Seven Bull Audio Video transcoding-resolution, bitrate, frame rate, clarity of contact and difference

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noun Introduction

1, the code rate: "Bit rate" is the distortion, the higher the rate of the clearer, the other is the picture rough and more mosaic. "Bit rate" is the number of bits per second that are transmitted. The unit is bps (bit per Second), the higher the bitrate, the faster the data is transmitted. The bit rate in sound refers to the amount of binary data in a unit of time after the analog sound signal is converted into a digital sound signal, which is an indicator of indirect measurement of audio quality. The principle of bit rate (bitrate) in video is the same as in sound, which refers to the amount of binary data in units of time after the analog signal is converted into a digital signal.

2, resolution: Resolution can be classified from the display resolution and the image resolution of two directions.
The Display resolution (screen resolution) is the precision of the screen image, which refers to how many pixels the display can display. Because the dots, lines, and polygons on the screen are made up of pixels, the more pixels the monitor can display, the finer the picture, and the more information that is displayed in the same screen area, so resolution is one of the most important performance indicators. The entire image can be imagined as a large chessboard, and the resolution is represented by the number of intersection points of all meridians and parallels. The display resolution is certain, the smaller the display, the clearer the image, conversely, when the display size is fixed, the higher the display resolution, the clearer the image.

3, Frame rate: framerate (frame rate) is a measure of how many frames are displayed. The so-called measurement units show the number of frames per second (Frames per Second, FPS) or "Hertz" (Hz). This word is used in film-making and video games.
Influence the smoothness of the screen, proportional to the flow of the picture: the greater the frame rate, the smoother the picture, the smaller the frame rate, the more the screen has a sense of beating. If the code rate is a variable, then the frame rate will also affect the volume, the higher the frame rate, the more screen per second, the need for the higher bit rate, the larger the volume.
The frame rate is the number of frames in a picture transmitted in 1 seconds, or it can be understood that the graphics processor can refresh several times per second,
4, sharpness
In the case of a certain rate, the resolution is inversely proportional to the definition: the higher the resolution, the less clear the image, the lower the resolution, the clearer the image.
In the case of certain resolution, the code rate is proportional to the definition, the higher the code rate, the clearer the image, the lower the bitrate, the less clear the image.
5, bandwidth, frame rate
For example, the transmission of the image on the ADSL line, the upstream bandwidth is only 512Kbps, but to transmit 4 CIF resolution of the image. According to the usual, CIF resolution recommended code rate is 512Kbps, then according to this calculation can only be transmitted all the way, reducing the bitrate will inevitably affect the image quality. In order to ensure image quality, it is necessary to reduce the frame rate, so that even the lower bitrate will not affect the image quality, but will have an impact on image coherence.

2. Code Rate Calculation formula:

bitrate = Sample rate x-bit depth X-Channel
So, the bitrate of the above file = 44.1Khz x 16 bit x 2 channel = 1411.2 Kbps

2. File size = bitrate x Duration = 1411.2 Kbps x (3 x + +) s = 1411.2Kbps x 227s
=38102.4 Kb
38102.4 kb/1024 kb/m = 37.2M
Approximately equals the MediaInfo tool displays a file size of 38.3M.

A little comment on audio and video transcoding.

Video Conversion
When using video conversion software to convert video file format, there is a key parameter need to set, this is the video bitrate, usually the higher the rate, the higher the sharpness of the video, but the larger the size of the file. In fact, in fixed resolution, video bitrate is an optimal value, not the higher the better. So we need to choose the right bit rate when we convert the video.
In addition to the video resolution, video bitrate is related to the video encoding format. At present, the common video coding methods include: Video coding scheme, support scheme: Libx264,libvpx,libtheora,libxvid and so on.

Seven cattle users how to transcode the video into Ching HD to adapt to different mobile or web-side-(recommended)

Seven Bull Audio Video transcoding-resolution, bitrate, frame rate, clarity of contact and difference