CN113194318A - Data transmission method without HDCP authentication feedback - Google Patents

Abstract

The invention discloses a data transmission method without HDCP authentication feedback, which comprises a sending end and a receiving end, wherein the sending end comprises a video acquisition module, a video compression module and a data sending module, the video acquisition module, the video compression module and the data sending module are sequentially and electrically connected, the receiving end comprises a data receiving module, a video decompression module and a video display module, the data receiving module, the video decompression module and the video display module are sequentially and electrically connected, and the data sending module and the data receiving module are connected through a network. The data transmission method without the HDCP authentication feedback uses a VC + + self-packaged Windows VFW SDK software development kit for secondary development, and can effectively solve the problems of video image ghosting, jittering, screen splash and the like caused by local instability of a network through Divx coding and decoding according to a formulated transmission strategy.

Description

Data transmission method without HDCP authentication feedback

Technical Field

The invention relates to the technical field of data transmission, in particular to a data transmission method without HDCP authentication feedback.

Background

Real-time transmission of video inside a local area network has been widely used. At present, most of local area networks for transmitting videos are wired local area networks, and the wired local area networks are mature in technology, high in transmission speed and good in stability. However, the video data volume is large, the wired network also has unstable work to cause data blockage, and serious delay is caused after long time, if the working environment is not fixed and mobility is required, a wireless network is adopted, the work of the wireless network card becomes unstable along with the change of the environment, so that the video transmission quality is greatly reduced, and the phenomena of double images, jitter, screen splash and the like of pictures are easily caused. The network is an important way for people to acquire and transmit information in learning, life and work, and network application puts higher requirements on the real-time performance of data transmission, so that novel high-speed network protocol support is needed. The RTP/RTCP protocol, the RTSP protocol and the RSVP protocol cooperate with each other to complete the data transmission and control, resource reservation, service quality guarantee and other works of the network real-time multimedia application together. Among them, the RTP/RTCP protocol is one of the important protocols for real-time video transmission. In the transmission process of real-time video data, if the speeds of a data reader and a data writer at a receiving end are different, the read-write load is unbalanced, and data loss or system errors are caused. Therefore, a universal solution for real-time video transmission is provided for different local area networks, a VC + + self-packaged Windows VFWSDK software development package is used for secondary development, and the problems of video image ghosting, jittering, screen splash and the like caused by local instability of the network can be effectively solved through Divx coding and decoding according to a formulated transmission strategy.

Disclosure of Invention

In view of the above problems, the present invention provides a data transmission method without HDCP authentication feedback to solve the problems set forth in the above background art. The method comprises the following specific steps: in order to achieve the purpose, the invention adopts the following technical scheme: a data transmission method without HDCP authentication feedback comprises a sending end and a receiving end, wherein the sending end comprises a video acquisition module, a video compression module and a data sending module, the video acquisition module, the video compression module and the data sending module are sequentially electrically connected, the receiving end comprises a data receiving module, a video decompression module and a video display module, the data receiving module, the video decompression module and the video display module are sequentially electrically connected, and the data sending module and the data receiving module are connected through a network. Further, the data of the video acquisition is a video frame in a bitmap mode. Further, the video compression module forms an Mpeg4 stream in frame format after being compressed by a Divx encoder. Further, the video decompression module adopts a Divx decoder to decompress in a frame format. Further, the method comprises the following steps: the method comprises the following steps that (1) a video acquisition module captures a video image from a video acquisition card by adopting AVICap to obtain a bitmap type video frame; (2) the video data is transmitted to a video compression module to be compressed by a Divx encoder, and real-time transmission of the compressed video data in the local area network is realized through Winsock; and (3) delivering the received data to a Divx decoder for decompression through a video decompression module, and finally realizing video display. Further, the sending end includes the following procedures: a thread is required to be created, which is specially used for sending data, and the main thread still continuously collects and compresses data. Further, the receiving end includes the following processes: the method comprises the steps of searching a frame starting mark from a data stream, extracting the size of a frame from immediately following data, reading the rest data of the frame from a receiving buffer area, searching a starting mark of the next frame, and the like. The invention has the following beneficial effects: 1. The invention uses a VC + + self-packaged Windows VFWSDK software development kit for secondary development, and can effectively solve the problems of video image ghosting, jitter, screen splash and the like caused by local instability of a network through Divx coding and decoding according to a formulated transmission strategy. 2. In the communication program, the annular buffer area is often used as a data structure to store data sent and received in communication, the read-write pointer of the annular buffer area can not operate in the same memory area at the same time, mutual exclusion synchronous processing is not needed, the annular buffer area can effectively utilize the space of the memory, the annular buffer area has an important role in real-time transmission, and the problem of data loss or system error caused by unbalanced read-write load is solved.

Drawings

FIG. 1 is a flow chart of the method of the present invention for real-time video transmission; FIG. 2 is a flow chart of a send thread operation of the present invention; FIG. 3 is a flow chart of the operation of the receiving end of the present invention; FIG. 4 is a diagram of a circular video buffer according to the present invention; FIG. 5 is a flow chart of the buffer read/write thread software according to the present invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further explained in the following combination. In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. In an embodiment, referring to fig. 1 to 3, the HDCP-free authentication feedback-based data transmission method provided by the present invention includes a sending end and a receiving end, where the sending end includes a video acquisition module, a video compression module, and a data sending module, the video acquisition module, the video compression module, and the data sending module are sequentially electrically connected, the receiving end includes a data receiving module, a video decompression module, and a video display module, the data receiving module, the video decompression module, and the video display module are sequentially electrically connected, and the data sending module and the data receiving module are connected through a network. The data of the video acquisition is a video frame in a bitmap form. The video compression module is compressed by a Divx encoder to form a frame format

Mpeg4 stream. The video decompression module adopts a Divx decoder to decompress in a frame format. It is proposed to transmit a video data stream in units of frames. In order to extract a frame conveniently at the receiving end, it is proposed to construct the frame in the following format. A complete frame consists of 5 fields, the meaning of each field being as follows: the start of frame flag, which marks the beginning of a frame, occupies a space of 4 bytes. Oxfliff is not used. The frame size, which represents the size of the entire frame, includes the size of 5 fields, and occupies a space of 4 bytes. The frame number indicates the sequence number of the frame, and occupies a space of 4 bytes. The frame type, which indicates whether the frame is a key frame, occupies a space of 1 byte. And frame data, storing the complete data of the compressed frame. The method comprises the following steps: the method comprises the following steps that (1) a video acquisition module captures a video image from a video acquisition card by adopting AVICap to obtain a bitmap type video frame; (2) the video data is transmitted to a video compression module to be compressed by a Divx encoder, and real-time transmission of the compressed video data in the local area network is realized through Winsock; and (3) delivering the received data to a Divx decoder for decompression through a video decompression module, and finally realizing video display. The sending end comprises the following procedures: a thread is required to be created, which is specially used for sending data, and the main thread still continuously collects and compresses data. Therefore, real-time video transmission is realized, and the compressed data is continuously sent to a receiving end. The workflow of the send thread is shown in figure 2. The receiving end comprises the following procedures: the method comprises the steps of searching a frame starting mark from a data stream, extracting the size of a frame from immediately following data, reading the rest data of the frame from a receiving buffer area, searching a starting mark of the next frame, and the like. In the second embodiment, the ring buffer is used at the receiving end to reassemble the video frames. A ring buffer typically has 1 read pointer and 1 write pointer. Wherein, the reading pointer points to the readable data in the ring buffer area, and the writing pointer points to the buffer area which can be written in the ring buffer area. Data reading and writing of the buffer is achieved by moving the read pointer and the write pointer. Under normal conditions, the read-write pointers of the ring buffer area cannot operate in the same memory area at the same time, so that the phenomenon of discarding due to the fact that received messages cannot be written in time in the data reading and writing process cannot occur, and mutual exclusion synchronization processing is not needed. However, it should be noted that some synchronization between the pointer for determining the full frame operation and the write thread operation is required, because the read thread of the video buffer involved in determining the full frame of video may collide with the write thread. But the synchronization process does not affect the working efficiency of the buffer because the time for determining the full frame operation is shorter than the time for operating the read and write pointer. As shown in fig. 4, the write pointer writes the human data from time 1 to time 2, storing the full frame. The full frame judgment pointer continuously and circularly judges whether the full frame exists or not from the reading pointer, and the specific judgment method comprises the following steps: first, a video frame header start and end portions are respectively designed to be 0X00000000 of 4 bytes and oxfffffffff of 4 bytes as video data start and end flags. Judging whether the pointer firstly judges whether the 4 bytes after the pointer is read is OXO0000000, if so, judging the frame start position, continuously reading the 2 bytes of data, and calculating the frame head and frame tail of which the actual length of the video frame is equal to the data minus 16 bytes. And (4) judging whether the pointer reaches the tail of the frame according to the actual length movement of the frame, and judging whether the pointer is an OXFFFFFFF. If yes, the video frame is judged to be full, and the video frame information can be directly read from the position of the reading pointer. In the writing data packet, if the out-of-order data packet is received, the data packet is directly discarded, and meanwhile, the writing pointer returns to the initial position of the current frame. In fig. 4, if the out-of-order packet is received at time 3, the packet is directly discarded, and the write pointer returns to time 2, and the writing is restarted after the 0 packet of the next frame arrives. When the write pointer reaches the end of the buffer at time 4, the remaining video data can continue to be filled into the head of the buffer, and so on, the flow of the buffer read-write thread software is as shown in fig. 5. The above are merely examples of the present invention, and common general knowledge of known specific structures and characteristics in the schemes is not described herein. It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (7)

1. A data transmission method without HDCP authentication feedback comprises a sending end and a receiving end, and is characterized in that: the receiving end comprises a data receiving module, a video decompressing module and a video display module which are sequentially electrically connected, and the data sending module and the data receiving module are connected with each other through a network.

2. The HDCP-free authentication feedback data transmission method according to claim 1, wherein: the data of the video acquisition is a video frame in a bitmap mode.

3. The HDCP-free authentication feedback data transmission method according to claim 1, wherein: the video compression module adopts a Divx encoder to compress and then forms an Mpeg4 stream with a frame format.

4. The HDCP-free authentication feedback data transmission method according to claim 1, wherein: the video decompression module adopts a Divx decoder to decompress in a frame format.

5. The HDCP-free authentication feedback data transmission method according to claim 1, comprising the following steps: the method comprises the following steps that (1) a video acquisition module captures a video image from a video acquisition card by adopting AVICap to obtain a bitmap type video frame; (2) the video data is transmitted to a video compression module to be compressed by a Divx encoder, and real-time transmission of the compressed video data in the local area network is realized through Winsock; and (3) delivering the received data to a Divx decoder for decompression through a video decompression module, and finally realizing video display.

6. The HDCP-free authentication feedback data transmission method according to claim 1, wherein the sending end includes the following procedures: a thread is required to be created, which is specially used for sending data, and the main thread still continuously collects and compresses data.

7. The HDCP-free authentication feedback data transmission method according to claim 1, wherein the receiving end comprises the following procedures: the method comprises the steps of searching a frame starting mark from a data stream, extracting the size of a frame from immediately following data, reading the rest data of the frame from a receiving buffer area, searching a starting mark of the next frame, and the like.

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