KR20070064750A - Receiver and method for receiving digital broadcast - Google Patents

Abstract

A digital broadcasting receiver and a method for receiving digital broadcasting thereof are provided to reproduce an inter picture even though recording of the inter picture is firstly performed, thereby maximally restoring a recorded image without loss. A tuner(205) receives digital broadcasting. A system decoder(210) decodes an MPEG(Moving Picture Experts Group)-2 TS(Transport Stream), which is received by the tuner(210), to an AU(Access Unit). A video decoder(220) video-decodes the AU. A reference image buffer unit(225) temporarily stores an intra picture among video-decoded image as a reference image. A still image codec unit(240) codes an image within the reference image buffer unit to a still image at the recording time. A memory(250) stores the received MPEG-2 TS and the coded still image.

Description

Receiver and method for receiving digital broadcast

1 is a diagram illustrating an exemplary image frame configuration of terrestrial DMB.

2 is a schematic structural block diagram of a digital broadcast receiver according to the present invention.

3 is a schematic flowchart of a digital broadcast receiving method according to the present invention.

<Description of the symbols for the main parts of the drawings>

200: broadcast receiver 205: tuner unit

210: system decoder unit 215: AU buffer unit

220: video decoder 225: reference image buffer

230: output image buffer unit 235: display unit

240: Still image codec unit 250: Memory unit

255: TS buffer unit

The present invention relates to digital broadcast reception, and more particularly, to a digital broadcast receiver and a reception method capable of receiving and recording digital broadcast.

Taking digital terrestrial DMB broadcasting as an example, the recording and reproduction of conventional digital broadcasting will be described.

The terrestrial DMB receiver demuxes MPEG-2 Transport Stream (TS) transmitted from a terrestrial broadcasting station to receive terrestrial DMB video and audio data, and then decodes an MPEG-4 SL (Sync Layer) packet. Extract AU (Access Unit) which is the minimum unit of video and audio. The extracted AU is restored through video and audio decoders so that the user can see or hear it. When the user starts recording, it is stored in the memory in the form of MPEG-2 TS, and when playing, the MPEG-2 TS is read / decoded from the memory for playback.

However, in order to increase the compression ratio of a video, a broadcasting station transmits a lot of images encoded in a form in which a ratio of an inter picture is considerably higher than an intra picture. Here, an intra picture (I picture) is a picture that forms the basis of an image that does not require motion prediction from another picture when reconstructed, and an inter picture is a picture that requires motion prediction from another picture when reconstructed. The inter picture is divided into a P picture (Predictive Picture) and a B picture (Bidirectional Picture). Terrestrial DMB uses H.264 for video compression, so only terrestrial DMB video has I picture and P picture. That is, in the terrestrial DMB video, one preceding I picture is required as a reference picture for reconstruction of the P picture, which is an inter picture.

A problem that may occur during video recording and playback of terrestrial DMB is described below with reference to FIG. 1. 1 is a diagram illustrating an exemplary image frame configuration of terrestrial DMB.

As shown in FIG. 1, assume that a picture is stored from a P picture P ₃ at the start of video recording. Although be restored from this case, when reproducing the recorded data P-picture (P _3), and the P-picture (P ₃₎ can not be restored because there is no preceding the I picture (I ₁₎ for the motion prediction. This problem continues until the turn of the I picture (I ₂ ) following the P picture (P ₃ ). Therefore, when recorded in this way, a problem occurs that the viewer cannot see the first recorded portions P ₃ to P ₅ . Such a problem may occur when recording / reproducing not only terrestrial DMB broadcasting but also all digital broadcasting using intra picture and inter picture including satellite DMB broadcasting and terrestrial / satellite digital TV broadcasting.

The present invention has been proposed to solve the above problems, and the digital broadcast receiver and the reception method capable of restoring the recorded image as much as possible without loss by allowing the inter picture to be reproduced even when recording from the inter picture when the digital broadcast is recorded. To provide that purpose.

In order to achieve the above object, the present invention provides a digital broadcast receiver capable of recording a digital broadcast, comprising: means for storing an intra picture for a digital broadcast video at the start of recording, and at the time of reproduction of the recorded digital broadcast, A digital broadcast receiver comprising a means for reproducing an intra picture as a reference picture.

In order to achieve the above object, the present invention provides a tuner unit for receiving digital broadcasting, a system decoder unit for decoding MPEG-2 Transport Stream (TS) received by the tuner into an access unit (AU), and the AU A video decoder for decoding a video, a reference image buffer for temporarily storing an intra picture among video decoded images as a reference image, and for coding an image in the reference image buffer at the start of recording as a still image. And a memory for storing the received MPEG-2 TS and the coded still image.

In addition, to achieve the above object, the present invention, receiving the MPEG-2 TS of digital broadcasting, decoding the received MPEG-2 TS into an access unit (AU), video decoding the AU, Temporarily storing an intra picture of the video decoded picture as a reference picture, restoring an inter picture of the video decoded picture based on the reference picture, and starting the recording Coding a still image and storing the coded still image and the received MPEG-2 TS.

Hereinafter, with reference to Figures 2 and 3 attached to a preferred embodiment of the present invention that can specifically achieve the above object.

Hereinafter, the present invention will be described by taking the terrestrial DMB service currently being promoted in Korea among various digital broadcasting services. However, the present invention is not limited to the terrestrial DMB service and can be applied to all digital broadcasts using intra picture and inter picture, including satellite DMB broadcast and digital TV broadcast.

2 is a schematic structural block diagram of a digital broadcast receiver according to the present invention, and FIG. 3 is a schematic flowchart of a digital broadcast receiving method according to the present invention.

The digital broadcast receiver 200 receives the MPEG-2 TS of the terrestrial DMB transmitted from a broadcasting station through the tuner 205 [S31].

The received MPEG-2 TS is transmitted to the system decoder 210 and decoded (or demuxed) into an access unit (AU) [S32]. Although not shown in detail in FIG. 1, the MPEG-2 TS is extracted to the AU through an MPEG-TS, a Packetized Elementary Stream (PES), and an MPEG-4 Synchronization Layer (SL) decoder in the system decoder 210.

The AU is transferred to the video decoder 220 through the AU buffer unit 215. The video decoder 220 decodes the AU into an I picture and a P picture, and reconstructs an image for final display from the I picture and the P picture [S33].

In detail, the decoded I picture is once stored in a reference picture buffer unit and used as a reference picture for determining motion prediction when reconstructing a P picture after the I picture. That is, each time an I picture is generated, the reference picture buffer unit is temporarily stored to be used for reconstruction of a subsequent P picture [S34, S35].

The output image reconstructed by the video decoder 220 is temporarily stored in the output image buffer 230 and then transferred to the display unit 235 [S36].

When the user starts broadcast recording while receiving [S37], the I picture in the reference picture buffer unit 225 at the start of recording is coded as a still picture through the still picture codec unit 240 [S38].

The coded still image is stored in the memory unit 250 while the received MPEG-2 TS after the start of recording is stored in the memory unit 250 via the TS buffer unit 255 [S39].

Therefore, when the user plays back the recorded image, the still image of the memory unit 250 is decoded as an I picture through the still image codec unit 240 and then input to the reference image buffer unit 225. . In addition, the MPEG-2 TS stored in the memory unit 250 is input to the system decoder unit 210 through the TS buffer unit 255, and the MPEG-2 TS input to the system decoder unit 210 is described above. It is displayed on the display unit 235 in the same manner as the image display procedure at the time of receiving a broadcast. Therefore, even if the memory unit 250 is stored from the MPEG-2 TS corresponding to the P picture, the P picture may be properly reconstructed as an output image through the motion prediction from the I picture of the reference image buffer unit 225. Can be.

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.

The effects of the digital broadcast receiver and the reception method according to the present invention described above are as follows.

As described above, according to the present invention, even if the inter picture is recorded from the digital broadcast, the inter picture can be reproduced, so that the recorded image can be restored as much as possible without loss.

Claims (9)

In a digital broadcast receiver capable of recording digital broadcasts, Means for storing an intra picture for the digital broadcast video at the start of recording; And And means for reproducing the stored intra picture as a reference image when reproducing the recorded digital broadcast. A tuner unit for receiving digital broadcasting; A system decoder for decoding the MPEG-2 Transport Stream (TS) received by the tuner into an access unit (AU); A video decoder for video decoding the AU; A reference image buffer unit for temporarily storing an intra picture among video decoded images as a reference image; A still image codec unit for coding an image in the reference image buffer unit as a still image at the start of recording; And And a memory for storing the received MPEG-2 TS and the coded still image. The method of claim 2, And the still image codec unit reads / decodes the still image stored in the memory and transfers the still image stored in the memory to the reference image buffer unit. The method of claim 3, wherein And the system decoder reads the MPEG-2 TS stored in the memory and decodes the AU at the start of playback. The method of claim 4, wherein The video decoder unit decodes the AU decoded from the MPEG-2 TS stored in the memory, and restores the inter picture among the video decoded images by using the still image read / decoded by the still image codec unit as a reference image. Digital broadcast receiver characterized. Receiving an MPEG-2 TS of digital broadcast; Decoding the received MPEG-2 TS into an access unit (AU); Video decoding the AU; Temporarily storing an intra picture of the video decoded picture as a reference picture; Restoring an inter picture of the video decoded picture based on the reference picture; And And coding the reference picture as a still picture at the start of recording, and storing the coded still picture and the received MPEG-2 TS. The method of claim 6, And reading out / decoding the still image stored in the memory and temporarily storing the still image as a reference image at the start of playback. The method of claim 7, wherein And reading out the stored MPEG-2 TS and decoding the stored MPEG-2 TS at the start of playback. The method of claim 8, Video decoding the AU decoded from the MPEG-2 TS stored in the memory, and reconstructing the inter picture among the video decoded images by using the still image read / decoded by the still image codec unit as a reference image. Digital broadcast receiving method, characterized in that.

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