JP2005184168A - Device and method for video coding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein image data are transmitted additionally for a part in which images overlap and communication costs increase in comparison with image data for one screen, when an image and a character image are displayed overlappingly at a receiver side since inputted video data and video data generated from the character data are accumulated as separate information for transmission in a conventional video coding device. <P>SOLUTION: A video coding device has a multiplexer for generating a multiplexing macroblock by synthesizing the output of a video converter for converting inputted video data to a first macroblock corresponding to a rectangular region, and the output of a character/video converter that allows one macroblock to correspond to one bit of the corresponding bit map data to inputted character data, and converts the character data to a second macroblock being arranged analogous to the bit of the first bit map data, thus suppressing multiplexing processing costs, suppressing the amount of transmitted video data, and reducing communication costs. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a video encoding apparatus and a video encoding method for multiplexing and transmitting a character signal to a video signal.

  When a conventional video encoding device transmits input data including video data and character data such as an HTML document, for example, the receiver side prepares font data for converting the character data into video and receives the received character. It was displayed after converting the data to video.

  However, in the above method, since a large amount of font data is prepared on the receiver side, the number of parts is increased, and a load is also imposed on conversion at the time of display. Therefore, on the transmission side, the video data and the video data obtained by converting the character data using the character font file are stored in the same storage device, and the image data is sequentially transmitted from the storage device after the conversion of the HTML document is completed. . (For example, refer to Patent Document 1).

Japanese Patent Application Laid-Open No. 2002-351774.

  In the conventional video encoding apparatus as described above, since the input video data and the video data generated from the character data are stored and transmitted as separate information, the image and the character image are transmitted on the receiver side. Is displayed in an overlapping manner, compared to the image data for one screen, there is a problem that the image data is transmitted only for the portion where the images overlap, which increases the communication cost. In addition, it is necessary to prepare a character font file for converting characters into images on the transmission side. However, since a normal font file has a large number of entries to deal with various character inputs, a large-capacity storage medium must be used. Necessary and increased the cost of the equipment. In addition, there is a restriction that input characters can be displayed only in a prepared font.

  The present invention has been made to solve such a problem, and a video encoding apparatus and a video encoding in which the amount of image data to be transmitted is suppressed by efficiently multiplexing input character data onto video data. It aims to provide a method.

  The video encoding apparatus according to the present invention converts an input unit of input data having character data and video data, and the video data into a first macroblock corresponding to a rectangular area including one or more pixels. A video conversion unit and storage means for storing the first bitmap data corresponding to the character data, and one macroblock corresponding to one bit of the bitmap data output from the storage means for character data input A character / video conversion unit for converting the character data into a second macroblock arranged in a manner similar to the bits of the first bitmap data; the first macroblock and the second macroblock; And a multiplexing unit for generating a multiplexed macroblock obtained by synthesizing.

  As described above, the video encoding apparatus according to the present invention includes an input unit for input data having character data and video data, and the first video data corresponding to a rectangular area including one or more pixels. A video conversion unit for converting into a macro block and a storage unit for storing the first bitmap data corresponding to the character data, and for character data input, 1 bit of the bitmap data output from the storage unit A character / video conversion unit that converts one macroblock into correspondence and converts the character data into a second macroblock arranged similarly to the bits of the first bitmap data; the first macroblock and the first macroblock; And a multiplexing unit that generates a multiplexed macroblock by combining the two macroblocks.

  Therefore, since multiplexing is performed in correspondence with the macroblocks of the video data and the bits of the character video data, the multiplexing processing cost can be suppressed, and the amount of the video data to be transmitted can be suppressed to reduce the communication cost.

Embodiment 1 FIG.
FIG. 1 is a block diagram of a video encoding apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, input data 100 including video data and character data input to the input unit 11 of the video encoding device 10 is distributed to video data 101 and character data 102. The video data 101 is converted by the video converter 14 to generate a video macro block 105. The character data 102 is converted by the character / video conversion unit 12 to generate a character macroblock 103 converted into video. The video macro block 105 and the character macro block 103 are overlapped by the multiplexing unit 13 and the multiplexed macro block 104 is output. The multiplexed macroblock 104 is encoded by the video encoding unit 15 and outputs video encoded data 106, which is transmitted by the video encoding device.

  In the present embodiment, only the video data 101 and the character data 102 are presented as the contents of the input data 100, but other types of data such as audio data may be included, and the present invention is not limited thereto. The video data 101 may not be a still image but may be moving image data in which a plurality of videos are collected. The encoded video data 106 includes a standardized standard such as MPEG-2 (ISO / IEC13818-2), but is not limited thereto. Further, the configuration is not limited to the configuration of FIG. 1, and for example, the multiplexing unit 13 and the video encoding unit 15 may be configured integrally, and the configuration is not limited thereto.

  Next, the operation of the case where the input data 100 to the video encoding apparatus according to the present embodiment is an HTML document will be described with reference to FIG. 1, but the input is not limited to an HTML document. In HTML, the content enclosed in <> is a tag-embedded language, which is a tag that defines the control content. For example, <IMG SRC = “xxx.gif”> is a file name: xxx. The display of gif video data is instructed. The video display position is the default position determined from the description up to immediately before the specified position when there is a separate designation in absolute coordinates or the like, unless otherwise specified. In HTML, a character string not particularly attached with a tag is displayed as character data. Also, tags are assigned as in <H1> table of contents </ H1>, and display size, display color, display font, and the like are designated. Also, the display position of characters can be controlled as in the case of video data.

  The input unit 11 analyzes the contents of the input data 100 based on the HTML grammar as described above, extracts the video data 101 and the character data 102, and sends them to the video conversion unit 14 and the character / video conversion unit 12, respectively. . In addition, extracted tag information such as a display position and a display size (not shown) is also sent to the video conversion unit 14 and the character / video conversion unit 12 as necessary. In this embodiment, a case where input data 100 in which video data 101 and character data 102 are multiplexed is input will be described. However, the input unit 11 does not perform analysis, and the video data 101 is transmitted to the video encoding device. The character data 102 may be input separately, and the present invention is not limited to this.

  FIG. 2 (extracted from Hiroshi Fujiwara “Latest MPEG Textbook” ASCII Publishing Bureau, P. 154) shows an example of MPEG-2 having a hierarchical structure as an example in which the video conversion unit 14 converts the video data 101 into a macroblock. It is a figure which shows a video data structure. In FIG. 2, the picture layer 301 includes a slice layer 302, and the slice layer 302 includes a macroblock 303. As shown in FIG. 2, the macro block 303 is configured by overlapping the luminance signal (Y) and the color difference signals (Pb, Pr), and the luminance signal (Y) is 8 when the chroma format is 4: 2: 0. There are four × 8 blocks 303Y, each of which has 8 × 8 blocks 303b and 8 × 8 blocks 303r each for color difference signals (Pb, Pr).

  FIG. 3 shows an example of a bitmap in which the character / video conversion unit 12 converts the character data 102 into the character macroblock 103 when the input character is “A”. The character / video conversion unit 12 generates one block 303Y for each bit constituting the character, and a block 303b and a block 303r that match the display color of the character. For example, a macro block such as black is associated with a portion representing a character stroke, and a macro block such as white is associated with a background portion and converted into a character macro block 103.

  Next, the multiplexing unit 13 determines a display area for each input video data 101 and stores the video macroblock 105. For each input character data 102, the display area is determined by referring to the tag information as necessary, and the character macro block 103 is accumulated.

  A procedure for multiplexing the video macro block 105 and the character macro block 103 stored in the multiplexing unit 13 will be described with reference to the flowchart of FIG.

  Here, each of the M character macroblocks 103 input to the multiplexing unit 13 is C (i) (M ≧ i ≧ 1). Further, it is assumed that the video macroblock 105 input to the multiplexing unit 13 refers to each display area and is preliminarily overlapped into one video macroblock 105. First, in step S101, 1 is substituted for i. Next, in step S102, it is determined whether or not C (i) overlaps with the video macro block 105. If so, the process proceeds to step S103, and if not, the process proceeds to step S105. In step S103, C (i) and the video macro block 105 are overlapped with reference to the respective display areas, and the video macro block 105 is updated to the overlapped data. In step S104, C (k) where M ≧ k ≧ i + 1 is shifted one by one, C (i) is removed from the character macroblock 103, and the total number of character macroblocks 103 is reduced to M-1. Here, when i = M, there is no k that satisfies the condition, and only the process of subtracting M from M−1 is performed. In step 105, it is determined whether i = M. If i = M, the process is completed. If not, the process proceeds to step S106. In step S106, i is incremented by 1, and the process returns to step S102.

  A plurality of methods can be considered as a method of superimposing and multiplexing video data. For example, if the order is defined between video A and video B, and video A has a higher order, video A is used in the overlapping portion, so that the higher-order video is overwritten and multiplexed. However, this is not a limitation.

  On the other hand, a plurality of methods for superimposing the video macro block 105 and the character macro block 103 corresponding to the video data 101 are also conceivable. For example, only a part representing a character stroke may be replaced with the character macroblock 103, or may be replaced with the character macroblock 103 including the background, and this is not limited.

  As a result of the processing of the flowchart of FIG. 4, the multiplexing unit 13 generates one video macroblock 105 that does not have an overlapping portion, is encoded by the video encoding unit 15, and is transmitted from the video encoding device 10. Is done.

  In the present embodiment, one bit representing a character is associated with one macroblock, but any number of macroblocks may be associated with any number of bit patterns, and this is not limiting.

  The character macroblock 103 may be described in software (not shown) that operates in the video encoding device 10 or may be described in a program that constitutes a circuit of the video encoding device 10.

  As described above, according to the present embodiment, since the video macroblock 105 and the character macroblock 103 are multiplexed and encoded and output in the video encoding device 10, compared to the case where no multiplexing is performed, The communication cost can be reduced by reducing the amount of video data to be transmitted.

  Further, according to the present embodiment, in order to multiplex and encode and output the video macroblock 105 and the character macroblock 103 in the video encoding device 10, in order to display characters on the video decoding device 31. There is no need to provide a special circuit or memory.

In addition, since one bit of a bitmap representing characters is associated with one video macroblock 105, the load of multiplexing processing is extremely light, and conversion of moving images and the like can be performed in real time.
Embodiment 2. FIG.
FIG. 5 is a block diagram of a video encoding apparatus according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG.

  In FIG. 5, input data 100 includes video data 101, character data 102, and conversion data 201. Here, the conversion data 201 is data composed of a set of one character and video data of this character, for example, a set of a character code and a bitmap. In the present embodiment, character data 102 included in the same input file 100 is converted into video data, and for example, character font data is used. In the input unit 11, the input data 100 is distributed to video data 101, character data 102, and converted data 201. Of these, the video data 101 is input to the video conversion unit 14, and the character data 102 and the conversion data 201 are input to the character / video conversion unit 12. The character / video conversion unit 12 converts the character data 102 into the character macroblock 103 based on the input conversion data 201 and outputs it to the multiplexing unit 13. The subsequent processing is the same as in the first embodiment.

  Here, in order to convert all the character data 102 into the character macroblock 103, it is necessary and sufficient if the conversion data 201 includes a set of characters and video data corresponding to the character types included in the character data 102. is there. (The character type here distinguishes characters with different sizes and fonts even when the same character is displayed.) In general, to convert a character into an image, a character based on a standard such as JIS or ISO. Although a font file is used, the character font file supports all characters conforming to the standard, and thus includes a large number of character and image sets. Therefore, the capacity of the converted data becomes very large, and it takes time to search for a set corresponding to the character data 102. However, only a few character types are required for documents that are normally handled, and most character font files are not accessed at all.

  As described above, according to the present embodiment, since only the data necessary and sufficient for converting characters into an image is input from the outside, a large-capacity dedicated memory such as a character font file is unnecessary. It is.

  Further, according to the present embodiment, even when character data including characters of various sizes and fonts is converted into an image, the conversion data can be made compact.

  Further, according to the present embodiment, since there are few data entries for converting characters into images, the conversion cost can be reduced.

1 is a block diagram of a video encoding apparatus shown in Embodiment 1. FIG. 6 is an explanatory diagram illustrating an example of conversion by a video conversion unit illustrated in Embodiment 1. FIG. 5 is an explanatory diagram illustrating an example of conversion by a character / video conversion unit illustrated in Embodiment 1. FIG. 3 is a flowchart showing a procedure of multiplexing video data of the video encoding device shown in the first embodiment. 6 is a block diagram of a video encoding device shown in Embodiment 2. FIG.

Explanation of symbols

10 video encoding device, 11 input unit, 12 character / video conversion unit, 13 multiplexing unit, 14 video conversion unit, 15 video encoding unit, 100 input data, 101 video data, 102 character data, 103 character macroblock, 104 multiplexed macroblocks, 105 video macroblocks, 106 video encoded data

Claims (5)

An input portion of input data having character data and video data;
A video conversion unit for converting the video data into a first macroblock corresponding to a rectangular area including one or more pixels;
Storage means for storing the first bitmap data corresponding to the character data, wherein one character block corresponding to one bit of the bitmap data output from the storage means is associated with the character data input, and the character data A character / video conversion unit for converting into a second macroblock, which is arranged in a similar manner to the bits of the first bitmap data,
A multiplexing unit that generates a multiplexed macroblock obtained by combining the first macroblock and the second macroblock;
A video encoding device comprising: The input data includes position data of the character data and / or the video data,
The video encoding apparatus according to claim 1, wherein the multiplexing unit superimposes the first macroblock and the second macroblock with reference to the position data. The input data has second bitmap data corresponding to characters included in the character data;
The video encoding apparatus according to claim 1 or 2, wherein the storage unit stores the second bitmap data extracted from the input data. An input step of input data including character data and video data;
A video conversion step of converting the video data into a first macroblock corresponding to a rectangular area including one or more pixels;
A character / video conversion step of converting the character data into a corresponding second macroblock based on the first bitmap data for converting the character data into a video;
A multiplexing step for generating a multiplexed macroblock obtained by superimposing the first macroblock and the second macroblock;
A video encoding method characterized by comprising: The input data includes second bitmap data corresponding to characters included in the character data,
A storage step of reading and storing the second bitmap data from the previous input data;
5. The video encoding method according to claim 4, wherein in the character / video conversion step, the character data is converted based only on the first and second bitmap data.

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