KR20060003650A - Method of providing video streamin service having higher times of rate - Google Patents

Abstract

The present invention relates to a method of providing a high speed video streaming service for minimizing a quality deterioration such as screen interruption in response to a request for transmission of a high speed screen of a receiving side in a real time video streaming service providing method such as VOD. A high speed video streaming service providing method according to the present invention includes a video streaming service providing method comprising the steps of: receiving an n-times video transmission request of a current (1x-speed) transmission rate from a receiving side; And transmitting an I frame corresponding to n times the number currently being transmitted within a reference time, and including at least one P frame between each I frame.

VOD, Video, High Speed, MPEG, I Frame, P Frame

Description

How to provide high speed video streaming service {Method of providing video streamin service having higher times of rate}

1 is a view for explaining the principle of the prior art for high-speed video transmission when transmitting 30 frames per second at 1x transmission.

2 is a view for explaining the principle of the prior art for high-speed video transmission when transmitting 15 frames per second in 1x transmission.

3 is a view for explaining a preferred embodiment of the present invention.

4 is a view for explaining another preferred embodiment of the present invention.

The present invention relates to a method of providing a high speed video streaming service, and more particularly, in a method of providing a real time video streaming service such as a VOD, for minimizing a quality deterioration such as an interruption of a screen in response to a request of a high speed screen transmission from a receiver. A high speed video streaming service is provided.

VOD (Video On Demand) refers to a new concept of video service that provides video-based services such as movies and news through telephone lines or cables according to the needs of service users. VOD service is a service that compresses a video program into a digital server and stores it in a video server, and provides a program desired by a subscriber through a high-speed communication network. The user can select, play, control, index search, and query a program. It is also possible to freely adjust the video playback speed.

The principle of data compression of the Moving Picture Experts Group (MPEG) is as follows. When a video composed of 30 frames per second is decomposed by frame, frames before and after a specific frame have many overlapping elements with the specific frame. In general, M-JPEG-based compression does not consider superposition of front and rear frames at all and only targets the current frame to be compressed. However, when MPEG plays frames sequentially, the frames before and after most of them have a lot of overlapping elements. Therefore, the overlapped parts are compressed without being compressed. . Since the data of the overlapped portion tracks the movement of the data and records only the coordinates of the movement, only the data about the movement relatively smaller than the original image data is stored.

MPEG has a form called group of pictures (GOP), which is composed of I frames (Index frames), B frames (Bi-Directional frames), and P frames (Predicted frames). An I frame is a frame that is an index of a subsequent B frame and a P frame and contains complete data of one frame. The following B frame analyzes the data of the front and rear frames and has data on the movement traces of the non-overlapping data and the overlapping data. The P frame contains data about the non-overlapping data about the current frame and the frame immediately before it, and a movement trace of the overlapping data. B frames and P frames cannot recover one complete frame separately.

In a conventional video streaming service such as VOD, when a user requests a fast forward (FF), only a proper number of I frames are transmitted to enable high speed video playback. Since the I frame is independently coded regardless of predictive coding, random access is possible, and the decoder can independently reproduce the information without information on neighboring P or B pictures. Therefore, in the related art, when a request for high speed transmission is received, the server transmits only I frames.

1 and 2 illustrate a conventional principle in which a server uses only I frames when a user requests high-speed video transmission and playback such as 2x and 3x speed through a fast forward (FF) command during a video on demand (VOD) service. It is a figure for demonstrating. Fig. 1 shows an example of video transmission of 30 frames per second in case of 1x transmission, and Fig. 2 shows an example of video transmission of 15 frames per second. The structure of the image shows a structure in which M = 3 and N = 15, which are the most commonly used structures. That is, the interval between I frames is 15 frames and the interval between P frames is 3 frames. In this case, the number of video frames corresponding to one second is 30 frames in total, and two of them become I frames.

As shown in FIG. 1, in the prior art, when a double speed transmission request is received, only two I frames of I1, I2, I3, and I4 need to be transmitted for one second because image information corresponding to two seconds is transmitted for one second. Will be sent. In this case, the screen rate per second is 4 fps (frame per second). When a 3x request is received, only 6 I frames, such as I1, I2, I3, I4, I5, and I6, corresponding to 3 seconds of information are transmitted for 1 second, so the screen rate per second becomes 6 fps. Likewise, in case of 5 times, 10 frames are transmitted from I1 to I10.

As described above, in the prior art, since the high speed transmission is performed using only I frames, the screen rate transmitted for each double speed is changed depending on the frame structure of the video. In the example of FIG. 1, 4 fps (frame per second) at 2x speed and 6 fps at 3x speed generally fall short of the maximum supportable screen rate of 30 fps. When the screen ratio is very low, the video serviced by the user has a problem that the unnatural video service is interrupted.

The present invention has been made to solve the problems of the prior art as described above, in the method of providing a real-time video streaming service, such as VOD, to minimize the quality degradation such as the screen is cut off in response to the request for high-speed transmission of the transmission side It is to provide a high speed video streaming service providing method.

Summary of the Invention

A high speed video streaming service providing method according to the present invention includes a video streaming service providing method comprising the steps of: receiving an n-times video transmission request of a current (1x-speed) transmission rate from a receiving side; And transmitting an I frame corresponding to n times the number currently being transmitted within a reference time, and including at least one P frame between each I frame.

Preferably, at least one or more P frames included and transmitted between the two I frames are selected from the order closest to the previously transmitted I frame among the two I frames when the video streaming is transmitted at the current rate. . In addition, it is preferable to transmit information on the changed aspect ratio to the receiving side at the time of n-times transmission of video streaming.

Example

Hereinafter, a preferred embodiment of a method for providing a high speed video streaming service according to the present invention will be described with reference to the accompanying drawings.

In the high-speed transmission using only I frames described with reference to FIGS. 1 and 2, the final transmission aspect ratio for the n-speed command is expressed as 2 x n fps (frame / sec). If a user requests a double speed service after receiving 30 VPS of service at 30 fps, the screen rate drops sharply to 4 fps. In order to solve this problem, the present invention proposes a method of implementing a high-speed transmission service that reduces the subjective picture quality degradation felt by a user using P frames in addition to I frames.

3 is a view for explaining a preferred embodiment of the present invention. In FIG. 3, 30 frames are transmitted by combining two I frames (I1, I2), 28 B frames, and 28 P frames in a unit time (1 second). In the case of double speed, as shown in Fig. 3, four I frames are included within a unit time, and four P frames are included between any two I frames to maintain the overall aspect ratio at 20 fps. In the case of 3x speed, six I frames are included within a unit time, and four P frames are included between any two I frames to maintain the overall aspect ratio of 30 fps.

In the case of 4x speed, 8 I frames are included in unit time and 2 P frames are included between any two I frames to maintain 24 fps. A frame, one P frame was included between two I frames to maintain 20 fps.

On the other hand, P frames included between the two arbitrary I frames in the high-speed transmission are in the order closest to the previously transmitted I frame among the two I frames when the video streaming is transmitted at the current rate (1x speed). The frames are located. Since P frames are encoded by using the omni-prediction coding technique, only the I or P frames immediately preceding in time are decoded during decoding. Therefore, since encoding and decoding are possible independently of a P frame located later in time, there is no problem when the P frames are included in the high-speed transmission service in a temporal order.

4 illustrates a high-speed transmission method according to the present invention when 1x transmission is 15 fps and M = 3 and N = 15. In FIG. 5, 15 frames are transmitted by combining one I frame I1, 14 B frames, and 14 P frames in a unit time (1 second). In the case of double speed, as shown in Fig. 4, two I frames are included within a unit time, and four P frames are included between any two I frames to maintain the overall aspect ratio at 10 fps. In the case of 3x speed, three I frames are included within a unit time, and four P frames are included between any two I frames to maintain the overall screen rate of 15 fps.

In the case of 4x, 4 I frames are included within the unit time, and 2 P frames are included between any two I frames to maintain a 12 fps refresh rate. Frame, one P frame was included between two I frames to maintain 10 fps.

It is desirable to deliver information about the changed aspect ratio to the user side at high speed transmission. Aspect ratio values required for high-speed transmission such as 20, 24, and 30 fps can be arbitrarily adjusted using vop_time_increment_resolution and fixed_vop_time_increment in the MPEG-4 video object layer header. That is, information about 10, 12, 15, 20, 24, and 30 fps can be delivered to the user by assigning the following values.

10 fps: vop_time_increment_resolution = 10, fixed_vop_time_increment = 1

12 fps: vop_time_increment_resolution = 12, fixed_vop_time_increment = 1

15 fps: vop_time_increment_resolution = 15, fixed_vop_time_increment = 1

20 fps: vop_time_increment_resolution = 20, fixed_vop_time_increment = 1

24 fps: vop_time_increment_resolution = 24, fixed_vop_time_increment = 1

30 fps: vop_time_increment_resolution = 30, fixed_vop_time_increment = 1

On the other hand, since the screen ratio changes when high-speed transmission is performed, the vop_time_increment information of the video object plane (VOP) header information of each screen must also be newly set. In the present invention, since all vop_time_increment is increased by 1 for each VOP, the value is increased as follows according to each screen ratio.

10 fps: 0, 1, 2, 3, 4, ..., 10

12 fps: 0, 1, 2, 3, 4, ..., 12

15 fps: 0, 1, 2, 3, 4, ..., 15

20 fps: 0, 1, 2, 3, 4, ..., 20

24 fps: 0, 1, 2, 3, 4, ..., 24

30 fps: 0, 1, 2, 3, 4, ..., 30

It is apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

When P frame is included in the high speed video transmission function of the video streaming service, a high quality high speed transmission service can be maintained at a screen rate close to 15 fps or 30 fps, which means that the user feels subjective. There is an effect of increasing the quality of.

Claims (3)

In the video streaming service providing method, Receiving an n-times video transmission request of the current (1x-speed) transmission rate from the receiving side; And A method of providing a high speed video streaming service comprising transmitting an I frame corresponding to n times the number currently being transmitted within a reference time, and including at least one P frame between each I frame. The method of claim 1, At least one or more P frames included and transmitted between the two I frames are selected from the order closest to the previously transmitted I frame among the two I frames when the video streaming is transmitted at the current rate. How to provide high speed video streaming service. The method according to claim 1 or 2, and transmitting information regarding the changed aspect ratio to the receiving side during n-speed transmission.

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