TWI523511B - Variable bit rate video panning method - Google Patents

Description

Variable bit rate video broadcast method

The invention relates to a video broadcast method, in particular to a variable bit rate video broadcast method for transmitting a variable bit rate video to a user terminal via a network.

1998/05/11 Taiwan Patent Application No. 086109409 "Method for transmitting variable bit ratio data on a fixed bit ratio channel" is an intermittent transmission method through an active program (transmission time) and a negative program (rest time) The interleaved configuration meets the transmission requirements of the variable bit rate data. This method does not transmit data during the negative program period, so the client must have enough memory space to store the data content played in this interval.

2007/11/26 US20080137658 "SYSTEM, SERVER, AND METHOD FOR VARIABLE BIT RATE MULTIMEDIA STREAMING" proposes to pre-segment the data to be transmitted into a custom small packet set on the server side with a packet producer (packet producer). A time stamp is added to the small packet to represent the time at which the packet needs to be transmitted to the client at the latest. When the server starts transmitting data to the client, the feeder module checks each. The timestamp of the small packet, if it needs to be transmitted immediately, removes the timestamp header and restores the data, and transmits the data to the client through the network, thereby controlling the transmission rate. However, this patent needs to be transmitted at the server end. The header of each small packet must be read and compared with whether the timestamp is overdue. Finally, the timestamp header is removed to restore the packet, which increases the burden of the server operation.

The main object of the present invention is to provide a variable bit rate video broadcast method in which the server end uses a variable transmission rate to make the transmission rate change with the bit rate, and the data transmission and consumption rate are close.

A secondary object of the present invention is to provide a variable bit rate video broadcast method capable of reducing a buffer storage space used by a client for reserving data and delaying buffer data before starting playback.

Another object of the present invention is to provide a movie that is analyzed before transmission and does not increase the burden on the server.

To achieve the above objective, the present invention provides a variable bit rate video playback method, which mainly includes a preprocessing stage and a transmission stage, wherein the preprocessing stage extracts each frame block by the video analysis module ( The frame block size, the total number of frames, and the number of frames per second (frame per second) are calculated by the transmission rate calculation module to calculate the transmission rate table, and the transmission phase is to package the video requested by the client. The unit is placed in the video package queue for transmission, and the transmission module transmits the packet to the user end, and then the flow control module obtains the transmission amount from the transmission rate table at the beginning of each unit time, and triggers the transmission module to start transmission. After the transmission module completes the transmission, the transmission module returns the amount of data transferred. After the accumulated data volume exceeds the value recorded in the rate table, the flow control module pauses the transmission module until the next unit time, and the flow is cycled per unit time. To the end of the video material.

1‧‧‧Video Analysis Module

2‧‧‧Transmission rate calculation module

3‧‧‧Transmission rate table

4‧‧‧Video package queue

5‧‧‧Flow Control Module

6‧‧‧Transmission module

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1 is a system architecture diagram of a variable bit rate video broadcast method according to the present invention; 2 is a flow chart of a variable bit rate video broadcast method according to the present invention; and FIG. 3 is a flow chart of a method for calculating a transmission rate of the variable bit rate video push method according to the present invention.

Referring to FIG. 1 to FIG. 3, the present invention is a variable bit rate video broadcast method, which mainly includes a preprocessing stage and a transmission stage, wherein the preprocessing stage is after the video file is imported into the streaming server. The process before the transmission starts, and the transmission phase is a process in which the user requests the video to be transmitted to the server after the video is requested to be played. The main process steps are as follows: Step 1: The video analysis module 1 extracts each The size of the frame block, the total number of frames, and the number of frames per second (frame per second) (101).

Step 2: The data captured by the film analysis module 1 is transferred to the transmission rate calculation module 2, and the transmission rate table 3 (102) is calculated.

Step 3: When the client transmits the play video request, the requested movie is placed in the video package queue 4 in units of packets, and the transmission module 6 is sent to the user terminal (103).

Step 4: The flow control module 5 obtains the transmission amount from the transmission rate table 3 at the beginning of each unit time, and triggers the transmission module 6 to start transmission, and the transmission module 6 returns the transmitted data amount after each single transmission is completed. (104).

Step 5: After the accumulated value of the accumulated data volume of the flow control module 5 exceeds the record value of the transmission rate table 3, the transmission module 6 is suspended until the next unit time, and the process is cycled to the end of the video data every unit time to end the transmission phase. (105).

Among them, the video analysis module 1 first finds all the video frames in the video file. The beginning position of (video frame), for example, H.264 can be used to find the beginning position by the 0x000001 keyword; all the data between the adjacent two beginning positions is defined as a frame block, which contains the header information and the video frame. After the audio frame, and after defining the frame of the output frame, record the size of each frame block and accumulate the total number of frames; the number of frames per second can be obtained from the video file header, for example: H.264 This information can be obtained from the SPS (Sequence Parameter Set); finally, the information is transmitted to the transmission rate calculation module 2.

Furthermore, the transmission rate table 3 records the transmission rate that should be set per unit time, for example, the unit time is set to 1 second, the first unit time is 16832 (bytes/s), and the second unit time is 9346 (bytes/s). This unit time is customized by the user, which indicates how long the server will change the transmission rate.

In addition, as shown in Fig. 3, the accumulated value in the figure includes the accumulated transmission data amount and the accumulated consumption data amount, and the time unit is a custom parameter, which represents how long the server interval changes the transmission rate, and each time unit is The number of frames per second (fps) is subdivided into time frames, so that each time frame has a frame, for example, the time unit is 1 second, the number of frames per second is 25, and the time frame is 1/25. Seconds; find the transmission rate satisfaction for each time unit: In each time grid, the cumulative transmission data amount is greater than the cumulative frame data amount.

As shown in the above table, the unit time is 1 second, and the number of frames per second is 6, each time grid is In 1/6 seconds, the process of Figure 3 finds that the transmission rate of this time unit is 2262 (bytes/s), and then repeats this process until the end of the video data ends, resulting in a transmission rate table 3.

As described above, the variable bit rate video broadcast method provided by the present invention uses a variable transmission rate, and the transmission rate varies with the bit rate, and the data transmission and consumption rate are close to each other, and the user terminal can be reduced for use. The buffer storage space of reserved data and the delay caused by buffering data before starting playback, and in the case of non-congested network, the amount of data accumulated by the server to the user during playback remains higher than that required for playback. For fixed-speed transmission, it is not necessary to pause the playback to wait for sufficient data when playing to the peak of the bit rate. In addition, when the server simultaneously serves the video broadcast request of different bit rates, the finite bandwidth can be used. The reasonable allocation transmission rate is connected at each user end, and the video is analyzed before transmission, which does not increase the burden on the server transmission.

Furthermore, the variable bit rate video broadcast method provided by the present invention is compared with the method of transmitting variable bit ratio data on a fixed bit ratio channel according to the 1998/05/11 Taiwan Patent Application No. 086109409. The invention uses the variable transmission rate to continuously transmit during the playing of the movie, and the user receives the new data while consuming the old data that has been received and decoded, and the receiving and the consumption rate are close, so that the data is effectively utilized, and the user is reduced compared with the previous case. Additional storage space required for the burden; and the variable bit rate video delivery method provided by the present invention is compared with the 2007/11/26 US20080137658 patent "SYSTEM, SERVER, AND METHOD FOR VARIABLE BIT RATE MULTIMEDIA STREAMING" In the process of transmitting data to the client end on the server side, the rate table can be determined from the pre-calculated rate table by means of table lookup, and the current transmission rate per unit time is determined, and the data content is not analyzed, and the server can be reduced. The computing burden can also serve the needs of a large number of clients.

The above detailed description is specific to one of the possible embodiments of the present invention, The embodiments are not intended to limit the scope of the invention, and equivalents or modifications of the invention are intended to be included in the scope of the invention.

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Claims (6)

A variable bit rate video playback method mainly includes the following steps: Step 1: The video analysis module extracts the size of each frame block, the total number of frames, and the number of frames per second (frame) Per second); Step 2: The data captured by the video analysis module is transferred to the transmission rate calculation module to calculate the transmission rate table; and step 3, when the client transmits the request for playing the video, the requested video is packaged as a packet. The unit is placed in the video package queue, waiting for the transmission module to transmit the video packet to the client; in step 4, the flow control module obtains the transmission amount from the transmission rate table at the beginning of each unit time, and triggers the transmission module to start transmission. The transmission module returns the transmitted data amount after each single transmission is completed; Step 5: The flow control module pauses the transmission module until the next unit time when the accumulated value of the accumulated transmission data exceeds the recorded value of the transmission rate table. The process is cycled to the end of the video data every unit time to end the transmission phase. The variable bit rate video paging method according to claim 1, wherein the transmission rate calculation module calculates each frame block size, the total number of frames, and the number of frames displayed per second. The transmission rate should be set at the lowest unit time, and the transmission rate table is generated. The variable bit rate video broadcast method according to claim 1, wherein the video analysis module first finds a beginning position of all video frames in the video file, and defines all data between the adjacent two start positions as After the frame block is defined, the frame size of each frame is recorded, and the total number of frames is accumulated. The variable bit rate video broadcast method of claim 1, wherein the frame block includes header information, a video frame, and an audio frame. The variable bit rate video broadcast method according to claim 1, wherein the video analysis module obtains the number of frames per second from the video file header. The variable bit rate video playback method of claim 1, wherein the transmission rate table records a transmission rate that should be set per unit time.