Standard bt.656 Parallel data structure

Transferred from the network, thanks to the original author and reprint.

Also reference: Encyclopedia Http://baike.baidu.com/link?url=bqBT3S7pz_mRJoQE7zkE0K-R1RgQ6FmHNOZ0EjhlSAN_ Oy-2-hj6g9ompftwpzvuomtc5pciauqtuxj0sy--c_

more important reference :http://www.spacewire.co.uk/video_standard.html

Original:

In addition to transmitting 4:2:2 YCBCR video data streams, the bt.656 parallel interface also has control signals for row and column synchronization. As shown in 3, a frame of image data consists of a 625-row, 1-728-byte block of data per line. Among them, 23~311 line is an even number of field video data, 336~624 line is an odd number of field video data, the rest is a vertical control signal .

bt.656 is shown in data structure 4 per row.

In Figure 4, each row of data contains a horizontal control signal and a ycbcr. Video data signal. The video data signal is arranged in the order of cb-y-cr-y. The 288 bytes starting at each line is the line control signal,

The beginning of the 4 bytes is the EAV signal (active video end), followed by 280 fixed fill data, and finally 4 bytes of SAV signal (effective video start).

Note: YCbCr value range:y:16~235;cb:16~240;cr:16~240;

Note: If you are careful enough when looking for material, you will find ... There are many places for the BT656 coding diagram, seemingly the same, in fact, the difference is very large. There are several differences:

1. The opening byte of EAV and Sav is ff 00 00, while some data are FF FF 00 (including the encyclopedia, as well as the resources in this article).

2, the 268 blanking is 16 in 80 10, and the valid data is 80 16 (such as BT656 encoding chip data TW2867).

So when you look at the information should be very careful, multi-check. and individuals are more convinced of the above illustration.

The SAV and EAV signals have a 3-byte preamble: FF, FF, 00, and the last 1 bytes of XY indicate where the line is located throughout the data frame and how to differentiate the SAV, EAV. The meaning of each bit of XY byte is shown in Figure 5.

In Figure 5, the highest bit bit7 is a fixed data 1;f=0 representing an even number of fields, f=1 represents an odd field, v=0 indicates that the behavior is valid video data, v=1 indicates that the row does not have valid video data;

H=0 is expressed as the SAV signal, H=1 is expressed as EAV signal, P3~P0 is a protection signal, generated by F, V, H signal calculation, P3=v XOR H;p2=f xor H;p1=f xor V;p0=f xor V xor or H.

Analysis: The last 1 bytes of the XY value case:

itu-      r601/656 formerly known as ccir601/656, is a video standard presented by the International Telecommunication Association. Noun Explanation: Bt.656:this ITU recommendation defines a parallel interface(8-bit or 10-bit, MHz) and a serial Interface (Mbps) for the transmission of 4:3 bt.601 4:2:2 YCbCr digital video between pro-        Video equipment. International Telecommunication Union radiocommunication Sector Recommendation No. 656-3: Work at the 4:2:2 level of itu-rbt.601 recommendations (Part A)525 rows and 625 rowsThe interface of the digital component video signal in the   TV system.         ITU Radiocommunication Plenary taking into account:          a) for television broadcasters and programme makers, Significant benefits of the same important parameters with the largest number of digital studio standards for 525-row and 625-row systems;          B) A world-compatible digital approach will enable the development of devices to have many common features that will be more economical to run and facilitate international program ' Exchange;          C) to achieve the above objectives, has been ITU-RBT. 601 The proposed form of the basic coding parameters for digital TV Studios was agreed;          D) itu-rbt. 601 The actual implementation of the recommendation requires that the details of the interface and the data flow through the interface;          e) These interfaces in 525 rows and 625 lines two type Q should have the greatest commonality;           f) in ITU-RBT. 601 the practical implementation of the proposed interface is expected to be both serial and parallel in both forms;          g) The digital television signals produced by these interfaces may be potential sources of interference to other services and must be in the radio rules No. 964 give due attention to it. It is recommended that where in a TV studio you need             component coded digital video signal interfaces, these interfaces and the data flow through them should conform to the specified bit parallel and bit serial implementation of the following instructions:  1, Introduction & nbsp       This recommendation describes running in 525-or 625-line formats and conforming to ITU-RBT. 601 The interconnection method of the digital television device (4:2:2) as defined in (Part a) of the proposed coding parameters.         Part one: Common signal format for interfaces           1, general description of the interface                 Interface forProvides one-way interconnection between a single source and a single endpoint. A single signal format common to both parallel and serial interfaces is described in section 2nd. The data signal takes the form of binary information encoded into 8-bit words (optionally 10-bit word ')            . These signals are:              1: Video signal,              2: Timing reference Signal, &N Bsp             3: Auxiliary signals.  2, video data                                                              table 1 field interval definition   & nbsp                               NOTE 1: signal F and V in Digital line Synchronized with the active video timing reference code to change the state.                     NOTE 2: The definition of line number is ITU-RBT. 470 recommendations. Note the line number of the number line as in the ITU-R BT. 601 the recommendation (Part A) describes the change in state before 011.         2.1 encoding features                 video data complies with ITU-R BT.601 recommendations (part A) and shown in table Definition of the field blanking of L.         2.2 videosData format                   8 Most significant bits are either L or 0 of the data word for identification purposes, so only 254 of the 256 8-bit words (1024 1016 of the 10-bit words) can be used to represent a signal value.             , the order is: CB,Y,CR,Y,CB,Y,CR, ... Among them, cb,y,cr these three words refers to the same address luminance and chromatic aberration signal sampling,            The following Y word corresponds to the next luminance sampling.        2.3 Interface signal structure                   diagram L shows how video sampling data is added to the interface data stream 。 The sample identification symbol in Figure L conforms to ITU-RBT. 601 the identification symbol for the recommendation (section A).        2.4 Video Timing Reference Code (SAV,EAV)                 Two timing reference signal, one in each video data The start of the block (start of Activevideo,sav) and the other is shown in the end of each video block (end of Active Video,eav),  L. Each timing reference signal consists of a sequence of 4 characters, formatted as follows:                                       FF xx (value in 16 binary, FF 00 reserved for timing reference signal.     First three is a fixed prefix, and the 4th Word contains information that defines the second field, the field blanking state, and the row blanking state. The bit allocations in the timing reference signal are listed in table 2.                                 data bit number the first word ( FF) The second word (00) the third Word (00) the fourth character (XY)                                            NOTE 1: The value shown is the recommended value for the 10-bit interface.                     NOTE 2: For compatibility with existing 8-bit interfaces, the value of D1 and do bits is specified at the end. F=0/1 l/2 field, V=0/1 Other places/field blanking. h=0/1        Effective video at the beginning (SAV)/Active video End (EAV) P0,P1,P2,P3: protection bit (see table 3) MSB: The most effective bit table L specifies the state of V and F bits. The status of the        P0,P1,P2,P3 bits is determined by the status of F,v bits, as shown in table 3. In the receiver, this arrangement allows correction of L-bit error and detection of 2 bit error.                          ,         &NB sp;          2.5 secondary data               The rate of mword/s in the blanking periodsynchronous insertion into the secondary data in the multiplexing group is provided.。 The secondary data signal can be transmitted in 10-bit form only during blanking, and can also be transmitted in 8-bit form only in the presence of the row in the blanking (it should be noted that the ITU-RBT is compliant. 657 the proposed digital video recorder does not record the data during the row blanking period, nor does it record some rows during the field blanking period. Data value 00. Xh and ff. Xb (see 2nd. Section 2) reserved for identification purposes.             Therefore, it cannot appear in the auxiliary data. All auxiliary data signals that are loaded in the valid portion of the row during the blanking period must be prefixed with: ff.x ff.x the auxiliary signal should not be changed by the device unless it is intended to function as a special device. 2.6 Data word during blanking during the digital blanking period when the data word is not used as a timing datum or auxiliary data, it should be filled in the appropriate position in the data that is reused to be equivalent to the cb,y,cr,y signal blanking level of 80. 0h,10. 0h,80. 0h, 10. 0h and other sequences. The overall format of a complete line for the horizontal format digital video data stream includes the following sections:EAVis considered to beHorizontal Scanthe opening part of            EAV-Effective video end (timing reference signal) 2 sample point (4 bytes)            . Horizontal blanking 134 sample points (268 bytes)         &NBS P   sav-Active Video Start (timing reference signal) 2 sample points (4 bytes)            . 720 Valid sampling points (1440 bytes)         EAV Timing Reference Signal:           . EAV Timing Reference includes four bytes in the following format:              f = Field Select (defines which vertical scan du Ring interlace scanning)              V = Vertical blanking        & nbsp    H = 1 indicating eav             E3 = V xor h        & nbsp    e2 = f xor h             E1 = f xor v          &N Bsp  E0 = F xor V xor h       Effective video:            Effective video format consists of the following parts: "Y", "Cb", "Cr" data, staggered composition.           

Add, in BT656 the YCBCR format to the different colors of the code such as:

Standard bt.656 Parallel data structure