What is the difference between CBR/VBR/ABR in audio/video conversion [I tried it]
Bitrate is an index that determines the quality of compressed video and audio. Bitrate is the number of bits per second, and in general, the higher the bitrate, the higher the quality. However, the file size will increase accordingly.
The compression method is the behavior of the bitrate at the time of compression, which is the constant bitrate (CBR) method, variable bitrate (VBR), or average bitrate method (Bitrate average, ABR) . be classified.
Constant Bit Rate (CBR) Characteristics
The method of compressing with a constant bit rate is called the constant bit rate (CBR) method. Since the bitrate is fixed, it is not only easy to predict the file size after compression, but also search the playback position at high speed. However, there are problems with videos, such as the quality changing between scenes with little movement and scenes with lots of movement.
WAVE and uncompressed AIFF can also be called CBR.
advantage
It is possible to predict the file size after compression
High-speed playback position search possible
Disadvantage
Quality tends to vary
Variable Bit Rate (VBR) Features
The method of compressing by changing the bit rate is called the variable bit rate (VBR) method. In the VBR method, the bit rate is high where the data jitters sharply, and the part where the jitter is gradual is low and compressed, so the quality can be kept constant as a whole and can be compressed with higher quality than CBR. .It is said that. However, the size of the compressed file is unpredictable because the bitrate changes from moment to moment. Also, it takes more time to search for playback position than CBR .
advantage
Easy to control quality
high quality
Disadvantage
Difficult to predict the size of the compressed file
It takes time to search for the playback position
Average Bit Rate (ABR) Features
Although the bit rate is variable, the method of compressing with a constant average bit rate is called the average bit rate (average bit rate, ABR) method. Although the bitrate fluctuates with this method, the final size of the file can be predicted to some extent because it is compressed so that the average bitrate of all data is constant. This allows you to maintain quality like VBR and predict file size like CBR. However, it takes longer to process than other methods because the data must be scanned at least once before compression.
advantage
It is possible to maintain quality up to a certain point.
File size can be predicted to some extent
Disadvantage
The compression process takes time
Bitrate method of major audio compression formats
MP3
CBR, VBR
WMA
CBR, VBR
CAA
VBR, ABR
Ogg Vorbis
VBR, ABR
