To put it simply, video bitrate is the amount of data contained in a video for every second it is transmitted.
In other words it is the number of bits processed in a second.
Every 8 bits represent 1 byte.
8 bits = 1 byte
8 000 000 bits = 8 Megabytes
So, if there’s one megabyte (1000000bytes) of data per second the data rate will be 8 mega bits per second – 8 million bits per second (8Mbps).
Why is Video Bitrate Important?
The quality of a video depends on its bitrate. The higher the bitrate, the higher the quality.
The higher the bitrate the bigger the size of the video file.
Does this mean the bitrate of a video be changed to improve its quality?
If you receive a video file with a bit rate of say 1mBps you can’t increase the quality of the video by changing the bitrate of the video to 2Mbps.
The bitrate of the source video can’t be changed to a higher quality.
But then it’s possible to lower the bitrate of a video. If you receive a video with a high bitrate, you can lower its bitrate with a video compressor to reduce its file size.
This is useful if you’re uploading video to the web and you want to stream it to those with slower Internet connections.
Video Bitrates and Camcorders
If you’re using a camcorder which records video into a memory card, then you should take note of video bitrate.
If you don’t have much storage space left in the memory card, then you should set your camcorder to record at a lower bit rate.
Remember the higher the bit rate of a video, the more space is needed to store it.
Also when buying a memory card, you should determine what’s the maximum video data transfer rate (Mbps) it could support.
For example if you have a class 2 memory card which records video at 2MB per second you can’t use it to record video at 4MBps. The card will not be able to support the high video transfer rate.
If you use a memory card with a higher video transfer rate say a Class 10 card – 10Mbps to record at 2Mbps, video will still be recorded at 2Mbps and you’ll end up paying more for a high video data transfer speed that you don’t need.
Check out the bitrates of different types of video formats at Wikipedia