What are the factors that affect video quality?
Bit rate
Resolution
encoding type
frames per second
The “image quality” of a video is actually a very complicated topic. Whether it is the fluidity of the image, the size of the image or the clarity of the image, it can be counted in the criteria of “image quality”.
Here we must first clarify some more important parameters
1. Bit rate (also called bitrate)
The bitrate affects the volume of the video, which is proportional to the final size of the video file. That is, the higher the bitrate, the larger the video file size. The lower the bitrate, the smaller the video file size. What role does the code rate play? In simple terms, bitrate size is the amount of data contained in one second of video. That is the sample rate. In this way, the higher the bitrate, the richer the content of the video file, the richer the image details, and the closer the overall image quality to the original material.
2. Frame rate
The frame rate affects the smoothness of the image. Under normal circumstances, if the video exceeds 24 frames per second, the human eye may assume that it is smooth by default. In most cases, the frame rate does not affect “image quality”, because the frame rate standards that can be selected are “scientific” and “effective”. Whether it is film (23.976), PAL (25), or NTSC (29.97), in these common formats, the frame rates shown in parentheses are the frame rates that can give people a good viewing experience. .
3. Resolution
The definition of resolution should be very familiar to everyone. N*M resolution essentially refers to the number of pixels. The resolution determines how fine the video is. If the original material can be guaranteed. The higher the resolution, the better the video content.
With that said, we can start to infer the image and video quality factors.
first priority
quality of original materials
The quality of good footage trumps everything, and the quality of footage can be hidden. That is, I have a 1920 x 1280 video in hand and downscale it to a 1280 x 720 video. If other parameters are reasonable, the image quality of this video can be guaranteed. For example, I only have a PAL material (720*576), I want to convert it to a 1920*1080 video, if the resolution of this material in this new video exceeds 720*576 (i.e. its original resolution), the quality of the video starts to drop off sharply and there is no way to compensate for this process.
Second, the code rate should be selected within a reasonable range. Under normal circumstances, the original 25M/s video material can still be viewed if it is compressed to 8M/s, but only if your display device is a common home device or general projector. Specific discussions are also required in the high definition environment.
The last and most problematic is the video format.
There are endless video formats, and we are also dazzled in the process of practical application.
