JP2006311078A - High efficiency coding recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high efficiency coding recorder for carrying out optimum coding processing with a small code amount by controlling coding for each scene. <P>SOLUTION: A database management circuit 108 acquires a correction value of a parameter for controlling the coding processing from a scene information database 104 on the basis of information associated with a genre of a video image being an object of the coding processing obtained by a genre/keyword searching circuit 103, scene characteristic information representing the characteristic of each scene separated by a scene separation circuit 107, on the basis of image characteristic information obtained by an image characteristic calculation circuit 105 from digital image data of the video image, and coding result information associated with a code amount obtained by a code amount control circuit 219 through the application of the coding processing to the digital image data, and a coded parameter correction circuit 109 corrects the parameter in the high efficiency coding recorder 10 on the basis of the acquired correction value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-efficiency encoding / recording apparatus capable of efficiently recording digital image data.

  In recent years, high-efficiency encoding has been applied to digitized video image data to compress information, thereby recording long-term content on recording media, satellite lines, terrestrial lines, telephone lines, etc. There are many services that send and receive data over these transmission paths. In these services, MPEG2, MPEG4-ASP, MPEG4-AVC and the like, which are international standards, are used as high-efficiency encoding methods for moving images and audio. In these standards, an image coding method is used in which the amount of information is compressed using the correlation between adjacent pixels (space direction) and the correlation between adjacent frames or between adjacent fields (time direction).

  For example, as an example of an image encoding / recording apparatus in the MPEG2 standard, there is an apparatus that performs encoding processing using the following algorithm. That is, one still image of 12 encoding target image frames that are temporally continuous is regarded as a reference frame, and is encoded using only the correlation in the spatial direction. The encoded data of this reference frame can be restored only with the encoded data of this frame.

  In 11 frames other than the reference frame, first, a predicted frame is created by predicting an image using a motion vector detected from the motion of the subject with the reference image frame, and a difference from the predicted frame is obtained. It is done. Since this difference is encoded using the correlation in the spatial direction and the correlation in the time direction, it can be encoded with higher encoding efficiency than the reference frame. Data encoded using the prediction frame is restored from the reference frame data, the motion vector data, and the encoded data of the difference from the prediction frame.

  The image encoding according to the MPEG2 standard will be specifically described with reference to FIG. FIG. 9 shows a state in which consecutive reference frames and prediction frames are arranged in a plane. An I picture (Intra-coded picture: I frame) indicated by I is an input encoding target image frame, which is periodically used in the encoding process and used as a reference frame in the decoding process. Further, P pictures (Predictive-coded pictures: P frames) indicated by P1 to P3 are prediction frames created using only a reference frame (I picture) that is temporally previous (past) as a reference frame, and B1 to B8. A B picture (Bi-directionally predictive coded picture: B frame) indicated by is a prediction frame created from two reference frames before and after (past and future) in terms of time. The P picture itself is a prediction frame, and also serves as a reference frame for a B picture and a P picture that are created subsequently.

  The arrows in FIG. 9 indicate the prediction direction. For example, P1 picture is predicted from temporally previous I picture, B1 picture and B2 picture are predicted from temporally previous I picture and P1 picture, and B3 picture and B4 picture are predicted from P1 picture and P2 picture. The

  The image data of an I picture is divided into processing units called macroblocks whose luminance signal is 16 horizontal pixels × 16 vertical pixels. The obtained macroblock data is further divided into two-dimensional blocks of 8 × 8 pixel units, and each two-dimensional block is subjected to DCT (Discrete Cosine Transform) conversion processing, which is a kind of orthogonal transformation, and quantum processing. Processing is performed.

  Data obtained by DCT conversion shows a value according to the frequency component of the two-dimensional block data, and in a general image, the component is concentrated in a low frequency region. This low frequency component has a characteristic that information deterioration is more visually noticeable than a high frequency component. Therefore, when quantization is performed, the low frequency component area is processed finely, the high frequency component area is processed coarsely, and the continuous length of the coefficient component and the coefficient 0 having no component is variable-length encoded, whereby the amount of information Is compressed.

  The process of compressing the encoding target frame using the P picture will be described with reference to FIG. The encoding target image frame temporally corresponding to the P1 picture, P2 picture, and P3 picture in FIG. 9 is also divided into macroblock units of horizontal 16 pixels × vertical 16 pixels, and an I picture that is a reference frame for each macroblock Alternatively, a motion vector between the P picture is detected. The motion vector is generally obtained by a block matching method. In this block matching method, the sum of absolute differences between each pixel of the macroblock data of the encoding target image frame that is the motion vector detection target and each pixel of the macroblock data of the macroblock data and the approximate reference frame (or The sum of squared differences) is obtained, and the value of the motion vector when the value is the minimum is output as the detected motion vector.

  An image created by shifting the image of the reference frame by the motion vector detected for each macroblock is defined as a P picture. An image signal of a P picture is divided into macroblock units of horizontal 16 pixels × vertical 16 pixels by a luminance signal as in the case of an I picture. Then, difference block data between each pixel of the obtained macroblock data of the P picture and each pixel of the macroblock data of the encoding target image frame is detected, and this difference block data is encoded. When an accurate motion vector is detected, the information amount of the difference block data is significantly smaller than the information amount of the original macroblock data. Therefore, the data encoded using the P picture can be subjected to coarser quantization processing than the data encoded using the I picture. Actually, whether to encode differential block data or non-differential block data (intra block data of the encoding target frame) is selected by the prediction mode determination, and an I picture is selected for the selected block data. The same DCT conversion process and quantization process are performed, and compression is performed.

  Processing for compressing the encoding target frame using the B picture will be described. The encoding target image frame temporally corresponding to the B1 picture, B2 picture,..., B8 picture in FIG. 9 is processed in the same way as when the P picture is used. Since they exist before and after in time, a motion vector is detected between each reference frame and the encoding target frame. At this time, the motion vector is detected by the prediction mode selected for each macroblock. This prediction mode includes a mode in which block data is predicted from a temporally previous reference frame (Forward prediction), and a block data is predicted from a temporally subsequent reference frame (Backward prediction). There are three types of modes in which block data is predicted from the average value of each block data pixel (Average prediction). Any one of four types of block data, that is, differential block data between the macro block data of the B picture and the macro block data of the encoding target image frame, and the intra block data of the encoding target frame, which are obtained by each of these three types of modes. The selected block data is subjected to DCT conversion processing and quantization processing similar to those for the I picture and P picture, and compression is performed on the selected block data.

  Since a B picture can be predicted from temporally preceding and following reference frames, the prediction efficiency is further improved than that of a P picture. Therefore, the quantization is generally coarser than that of the P picture.

  Since the encoding using the B picture is also performed with a prediction process from a later reference frame, the encoding using the reference frame is performed prior to the encoding using the B picture. Therefore, as shown in FIG. 10, the input image signal is encoded using the B picture, and the encoding target image frame is rearranged after the I picture or P picture that is the reference frame. It becomes. At the time of decoding, as shown in FIG. 11, by performing the reverse rearrangement of FIG. 10 and outputting, the decoded images are reproduced in the order of the input image signals.

  Next, the configuration of a conventional image encoding / recording apparatus that realizes MPEG2 image encoding will be described. FIG. 12 is a block diagram showing a conventional image encoding / recording apparatus 20. The conventional image encoding / recording apparatus 20 includes a target image input terminal 201, an input image memory 202, a two-dimensional block data conversion circuit 203, a subtractor 204, an orthogonal conversion circuit 205, a quantization circuit 206, a code, Circuit 207, encoding table 208, multiplexer 209, image bitstream buffer 210, inverse quantization circuit 212, inverse orthogonal transform circuit 213, adder 214, deblocking circuit 215, and reference image memory 216, a motion vector detection circuit 217, a motion compensation prediction circuit 218, and a code amount control circuit 219.

  The target image input terminal 201 inputs digital image data to be encoded.

  The input image memory 202 stores and delays the digital image data input at the target image input terminal 201, rearranges the frames in the encoding order, and transmits the frames to the two-dimensional block data conversion circuit 203.

  The two-dimensional block data conversion circuit 203 divides the received digital image data frame into macroblock data.

  If the encoding target frame is an I picture, the subtracter 204 transmits the difference between a prediction block data (to be described later) and the macro block data of the encoding target frame to be orthogonal if it is not an I picture. The data is transmitted to the conversion circuit 205.

  The orthogonal transform circuit 205 performs DCT transform on the received macroblock data, and transmits the DCT coefficient obtained by this DCT transform to the quantization circuit 206.

  The quantization circuit 206 performs a quantization process by dividing the received DCT coefficient by a value calculated by a quantization matrix.

  The encoding circuit 207 encodes the quantized DCT coefficient with a variable length or a fixed length at an encoding rate obtained by referring to the encoding table 208, and transmits the encoded DCT coefficient to the multiplexer 209.

  The encoding table 208 stores an encoding rate corresponding to the DCT coefficient.

  The multiplexer 209 multiplexes the encoded data received from the encoding circuit 207 and the additional information indicating the position of the macroblock data in the frame received from the two-dimensional block data conversion circuit 203 into an output image bit stream, The data is transmitted to the image bit stream buffer 210 and the code amount control circuit 219.

  The image bit stream buffer 210 stores the output image bit stream received from the multiplexer 209 and transmits it to the recording medium or the transmission path 211 as necessary.

  The inverse quantization circuit 212 inversely quantizes the quantized DCT coefficient received from the quantization circuit 206 and transmits the obtained DCT coefficient to the inverse orthogonal transform circuit 213.

  The inverse orthogonal transform circuit 213 performs inverse DCT transform processing on the received DCT coefficient, and transmits the obtained macroblock data to the adder 214.

  The adder 214 adds prediction block data obtained from a motion compensation prediction circuit 218 described later to the macroblock data received from the inverse orthogonal transform circuit 213, and transmits the result to the deblocking circuit 215.

  The deblocking circuit 215 receives and decodes the macroblock data to which the prediction block data is added, and transmits the obtained reference image data to the reference image memory 216.

  The reference image memory 216 stores the received reference image data and transmits it to the motion vector detection circuit 217 and the motion compensation prediction circuit 218 as a reference frame of a P picture or a B picture.

  The motion vector detection circuit 217 detects a motion vector between the macroblock data of the encoding target image received from the two-dimensional block data conversion circuit 203 and the macroblock data of the reference image received from the reference image memory 216.

  The motion compensation prediction circuit 218 creates prediction block data by shifting the macroblock data of the reference frame received from the reference image memory 216 by the motion vector obtained by the motion vector detection circuit 217, and creates a subtractor 204 and an adder 214. Send to.

  The code amount control circuit 219 compares the code amount of the output image bit stream transmitted from the multiplexer 209 with a target code amount set in advance, and performs fineness (quantization) so as to approach the target code amount. Scale) is calculated, and the quantization circuit 206 is controlled so that the quantization is performed with the calculated quantization scale.

  Next, the operation of the conventional image encoding / recording apparatus 20 will be described.

  First, digital image data of a video to be encoded is input from the target image input terminal 201 and transmitted to the input image memory 202. In the input image memory 202, the received digital image data is stored and delayed, and the frames are rearranged in the order of encoding according to the encoding syntax of FIG. 10 and transmitted to the two-dimensional block data conversion circuit 203. In the two-dimensional block data conversion circuit 203, the received digital image data is divided into macroblock data.

  Next, an encoding process when digital image data input from the input image memory 202 is an I picture will be described. First, the I-picture image data divided into macroblock data is transmitted to the orthogonal transform circuit 205 via the subtractor 204. Then, the orthogonal transform circuit 205 further divides the pixel into horizontal 8 pixels × vertical 8 pixels and performs DCT transform processing to output DCT coefficients. The output DCT coefficients are grouped into macroblock units each having a luminance signal of 16 horizontal pixels × 16 vertical pixels, and sent to the quantization circuit 206. In the quantization circuit 206, the DCT coefficient is divided by a value calculated by a quantization matrix having a different value for each frequency component, thereby performing a quantization process. The quantized DCT coefficient is subjected to variable length or fixed length coding by referring to an address corresponding to the DCT coefficient of the coding table 208 in the coding circuit 207, and the obtained coding Data is transmitted to the multiplexer 209.

  The multiplexer 209 multiplexes the encoded data received from the encoding circuit 207 and the additional information indicating the position of the corresponding macroblock data in the frame received from the two-dimensional block data conversion circuit 203, Stored in the bitstream buffer 210. The multiplexed data is output to a recording medium or transmission path 211 as an output image bit stream.

  On the other hand, the DCT coefficient quantized in the quantization circuit 206 is subjected to inverse quantization and inverse DCT transform processing in the inverse quantization circuit 212 and the inverse orthogonal transform circuit 213, and the quantized DCT coefficient is decoded to generate a macroblock. Each data is obtained. The obtained data for each macroblock is transmitted to the deblocking circuit 215 via the adder 214, and the reference image data deblocked and decoded by the deblocking circuit 215 is obtained. The decoded reference image data is supplied to the reference image memory 216 and stored therein. The image data stored in the reference image memory 216 is used as a reference frame when encoding is performed using a P picture or B picture that is a predicted frame.

  Next, a case where the digital image data output from the input image memory 202 is encoded using a P picture or B picture that is a prediction frame will be described. First, the motion vector between the macroblock data of the image frame to be encoded divided by the two-dimensional block data conversion circuit 203 and the macroblock data of the reference image stored in the reference image memory 216 is a motion vector. It is obtained by the detection circuit 217. The motion vector data obtained by the motion vector detection circuit 217 is transmitted to the motion compensation prediction circuit 218. The motion compensated prediction circuit 218 creates predicted block data by shifting the macroblock data of the reference frame acquired from the reference image memory 216 by the motion vector obtained by the motion vector detection circuit 217. Further, the motion compensation prediction circuit 218 selects prediction block data created in the optimum prediction mode from among a plurality of prediction modes. Then, difference data between the macroblock data of the image to be encoded by the subtractor 204 and the prediction block data selected by the motion compensated prediction circuit 218 is calculated and transmitted to the orthogonal transform circuit 205. The difference data is subjected to DCT transform processing and quantization processing in the same manner as the I picture, and is output from the image bit stream buffer 210 to the recording medium or transmission path 211 as an output image bit stream together with motion vector data and prediction block data.

  With regard to the control of the code amount, the code amount control circuit 219 compares the code amount of the image bitstream output from the multiplexer 209 with the target code amount, and a quantization scale (quantum for approaching the target code amount). Calculation) is calculated. Then, the quantization circuit 206 is controlled so that the quantization is performed with the calculated quantization scale.

  In this apparatus, the encoding processing with different information amounts using the three types of picture types described above is performed, so that the target code amount of each picture type is calculated based on the nature of the picture type and the appearance frequency.

In general, the target code amount of each image frame is calculated and assigned from the information amount of an encoded image using each picture type with respect to the target code amount in a fixed time. Specifically, if the coding amount required when coding using each picture type before is Bits and the average value of the quantization scale of each picture type is AvgQ, the coding complexity of each picture type is The approximate value C of the degree (hereinafter referred to as “encoding difficulty”) is calculated by the following equation (1).

  This value C is larger for complex scenes and scenes with large movements. Here, A is a weight set for each picture type assuming the importance of the picture type and the degradation level at the time of encoding. Generally, this weighting is A (I)> A (P)> A (B).

For the target code amount TotalBits given to F frames included in a certain time, the target code amount Budget given to Fnum frames for which each picture type is used is expressed by the following equations (2) to (4). Calculated.

  The code amount control circuit 219 is set as described above so that an overflow or underflow does not occur in the decoding buffer with respect to a stream buffer called a VBV (Video Buffer Verifier) buffer virtually simulated by the decoding device. The target code amount Budget is limited.

  The quantization scale and the output code amount are generally in an inversely proportional relationship. Using this, a quantization scale value for each macroblock data in the picture is calculated from the target code amount Budget for each frame type, and a quantization process is performed. Then, by changing the quantization scale so as to approach the target code amount for each block, the output image bit stream is suppressed within the target code amount.

  As described above, when a method of compressing the information amount using the spatial direction correlation or the time direction correlation of the image signal is used, high encoding efficiency cannot be obtained in a scene where the encoding difficulty is high. For this reason, in order to keep the information amount within a certain target code amount, it is necessary to perform a quantization process on a coarse quantization scale, and image deterioration is increased when the image signal is restored.

  In order to suppress such deterioration of the image, in the MPEG2 standard, when an image with a known encoded information amount is stored in the recording medium, the above encoding is performed within the encoding rate of the maximum transfer rate of the recording medium. Variable transfer rate (VBR) encoding, in which the encoding rate is changed according to the difficulty level, is possible.

  For example, Patent Document 1 discloses a control method of VBR encoding processing when a real-time input signal in which the amount of encoded information is not known and a future scene (scene) cannot be predicted is stored in a recording medium. There is a method that has been. In this method, a minimum quantization scale is set to a level at which deterioration of the restored image signal is not conspicuous with respect to the set average encoding rate, and portions where the output of the encoding information does not satisfy the average encoding rate are Assigned to the encoding process. By this processing, resistance to a scene with a high degree of difficulty in encoding is increased, and image degradation is suppressed.

  Patent Document 2 describes a method of changing the coding rate for each program when a television program is recorded on a recording medium. This method makes use of the fact that there is a general tendency of encoding difficulty depending on the contents of the program. When processing is performed, program genre information is acquired from an electronic program guide (hereinafter referred to as “EPG”), a preferred encoding rate is referred to from the table based on this information, and encoding processing is performed at the encoding rate. Done.

By these methods, it is possible to omit useless encoding information for a set encoding rate, or to use content information that can be recognized in advance, and to perform global control.
Patent 3307367 JP 2002-44604 A

  However, in the method described in Patent Document 1 or Patent Document 2 described above, the encoding process for a scene whose encoding difficulty is instantaneously high has not been improved. For this reason, there has been a drawback that a method for increasing the correlation in the time direction according to the scene and a method for reducing information according to the characteristics of the image are not considered.

  Specifically, since a high-efficiency encoding / recording apparatus as shown in Patent Document 1 has a configuration in which data to be input in the future cannot be known in advance, a scene with a high degree of difficulty in encoding instantaneously exists. There is a problem that it is difficult to increase the compression rate and reduce the deterioration of image quality when input.

  Moreover, since a high-efficiency encoding / recording apparatus as shown in Patent Document 2 performs one setting for each program depending on the genre information of the program, the program of one genre is recorded on one entire recording medium. There was a problem that it was not effective. Furthermore, since there is a feature for each scene in programs classified by genre, a single program does not have a sufficient effect with the same control. For example, there is a scene with a high degree of difficulty in encoding instantaneously. There was also a problem that effective control according to the scene could not be performed when it was input. In addition to these, there is another problem that genre information cannot be acquired from an input source that does not have EPG information, so that effective processing cannot be performed.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a high-efficiency encoding and recording apparatus that performs optimal encoding processing with a small amount of code by controlling encoding for each scene. To do.

  In order to achieve the above object, a high-efficiency encoding / recording apparatus according to claim 1, wherein a digital image is obtained by performing an encoding process controlled by an encoding control parameter on digital image data of an input video. Data is compressed and stored in a recording medium. Based on electronic program guide information added to digital image data or based on genre prediction information calculated from digital image data, Genre information acquisition means for acquiring information relating to the genre of the video, at least of information relating to spatial correlation of video information, information relating to temporal correlation, information relating to luminance level, and information relating to color difference level from digital image data Image characteristic calculating means for calculating one as image characteristic information, and based on the calculated image characteristic information, Scene change point detection means for detecting scene break information regarding scene change points where the scene changes from digital image data, and digital image data is divided into scenes by the detected scene break information, and image characteristic information for each divided scene Scene classification means for calculating scene characteristic information based on the above, encoding result information acquisition means for acquiring encoding result information relating to the code amount of digital image data already encoded among digital image data of video, and the genre An encoding control parameter that calculates a correction value of the encoding control parameter based on the scene identification signal calculated from the information and the scene characteristic information and the encoding result information, and corrects the encoding control parameter by the calculated correction value According to the correction means and the encoding control parameters set for each divided scene Te, characterized in that it comprises an encoding unit for performing encoding for each delimited scene of the digital image data.

  According to a second aspect of the present invention, there is provided the high-efficiency encoding / recording apparatus according to the first aspect, wherein the image characteristic calculation means includes, as image characteristic information, an average luminance level value calculated for each frame of the digital image data, and a digital image The average color difference level value calculated for each frame of data, the sum of absolute difference values between adjacent pixels in the frame calculated for each frame of digital image data, and calculated between two consecutive frames of digital image data And calculating at least one value of the sum of absolute differences between pixels belonging to the same position.

  A third aspect of the present invention is the high-efficiency encoding / recording apparatus according to the first or second aspect, wherein the scene change point detection processing means performs an instantaneous scene change of a video or a continuous period. It is characterized by detecting a change in the scene to be displayed.

  A fourth aspect of the present invention is the high-efficiency encoding / recording apparatus according to any one of the first to third aspects, wherein the scene classification means calculates the average luminance calculated for each frame of the digital image data as the scene characteristic information. The level value, the average color difference level value calculated for each frame of the digital image data, the sum of absolute differences between adjacent pixels calculated for each frame of the digital image data, and the continuous digital image data At least one value of the sum of absolute differences between pixels belonging to the same position calculated between two frames is calculated, and the encoding result information acquisition unit performs motion compensation prediction as the encoding result information. The sum of motion vector distances calculated for each frame and the encoded digital image data calculated for each frame of digital image data. And calculating at least one value of the distribution amount.

A fifth aspect of the present invention is the high-efficiency encoding / recording apparatus according to any one of the first to fourth aspects, wherein the encoding control parameter correction means detects a motion vector that is a parameter for controlling the encoding process. , A value for specifying an interval for inserting a frame to be a reference frame when detecting a motion vector, a value for controlling a target code amount for each frame, and a maximum instantaneous encoding rate A value for controlling, a quantization matrix value for quantizing the luminance signal,
A correction value of at least one of the quantization matrix values for quantizing the color difference signal is output.

  Further, claim 6 is the high-efficiency encoding and recording apparatus according to any one of claims 1 to 5, wherein the genre information acquired by the genre information acquisition means is an electronic program added to digital image data. It includes information acquired from guide information and information acquired by searching text data acquired from electronic program guide information with keyword information set in advance to specify a genre.

  A seventh aspect of the present invention is the high-efficiency encoding / recording apparatus according to any one of the first to fifth aspects, comprising frequency recording means for accumulating and recording the appearance frequencies of scene identification signals, and genre information The acquisition means calculates the scene identification signals for all genres based on the scene characteristic information acquired from the scene classification means when the information about the video genre cannot be acquired from the electronic program guide information. Genre prediction information is calculated by selecting a scene identification signal having the highest appearance frequency cumulatively added from the scene identification signals.

  According to the high-efficiency encoding / recording apparatus of the present invention, when recording digital image data of video, appropriate encoding control is performed for scenes with high encoding difficulty and features that are input instantaneously. It can be performed. Thereby, digital image data can be efficiently recorded on a recording medium having a limited capacity while maintaining the encoding quality.

<Configuration of high-efficiency encoding / recording apparatus 10>
The configuration of the high-efficiency encoding / recording apparatus 10 according to the first embodiment of the present invention will be described with reference to FIG. A high-efficiency encoding / recording apparatus 10 according to the present embodiment includes an EPG information input terminal 101, a program information acquisition circuit 102, a genre / keyword search circuit 103, a scene information database (recording medium) 104, and an image characteristic calculation circuit 105. A scene detection circuit 106, a scene classification circuit 107, a database management circuit 108, an encoding control parameter correction circuit 109, an encoding syntax control circuit 110, a genre prediction circuit 111, and a target image input terminal 201. , Input image memory 202, two-dimensional block data conversion circuit 203, subtractor 204, orthogonal transform circuit 205, quantization circuit 206, encoding circuit 207, encoding table 208, multiplexer 209, image Bit stream buffer 210 and recording medium or transmission path 211 , Inverse quantization circuit 212, inverse orthogonal transform circuit 213, adder 214, deblock circuit 215, reference image memory 216, motion vector detection circuit 217, motion compensation prediction circuit 218, and code amount control circuit 219. Among these, the constituent elements described after the target image input terminal 201 are the same as those of the conventional image encoding and recording apparatus shown in FIG.

  The EPG information input terminal 101 inputs EPG information and transmits it to the program information acquisition circuit 102. The EPG information is information transmitted together with the synchronization data in the blanking section of the TV video signal at a specific channel / specific time of terrestrial analog broadcasting, or TS (Transformer) which is packetized data in terrestrial / BS digital broadcasting. It can be acquired from SI (program sequence information) periodically sent with specific identification information in data called “port stream”.

  The program information acquisition circuit 102 acquires the genre information of the program being processed and the text data indicating the program content from the received EPG information, and transmits it to the genre / keyword search circuit 103.

  The genre / keyword search circuit 103 receives genre information and text data indicating program contents, reads keyword information stored in a scene information database 104 described later, and includes the keyword information in the text data indicating program contents. Search for any keywords. The genre information ID of the keyword information extracted as a result of the search and the genre information received from the program information acquisition circuit 102 are transmitted to the scene classification circuit 107. Here, if both the genre information and the keyword information extraction data cannot be acquired because the EPG information cannot be acquired, information indicating that the information cannot be acquired is transmitted to the scene classification circuit 107 and the genre prediction circuit 111. .

  The scene information database 104 includes keyword information composed of main genre information, sub-genre information as keywords indicating program details for subdividing the main genre information, and genre information ID corresponding to the sub-genre information. Is stored. In addition, for each genre information ID, a scene identification signal that is data for setting an encoding control parameter set in advance to perform encoding control is stored. For each genre ID, data obtained by accumulating the appearance frequency is stored.

  The image characteristic calculation circuit 105 acquires digital image data to be encoded from the input image memory 202, calculates image characteristic information related to spatial or temporal correlation of image information, luminance, and color difference level for each frame, This is transmitted to the scene detection circuit 106.

  In this embodiment, as this image characteristic information, the average luminance level value calculated for each frame of digital image data, the average color difference level value calculated for each frame of digital image data, and the frame of digital image data The sum of absolute differences between adjacent pixels in the calculated frame and the sum of absolute differences between pixels belonging to the same position calculated between two consecutive frames of digital image data are calculated.

  The scene detection circuit 106 performs processing for detecting a scene change point using the received image characteristic information. As a result, scene delimiter information indicating whether or not the scene change point is detected is generated and transmitted to the scene classification circuit 107. At this time, the image characteristic information is also transmitted to the scene classification circuit 107.

  The scene classification circuit 107 recognizes a scene break based on the scene break information received from the scene detection circuit 106. Further, an average value of one scene section of the image information characteristics received from the scene detection circuit 106 (hereinafter referred to as “scene characteristic information”) is calculated, and the database is combined with the genre information ID received from the genre / keyword search circuit 103. Transmit to the management circuit 108.

  The database management circuit 108 creates a scene identification signal from the scene characteristic information and the encoding result information regarding the encoding difficulty level and the motion vector distance acquired from the code amount control circuit 219. Then, based on the scene identification signal and the genre information ID received from the scene classification circuit 107, the scene information database 104 is accessed to obtain the encoding control parameter correction data and transmitted to the encoding control parameter correction circuit 109.

  The encoding control parameter correction circuit 109 compares the encoding parameter currently being controlled with the received encoding control parameter correction data, and if it is determined that they are different, the encoding control parameter correction circuit 109 performs encoding so as to correct the necessary processing module. The encoding control parameter correction data is transmitted to the encoding syntax control circuit 110.

  The encoding syntax control circuit 110 transmits the encoding control parameter correction data to the processing module to be controlled according to the received encoding control parameter correction data.

  The genre prediction circuit 111 acquires scene delimiter information from the scene detection circuit 106, and creates a predicted genre information and transmits it to the scene classification circuit 107 when a genre information non-acquisition flag exists.

<Operation of High Efficiency Encoding / Recording Apparatus 10>
The operation of the high-efficiency encoding / recording apparatus 10 according to the first embodiment of the present invention will be described.

  Among the operations of the high-efficiency encoding / recording apparatus 10 in the present embodiment, the flow of digital image data of a video to be encoded is the same as that of the conventional image encoding / recording apparatus 20, and thus the description thereof is omitted.

  First, EPG information is input from the EPG information input terminal 101 separately from input of digital image data to be encoded. As an example of the acquired EPG information, FIG. 2 shows a rough content of EPG information transmitted by digital broadcasting.

  Next, “program name”, “program description”, “genre”, and “program detailed information” of the program being encoded as information for specifying the genre by the program information acquisition circuit 102 from the EPG information shown in FIG. Is acquired and transmitted to the genre / keyword search circuit 103.

  Genre / keyword search circuit 103 creates genre information from “genre” among the information received from program information acquisition circuit 102. Further, the genre / keyword search circuit 103 acquires keyword information from the scene information database 104 and includes the keyword information in the information contents of “program name”, “program description”, and “program detailed information” received from the program information acquisition circuit 102. It is searched whether the keyword of is included.

  A data configuration example of the keyword information stored in the scene information database 104 is shown in FIG. This keyword information is composed of main genre information, sub-genre information as keywords indicating program details for subdividing the main genre information, and genre information ID corresponding to the sub-genre information.

  The genre information created by the genre / keyword search circuit 103 and the genre information ID of the keyword information extracted as a result of the search are transmitted to the scene classification circuit 107. At this time, if the genre / keyword search circuit 103 cannot acquire both the genre information and the genre information ID by extracting the keyword information because the EPG information cannot be acquired, the genre / keyword search circuit 103 sends the scene classification circuit. Information indicating that genre information cannot be acquired is transmitted to 107.

  On the other hand, digital image data to be encoded input to the input image memory is transmitted to the image characteristic calculation circuit 105, and image characteristics that are information relating to spatial or temporal correlation of image information and information relating to luminance and color difference levels. Information is calculated.

  Calculation of image characteristic information in the image characteristic calculation circuit 105 will be described. Specifically, the calculated image characteristic information includes frame average luminance information LDC, frame average color difference information CBDC and CRDC, frame total value FAct of absolute difference between adjacent pixels in the frame, and in-screen between consecutive frames. This is the sum FDfiff of the absolute differences between pixels belonging to the same position.

Frame average luminance information LDC (hereinafter referred to as “frame luminance DC”) is calculated by the following equation (5), where the luminance signal level is luma ().

The frame average color difference information CBDC and CRDC are calculated by the following formulas (6) and (7), where the level of the color difference signal is cb () and cr ().

  Further, the frame sum value FAct of the difference value between adjacent pixels in the frame (hereinafter referred to as “frame activity”) is an arrow as shown in FIG. 4 in units of 8 × 8 pixels for performing DCT processing as frame activity. An in-plane correlation activity between pixels is calculated. Then, by calculating the frame sum of the in-plane correlation Activity, the frame sum value of the frame activity is obtained.

This in-plane correlation activity is calculated by the following equation (8).

Then, the frame activity FAct as the frame total value of the in-plane correlation activity is calculated by the following equation (9).

Also, the sum FDfiff (hereinafter referred to as “frame difference”) of the absolute differences between pixels belonging to the same position in the screen between consecutive frames is the luminance component one frame before the input image frame to be encoded. Is prev_luma (), and chrominance components one frame before are prev_cb () and prev_cr (), the following equation (10) is calculated.

  The image characteristic information calculated as described above by the image characteristic calculation circuit 105 is transmitted to the scene detection circuit 106. The scene detection circuit 106 performs processing for detecting a scene change point at which a scene switches using the received image characteristic information. This scene change point is the detection of a scene change where the screen changes instantaneously, and the screen changes with a continuous period of time (the fade-in where the screen gradually becomes brighter and the fade-out where the screen gradually disappears) State).

  These detection processes will be described with reference to FIG. In this processing, processing is performed using the frame total value FAct of the frame activity and the frame luminance DC component in the input image characteristic information.

  The frame total value of the latest frame activity stored is FAct (N), the frame total value of the frame activity one frame before is FAct (N-1), and the frame total value of the frame activity N frames before is FAct (0 ). Similarly, for the frame luminance DC component, the latest frame luminance DC component is LDC (N), the frame luminance DC component one frame before is LDC (N-1), and the frame luminance DC component N frames before is LDC (0). To do. I, J, K, and L are variables.

First, in order to detect a scene change, a frame sum value of frame activity between N frames and an inter-frame difference absolute value of a frame luminance DC component are calculated. At this time, since the frame activity absolute value of the frame activity and the frame luminance DC component for the frame I = 0 to N-2 remains from the calculation result in the previous frame, the frame I = 0 to N-2 first. Is determined (S1). If the frame is I = 0 to N−2 (“Yes” in S1), the following expressions (11) and (12) are performed (S2).

In step S1, when frame I = N−1 (“No” in S1), the difference in frame activity between frame I = N−1 and frame I = N is calculated by the following equation (13), and similarly The interframe difference of the frame luminance DC component is calculated by the following formula (14) (S3).

  Next, in order to determine whether frame J (1 ≦ J ≦ N-2) is a scene switching point, the frame activity from I = JK (0 ≦ K ≦ J) to I = N-2 The total value and the frame activity value of frame J are compared by the following equation (15) (S4). As a result of the comparison, if Expression (15) is satisfied (“Yes” in S4), it is determined that a scene conversion point has been detected, and frame J is output as a scene change point (S5).

When Expression (15) is not satisfied (“No” in S4), the sum of the difference values of the frame luminance DC components from I = JK (0 ≦ K ≦ J) to I = N−2 and the frame The difference value of the J frame luminance DC component is compared by the following equation (16) (S6). As a result of the comparison, if Expression (16) is satisfied (“Yes” in S6), it is determined that a scene conversion point has been detected, and frame J is output as a scene change point (S6).

  Here, the normal threshold is a value sufficiently larger than 0.5 and close to 1. When the condition of Expression (16) is not satisfied (“No” in S6), information indicating that the scene change point has not been detected is output (S7).

  Next, in order to detect overlapping and changing overlap scenes, the change in frame activity between N frames is measured and a search is made as to whether the values are uniformly increasing or decreasing. The specific processing is as follows.

When the detection of the scene change point is completed, the overlap scene is detected at L = J + 1 to N-1 (S9) of the frame J = 0 to N-1 (S8). First, FAct (J) and FAct (N) are compared (S10), and it is determined whether or not the following equation (17) is satisfied.

As a result of the determination, if the expression (17) is satisfied (“Yes” in S10), it is further determined whether the following expression (18) is satisfied (S11).

  If the determination is repeated until N-1 (S12, S13) and equation (18) is satisfied (“Yes” in S12), it is determined that there is a possibility of an overlapped fade-in state. It is determined that it is in a fade-in state (S14).

If the expression (17) is not satisfied (“No” in S10), it is determined whether or not the following expression (19) is satisfied (S15).

  If the determination is repeated up to N-1 (S16, S17) and equation (19) is satisfied (“Yes” in S16), it is determined that there is a possibility of an overlapped fadeout, and a temporary fadeout is performed. The state is determined (S18).

  When the above equation (18) is not satisfied (“No” in S11) or when equation (19) is not satisfied (S15 “No”), frames J = 1 to M (M <N− The processing from step S9 to step S18 is repeated until 1) (“No” in S19 and S20). As a result of the repetition up to frame J = N−1, when it is not determined that the temporary fade-in state or the temporary fade-out state is present (“Yes” in S20), it is determined that no overlap scene has been detected (S21). ).

  If it is determined in step S14 that it is in the temporary fade-in state, or if it is determined in step S18 that it is in the borrowed fade-out state, the transition of the luminance DC component in the same section is measured. The luminance DC component is determined in consideration of the error γ by the following process. Here, the error γ is preferably about 1/10 of the difference value LDC (N) −LDC (J) of the luminance DC component between the N−J frames.

The process is repeated from L = J + 1 to N−1 (S22). First, LDC (J) and LDC (N) are compared (S23), and it is determined whether or not the following equation (20) is satisfied.

As a result of the determination, if the expression (20) is satisfied (“Yes” in S23), it is further determined whether or not the following expression (21) is satisfied (S24).

  If the determination is repeated until N-1 (S25, S26), equation (21) is satisfied (“Yes” in S25), and it is determined in step S14 that the temporary fade-in state is present, fade-in Is determined to be in the overlap state, and it is determined that fade-in has been detected (S27). If it is determined that the formula (21) is satisfied (“Yes” in S25) and the temporary fade-out state is determined in step S18, it is determined that the fade-out overlap state is detected, and it is determined that the fade-out is detected. (S28).

Further, when the formula (20) is not satisfied (“No” in S23), it is determined whether the following formula (22) is satisfied (S29).

  This determination process is repeated between frames L = J + 1 to N−1 (S30, S31). As a result of the determination being repeated up to N−1, equation (22) is satisfied (“Yes” in S30), and if it is determined in step S14 that the temporary fade-in state is present, the fade-in overlap state is established. It is determined that a fade-in has been detected (S27). If it is determined that the formula (22) is satisfied (“Yes” in S30) and the temporary fade-out state is determined in step S18, it is determined that the fade-out overlap state is detected, and it is determined that the fade-out is detected. (S28).

  When the above equation (21) is not satisfied (“No” in S24) or when equation (22) is not satisfied (S29 “No”), it is determined that no overlap scene has been detected. (S21).

  In the scene detection circuit 106, from the above processing result, a flag indicating whether or not the frame J is a frame in which a scene conversion point is detected, a flag indicating whether or not an overlap scene is detected, Scene delimiter information including a flag indicating whether the activity is in the upward direction (fade-in tendency) or the downward direction (fade-out tendency) in the frame in which the lap scene is detected is generated and transmitted to the scene classification circuit 107. . Similarly, image characteristic information is also transmitted from the scene detection circuit 106 to the scene classification circuit 107.

  The scene separation circuit 107 recognizes a scene break based on the scene break information received from the scene detection circuit 106. At this time, when the flag indicating that the overlap scene is detected is included, it is recognized that the timing at which the flag disappears is a scene break, and thereafter a new scene is started.

  The scene classification circuit 107 receives image characteristic information for each frame from the scene detection circuit 106 and receives a genre information ID from the genre / keyword search circuit 103. From this image characteristic information, an average value (hereinafter referred to as “scene characteristic information”) of a section in which one scene continues is calculated and combined with the genre information ID received from the genre / keyword search circuit 103, It is transmitted to the management circuit 108.

This scene characteristic information is calculated by the following equations (23) to (27), where P is the number of frames after the start of the scene.

  The scene characteristic information calculated as described above is corrected by the image characteristic information of a newly input frame while it is determined that the scene continues, and is reset at a scene break.

On the other hand, in the code amount control circuit 219, the average value Complex of the past M frames calculated for each frame from the code amount Bitused of the output image bitstream and the average value AvgQ of the quantization scale is expressed by the following equation (28). ).

Similarly, in the code amount control circuit 219, an average value AvgMV of past M frames of the frame sum SumMV of motion vector distances with respect to the prediction frame is calculated by the following equation (29).

  In these code amount control circuits 219, Complex and AvgMV calculated by Expression (28) or (29) are transmitted to the database management circuit 108 as encoded result information.

  In the database management circuit 108, the encoding control parameter correction data for performing the encoding control based on the scene characteristic information received from the scene classification circuit 107 and the encoding result information received from the encoding control circuit 219 is the scene information. Obtained from the database 104.

  The operation when the parameter correction value is acquired from the scene information database 104 in the database management circuit 108 will be described with reference to FIG. FIG. 6 is a flowchart of an algorithm showing an operation when a parameter correction value is acquired from the scene information database 104, and R is a variable.

  First, the threshold value for dividing the scene characteristic information and the encoding result information based on the genre information ID is read from the scene information database 104 from the database management circuit 108. When this threshold is classified into N types, (N-1) types are stored in the scene information database 104 for each genre information ID. This threshold is created for seven types of scene characteristic information and encoding result information AvgFAct, AvgLDC, AvgCBDC, AvgCRDC, AvgFDiff, Complex, and AvgMV, and each information is compared with the corresponding threshold and classified. Done. In this embodiment, AvgCBDC, AvgCRDC, and AvgMV are divided into two types, and AvgFAct, AvgLDC, AvgFDiff, and Complex are divided into four types.

  Of these values, AvgFAct is first classified. In the operation, first, the scene information database 104 is accessed from the database management circuit 108, and three kinds of thresholds ε (R) (R = 0 to 2) relating to AvgFAct are read based on the genre information ID (S41). Then, AvgFAct and ε (R) at R = 0 are compared (S42, S43). As a result, when AvgFAct <ε (R) (“Yes” in S43), “R” is output (S44). This process is repeated until R = 2 (S45, S46). Finally, when AvgFAct = ε (2), “3” is output (S47).

  Similar to this AvgFAct segmentation process, segmentation processes are also performed for AvgLDC, AvgCBDC, AvgCRDC, AvgFDiff, Complex, and AvgMV (S48 to S53). As a result, the output values are bundled, and a total 11-bit signal (hereinafter referred to as “scene identification signal”) is created (S54).

  Based on the scene identification signal and the genre information ID, data in a table (hereinafter referred to as “encoding control parameter correction data”) stored in the scene information database 104 as a parameter for controlling the encoding process is referred to as the database management circuit 108. (S55). A configuration example of the encoding control parameter correction data is shown in FIG. By accessing this table of the scene information database 104 from the database management circuit 108, MVMax indicating the detection range of the motion vector, Syntax M indicating the value for specifying the reference frame insertion interval, and the target code length for each frame type A (T) indicating a weighting multiplier, MaxRate which is a value indicating the maximum allocation rate at the time of VBR encoding, TargetVBV which is a parameter indicating how much the VBV buffer is controlled toward the degree of fullness, and a luminance signal quantization matrix The encoding parameters of QmatL, which is the value, and QmatC, which is the quantization matrix value for the color difference signal, are acquired.

  A case where “sports / soccer” is selected as genre information in the encoding parameter acquisition process will be described.

  When “Sports / Soccer” is selected as the genre information, the lawn characterized by the AvgLDC, AvgCBDC, and AvgCRDC scene characteristics information is recognized for each detected scene. The degree of zoom is measured. If the AvgFAct is large when the lawn is not recognized, it is recognized that the spectator seat is shown.

  When it is recognized that the lawn is reflected, the attention point on the program is the movement of the player in the game. At this time, when the image is displayed in a distant view, the movement of the small player can be accurately captured on the screen by setting the motion vector detection range MVMax to be large in the horizontal direction. Also, in the case of a close-up view, the motion vector detection range MVMax is given in the same way horizontally and vertically to correspond to instantaneous fast movement, the MaxRate value is large, and the TargetVBV value is set high. In addition, the prediction efficiency is improved by setting the interval SyntaxM for inserting the reference frame to be shorter.

  On the other hand, when it is recognized that the audience seat is shown, the motion vector detection range MVMax is set to be small, and MaxRate is set to be small so that a large code amount is not given instantaneously. Furthermore, the allocation of I pictures is increased, and control is performed so that encoding noise such as block noise is less likely to appear than smoothness of movement in a high-resolution auditorium.

  Even if it is recognized that the lawn is reflected in the scene characteristic information as described above, for example, when “music / live” is selected as the keyword information and AvgFAct is high, The same control is performed. At this time, since the degree of importance of the audience seats is low, control is performed with the high-frequency luminance signal quantization matrix value QmatL and the color difference signal quantization matrix value QmatC, and coarse quantization processing is permitted.

  Such encoding control parameter correction data is set for various scenes that can be predicted from characteristic transitions of the scene identification signal and stored in the scene information database.

  When a scene change point is detected due to a scene change (S56), the appearance frequency count Times of the data managed by the last genre information ID and scene identification signal before the scene change is increased by one. Data is transmitted to the scene information database 104 and recorded (S57, S58).

  Next, the encoding control parameter correction data is transmitted from the database management circuit 108 to the encoding control parameter correction circuit 109 together with the scene break information. The encoding control parameter correction circuit 109 compares the currently controlled encoding parameter with the received encoding control parameter correction data. As a result of the comparison, if it is determined that they are different, a control signal for a necessary processing module is generated and transmitted to the encoding syntax control circuit 110. Specifically, when a scene changes, a control signal due to a change in the encoding parameter is transmitted to the encoding syntax control circuit 110. However, if there is no change in the scene and the encoding parameter does not fluctuate greatly, the control is performed. No signal is transmitted. In the present embodiment, the control signal is not transmitted when only one of the encoding parameters has changed.

  In the encoding syntax control circuit 110, the received control signal is transmitted to the corresponding processing module. Specifically, MVMax is sent to the motion vector detection circuit 217, SyntaxM is sent to the encoding circuit 207, the motion vector detection circuit 217, the motion compensation prediction circuit 218, and the code amount control circuit 219, and A (T), MaxRate, and TargetVBV is transmitted to the code amount control circuit 219, and QmatL and QmatC are transmitted to the quantization circuit 206, the encoding circuit 207, and the inverse quantization circuit 212 for control.

  As described above, according to the present embodiment, since the encoding control parameter correction data is set for various scenes that can be predicted from the characteristic transition of the scene identification signal, the encoding control suitable for the scene switching is performed. It is possible to switch, and it is possible to realize dynamic control adapted to each scene, which has been difficult in the past.

  The operation of the high-efficiency encoding / recording apparatus 10 when EPG information can be acquired by the program information acquisition circuit 102 has been described above. Next, the case where EPG information cannot be acquired will be described.

  When digital image data to be encoded is input from a TV other than a TV program, it is impossible to obtain genre information and keyword information created from EPG information. In such a case, a genre information prediction process is performed.

  The genre information prediction process will be described with reference to FIG. FIG. 8 is a flowchart showing an algorithm of the operation for predicting genre information, where H is a variable.

  First, in the genre / keyword search circuit 103, when the information included in the EPG information is not acquired from the program information acquisition circuit 102, the genre information non-acquisition flag that informs the genre prediction circuit 111 that the information cannot be acquired. Is sent.

  The genre prediction circuit 111 receives the scene break information from the scene detection circuit 106 when the scene break information exists in the scene detection circuit 106 (S61). At this time, if the genre information non-acquisition flag exists in the genre prediction circuit 111 (“Yes” in S62), a genre acquisition request is transmitted from the genre prediction circuit 111 to the database management circuit 108 (S63). .

  In the database management circuit 108, scene identification signals for all genres are generated based on the scene characteristic information acquired from the scene classification circuit 107. Then, the appearance frequency of each genre information ID belonging to each generated scene identification signal is acquired (S64, S65, S66). Next, the appearance frequencies of the acquired genre information IDs are compared (S67), and the most frequently detected genre information IDs and their appearance frequencies are transmitted to the genre prediction circuit 111 (“Yes” in S68 and S65).

  The genre prediction circuit 111 determines that the genre information ID is valid when the received appearance frequency is greater than or equal to Λ (S69), and transmits this genre information ID to the scene classification circuit 107 as predicted genre information. (S70).

  The predicted genre information received by the scene classification circuit 107 is transmitted to the database management circuit 108, and the encoding control parameter is corrected by the predicted genre information.

  As described above, according to the present embodiment, by comparing the appearance frequencies of the genre information IDs, even if the EPG information cannot be obtained, the genre prediction is performed from the appearance probabilities of the genres belonging to the corresponding scene identification signal. In addition, the user's genre preference is added to the selection determination, and effective predictive control becomes possible.

  In the present embodiment, scene change point detection processing is performed using only frame activity and frame luminance DC components, but processing can also be performed using frame color difference DC components.

  In this embodiment, the average value of the image characteristic information for each scene is calculated as the scene characteristic information. However, the present invention is not limited to this calculation method, and a representative value is obtained by taking a histogram of the image characteristic information in the scene. It may be calculated as scene characteristic information.

  In this embodiment, seven types of encoding parameters are used. However, since a scene with a large feature can be identified with a small number of encoding parameters, it is possible to identify in a form specialized for the scene to be considered at the time of encoding. It is also possible to manage the encoding parameters. In that case, the amount of data stored in the database can be reduced in a state where necessary encoding control is realized. Accordingly, the types of image characteristic information and scene characteristic information to be calculated can be reduced.

  In this embodiment, the block diagram of the circuit configuration has been described as the high-efficiency encoding / recording apparatus. However, these circuits are the same when they are processed on software such as a computer using the same processing algorithm. The effect is obtained.

In this embodiment, the MPEG2 standard encoding apparatus has been described. Similarly, the correlation between adjacent pixels (spatial direction) of an image signal and the correlation between adjacent frames or adjacent fields (time direction) are used. The present invention can also be applied to an encoding / recording apparatus using MPEG4 ASP or MPEG4 AVC that compresses the amount of information, and similar effects can be obtained. In the case of MPEG4 AVC, since the fineness of quantization can be encoded with different settings for the luminance signal and the color difference signal, a value for controlling the quantization ratio of the luminance signal and the color difference signal is set as an encoding parameter. By preparing, it becomes possible to perform effective control.

1 is a block diagram showing a high-efficiency encoding / recording apparatus according to a first embodiment of the present invention. It is explanatory drawing which shows the example of a display of the program information transmitted as EPG information utilized with the highly efficient encoding recording device in 1st Embodiment of this invention. It is explanatory drawing which shows the data structural example of the keyword information utilized with the highly efficient encoding recording device in 1st Embodiment of this invention. It is explanatory drawing which shows the relationship of the area | region of the activity calculated with the highly efficient encoding recording device in 1st Embodiment of this invention, and object pixel. It is a flowchart which shows the algorithm of the operation | movement in which the scene change point is detected in the high efficiency encoding recording device in 1st Embodiment of this invention. It is a flowchart which shows the algorithm of the operation | movement by which encoding control parameter correction data is acquired in the high efficiency encoding recording device in 1st Embodiment of this invention. It is explanatory drawing which shows the table content of the encoding control parameter correction data stored in the scene information database of the high efficiency encoding recording device in 1st Embodiment of this invention. It is a flowchart which shows the algorithm of the operation | movement by which prediction genre information is acquired in the high efficiency encoding recording device in 1st Embodiment of this invention. It is a schematic diagram which shows the encoding system used by the conventional MPEG2 image encoding. It is a schematic diagram which shows the timing of the rearrangement to the encoding order at the time of the encoding used by the conventional MPEG2 image encoding. It is a schematic diagram which shows the timing of rearrangement from the stream arrival order at the time of decoding used in the conventional MPEG2 image encoding to the decoded image output order. It is a block diagram which shows the conventional MPEG2 image coding recording apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... High-efficiency encoding / recording apparatus 20 ... Image encoding / recording apparatus 101 ... EPG information input terminal 102 ... Program information acquisition circuit 103 ... Genre / keyword search circuit 104 ... Scene information database 105 ... Image characteristic calculation circuit 106 ... Scene detection circuit DESCRIPTION OF SYMBOLS 107 ... Scene classification circuit 108 ... Database management circuit 109 ... Coding control parameter correction circuit 110 ... Coding syntax control circuit 111 ... Genre prediction circuit 201 ... Target image input terminal 202 ... Input image memory 203 ... Two-dimensional block data conversion circuit 204 ... Subtractor 205 ... Orthogonal transformation circuit 206 ... Quantization circuit 207 ... Encoding circuit 208 ... Encoding table 209 ... Multiplexer 210 ... Image bit stream buffer 211 ... Recording medium or transmission path 212 ... Inverse quantization circuit 213 ... Inverse Interconversion circuit 214 ... Adder 215 ... Deblocking circuit 216 ... Reference image memory 217 ... Motion vector detection circuit 218 ... Compensation prediction circuit 219 ... Code amount control circuit

Claims (7)

In a high-efficiency encoding / recording apparatus for compressing the digital image data and storing it in a recording medium by performing an encoding process controlled by an encoding control parameter on the input digital image data of the video,
Genre information for acquiring information related to the genre of the video to be encoded based on electronic program guide information added to the digital image data or based on genre prediction information calculated from the digital image data Acquisition means;
Image characteristics for calculating at least one of information relating to spatial correlation of video information, information relating to temporal correlation, information relating to luminance level, and information relating to color difference level from the digital image data as image characteristic information A calculation means;
Based on the calculated image characteristic information, scene change point detection means for detecting scene break information about the scene change point at which the video scene changes from the digital image data;
Scene classification means for dividing the digital image data into scenes according to the detected scene separation information and calculating scene characteristic information based on the image characteristic information for each divided scene;
Encoding result information acquisition means for acquiring encoding result information relating to a code amount of digital image data already encoded among the digital image data of the video;
A correction value of the encoding control parameter is calculated based on the scene identification signal calculated from the information related to the genre and the scene characteristic information and the encoding result information, and the encoding control is performed based on the calculated correction value. Encoding control parameter correction means for correcting parameters for each scene;
Encoding means for encoding the digital image data for each of the divided scenes according to the encoding control parameter corrected for each of the divided scenes;
A high-efficiency encoding / recording apparatus comprising: The image characteristic calculation means, as the image characteristic information,
An average luminance level value calculated for each frame of the digital image data;
An average color difference level value calculated for each frame of the digital image data;
A sum of absolute values of differences between adjacent pixels in a frame calculated for each frame of the digital image data;
A sum of absolute differences between pixels belonging to the same position calculated between two consecutive frames of the digital image data;
The high-efficiency encoding / recording apparatus according to claim 1, wherein at least one value is calculated. 3. The high scene according to claim 1, wherein the scene change point detection processing unit detects an instantaneous scene change of the video or a scene change performed in a continuous period. Efficiency coding recording device. The scene classification means, as the scene characteristic information,
An average luminance level value calculated for each frame of the digital image data;
An average color difference level value calculated for each frame of the digital image data;
A sum of absolute values of differences between adjacent pixels in the frame calculated for each frame of the digital image data;
A sum of absolute differences between pixels belonging to the same position calculated between two consecutive frames of the digital image data;
Calculate at least one of the values
The encoding result information acquisition means, as the encoding result information,
A sum of motion vector distances calculated for each frame for which motion compensation prediction has been performed;
Information amount of encoded digital image data calculated for each frame of the digital image data;
The high-efficiency encoding / recording apparatus according to claim 1, wherein at least one value is calculated. The encoding control parameter correction means is a parameter for controlling the encoding process.
A value indicating a motion vector detection range;
A value specifying an interval for inserting a frame to be a reference frame when detecting the motion vector;
A value for controlling a target code amount for each frame;
A value that controls the maximum instantaneous encoding rate;
A quantization matrix value for quantizing the luminance signal;
A quantization matrix value for quantizing the color difference signal;
5. The high-efficiency encoded recording apparatus according to claim 1, wherein a correction value of at least one value is output. Information on the genre acquired by the program information acquisition means is
Information obtained from electronic program guide information added to the digital image data;
Information obtained by searching text data obtained from the electronic program guide information with keyword information set in advance to specify a genre;
The high-efficiency encoding / recording apparatus according to claim 1, comprising: A frequency recording means for accumulating and recording the appearance frequency of the scene identification signal;
The genre information acquisition unit calculates scene identification signals for all genres based on the scene characteristic information acquired from the scene classification unit when information about the genre of the video cannot be acquired from the electronic program guide information. 6. The genre prediction information is calculated by selecting a scene identification signal with the highest cumulative appearance frequency among the calculated scene identification signals. The high-efficiency encoding / recording apparatus according to the item.

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