KR20020056037A - sub-picture decoder architecture - Google Patents

Abstract

PURPOSE: A sub-picture decoder is provided to have a DVD(Digital Versatile Disk) playing function, to support display outputs such as 1080I, 720P, 480P besides an NTSC(National Television System Committee) or PAL(Phase Alternation by Line system) display output in a DVD player. CONSTITUTION: Mux units(34,35) respectively output temporarily stored stream data to 4 bits indexed color information and bitmap type contrast information. An external memory(20) stores information data decoded and outputted in the mux units by a predetermined unit. A PLT(Palette) unit(51) detects 8 bits of extended sub-picture data of Y, Cb, Cr, using the indexed color information stored in the external memory. FCs(Format Converters:70,80) convert the extended sub-picture data and the contrast information by predetermined units, appropriately to a current display output. And a blending unit(90) blends the sub-picture data converted to a specific size in the FCs with video data decoded in a video decoder(4) according to a contrast value, and displays the blended data.

Description

Sub-picture decoder architecture

The present invention relates to a system on a chip including a DVD playback function, and more particularly to a subpicture decoder for supporting various display outputs.

The main contents of multimedia are video and sound. If they are processed by simple PCM, there is a lot of difficulty in storing or transmitting because of excessive amount of data. Therefore, the key to the realization of multimedia is the efficient compression technology of image data and audio data.

MPEG is a representative international standard for the compression and multiplexing of video and audio data. Recently, MPEG-1 and MPEG-2 have been completed and are being applied to many fields.

In particular, MPEG-2 can reproduce the image quality that is received in current homes with information rate of 10Mbps or less, and in the audio field, AC-3, an audio compressor method capable of multi-channel audio playback, has been introduced to provide high quality audio and multisound. It can be enjoyed by ordinary families.

As a medium for recording such compressed video data and audio data, a DVD (Digital Video Disc) has emerged. Accordingly, a DVD player as a playback device is rapidly spreading. The DVD player is provided with an A / V decoder for decoding compressed video data and audio data.

FIG. 1 is a block diagram of a general DVD system. Referring to FIG. 1, five types of presentation data demultiplexed are represented by respective decoders, that is, audio decoders 3 and video decoders. 4), it is decoded by the subpicture decoder 5, the PCI decoder 6, and the OSD (On Screen Display) 7 and then represented, wherein the subpicture data and the video data are mixed with the mixer 9 It is muxed by and displayed. In this case, the display is encoded by the NTSC / PAL encoder 10 as an NTSC or PAL type display.

FIG. 2 is a diagram illustrating a general structure of the sub picture decoder illustrated in FIG. 1. In FIG. 2, a sub picture external memory 2 temporarily storing sub picture data read from a disc, and a sub picture decoder in FIG. DCSQ decoder 5a that decodes the DCSQ to be currently displayed among the stored data and obtains information necessary for display, that is, information such as position, time, color, and contrast, and RL stored in the external memory 2. (Run-Length) Run-Length Decoder (RLD) unit 5b for decoding bit-coded pixel data to generate a bitmap picture, and decoding highlight information among data stored in the external memory 2. A first mux section 5d for muxing and outputting 4-bit contrast information decoded by the HLI decoder 5c, the DCSQ decoder 5c and the HLI decoder 5c, and the RLD section 5 b) and a second mux section 5e which muxes and selects and outputs the 4-bit indexed color decoded by the HLT decoder 5c and 24-bit using the output of the second mux section 5e. A PLT section 5f for outputting the color of the color, a first mux section 5d, a PLT section 5f, and a synthesis section 9 'for synthesizing and displaying the signals output from the video decoder 4; do.

FIG. 3 shows the four-bit contrast and the four-bit indexed color as described in FIG. 2 converted into 8-bit YCbCr information after passing through the PLT (palette) section 5f and synthesized by the synthesizer 9 '. A detailed process of the data is shown graphically.

Referring to FIG. 3, 4-bit indexed color and contrast information of PXD (Pixel Data), which is run-length encoded into 2-bit symbols in the Run-Length Decoder (RLD) unit 5b, is muxed. The 4-bit index color is converted into 8-bit YCbCr information while passing through the PLT (palette) section 5f, and then synthesized with the index color and contrast of the highlight information as necessary.

In this case, the contrast has a 4-bit value and 16 levels of blending are possible.

The DVD player constructed and operated as described above is becoming more common in recent years with the development of home appliances, and according to this, TV is changing from the existing NTSC / PAL type analog TV to digital TV.

This digital TV supports SD broadcasting in HD or progressive format, which has better resolution than conventional analog broadcasting. In order to receive the enhanced digital broadcasting with the existing analog TV, a separate set-top box (set- In this case, the degradation of the picture quality is obvious because the conversion to NTSC / PAL is performed even in HD broadcasting.

As a means to solve this problem, if you connect with a READY type TV that supports HD display, you can enjoy broadcasting in HD quality, but in this case, the burden of separately purchasing TV and set-top box is have.

Therefore, it is expected that HD TV of built-in type will become common in the future.

Therefore, it would be competitive to develop a DVD player that supports an HD display, or to develop a built-in (BUILT-IN) HDTV that incorporates a DVD player function.

Also, thanks to the development of technology, system on chip technology, in which all functions are integrated and become one chip, is also becoming popular.

The subpicture decoder according to the related art described above has a problem in that the display output is not set to NTSC / PAL because the standard is determined with the display output set to NTSC / PAL. Since the devices must be connected, they are less efficient, both economically and in terms of hardware size.

Therefore, the present invention has been made to solve the above problems, the structure of the sub-picture decoder including a DVD playback function to support a variety of display outputs, such as 1080I, 720P, 480P in addition to NTSC or PAL display output in the DVD player The purpose is to provide.

1 is a block diagram of a DVD system according to the prior art

2 is a block diagram of a subpicture decoder according to the prior art;

3 is a diagram illustrating data extension of a conventional picture decoder according to the prior art;

4 is a block diagram of a subpicture decoder according to the present invention;

5 is an RLD decoding timing diagram according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Demux 2, 20: External memory

3: audio decoder 4: video decoder

5, 30: subpicture decoder 5a, 31: DCSQ decoder

5b, 32: RLD part 5c, 33: HLI decoder

5d, 34, 5e, 35: 1st, 2 mux parts 5f, 51: PLT part

6: PCI decoder 7: OSD

8: picture processing unit 9: mixer section

9 ', 90: Mixing unit 10: NCSC / PAL encoder

40, 52, 53: FIFO buffer 60, 70, 80: format converter

A feature of the subpicture decoder according to the present invention for achieving the above object is a mux unit for outputting the temporarily stored stream data as 4-bit index color information and bitmap-type contrast information, respectively, decoded in the mux unit A memory unit for storing the output information data in a predetermined unit, a PLT unit for detecting Y, Cb, and Cr extended subpicture data of 8 bits using index color information stored in the memory unit, and the PLT unit A format converter for converting the detected extended subpicture data and the contrast information into a size suitable for the current display output by predetermined units, subpicture data converted into a specific size by the format converter, and video decoded by the video decoder. And a synthesis unit for synthesizing and displaying data according to contrast values.

The MUX unit decodes the DCSQ to be displayed and obtains information necessary for display, decodes RLD generating a bitmap picture by decoding RL (Run-Length) compression-encoded pixel data, and decoding highlight information. A first MUX unit which muxes 4-bit contrast data decoded by the DCSQ decoder and the HLI decoder to output contrast information, and a 4-bit indexed color decoded by the RLD and HLT decoders; ) A second mux unit for muxing data to output index color information.

The memory unit includes a write interface unit for storing the value of the highlight information and the indexed color and contrast, and a read interface unit for reading the stored index color and contrast and storing the indexed color and contrast in a buffer to enable format conversion. There is this.

The format converter has another feature for size-decoding the decoded video data, the depth expansion subpicture data, and the contrast information to fit the display output.

The MUX unit, the memory unit, the PLT unit, the format converter, and the synthesizer are configured on one chip.

Other objects, features and advantages of the invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of a subpicture decoder according to the present invention will be described below with reference to the accompanying drawings.

4 is a diagram illustrating a structure of a subpicture decoder according to the present invention.

Referring to FIG. 4, the sub picture data in a stream form read from the disc is temporarily stored in the sub picture external memory 20.

The DCSQ decoder 31, the RLD unit 32, the HLI decoder 33, and the video decoder 4 respectively perform decoding.

At this time, the DCSQ decoder 31 decodes the DCSQ to be currently displayed among the data stored in the external memory 20 to obtain information necessary for display, that is, information such as position, time, color, and contrast.

The run-length decoder (RLD) unit 32 decodes the run-length compressed coded pixel data stored in the external memory 20 to generate a bitmap picture.

The HLI decoder 33 decodes highlight information, which is an area to be brightly displayed on display, among the data stored in the external memory 20, and the video decoder 4 decodes a general video signal.

Subsequently, 4-bit contrast information decoded by the DCSQ decoder 31 and the HLI decoder 33 through the first mux unit 34 and the second mux unit 35 is obtained. The 4-bit indexed color information decoded by the HLT decoder 33 is muxed.

In this case, the first mux unit 34 outputs 4-bit contrast information, and the second mux unit 35 outputs index color information, which is a 4-bit bitmap.

The index color and contrast of the bright portion information are written to the first FIFO buffer 41 and the second FIFO buffer 42 via the first mux 34 and the second mux 35, respectively.

In the first and second FIFO buffers 40, when a certain amount of data is accumulated, the first and second FIFO buffers 40 store the data in the external memory 20 in a burst mode.

The system operates according to the bandwidth state, that is, if the state of the first and second FIFO buffer 40 is full, the RLD unit 32 stops operating.

The 4-bit index color information stored in the external memory 20 is changed into 8-bit extended subpicture data of Y, Cb, and Cr through the PLT (Palette) unit 51 when being read, and is transferred to the third FIFO buffer 52. As written, the format converter 60 converts the information into a size suitable for the current display output by using this information.

In this case, the contrast information is also converted into the same size as the extended subpicture data through the fourth FIFO buffer 53 and the format converter (FC) 70.

The video data of the video decoder 4 is also converted into the same size as the extended subpicture data by the format converter 80.

The size-expanded expanded subpicture data is similarly blended and output through the synthesis unit 90 according to the contrast value.

At this time, the external memory 20 includes a write interface and a read interface. The external memory 20 stores a value of highlight information, a mixed 4-bit index color, and contrast.

The read interface reads the stored 4-bit index color and contrast and stores them in the third and fourth FIFO buffers 52 and 53 to enable format conversion. At this time, the 4-bit index color is extended to 24 bits of YCbCr via the PLT unit 51 and then stored in the third FIFO buffer 52.

In addition, the process of reading the sub picture data from the external memory 20 and converting the format and the process of converting the video data are performed according to the synchronization of the output display. The RLD unit 32 decodes the data by the push_full flag of the write interface. Is controlled.

Through the above process, the amount of sub picture data stored in the external memory 20 is 720 X as NTSC / PAL's active pixel (PEL) size, which is an 8-bit DVD output standard by adding index color and contrast. It corresponds to 480/576.

As described above, the present invention can reduce the required external memory size by storing index color values without storing the expanded color information, and also obtains a considerable benefit in terms of bandwidth of the system.

FIG. 5 illustrates a decoding timing diagram of an RLD that operates to adjust a bandwidth bottleneck that may occur when writing and reading the index color and contrast decoded in FIG. 4 into an external memory.

In case of a display that supports real SD and HD simultaneously, the number of active HSYNC dot clocks (DOTCLK) varies from 720 to 1920 depending on the output resolution, and the subpicture data to be run-length decoded is maximum per line. Since it is 720 pixels (PEL), in case of a 1920 X 1080I display, it may have a RLD operation margin for 1200 dot clock DOTCLK. In FIG. 5, the case where the display section of the sub picture data is 3 to 720 on the X axis of the display is illustrated as an example.

The subpicture decoder according to the present invention as described above has the following effects.

First, DVD can be implemented in any other display as well as NTSC / PAL.

Second, by storing the decoded index color and contrast in memory instead of the expanded data, the amount of external memory required and overall bandwidth in terms of system can be saved.

Third, since the RLD can have an operating margin within one display line, it is possible to effectively use the entire bandwidth in the entire system.

Fourth, the implementation of one chip consisting of transport + video decoder + audio decoder + OSD + DVD is applied to system-on-chip design. I can make it.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (7)

A mux part for outputting the temporarily stored stream data as 4-bit index color information and bitmap contrast information, respectively; A memory unit for storing the information data decoded and output by the mux unit in a predetermined unit; A PLT unit for detecting Y, Cb, and Cr extended subpicture data of 8 bits using index color information stored in the memory unit; A format converting unit converting the extended subpicture data and the contrast information detected by the PLT unit into sizes corresponding to the current display output by predetermined units; And a synthesizer for synthesizing and displaying the subpicture data converted to a specific size by the format converter and the video data decoded by the video decoder according to contrast values. The method of claim 1, The predetermined unit processed by the memory unit and the format converter uses a FIFO type buffer. The method of claim 1, wherein the mux portion A DCSQ decoder that decodes the DCSQ to be displayed and obtains the information needed for display; An RLD for generating a bitmap picture by decoding RL (Run-Length) compression-encoded pixel data; An HLI decoder for decoding highlight information, A first mux unit which muxes 4-bit contrast data decoded by the DCSQ decoder and the HLI decoder to output contrast information; And a second mux unit for muxing 4-bit indexed color data decoded by the RLD and HLT decoders to output indexed color information. The method of claim 3, wherein And information required for display obtained by the DCSQ decoder is position, time, color, and contrast. The method of claim 1, wherein the memory unit A light interface that stores the value of the highlight information and the muted index color and contrast; And a read interface unit which reads the stored index color and contrast, and stores them in a buffer to enable format conversion. The method of claim 1, wherein the format conversion unit And sub-size the decoded video data, the depth expansion subpicture data, and the contrast information to fit the display output. The method of claim 1, And the mux unit, the memory unit, the PLT unit, the format converter, and the synthesizer are configured on one chip.