What is the bitrate of the mp4 video?
The mp4 video bitrate is usually set to around 800.
The basic algorithm is: bit rate (kbps) = file size (KB) * 8 / time (seconds), for example, D5 disk, the capacity is 4.3G, which takes into account the different audio formats, it is calculated as 600M, (so the remaining capacity is 4.3*1024-600=3803.2M), so the video file should be no more than 3.7G.
And if the capacity of the video file is 3.446G and the length of the video is 100 minutes (6000 seconds), the calculation result: the bit rate is approximately equal to 4818kbps (3.446*1024*1024*8/6000= 4817,857).
Bit Efficiency:
1. The bit rate in sound refers to the amount of binary data per unit time after converting the analog sound signal into a digital sound signal, which is an indicator to indirectly measure the audio quality. The principle of bitrate in video is the same as in sound, both refer to the amount of binary data per unit of time after the analog signal is converted to a digital signal.
2. In channel coding, a source data block of symbol size K is mapped to a codeword of symbol size N through coding, and K/N becomes the code rate, where assumes that the symbol table before and after encoding does not change.
The frame rate of 29.97 is the best.
usually:
1080*720 split resolution is about 5000K;
720*576 resolution is about 3500K;
640*480 resolution is about 1500K.
Extended information:
Some code rate principles:
1. Bitrate is proportional to quality, but file size is also proportional to bitrate.
2. If the bitrate exceeds a certain value, it has little effect on the image quality.
3. DVD capacity is limited, whether it is 4.3G standard, overdubbed or D9, there are limits. The information in the computer is represented by binary 0 and 1, and each 0 or 1 is called a bit, which is represented by a lowercase b, that is, bit (bit); uppercase B is byte, ie byte, one byte = Eight bits, ie 1B=8b; the capital K in front means 1024, that is, 1024 bits (Kb) or 1024 bytes (KB). Indicates the size of the file, usually using bytes (KB) to indicate the size of the file.
