Difference between ITU-R BT 601 and ITU-R BT 656 Signal

Source: Internet
Author: User
TU-R BT 601: 16-bit data transmission; 21-core; y, U, V signal simultaneous transmission.
ITU-R BT 656:
9-core, no synchronous signal; 8-bit data transmission; Serial video transmission; transmission rate is twice the rate of 601; first transfer y, then pass UV. 656 output is the serial data, and the synchronous signal of the line field is embedded in the data stream.
601 is parallel data, and the row-field synchronization has a separate output;

656 is only a data transmission interface. It can be said that it is used as a transmission method of 601. Simply put, ITU-R
Bt.601 is "Studio digital TV encoding Parameters" standard, while ITU-R bt.656 is ITU-R
Bt.601 digital interface standard in Appendix A, used for main digital video devices (including core
(27 MHz/S parallel port or 243 Mb/s serial interface.

Ccir601 is designed to unify and standardize the parameters of digital television broadcasting systems.
The first step. In this proposal, the basis for the digital coding of the television center studio of the 625 and 525 lines system is defined
This parameter value. The coding standard of the TV studio is specified separately in the Recommendation No. 601. It is used to compile color TV signals.
The code method, sampling frequency, and sampling structure are clearly defined. The color TV signal must adopt component encoding. The so-called component encoding means that a color full TV signal is first separated into a brightness signal and a chromatic aberration signal before being converted into a digital form, and then separated
Encoding. The component signal (Y, B -- y, r -- Y) is encoded separately, and then the digital signal is synthesized.
It specifies the sampling frequency and structure. For example, in the encoding
The sampling frequencies of the Degree signal and chromatic aberration signal are 13.5mhz and 6.75 MHz, respectively.
The sampling structure is orthogonal structure, that is, sampling by row, field, frame repetition, R-Y and B-Y in each line with odd times (1, 3, 5 ......) Y sampling in the same position
The sampling structure is fixed, and the relative position of the sampling point on the TV screen remains unchanged.
It specifies the encoding method. Linear PCM encoding is performed on the Brightness Signal and two chromatic aberration signals. 8 bits are used to quantify each sampling point. At the same time, it is stipulated that the entire dynamic range of A/D conversion is not used during digital encoding, and only 220 quantization levels are allocated to the brightness signal. The black level corresponds to the quantization level 16, the white level corresponds to the quantitative level of 235. Assign 224 quantization levels for each chromatic aberration signal. The zero level of the chromatic aberration signal corresponds to a quantization level of 128.

To sum up, we know that the encoding data stream of the component signal is very high. Taking the encoding standard as an example, the bit stream is 13.5 × 8 + 6.75 × 8 × 2 = 216 Mb/s. If the encoding method is used, that is, the compound signal is directly encoded, and the sampling frequency is 13.3 × 8 = 106.4.

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.