KR100871239B1 - Method for reproducting image in digital multimedia broadcasting - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal for improving the stoppage of a broadcast which may occur when receiving a digital broadcast. The present invention provides a function of checking data loss of transport stream packets constituting each frame. Improve freezes.

Terrestrial Digital Multimedia Broadcasting (DMB), Transport Stream, Frame

Description

Image playback method of digital multimedia broadcasting {METHOD FOR REPRODUCTING IMAGE IN DIGITAL MULTIMEDIA BROADCASTING}

1 is a flowchart of a conventional digital broadcast service video reproduction process;

2 is a diagram illustrating an existing frame process;

3 is a block diagram of a digital multimedia broadcasting (DMB) receiving terminal according to an embodiment of the present invention;

4 is a block diagram illustrating a video frame according to an embodiment of the present invention;

5 is a configuration diagram of a transport stream according to an embodiment of the present invention;

6 is a flowchart illustrating a process of playing a digital broadcast service video according to an embodiment of the present invention;

7 is an exemplary frame processing diagram according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to terrestrial digital multimedia broadcasting (DMB), and more particularly, to a method of reproducing an image during a broadcast service.

In general, digital broadcasting is to digitally transmit a broadcast signal that has been transmitted in an analog manner in order to provide a user with high quality, high sound quality, and more various services. Such digital broadcasting may be of various types such as Digital Video Broadcasting-Terrestrial (DVB-T), Digital Audio Broadcasting (DAB), Digital Multimedia Broadcasting (DMB), MediaFLO, and Digital Video Broadcasting-Handheld (DVB-H).

Among these, terrestrial DMB is a technology standard established to provide terrestrial digital broadcasting with high reception rate to mobile terminals, and it is possible to implement digital multimedia broadcasting that can provide high quality and high quality broadcasting or contents anytime and anywhere, even while driving or walking. Can be.

The terrestrial digital broadcast receiving terminal generates a video frame by receiving a packet of a transport stream as shown in FIG. 1 and checks whether data of the generated frame is lost. The terrestrial digital broadcast receiving terminal outputs a video frame to the display unit according to the test result. In this process, when the terrestrial digital broadcast receiving terminal loses data in one of the P-frames as in the case of 201 shown in FIG. 2, the terrestrial digital broadcast receiving terminal outputs all the P-frames to the display unit until the next I-frame is received. Throw it away. When data loss occurs in an I-frame as in the case of 202 of FIG. 2, the terrestrial digital broadcast receiving terminal discards all P-frames until the next I-frame is received. According to the data loss test result of the frame, the terrestrial digital broadcast receiver terminal may freeze while performing a broadcast service. That is, when the data of the frame is lost, there is a problem that the broadcast screen is stopped for a maximum of 1 to 2 seconds. In addition, such a screen freeze has a problem of causing fatigue and rejection of DMB broadcasting to viewers watching DMB broadcasting.

Accordingly, the present invention provides a video reproducing method for improving a screen freeze during a DMB broadcasting service.

In addition, the present invention provides a method for reproducing an image of a viewer, which can reduce fatigue and rejection caused by a screen freeze.

In order to solve the above problems, in a video reproducing method during a digital multimedia broadcasting service, a transport stream packet corresponding to a channel selected by a user is received to check whether data loss has occurred, and a transport stream having data loss as a result of the inspection. If the packet is associated with a P-frame, the transport stream packets that can generate the current P-frame are removed, and if the transport stream packet with data loss is associated with the I-frame, the packet of the transport stream corresponding to the next I-frame is lost. It is characterized in that all transport streams are removed until receiving the data, the data loss is detected for the next transport stream packets received, and if the data loss does not occur as a result of the inspection, the video is normally played.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

3 is a block diagram of a digital multimedia broadcasting (DMB) receiving terminal according to a preferred embodiment of the present invention. Referring to Figure 3 will be described the configuration of a mobile terminal according to the present invention.

The terrestrial DMB receiving unit 305 performs a function of wirelessly receiving a transport stream broadcast from a digital broadcasting device (not shown). Particularly, in the present invention, the terrestrial DMB receiving unit 305 is requested by the user for digital broadcasting, and when a channel to be broadcast is selected, a multiplexing unit of the control unit 301 receives a transport stream (TS) packet from the corresponding channel. Send to 315.

The transport stream packet includes information for performing a digital multimedia broadcasting service, and this transport stream packet will be described in detail with reference to FIGS. 4 and 5. 4 illustrates a configuration of a transport stream packet and a configuration of a video frame (PES) according to a preferred embodiment of the present invention. Referring to FIG. 4, the transport stream packet 401 includes program configuration information (PMT) and audio / video frame fragment information. In more detail, in the transport stream packet 401 including the transport stream header 403 and the transport stream payload 405, the payload 405 is an audio / video. Frame fragment information and the like. Therefore, in the present invention, the terrestrial digital broadcast receiving terminal receives packets of at least one transport stream, extracts audio / video frame fragment information from the payload of the received transport stream packets, and generates one audio frame or video frame. . For example, assuming that four transport stream packets constitute one video frame (PES), the terrestrial digital broadcast receiving terminal receives a video frame from the payload portion of four transport stream packets 407, 409, 411, and 413. The fragment information may be extracted to generate one video frame (PES) 415.

The configuration of the header portion 403 of the transport stream packet 401 shown in FIG. 4 will now be described with reference to FIG. 5. The header portion 501 of the transport stream packet includes a transport error indicator bit 503, a payload unit start indicator 505, a frame acknowledgment bit 511 and a random access indicator 511; A program indicator (PID) 507 or the like. The header portion 501 of the transport stream packet includes a counter bit (continuity counter) 509.

The transmission error identification bit 503 indicates whether the corresponding transport stream packet is a normal packet or an error packet. For example, when the setting value of the transmission error identification bit 503 is '1', it indicates that an error has occurred in the transport stream packet, and when it is '0', it indicates that no error occurs in the transport stream packet.

The program identification code (PID) 507 enables to extract the audio / video frame fragment information included in the received transport stream packet, respectively.

The frame start identification bit 505 indicates which packet is the first transport stream packet when generating one video frame from several transport stream packets. For example, when generating one video frame (PES) 415 with four transport stream packets 407, 409, 411, and 413 shown in FIG. 4, the first video frame fragment information is included. The first transport stream packet 407 must be known. At this time, the frame start identification bit 505 is used. That is, the frame start identification bit 505 included in the header portion of the TS1 407 is set to '1' and is included in the header portion of the TS2 409, TS3 411, and TS4 413. The frame start identification bit 505 is set to '0'. Therefore, when the frame start identification bit 505 is '1', the multiplexing unit 315 recognizes the first transport stream packet 407 including the first video frame fragment information.

The frame confirmation identification bit 511 indicates whether the video frame fragment information of the transport stream packet is information corresponding to an I-frame or information corresponding to a P-frame. For example, when the setting value of the frame acknowledgment identification bit 511 is '1', it may be regarded as a transport stream packet corresponding to an I-frame, and when it is '0', it may be regarded as a transport stream packet corresponding to a P-frame. have. In this case, the I-frame is still image information representing the entire screen and is commonly called a key frame. This I-frame contains all the information to decode, creating a complete picture. The P-frame is image information that is changed from the previous frame among the entire screens, and a normal image screen can be generated only when the previous frame exists.

The counter bit 509 indicates whether transport stream packets are transmitted properly. For example, it can be seen that the transport stream packet is not lost when the counter bit 509 of each transport stream packet is continuously increased, and that the transport stream packet is lost when the stream bit is discontinuously increased.

The multiplexing unit 315 of the control unit 301 receives the transport stream packet configured as described above, extracts the audio frame fragment information and the video frame fragment information, and transmits the extracted audio frame fragment information to the audio / video decoder unit 303 of the control unit 301. do. When separating the audio frame fragment information and the video frame fragment information from the transport stream packet, the terrestrial DMB receiving unit 305 uses a program identification code (PID) 507. In more detail, the multiplexing unit 315 extracts the program identification code 507 of the audio / video frame from the header unit 403 of the transport stream packet 401. The multiplexing unit 315 extracts frame fragment information corresponding to the program identification code of the audio frame from the payload unit 405 of the transport stream packet 401, and extracts the frame fragment information corresponding to the program identification code of the video frame. Extract. Thereafter, the multiplexing unit 315 transmits the extracted audio / video frame fragment information to the audio / video decoder unit 303 of the controller 301.

The sound processor 307 converts the audio signal output from the controller 301 into an audible sound or converts an audible sound input from the outside into a voice signal.

The key input unit 309 is composed of numeric keys (including * and # keys) for viewing digital broadcasts and function keys for various functions, and generates a key signal corresponding to a key pressed by the user to control the controller 301. Will output

The memory unit 311 stores data necessary for controlling the digital broadcast receiving terminal.

The display unit 313 displays the current state of the digital broadcast receiving terminal and the operating state of the digital broadcast receiving terminal under the control of the control unit 301. In general, the display unit 313 is a liquid crystal display (LCD) and organic light emitting diodes (OLED). Can be configured.

The controller 301 controls each part of the terrestrial DMB receiving terminal to perform a digital multimedia broadcasting service. In particular, in the present invention, the multiplexing unit 315 of the control unit 301 sequentially lists the transport stream packets when the transport stream packets are input from the terrestrial DMB receiver 305. The multiplexing unit 315 checks the data loss of each transport stream packet, extracts audio / video frame fragment information from the payload unit of the transport stream packets, and extracts audio / video frame fragment information from the payload unit of the transport stream packets. 303). The audio / video decoder 303 generates one audio frame and one video frame using audio / video frame fragment information.

The operation of the multiplexer 315 of the controller 301 will be described in more detail. When a plurality of transport stream packets constituting one video frame are sequentially input, the multiplexer 315 is configured to transmit each transport stream. Check for data loss in the packet. If data loss is found as a result of the check, the audio / video decoder unit 303 checks whether the lost transport stream packet is a transport stream packet that can constitute an I-frame or a transport stream packet that can constitute a P-frame. Do. If the lost transport stream packet corresponds to an I-frame, the multiplexing unit 315 starts from the present and transport stream packets corresponding to the current I-frame until the transport stream packet corresponding to the next I-frame is input. Remove all incoming transport stream packets. If the lost transport stream packet corresponds to a P-frame, the multiplexer 315 removes all transport stream packets corresponding to the current P-frame.

The audio / video decoder 305 of the controller 301 generates an I-frame or a P-frame from frame fragment information input from the multiplexing unit 315. In this process, if the frame fragment information is information constituting the I-frame, the audio / video decoder 305 generates an I-frame using only the input frame fragment information. However, if the frame fragment information is information constituting the P-frame, the audio / video decoder 305 generates a P-frame using the input frame fragment information and previous frame information (I-frame or P-frame). .

So far, the configurations of the terrestrial digital broadcasting receiver terminal and the transport stream packet have been described. The operation of the terrestrial digital broadcasting receiver according to the present invention will now be described with reference to FIGS. 6 and 7. 6 is a flowchart of a digital broadcast service according to an embodiment of the present invention. 1 to 6, the operation of the terrestrial digital broadcast receiving terminal according to the present invention will be described.

When the digital multimedia broadcasting service is requested by the user and the channel is selected by the user in step 601, the multiplexing unit 315 of the terrestrial digital broadcast receiving terminal controller 301 receives one packet of a transport stream input from the terrestrial DMB receiving unit 305. Lists a number of transport stream packets that can constitute a video frame. In operation 603, the multiplexing unit 315 checks whether each of the input transport stream packets has data loss. At this time, the multiplexing unit 315 transmits the value of the transmission error identification bit 503 included in the header 403 of the transport stream packet 401 to '1' or the value of the counter bit 505 to the previous transmission. If it is not continuous with the value of the counter bit of the stream packet, it can be determined that the data of the current transport stream packet is lost. When the data loss of the transport stream packet 401 is found, the multiplexing unit 315 proceeds to step 605. If the data loss of the transport stream packet 401 is not detected, the multiplexing unit 315 proceeds to step 621. In operation 621, the multiplexer 315 extracts video frame fragment information and audio frame fragment information from the payload unit of a plurality of transport stream packets capable of generating one audio / video frame. The multiplexer 315 transmits the extracted video frame fragment information and the audio frame fragment information to the audio / video decoder 303. In operation 623, the audio / video decoder unit 303 of the controller 301 generates one video frame using the video frame fragment information transmitted in operation 621, and outputs one video frame to the display unit 313. At this time, the video frame generation method varies depending on whether the video frame fragment information constitutes an I-frame or P-frame.

In operation 605, the multiplexer unit 315 determines whether the currently lost transport stream packet 401 is a packet corresponding to an I-frame or a packet corresponding to a P-frame. At this time, no data loss occurs in the header portion 403 of the transport stream packet 401, and the frame acknowledgment bit 511 included in the header portion 403 of the transport stream packet 401 is set to '1'. If set, it can be recognized as a packet corresponding to an I-frame. If the frame check identification bit 511 is set to '0', it can be identified as a packet corresponding to the P-frame. If data loss occurs in the header portion 403 of the transport stream packet 401, the transport stream packet 401 corresponds to an I-frame by using a predetermined Instantaneous Decoding Refresh (IDR) period. Check if it is. The decoding reset (IDR) period is the number of frames from the current I-frame until the next I-frame is transmitted, and is used by the audio / video decoder 305. For example, if the video frame per second is 30 fps (frame per second) consisting of one I-frame and 29 P-frames, the decoding reset (IDR) period of the audio / video decoder unit 305 is 30 to 1. Will decrease by one per frame. Therefore, when the decoding reset (IDR) period is 30, the current transport stream packet 401 can be identified as a packet corresponding to the I-frame. As a result of checking in step 605, if the transport stream packet 401 corresponds to an I-frame, the flow proceeds to step 607, and if it corresponds to a P-frame, the flow proceeds to step 609.

In operation 607, the multiplexer unit 315 removes all transport stream packets until a transport stream packet corresponding to the next I-frame is input. The multiplexer 315 proceeds to step 611. Whether the transport stream packet corresponding to the next I-frame is input may be determined by a setting value of the frame acknowledgment identification bit 511 or a setting value of a decoding reset (IDR) period of the audio / video decoder 305.

In operation 609, the multiplexer unit 315 removes the transport stream packet corresponding to the current P-frame from the received transport stream packet, and proceeds to step 611.

In step 611, the multiplexer unit 315 terminates the digital broadcasting when the user requests the termination of the digital multimedia broadcasting service. If the termination of the digital multimedia broadcasting service is not requested, the multiplexer unit 315 proceeds to step 603 and proceeds with steps 603 to 623. Repeat the process.

7 is a diagram illustrating frame processing according to a preferred embodiment of the present invention. A case of frame processing according to the present invention will be described with reference to FIGS. 1 to 7. In the following description, it is assumed that a video frame per second is 30 fps including one I-frame and 29 P-frames, and the present invention will be described. A case 701 in which data of a transport stream packet 401 corresponding to a P-frame is lost and a case 711 in which data of a transport stream packet 401 corresponding to an I-frame are lost will be described as an example.

In case 711, when the data of the transport stream packet 401 corresponding to the I1 frame 713 is lost, the multiplexer unit 315 drops all transport stream packets until the next I-frame, I2 frame 715, is input. Remove Therefore, when data of a transport stream packet corresponding to an I-frame is lost, a screen freeze of up to 1-2 seconds may occur.

However, in another case 701, when data of the transport stream packet 401 corresponding to the P6 frame 705 is lost, the multiplexer 315 of the controller 301 removes all transport stream packets corresponding to the P6 frame 705. . The multiplexer 315 checks whether data of the transport stream packets corresponding to the P7 frame 707 are lost or not. If not, the multiplexer 315 extracts the video frame fragment information included in the transport stream packets to determine the audio / audio of the controller 301. The video decoder 303 transmits the data. The audio / video decoder 303 receives video frame fragment information corresponding to the P7 frame 707. Since the video frame corresponding to the P6 frame 705 is not generated, the audio / video decoder 303 uses the video frame information corresponding to the P5 frame 705 and the video frame fragment information of the P7 frame 707. P7 frame 707 is generated. Due to this process, when data of a transport stream packet corresponding to a P-frame is lost, a broadcast can be output with minimal screen loss without causing a screen freeze.

In the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. For example, when data of transport stream packets corresponding to the P6 frame 705 and the P7 frame 707 are lost in FIG. 7, the P5 frame 703 may be referred to when generating a P8 frame (not shown). have. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined not only by the claims but also by the equivalents of the claims.

As described above, according to the present invention, a method of improving a screen freeze during a digital multimedia broadcasting (DMB) broadcasting service can be provided, and a method for resolving a viewer's fatigue and rejection caused by the screen freeze can be provided. Can provide.

Claims (8)

delete In the video reproduction method of digital multimedia broadcasting, Receiving transport stream packets corresponding to a channel selected by a user and checking whether data loss has occurred; If the test result indicates that the transport stream packet that caused the data loss is associated with the P-frame, the transport stream packets that may generate the current P-frame are removed. Removing all transport streams until a packet of a transport stream corresponding to a frame is received, and checking whether data loss has occurred for the next received transport stream packets; If the data loss does not occur as a result of the inspection includes the step of playing the video normally, If data loss does not occur as a result of the inspection, the step of reproducing the image normally, If a transport stream packet having no data loss caused by the inspection is associated with a P-frame, video frame fragment information extracted from transport stream packets that can generate a current P-frame and a recently received normal P-frame If a transport stream packet that generates a current P-frame with information and no data loss occurs by the check is associated with an I-frame, the transport stream packet associated with a recently received I-frame that has not caused the data loss. And generating a current I-frame from the video frame fragment information extracted from the video data. The method of claim 2, wherein the determining whether the data loss occurs comprises checking whether the data loss occurs by setting a value of a transport error indicator included in a header of the transport stream packet. How to play video. The method of claim 2, wherein the determining whether the data loss occurs comprises checking whether the data loss occurs based on a value of a continuity counter included in a header of the transport stream packet. . The method of claim 2, wherein the transport stream packet is identified by a frame access random bit. 3. The method of claim 2, wherein the association of the transport stream packet with the P-frame is determined by a predetermined Instantaneous Decoding Refresh (IDR) period value. 3. The method of claim 2, wherein the transport stream packet is identified by a frame access identification bit (random access indicator). The method of claim 2, wherein the transport stream packet is associated with an I-frame by a predetermined Instantaneous Decoding Refresh (IDR) period value.

Images