VBR Part 2
For audio compression, such as MP3, the traditional CBR (Constant Bit Rate) is a static bit rate.
CBR accepts that the MP3 sampling rate is a fixed value. An MP3 is compressed with a fixed value like 128 KBit/s from start to finish. VBR adopts a new compression method with full dynamic adjustment technology to strike a balance between sound quality and file size. When VBR encodes an audio file, the program will try to maintain the selected quality of the entire file and will select different bit rates to encode different parts of the music file. When in the low range (simple part), VBR will automatically use a lower bit rate, such as 32 KBit/s, to compress the sound quality; when in the high range (complex part), it will use a higher bit rate, such as 224 KBit/s. s to compress sound quality Compression is performed; at the high end, use up to 320 KBit/s for compression. VBR MP3 maximizes MP3 sound quality while controlling file size. VBR automatically allocates fewer bits to the simple part of the content during encoding, leaving enough bits to generate high-quality complex parts. The output result of VBR encoding is of better quality than that of CBR encoding, and the encoded file is relatively small and suitable for storage. However, the disadvantage of VBR is that the amount of computation is large, the compression time is long, the size of the compressed file cannot be estimated during encoding, the requirements for the decoding algorithm are also much more complicated, and the Requirements for the hardware (such as the CPU) of the decoder are also high.
Differences between CBR and VBR:
(1) CBR: The size of the FRAME with a fixed bit rate is also fixed. As long as the total file length and frame length are known, the total mp3 playback time can be calculated from the 26 ms required to play each. frame, and can also be controlled by counting the number of frames. Fast forward, fast rewind, slow playback, etc.
(2) VBR: VBR is an algorithm released by XING company, so there will be the keyword “XING” in the FRAME of MP3 (many popular small software can also do VBR compression, whether they abide by this agreement, then it is impossible to Got it), it is stored in the first valid FRAME in the MP3 file, and identifies that the MP3 file is VBR. At the same time, the first FRAME stores the total number of FRAMEs in the MP3 file, making it easy to get the total playing time. At the same time, there are 100 bytes that store the INDEX of the 100 time-sliced FRAMEs. of the total playing time.
beginning
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VBR is a variable encoding rate MP3 compression method. Its principle is to encode the complex part of a song with a high bit rate and the simple part with a low bit rate. Through this dynamic adjustment of the encoding rate, the sound quality can be improved. additionally obtained and the size of the file. Its main advantage is that the entire song can approximately meet our sound quality requirements, but the disadvantage is that the size of the compressed file cannot be estimated during encoding.
Most MP3 players released now support VBR, but although some machines can play songs in VBR format, they cannot display the playing time correctly (especially in car stereos). Many high-quality MP3s today are encoded with VBR. when purchasing, please pay attention to whether MP3 Walkman supports VBR effectively.
other acronyms
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VBR: Valid Business Reason
VBR: Vector Base Register
VBR: Vertebral Body Replacement
VBR: Virginia Blue Ridge Railroad
VBR – Variable Diameter Ram (Oil Drilling)
VBR: Basic Rule Violation (Oregon Traffic Division)
VBR: Kind regards
VBR: ventricle-brain ratio
VBR: Virgin Branson Richard
VBR: Visual Basic custom control file control file,
Visual Basic customization
VBR: VärnamoBygdens Ryttarförening VärnamoBygdens Ryttarförening
VBR: Visions come true
VBR: Vinnell, Brown and Root Vinnell, Brown, Root
VBR: Varsity Brands, Inc. Some brand companies
