KR20050050315A - Method of handling broadcasting channel and a/v device thereof - Google Patents

Abstract

The present invention relates to a method for processing a broadcast channel and an A / V device using the same. The method for processing a broadcast channel according to the present invention comprises the steps of receiving a signal, determining whether it is a processable signal, and outputting a processable multimedia signal. The A / V apparatus for processing a broadcast channel according to the present invention comprises a receiver for receiving a signal, a video / audio signal processor for processing video and audio signals of the received multimedia signal, and an output for outputting a processable multimedia signal. According to the present invention, it is possible to decode only a multimedia signal that can be processed to deliver more information that can be provided to a user, to output an unprocessable message, to solve a user's question, and to stably operate an A / V device. It can be effective.

Description

Method of processing broadcast channel and A / V device using same {METHOD OF HANDLING BROADCASTING CHANNEL AND A / V DEVICE THEREOF}

As digital broadcasting has become a reality worldwide, commercialization of digital TVs and set-top boxes is accelerating as A / V devices for receiving them. Digital broadcasting also has a transitional form, such as OFDM and VSB, and HD and SD broadcasting.

The quality of digital broadcasting is more than compact disc (CD) and can reproduce more realistic sounds such as 5.1Ch. In terms of image quality, the SD class broadcast uses the double scan method and it can be used with conventional NTSC or PAL analogue. It is about twice as sharp as the method, and the aspect ratio of the screen supports both 4: 3/16: 9, and the HD broadcasting increases the number of scanning lines and the total number of pixels, and the aspect ratio. By supporting only 16: 9, it realizes about 5 times higher image quality than analog broadcasting to increase the realism. Typical digital broadcasting standards include MUSE in Japan, European Digital Video Broadcasting (DVB) jointly proposed by Europe, and Advanced Television (ATSC) in the United States.

However, when various broadcast channels are simultaneously transmitted as described above, there has been a problem that an A / V device that receives a channel signal that cannot be processed cannot properly output. For example, when the SD and HD channels are simultaneously transmitted in one frequency band, the SD set-top box receiving the HD broadcast channel determines whether the received multimedia signal is an SD or HD signal. Instead, the video and audio signals were decoded and output. Therefore, not only the user may be unaware that there is a problem with the set-top box, but there has been a problem that it is not possible to provide a speech signal as much as possible.

The present invention has been made to solve the above problems, when a multimedia signal is received in the A / V device having a limited performance, the A / V having a limited performance by decoding or output only the data that can be processed or output a message The purpose is to improve the performance of the device. It also aims to enable stable operation of A / V devices with limited performance by not processing unprocessable multimedia signals.

In order to achieve the above object, as an embodiment of the present invention will be described an SD-class set-top box device for processing an HD-class broadcast channel signal and a processing method using the same.

Advantages and features of the present invention, and a method of achieving the same will be apparent with reference to the embodiments described below in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be embodied in various forms beyond the embodiments, and the embodiments described herein are intended to complete the disclosure of the present invention, and to which the present invention pertains. It is provided to fully alert those skilled in the art to the scope of the invention, which is to be defined only by the claims and the description. In addition, like reference numerals refer to like elements throughout the specification.

In an embodiment of the present invention, a coding method of a multimedia signal is described based on MPEG-2. In another embodiment, a multimedia signal is coded and transmitted as a stream, such as MPEG-4, MPEG-7, and the like. By including the information on the stream can be applied to other transmission schemes.

For reference, MPEG-2 (Moving Picture Coding Experts Group / Moving Picture Experts Group2) video is a high efficiency coding scheme of video signals specified in H.262 recommended by ISO / IEC 13818-2 and ITU-T.

In one embodiment of the present invention, the SD class top-top apparatus for processing an HD broadcast channel includes a receiver for receiving a signal, a video / audio signal processor for processing a video signal and an audio signal of the received multimedia signal, and the determination unit. If it is determined that the HD video signal is decoded and outputs only the audio signal and outputs a message that the processing is not made.

According to an embodiment of the present invention, a method for processing an HD broadcast channel in an SD class set-top box device includes receiving a signal, determining whether the received signal is an HD video signal, and determining the HD signal. In the case of the video signal, only the audio signal is decoded and output, and a message indicating that the video signal cannot be processed is output.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating components of an SD class set-top box for processing an HD class broadcasting channel according to an embodiment of the present invention.

As shown in FIG. 1, an SD class set-top box apparatus for processing an HD-class broadcasting channel includes a receiver 11 for receiving a multimedia signal by a tuning method, and a video signal and an audio signal of the received multimedia signal. And a video / audio signal processor 13 and an output unit 15 for decoding and outputting a signal capable of being processed according to the determined kind of multimedia signal.

The video / audio signal processor 13 decodes an MPEG-2 coded video signal or processes an audio signal. The decoding process of the video signal will be described later with reference to FIG. 2.

The output unit 15 decodes and outputs only an audio signal when the SD set-top box receives an HD broadcast channel and outputs a message indicating that the video cannot be output because it is an HD signal. An operation process of the output unit 15 will be described later with reference to FIG. 7.

FIG. 2 is a diagram illustrating components of an MPEG-2 video decoder included in the video / audio signal processor 13 and determining a broadcast type according to an embodiment of the present invention.

As shown in Fig. 2, the MPEG-2 video decoder includes a stream input circuit 211, a buffer control circuit 212, a clock generation circuit 213, a start code detection circuit 214, a decoder 215, and motion compensation. An integrated circuit (IC) 21 composed of a circuit 216 and a display output circuit 217, a stream buffer 221, and a video buffer 222, for example, a DRAM (Dynamic Random Access Memory) It is comprised by the buffer 22 which consists of).

The stream input circuit 211 of the IC 21 receives a highly efficient coded stream and supplies it to the buffer control circuit 212. The buffer control circuit 212 inputs the input coded stream into the stream buffer 221 of the buffer 22 according to the basic clock supplied from the clock generation circuit 213. The stream buffer 221 has a capacity of 1,835,008 bits, for example, a VBV buffer size required for decoding of MP @ ML. The coded stream stored in the stream buffer 221 is sequentially read from the data written first and supplied to the start code detection circuit 214 under the control of the buffer control circuit 212.

The start code detection circuit 214 detects a start code from the input stream, and outputs the detected start code and the input stream to the decoder 215.

The decoder 215 decodes the input stream based on MPEG syntax. The decoder 215 first decodes the header parameter of the picture layer, decodes the slice layer into macroblocks based on the decoding parameter, and decodes the macroblock based on the start code, and compensates the resulting prediction vector and pixels for motion compensation. Output to the circuit 216. A process of determining the type of the signal received by the decoder 215 will be described later with reference to FIG. 6.

When the macro block output from the decoder 215 is using motion compensation, the motion compensation circuit 216 passes through the buffer control circuit 212 according to the prediction vector output from the decoder 215. Reference pixel data is read from the video buffer 222 of the buffer 22. The read reference pixel data is added to the pixel data supplied from the decoder 215 to perform motion compensation. The motion compensating circuit 216 writes the pixel data subjected to motion compensation to the video buffer 222 of the buffer 22 through the buffer control circuit 212 to prepare for the display output and the pixel data. Is prepared even when it becomes reference data of another pixel.

The display output circuit 217 generates a synchronous timing signal for outputting decoded image data, and reads pixel data from the video buffer 222 through the buffer control circuit 212 based on the timing. Output as a decoded video signal. Hereinafter, the MPEG-2 video bit stream will be described.

MPEG-2 coded streams are classified into classes determined by the coding method and levels determined by the number of pixels to be processed, so that they can correspond to a wide range of applications. For example, MP @ ML (Main Profile Main Level) is one of the classes, and is widely used in DVB (Digital Video Broadcast) and DVD (Digital Versatile Disk).

Profiles and levels are described in sequence_extension described later using FIG. 5 or FIG. In addition, in producing a video signal at a broadcasting station, a 4: 2: 2P (4: 2) in which a color difference signal of a video is processed in a 4: 2: 2 manner similar to a conventional baseband, and the upper limit of the bit rate is increased. : 2 profile). In addition, HL (high level) is defined to cope with next-generation high resolution video signals.

3 is a diagram illustrating a level structure of an MPEG-2 video bit stream.

As shown in Fig. 3, sequence_header is described first of the picture layer which is the highest layer. sequence_header defines header data of a sequence of an MPEG-2 bit stream. If sequence_extension is not followed by the first sequence_header of the sequence, the provisions of ISO / IEC 11172-2 apply to this bit stream. If sequence_extension follows the first sequence_header of the sequence, sequence_extension follows immediately after all sequence_headers that occur. That is, in the case shown in FIG. 5, sequence_extension follows immediately after all sequence_headers.

sequence_extension defines extension data of a sequence layer of an MPEG-2 bit stream. The sequence_extension only occurs immediately after the sequence_header and must not come immediately before the sequence_end_code located at the end of the bit stream, in order to avoid loss of frames after decoding and frame rearrangement. In addition, when sequence_extension occurs in the bit stream, picture_cording_extension follows immediately after each picture_header. Hereinafter, sequence_header and sequence_extension, which contain information about a video sequence, are collectively referred to as mode video sequence header information.

A plurality of pictures are included in the GOP (group_of_picture). The GOP_header defines the header data of the GOP layer of the MPEG bit stream, and data elements defined by picture_header and picture_coding_extension are described in this bit stream. One picture is coded as picture_data following picture_header and picture_coding_extension. Also, the first coded frame following the GOP_header is an I frame (ie, the first picture of the GOP_header is an I picture). In addition to sequence_extension and picture_cording_extension, various extensions are defined in ITU-T Recommendation H.262, but the illustration and description thereof are omitted here.

The picture_header defines header data of the picture layer of the MPEG bit stream, and the picture_coding_extension defines extension data of the picture layer of the MPEG bit stream.

picture_data describes data elements for a slice layer and a macroblock layer of an MPEG bit stream. As shown in Fig. 3, the picture_data is divided into a plurality of slices, and the slice is divided into a plurality of macro_blocks. The macro block is composed of 16 x 16 pixel data. Each block is composed of 8x8 pixel data.

Next to the picture_data, a sequence_header and a sequence_extension are arranged. The data elements described by this sequence_header and sequence_extension are very identical to the data elements described by sequence_header and sequence_extension described at the beginning of the sequence of the video stream. The reason for describing the same data in the stream in this way is that the reception of the data of the sequence layer can be received when the reception is started from the middle of the data stream (for example, the bit stream portion corresponding to the picture layer) on the bit stream receiving apparatus side. To prevent the stream from being decoded.

The 32-bit sequence_end_code that indicates the end of the sequence is described next to the data element defined by the last sequence_header and sequence_extension, that is, at the end of the data stream.

4 shows a data structure of sequence_header.

As shown in FIG. 4, the data elements included in the sequence_header are sequence_header_code, horizontal_size_value, vertical_size_value, aspect_ratio_information, frame_rate_code, bit_rate_value, marker_bit, vbv_buffer_size_value, constrained_parameter_flag, load_intra_quantiser_matratra, quantiser_matrix, intra_quantiser_matrix, intra_loader,

sequence_header_code is data indicating a start synchronization code of the sequence layer. The horizontal_size_value is data consisting of the lower 12 bits of the number of pixels in the horizontal direction of the image. The vertical_size_value is data consisting of the lower 12 bits of the number of vertical lines of an image. aspect_ratio_information is data indicating an aspect ratio (aspect ratio) or a display screen aspect ratio of a pixel. frame_rate_code is data indicating a display period of an image. bit_rate_value is the lower 18 bits of data of the bit rate for limiting the amount of bits generated.

And marker_bit is bit data inserted to prevent starting code emulation. vbv_buffer_size_value is lower-order 10-bit data of a value that determines the size of the virtual buffer VBV (Video Buffering Verifier) for generation coding amount control. constrained_parameter_flag is data indicating that each parameter is within a limit. load_non_intra_quantiser_matrix is data indicating the presence of quantization matrix data for non-intra-MB.

load_intra_quantiser_matrix is data indicating the presence of quantization matrix data for intra MB. intra_quantiser-matrix is data indicating the value of an intra MB quantization matrix. non_intra_quantiser_matrix is data indicating the value of a non-intra-MB quantization matrix.

5 shows a data structure of sequence_extension. sequence_extension consists of extension_start_code, extension_start_code_identifier, profile_and_level_indication, progressive_sequence, chroma_format, horizontal_size_extension, vertical_size_extension, bit_rate_extension, marker_bit, vbv_buffer_size_extension, low_delay, frame_rate_extension_n, and frame_rate_d_, etc.

extension_start_code is data indicating a start synchronization code of extension data. extension_start_code_identifier is data indicating what extension data is transmitted.

profile_and_level_indication is data for specifying a profile and level of video data. progressive_sequence is data indicating that the video data is sequential scanning (progressive picture). chroma_format is data for specifying a color difference format of video data. The horizontal_size_extension is upper two bits of data added to the horizontal_size_value of the sequence header. The vertical_size_extension is upper two bits of data added to the vertical_size_value of the sequence header.

Bit_rate_extension is upper 12 bits of data added to bit_rate_value of the sequence header. The marker_bit is bit data inserted to prevent starting code emulation. vbv_buffer_size_extension is the upper 8 bits of data added to vbv_buffer_size_value of the sequence header. low_delay is data indicating that the B picture is not included. frame_rate_extension_n is data for obtaining a frame rate in combination with frame_rate_code of a sequence header. frame_rate_extension_d is data for obtaining a frame rate in combination with frame_rate_code of a sequence header.

As described above, the MPEG2 stream has a hierarchical structure. The data amount of sequence_header to picture_coding_extension of the picture layer is not changed so much even when the profile and level are different. On the other hand, the amount of data below the slice layer depends on the number of pixels to be coded.

FIG. 6 is a table for classifying level information used when determining a broadcast signal type in an MPEG-2 video decoder according to an embodiment of the present invention.

When determining the type of the received signal, the profile_and_level_indication portion of the MPEG-2 coded video sequence header information, that is, the profile information and the level information, is examined. It is also possible to use only the level information in determining whether the HD signal.

The level information is classified by placing constraints on related variables in a specific profile. For example, what can be done is limiting the size of the image that can be accepted as input, although similar, making it more economical for different applications. The level information is defined as a low level, a main level, a high-1440 level, and a high level.

As shown in FIG. 6, when the level information is composed of four bit strings in the video sequence header information of the MPEG-2 coded signal according to an embodiment of the present invention, the level information corresponding to each bit string is Low level, Main. It can be classified into Level, High Level, and High-1440 Level. As described above with reference to FIG. 2, the MPEG-2 video decoder is responsible for decoding a video signal of a received broadcast signal. In the decoding process, header parameters are decoded and profile and level information are obtained from sequence_extension information. The level information extracted in the above process may be used to determine the type of broadcast signal received. For example, an MPEG-2 coded signal is received in a set-top box capable of processing SD-level signals, and the received signal is decoded. If the extracted level information bit string is 1010 or 1000 as a result of the processing, the received broadcast signal according to the table shown in FIG. 6 may be regarded as an SD class signal, and if the bit string is 0110 or 0100, it may be determined as an HD class signal. The correspondence of the level information with respect to the bit string may be implemented differently according to embodiments.

7 is a flowchart illustrating a method of processing a broadcast channel in an SD set-top box according to an embodiment of the present invention.

In the method for processing an HD broadcast channel in an SD set top box, the receiving unit receives a multimedia signal (S70) and the determining unit determines whether it is an HD video signal through a video sequence header of the received multimedia signal. In operation S74, the output unit decodes only the audio signal and outputs a banner message indicating that the video signal cannot be output because it is an HD broadcast channel on the screen.

In the reception step (S70), if there is no multimedia signal, the channel change command input standby state (S700) is maintained, and if there is a multimedia signal, the tuner receives the signal through tuning (S702). The receiving step S70 includes a case of receiving by means of a cable or satellite in addition to terrestrial waves.

In the determination step (S72) performs a syntax analysis (S720) for the packet identification data of the signal received in the reception step (S70). The video sequence header is examined (S722) through the syntax analysis (S720), and it is determined whether the signal is an HD signal based on the level information found through the sequence_extension of the received signal (S724). The determination process has been described with reference to FIGS. 5 and 6.

In the outputting step S74, when it is determined that the HD level signal is determined in the determination step S72, only the audio signal is decoded (S740) and output (S742), and a banner message indicating that it cannot be output because it is an HD level signal on the screen. It will be output (S744). On the other hand, if it is determined that the SD-class signal in the determination step, both the audio and video signals are decoded (S746) and output (S748).

In the step of decoding only the audio signal (S740), it is possible to efficiently operate the set-top box by stopping the decoding of the HD-quality video signal that cannot be processed in the SD-level set-top box.

The banner message output (S744) is to inform the user that the received signal cannot be processed in the set-top box. This may be implemented as a method of outputting a banner message on a screen as in the embodiment, using a variety of video signals and audio signals or outputting only an audio signal without any message.

In the above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. It is possible.

According to the present invention, in the case of a multimedia signal that cannot be processed in the A / V device, only the multimedia signal that can be processed is processed and outputted, thereby providing the user with more information that can be provided in the A / V device.

In addition, in the case of a non-printable multimedia signal, there is an effect that can solve the user's questions by outputting a message.

Next, by not decoding the unprocessed multimedia signal, there is an effect that can be operated stably by preventing the malfunction of the A / V device.

1 is a block diagram showing the components of an SD class set-top box for processing an HD class broadcasting channel according to an embodiment of the present invention.

2 is a diagram illustrating components of an MPEG-2 video decoder for determining a type of broadcast according to an embodiment of the present invention.

3 illustrates the level structure of an MPEG-2 video bit stream.

4 is a diagram showing a data structure of sequence_header.

5 is a diagram showing a data structure of sequence_extension.

FIG. 6 is a table for classifying level information used when determining a broadcast signal type in an MPEG-2 video decoder according to an embodiment of the present invention. FIG.

7 is a flowchart illustrating a method of processing a broadcast channel in an SD set-top box according to an embodiment of the present invention.

Claims (6)

A receiving step of receiving a multimedia signal coded with MPEG-2; Parsing the video sequence header information of the received multimedia signal to determine whether it is an SD signal; An output step of decoding and outputting a processable multimedia signal according to the determined result; And outputting an unprocessable message if the multimedia signal includes an unprocessable signal. The method of claim 1, wherein if it is determined as an HD signal in the outputting step, the method further comprises decoding and outputting only a voice signal. The method of claim 1, wherein the message in the outputting step comprises a banner message or a warning sound. A receiving unit for receiving a multimedia signal encoded in MPEG-2; A video / audio signal processor configured to decode the received video signal or audio signal and determine the type of the received video signal from the video sequence header information; And a output unit for decoding and outputting a processable video signal according to the determined result, and outputting a predetermined message when the multimedia signal includes an unprocessable signal. The set-top box apparatus of claim 4, wherein the output unit processes a broadcast channel for decoding and outputting only a voice signal when the output unit determines that the signal is an HD signal. 5. The set top box apparatus of claim 4, wherein the message at the output unit is a banner message or a warning sound.