fixed sampling rate. The advantage is that it compresses quickly and can be supported by most software and equipment. The disadvantage is that it takes up relatively large space and the effect is not very satisfactory. It has been gradually replaced by VBR. Fixed bit rate is a term used to describe the communication quality of service (QoS, Quality of Service). The word corresponding to this word is variable bit rate or variable bit rate (English variable bit rate, abbreviated VBR).
When describing a codec, CBR encoding means that the output code rate of the encoder (or the input code rate of the decoder) should be a fixed system (constant). CBR is very useful when performing multimedia communication in a channel with limited bandwidth, because the highest bit rate is limited at this time, and CBR can make it easier to use such a channel. But CBR is not suitable for storage, because CBR will result in insufficient bit rate to encode complex content parts (thus causing quality degradation), and at the same time, some code rates will be wasted in simple content parts.

The difference between CBR encoding and VBR encoding in video encoding
VBR is variable bit rate. It has some differences from constant bit rate CBR. The difference between CBR or VBR encoding is as follows:
By using the Windows Media encoder, you can use constant bit rate (CBR) or variable bit rate (VBR) to encode audio and video content.
1. CBR encoding
　It is most effective to use CBR encoding in streaming programs. When using CBR encoding, the bit rate remains basically constant during the streaming process and is close to the target bit rate, always within the time window determined by the buffer size. The disadvantage of CBR encoding is that the quality of the encoded content is unstable. Because some segments of the content are more difficult to compress than others, some parts of the CBR stream are of worse quality than others. In addition, CBR encoding will cause the quality of adjacent streams to be different. Usually at lower bit rates, the quality changes will be more pronounced.
2.VBR encoding
　When you plan to provide content for users to download, play the content locally, or play it on a device with limited reading speed (such as a CD or DVD player), please use VBR encoding. (The peak VBR encoding mode can also be used when planning to stream content.) VBR encoding is advantageous when simple data and complex data (for example, videos that switch between fast motion and slow motion) are mixed in the encoded content. When VBR encoding is used, the system will automatically allocate fewer bits for the simple parts of the content, thereby leaving enough bits for generating high-quality complex parts. This means a constant complexity
Content (such as news broadcasting) will not benefit from VBR encoding. When VBR encoding is used for mixed content, the output result of VBR encoding is much better than that of CBR encoding under the condition of the same file size. In some cases, a VBR-encoded file with the same quality as a CBR-encoded file may be only half the size of the former.
Under normal circumstances, when composing programs of the same quality, the program synthesis time will be shorter when the CBR encoding method is used, but the file length will be larger (that is, programs of the same duration will occupy more space or the same space can only accommodate more Short show).
1. The suitable application scenario of VBR is media storage, not network transmission, so don't let Wu Zhuangyuan become a civil official;
2. In fact, the so-called CBR in actual network transmission is generally ABR (average bit rate), that is, as long as the code rate is controlled at the rated code rate per unit time, it is enough to buffer the code output to smooth fluctuations. The role of
3. What you call CBR in the strict sense is that every frame is assigned the same codeword. Just imagine if a frame requires very few codewords, but you must assign a lot of codewords to it. Isn't that a waste? On the other hand, if a frame requires a lot of codewords, but you give very little, then the effect of this frame will be very poor. Compiled in this way, the overall sequence quality will change continuously from good to bad, but it has a great visual impact; therefore, ABR is the most suitable solution for network transmission;
4. Regardless of whether it is CBR, ABR or VBR, it belongs to rate control, and rate control is an open part of video encoding. It will not change the legality of the stream structure. Therefore, whether in MPEG2, MPEG4 or H.263, H There are no regulations in .264;
5. Since the current video coding standards are based on a mixed coding framework of block coding, a rate control algorithm can be used on any protocol (of course, sometimes a small change is needed), but the control effect is good or not. The problem, no RC is exclusive to which protocol.

 

 

 

How far(long) the transmitter cover? The transmission range depends on many factors. The true distance is based on the antenna installing height , antenna gain, using environment like building and other obstructions , sensitivity of the receiver, antenna of the receiver . Installing antenna more high and using in the countryside , the distance will much more far. EXAMPLE 5W FM Transmitter use in the city and hometown: I have a USA customer use 5W fm transmitter with GP antenna in his hometown ,and he test it with a car, it cover 10km(6.21mile). I test the 5W fm transmitter with GP antenna in my hometown ,it cover about 2km(1.24mile). I test the 5W fm transmitter with GP antenna in Guangzhou city ,it cover about only 300meter(984ft). Below are the approximate range of different power FM Transmitters. ( The range is diameter ) 0.1W ~ 5W FM Transmitter ：100M ~1KM 5W ~15W FM Ttransmitter : 1KM ~ 3KM 15W ~ 80W FM Transmitter : 3KM ~10KM 80W ~500W FM Transmitter : 10KM ~30KM 500W ~1000W FM Transmitter : 30KM ~ 50KM 1KW ~ 2KW FM Transmitter : 50KM ~100KM 2KW ~5KW FM Transmitter : 100KM ~150KM 5KW ~10KW FM Transmitter : 150KM ~200KM How to contact us for the transmitter? Call me +8618078869184 OR Email me [email protected] 1.How far you want to cover in diameter ? 2.How tall of you tower ? 3.Where are you from ? And we will give you more professional advice. About Us FMUSER.ORG is a system integration company focusing on RF wireless transmission / studio video audio equipment / streaming and data processing .We are providing everything from advice and consultancy through rack integration to installation, commissioning and training.   We offer FM Transmitter, Analog TV Transmitter, Digital TV transmitter, VHF UHF Transmitter, Antennas, Coaxial Cable Connectors, STL, On Air Processing, Broadcast Products for the Studio, RF Signal Monitoring, RDS Encoders, Audio Processors and Remote Site Control Units, IPTV Products, Video / Audio Encoder / Decoder, designed to meet the needs of both large international broadcast networks and small private stations alike.   Our solution has FM Radio Station / Analog TV Station / Digital TV Station / Audio Video Studio Equipment / Studio Transmitter Link / Transmitter Telemetry System / Hotel TV System / IPTV Live Broadcasting / Streaming Live Broadcast / Video Conference / CATV Broadcasting system.   We are using advanced technology products for all the systems, because we know the high reliability and high performance are so important for the system and solution . At the same time we also have to make sure our products system with a very reasonable price.   We have customers of public and commercial broadcasters, telecom operators and regulation authorities , and we also offer solution and products to many hundreds of smaller, local and community broadcasters .   FMUSER.ORG has been exporting more than 15 years and have clients all over the world. With 13 years experience in this field ,we have a professional team to solve customer's all kinds of problems. We dedicated in supplying the extremely reasonable pricing of professional products & services. Contact email : [email protected] Our Factory We have modernization of the factory . You are welcome to visit our factory when you come to China. At present , there are already 1095 customers around the world visited our Guangzhou Tianhe office . If you come to China , you are welcome to visit us . At Fair This is our participation in 2012 Global Sources Hong Kong Electronics Fair . Customers from all over the world finally have a chance to get together. Where is Fmuser ? You can search this numbers " 23.127460034623816,113.33224654197693 " in google map , then you can find our fmuser office . FMUSER Guangzhou office is in Tianhe District which is the center of the Canton . Very near to the Canton Fair , guangzhou railway station, xiaobei road and dashatou , only need 10 minutes if take TAXI . Welcome friends around the world to visit and negotiate . 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