JP2006154350A - Encoded data converting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reproduce encoded data of a 2nd encoding mode using no additional encoding tool with equipment for encoded data of a 1st encoding mode by converting the encoded data into the encoded data of the 1st encoding mode with a small processing amount without making sound quality worse. <P>SOLUTION: In addition to encoding and decoding tools usable for the 1st encoding mode, an encoded data converting device is equipped with: an additional tool use decision section 310 which inputs encoded data of the 2nd encoding mode for which the additional encoding and decoding tools are usable and decides whether the encoded data use the additional encoding tools; and an encoding mode change section 320 which changes the encoding mode of the encoded data from the 2nd encoding mode to the 1st encoding mode, converts the encoded data into the encoded data of the 1st encoding mode, and outputs the data when the additional tool use decision section 310 decides that no additional encoding tool is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a conventional reproduction device that can reproduce encoded data in the first encoding mode but cannot reproduce encoded data in the second encoding mode, and does not use an additional encoding tool. The present invention relates to an apparatus for converting encoded data in the second encoding mode into encoded data in the first encoding mode so that encoded data in the encoding mode can be reproduced.

  As a conventional encoded data converter, the encoded data of the second encoding mode is input, the encoded data of the second encoding mode is decoded, and then encoded by the first encoding mode. An apparatus that converts into encoded data of a first encoding mode and outputs the encoded data is known (see, for example, Patent Document 1).

  FIG. 8A shows a configuration of a conventional encoded data conversion apparatus described in Patent Document 1. In FIG. In FIG. 8A, 810 is a full rate decoding unit, 820 is a low rate encoding unit, 830 is an encoded data conversion device, and 840 is an answering machine message storage unit. The encoded data conversion apparatus 830 includes a full rate decoding unit 810 and a low rate encoding unit 820. In FIG. 8A, full-rate encoded data is input, and once decoded by the full-rate decoding unit 810, it is input to the low-rate encoding unit 820 to obtain low-rate encoded data. The obtained low rate encoded data is stored in the answering machine message storage unit 840.

FIG. 8B is a diagram in which the names of the constituent blocks of the conventional example shown in FIG. 8A are generalized and rewritten to compare the conventional example with the embodiment of the present invention. That is, the full-rate encoded data in FIG. 8A is the encoded data in the second encoding mode in FIG. 8B, and similarly, the full-rate decoding unit 810 is converted into the decoding unit 850 in the second encoding mode, the low rate. It is the figure which made the encoding part 820 the encoding part 860 by a 1st encoding mode, and set the answering machine message storage part 830 as the encoding data storage part 880 of a 1st encoding mode. The encoded data conversion apparatus 870 in FIG. 8B includes a decoding unit 850 according to the second encoding mode and an encoding unit 860 according to the first encoding mode.
JP-A-9-298591

  However, the encoded data conversion apparatus having the above-described conventional configuration has a problem that the amount of processing for converting encoded data is large because both decoding and encoding must be performed. In addition, there has been a problem that sound quality deteriorates due to repeated encoding.

  The present invention solves the above-mentioned conventional problems, and the encoded data of the second encoding mode that does not use the additional encoding tool is converted into the first code without degrading the sound quality with a small processing amount. It is an object of the present invention to provide an apparatus for converting into encoded data in a normal mode.

  In order to solve the above-described conventional problems, the encoded data conversion apparatus of the present invention can use an additional encoding and decoding tool in addition to the encoding and decoding tools that can be used in the first encoding mode. The additional tool usage determining means for determining whether or not the encoded data uses the additional encoding tool using the encoded data of the second encoding mode, and the additional tool usage determining means includes the When it is determined that an additional encoding tool is not used, the encoding mode of the encoded data is changed from the second encoding mode to the first encoding mode, and the encoding of the first encoding mode is performed. The most important feature is that it comprises a coding mode changing means for converting to data and outputting the data.

  According to the encoded data conversion apparatus of the present invention, the additional tool use determining means detects the encoded data of the second encoding mode not using the additional encoding tool, and the encoding mode changing means By changing the encoding mode of the detected encoded data from the second encoding mode to the first encoding mode, the encoded data is converted into the encoded data of the first encoding mode and output. Therefore, it is possible to realize an encoded data conversion device that is small and has no deterioration in sound quality.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  First, the relationship between the second encoding mode that is the conversion input target and the first encoding mode that is the conversion output target in the encoded data conversion apparatus of the present invention will be described.

  FIG. 1 is a diagram illustrating a relationship between encoding and decoding tools (modules) that can be used in the first encoding mode and the second encoding mode. As shown in FIG. 1, the encoding / decoding tool 120 that can be used in the second encoding mode is different from the encoding / decoding tool 100 that can be used in the first encoding mode. Is added. Here, the implementation and use of the additional encoding tool in the encoding apparatus according to the second encoding mode is an option (free selection) and is not essential. On the other hand, since the decoding apparatus must cope with decoding of encoded data using the additional encoding tool, it is essential to implement the additional decoding tool.

  As an example of such an encoding mode, AAC (Advanced Audio Coding) of MPEG (Moving Picture Experts Group) is known. In the case of AAC, the first encoding mode is MPEG-2 AAC (see ISO / IEC 13818-7), the second encoding mode is MPEG-4 AAC (see ISO / IEC 14496-3), additional encoding / The decryption tool corresponds to PNS (Perceptual Noise Substation).

  In the following embodiments, a case will be described in which the first encoding mode is MPEG-2 AAC, the second encoding mode is MPEG-4 AAC, and the additional tool is PNS. The encoded data format of MPEG-2 AAC or MPEG-4 AAC is an ADTS (Audio Data Transport Stream) format.

  FIG. 2 is a diagram illustrating a configuration of ATS encoded data in the ADTS format. As shown in FIG. 2, AAC encoded data in ADTS format is composed of a plurality of ADTS frames. One ADTS frame includes an ADTS header and an AAC raw data block.

  The ADTS header is composed of header data such as a synchronization word, ID, sampling frequency, and frame length. Here, the value of ID represents MPEG-2 AAC or MPEG-4 AAC. When ID = 1, MPEG-2 AAC is represented, and when ID = 0, MPEG-4 AAC is represented. An AAC raw data block is an AAC encoded data block without a header that constitutes an ADTS frame. The format of the MPEG-4 AAC raw data block that does not use PNS is the same as the format of the MPEG-2 AAC raw data block.

  Hereinafter, embodiments of the present invention will be described more specifically.

(Embodiment 1)
FIG. 3 is a block diagram showing a configuration of the encoded data conversion apparatus according to Embodiment 1 of the present invention. In FIG. 3, reference numeral 300 denotes a storage medium such as a semiconductor memory or a hard disk, 310 denotes an additional tool use determination unit, 320 denotes an encoding mode change unit, and 330 denotes an encoded data conversion device. In the first embodiment, the encoded data conversion device 330 includes an additional tool use determination unit 310 and an encoding mode change unit 320. The operation of the encoded data converter 330 configured as described above will be described below.

  It is assumed that encoded data of the second encoding mode (MPEG-4 AAC) is stored in the storage medium 300 in an ADTS (Audio Data Transport Stream) format.

  The encoded data of the second encoding mode read from the storage medium 300 is input to the additional tool usage case unit 310.

  The additional tool usage determination unit 310 determines whether or not the input encoded data in the second encoding mode uses the additional encoding tool (PNS), and encodes the determination result as a mode change flag. The data is output to the mode change unit 320.

  FIG. 4 is a flowchart showing an operation sequence of the additional tool use determination unit 310. In step 401, the mode change flag is set to 0, and the data of the first frame (ADTS frame) is read.

  In step 402, it is determined whether or not the ID value of the read ADTS header is 0, so that the encoded mode of the read encoded data is the second encoding mode (MPEG-4 AAC). It is determined whether or not. If the value of ID is 0, that is, if it is the second encoding mode, go to step 403. If the ID value is not 0, that is, if it is the first encoding mode (MPEG-2 AAC), the process ends with the mode change flag remaining at 0.

  In step 403, it is determined whether or not reading of data of all frames is completed. When reading of data of all frames is completed, the process goes to step 406. If the reading of all the frame data has not been completed, the process goes to step 405.

  In step 405, section data is extracted from the AAC raw data block. The section data is extracted by separating (demultiplexing) the encoded data of the AAC raw data block until the section data is extracted. Next, go to step 407.

  In step 407, it is determined whether the PNS of the additional encoding tool is used from the spectrum Huffman codebook number of the section data. In the case of MPEG-4 AAC, when the spectrum Huffman codebook number is 13, PNS is used, and otherwise, PNS is not used. In step 407, the spectrum Huffman codebook numbers for all sections constituting the section data are checked, and if at least one is equal to 13, it is determined that PNS is used. If it is determined that PNS is used, the process is terminated. If it is determined that the PNS is not used, the process goes to step 404. In step 404, the data of the next frame is read, the process goes to step 402, and each step is repeated in the same manner.

  The branch from step 403 comes to step 406 if the additional encoding tool PNS is not used across all frames. In step 406, the mode change flag is set to 1 and the process is terminated.

  The additional tool usage determining unit 310 sets the mode change flag as described above and outputs the result as a determination result.

  In the encoding mode changing unit 320, when the mode change flag output from the additional tool use determining unit 310 is 1, the encoding mode is changed by changing the ID of the ADTS header of the encoded data from 0 to 1. The second encoding mode (MPEG-4 AAC) is changed to the first encoding mode (MPEG-2 AAC), converted into encoded data of the first encoding mode, and output. When the mode change flag is 0, the encoding mode is not changed and encoded data is not output.

  The encoded data of the first encoding mode output from the encoding mode changing unit 320 is stored in the storage medium 300. In order to save the use area of the storage medium 300, the encoded data of the second encoding mode may be overwritten with the converted encoded data of the first encoding mode.

  In the first embodiment, since only a very partial decoding process of extracting all the spectrum Huffman codebook numbers of the section data is required, the process is much more compared with the complete decoding process required in the conventional example. The amount is small. Further, since the re-encoding process that is necessary in the conventional example is unnecessary, the processing amount required for the encoded data conversion is extremely small. Further, in the first embodiment, only the ID representing the coding mode of the ADTS header is changed, and the AAC raw data block itself is not changed, so that the sound quality is not deteriorated.

  As described above, in the encoded data conversion device 330 according to the first embodiment, the second encoding mode in which the additional encoding tool is not used is provided by providing the additional tool use determining unit 310 and the encoding mode changing unit 320. Can be converted into encoded data of the first encoding mode with a small amount of processing without degrading sound quality.

  In the above embodiment, the case where the encoding mode is recorded only in the ADTS header has been described. However, the encoding mode is set as attribute information in an area different from the AAC encoded data, for example, at the head of the encoded data. In addition, it may be recorded. In this case, the encoding mode changing unit 320 also changes the encoding mode recorded in a different area from the AAC encoded data.

  Note that the storage medium 300 may be built in the device or a removable storage medium such as a memory card. When the storage medium is a removable storage medium, the encoded data of the second encoding mode is converted into the encoded data of the first encoding mode by a device equipped with the encoded data conversion apparatus according to the present embodiment, for example, a personal computer. The removable storage medium is stored in the removable storage medium, and then the encoded data in the first encoding mode can be reproduced. However, the removable storage medium is installed in a conventional device that cannot reproduce the encoded data in the second encoding mode. If connected, the encoded data can be reproduced.

(Embodiment 2)
FIG. 5 is a block diagram showing a configuration of the encoded data conversion apparatus according to Embodiment 2 of the present invention. In FIG. 5, 500 is a storage medium, 510 is a decryption unit, 520 is an additional tool use determination unit, 530 is an encoding mode change unit, 540 is an encryption unit, and 550 is an encoded data conversion device. In the second embodiment, the encoded data conversion apparatus 550 includes a decryption unit 510, an additional tool use determination unit 520, an encoding mode change unit 530, and an encryption unit 540.

  Since the additional tool usage determining unit 520 and the encoding mode changing unit 530 are the same as the additional tool usage determining unit 310 and the encoding mode changing unit 320 of the first embodiment, detailed description of the operation is omitted. The operation of the encoded data conversion apparatus 550 configured as described above will be described below.

  The difference between the first embodiment and the second embodiment is that in the first embodiment, the encoded data is stored as it is in the storage medium 300, whereas in the second embodiment, the contents to be recorded are stored. That is, the encoded data is encrypted and stored in the storage medium 500 in order to protect the copyright.

  In the storage medium 500, the encoded data of the second encoding mode is encrypted and stored. The encrypted encoded data of the second encoding mode read from the storage medium 500 is input to the decryption unit 510.

  The decryption unit 510 decrypts the encrypted encoded data of the second encoding mode and outputs the encoded data of the plaintext second encoding mode. The encoded data of the second encoding mode output from the decryption unit 510 is input to the additional tool usage case unit 520.

  The additional tool use determination unit 520 determines whether the input encoded data in the second encoding mode uses the additional encoding tool, and uses the determination result as a mode change flag as an encoding mode conversion unit. Output to 530.

  In the encoding mode changing unit 530, when the mode change flag output from the additional tool use determining unit 520 is 1, the encoding mode of the encoded data is changed from the second encoding mode to the first encoding mode. The data is changed, converted into encoded data of the first encoding mode, and output. When the mode change flag is 0, encoded data is not output.

  The encryption unit 540 re-encrypts the encoded data of the first encoding mode, which is the output from the encoding mode change unit 530, and outputs it as encrypted data.

  The encrypted encoded data of the first encoding mode output from the encryption unit 540 is stored in the storage medium 500. In order to save the use area of the storage medium 500, the encoded data of the second encoding mode encrypted with the encoded data of the first encoding mode converted and encrypted is overwritten and stored. May be. Alternatively, when storing the encoded data of the first encoding mode that has been converted and encrypted, the encoded data of the second encoding mode may be deleted.

  As described above, in the encoded data conversion apparatus 550 according to the second embodiment, the decryption unit 510, the additional tool use determination unit 520, the encoding mode change unit 530, and the encryption unit 540 are provided, so that the additional encoding tool can be used. Converting encoded data in the second encoding mode that is not being used into encoded data in the first encoding mode that has not been used, with a small amount of processing and without degrading sound quality. Can do.

  In the encoded data conversion apparatus 550 according to the second embodiment, since the input / output encoded data is encrypted, it is possible to convert the encoded data while protecting the copyright of the content.

(Embodiment 3)
FIG. 6 is a block diagram showing the configuration of the encoded data conversion apparatus according to Embodiment 3 of the present invention. In FIG. 6, 600 is a distribution server, 610 is a decryption unit, 620 is a buffer memory, 630 is an additional tool use determination unit, 640 is an encoding mode change unit, 650 is an encryption unit, 660 is an encoded data converter, Reference numeral 670 denotes a storage medium. In the third embodiment, the encoded data conversion device 660 includes a decryption unit 610, a buffer memory 620, an additional tool use determination unit 630, an encoding mode change unit 640, and an encryption unit 650.

  Since the operation of the additional tool usage determining unit 630 is the same as that of the additional tool usage determining unit 310 of the first embodiment, detailed description of the operation is omitted. The operation of the encoded data conversion apparatus 660 configured as described above will be described below.

  In the third embodiment, when the encoded data in the second encoding mode transmitted from the distribution server 600 is received by the encoded data conversion device 660 and the additional encoding tool is not used. Is converted into the encoded data of the first encoding mode, and if not, the encoded data of the second encoding mode is output and stored in the storage medium 670.

  In distribution server 600, encoded data of the second encoding mode is encrypted and stored in order to protect the copyright of the content to be distributed. Distribution server 600 transmits the encoded data of the second encoding mode that has been encrypted.

  The decryption unit 610 receives and decrypts the encrypted encoded data of the second encoding mode, and outputs the encoded data of the plaintext second encoding mode.

  The encoded data of the second encoding mode output from the decryption unit 610 is temporarily stored in the buffer memory 620. Since the additional tool usage determining unit 630 requires the encoded data of all the frames to determine the usage of the additional encoding tool, in the third embodiment, the encoded data of all the frames is temporarily stored using the buffer memory 620. Remember me.

  The additional tool use determination unit 630 determines whether the encoded data of the second encoding mode read from the buffer memory 620 is using the additional encoding tool, and uses the determination result as a mode change flag. Output.

  In the encoding mode change unit 640, when the mode change flag output from the additional tool use determination unit 630 is 1 (when the additional tool is not used), the encoded data read from the buffer memory 620 is read. The encoding mode is changed from the second encoding mode to the first encoding mode, converted into encoded data of the first encoding mode, and output. When the mode change flag is 0, the encoded data of the second encoding mode read from the buffer memory 620 is output as it is.

  The encryption unit 650 encrypts the encoded data of the first encoding mode or the second encoding mode, which is the output of the encoding mode change unit 640, and outputs the encrypted data. Note that the encryption method used in the distribution server 600 and the encryption used in the storage medium 670 may be different.

  The encrypted encoded data of the first encoding mode or the second encoding mode output from the encryption unit 650 is stored in the storage medium 670.

  As described above, in the encoded data conversion apparatus 660 according to the third embodiment, the decryption unit 610, the buffer memory 620, the additional tool use determination unit 630, the encoding mode change unit 640, and the encryption unit 650 are provided, thereby providing distribution. A small amount of processing is performed by converting the encoded data of the second encoding mode transmitted from the server 600 and not using the additional encoding tool into the encoded data of the first encoding mode that has been encrypted. Can be converted without degrading the sound quality.

  Also, in the encoded data conversion device 660 of Embodiment 3, since the input / output encoded data is encrypted, the encoded data can be converted while protecting the copyright of the content.

(Embodiment 4)
FIG. 7 is a block diagram showing the configuration of the encoded data conversion apparatus according to Embodiment 4 of the present invention. In FIG. 7, 700 is a storage medium, 710 is a decryption unit, 720 is an additional tool use determination unit, 730 is an encoding mode change unit, and 740 is an encoded data converter. In the fourth embodiment, the encoded data conversion device 740 includes a decryption unit 710, an additional tool use determination unit 720, and an encoding mode change unit 730.

  Since the additional tool usage determining unit 720 is the same as the additional tool usage determining unit 310 of the first embodiment, a detailed description of the operation is omitted. The operation of the encoded data converter 740 configured as described above will be described below.

  The difference between the second embodiment and the fourth embodiment is that the encryption unit 540 is required in the second embodiment, whereas the encryption unit 540 is not required in the fourth embodiment, which is compared with the second embodiment. Therefore, the amount of processing required for encoded data conversion is small.

  The fourth embodiment is applied to the case where the data representing the encoding mode is not encrypted among the encoded data that has been encrypted. For example, in the MPEG-2 AAC encoding mode of the SD-Audio standard, which is an application standard related to the SD memory card, ATS encoded data in ADTS format is encrypted and stored in the card. In order to support playback, the ADTS header that records synchronization, ID, frame length, and the like is not encrypted, and only the AAC raw data block is encrypted. The fourth embodiment is applied when the AAC raw data block is encrypted as described above, but the encoding mode is not encrypted. In addition, when the encoding mode referred to in Embodiment 1 is recorded as attribute information in a different area from the AAC encoded data, it is assumed that the attribute information is not encrypted.

  In the storage medium 700, the encoded data of the second encoding mode is encrypted and stored in order to protect the copyright of the content.

  The encrypted encoded data of the second encoding mode read from the storage medium 700 is input to the decryption unit 710. The decryption unit 710 decrypts the encrypted encoded data of the second encoding mode and outputs the encoded data of the plaintext second encoding mode.

  The encoded data of the second encoding mode output from the decryption unit 710 is input to the additional tool usage case unit 720.

  The additional tool use determination unit 720 determines whether or not the input encoded data in the second encoding mode is using the additional encoding tool, and outputs the determination result as a mode change flag.

  In the encoding mode change unit 730, when the mode change flag output from the additional tool use determination unit 720 is 1 (when the additional tool is not used), the encrypted mode read from the storage medium 700 is encrypted. The encoding mode of the encoded data is changed from the second encoding mode to the first encoding mode, converted into encoded data of the first encoding mode, and encrypted first encoding mode Is output as encoded data. When the mode change flag is 0, encoded data is not output.

  The encoded data of the first encoding mode output from the encoding mode changing unit 730 and encrypted is stored in the storage medium 700. In order to save the use area of the storage medium 700, the encoded data of the second encoding mode encrypted with the encoded data of the first encoding mode converted and encrypted is overwritten and stored. May be. Alternatively, when storing the encoded data of the first encoding mode that has been converted and encrypted, the encoded data of the second encoding mode may be deleted.

  As described above, in the encoded data conversion apparatus 740 according to the fourth embodiment, by providing the decryption unit 710, the additional tool use determination unit 720, and the encoding mode change unit 730, the encryption that does not use the additional encoding tool. The encoded data in the second encoding mode can be converted into the encoded data in the first encoding mode with a small amount of processing without degrading sound quality.

  In the encoded data conversion apparatus 740 according to the fourth embodiment, since the input / output encoded data is encrypted, the encoded data can be converted while protecting the copyright of the content.

  In each of the above embodiments, the encoded data in the first encoding mode is described as MPEG2 AAC, and the encoded data in the second encoding mode is described as MPEG4 AAC. However, the additional encoding as shown in FIG. This is not the case as long as the encoding / decoding has a relationship that can be used by the decoding / decoding tool.

  The encoded data conversion apparatus according to the present invention converts encoded data of the second encoding mode that does not use the additional encoding tool without changing the sound quality with a small amount of processing into the first encoding mode. The encoded data in the first encoding mode can be reproduced by converting the encoded data into the encoded data. However, it is possible to reproduce the encoded data in the conventional apparatus that cannot reproduce the encoded data in the second encoding mode. For this reason, it can be suitably used by being installed in a personal computer, a portable terminal, an AV encoded data recording / reproducing device, or the like.

The conceptual diagram which shows the relationship between the encoding and decoding tool which can be used by the 1st encoding mode in this invention, and a 2nd encoding mode. Schematic diagram showing the configuration of ATS encoded data in ADTS format in the present invention 1 is a block diagram showing a configuration of an encoded data conversion apparatus according to Embodiment 1 of the present invention. The flowchart which shows the operation | movement sequence of the additional tool use determination part in the same Embodiment 1. The block diagram which shows the structure of the coding data converter in Embodiment 2 The block diagram which shows the structure of the encoding data converter in Embodiment 3 The block diagram which shows the structure of the coding data converter in Embodiment 4 The block diagram which shows the structure of the conventional coding data converter.

Explanation of symbols

300, 500, 670, 700 Storage media 310, 520, 630, 720 Additional tool use size unit 320, 530, 640, 730 Coding mode change unit 330, 550, 660, 740 Encoded data converter 510, 610, 710 Decryption unit 540, 650 Encryption unit 600 Distribution server 620 Buffer memory

Claims (4)

In addition to the encoding and decoding tools that can be used in the first encoding mode, in addition to the encoded data of the second encoding mode that can use additional encoding and decoding tools, the encoded data is the An additional tool use determination means for determining whether or not an additional encoding tool is used;
When the additional tool usage determining means determines that the additional encoding tool is not used, the encoding mode of the encoded data is changed from the second encoding mode to the first encoding mode, An encoded data conversion device comprising: encoding mode changing means for converting into encoded data of one encoding mode and outputting the encoded data. In addition to the encoding and decoding tools that can be used in the first encoding mode, in addition to the encoded data of the encoded data in the second encoding mode that can use the additional encoding and decoding tools, Decryption means for decrypting the encrypted data and outputting the encoded data of the second encoding mode;
Additional tool usage determining means for determining whether the encoded data is using the additional encoding tool, with the encoded data from the decryption means as an input,
When the additional tool usage determining means determines that the additional encoding tool is not used, the encoding mode of the encoded data is changed from the second encoding mode to the first encoding mode, Encoding mode changing means for converting into encoded data of one encoding mode and outputting the encoded data;
An encoded data conversion apparatus comprising: encryption means for outputting data obtained by encrypting encoded data in the first encoding mode. In addition to the encoding and decoding tools that can be used in the first encoding mode, in addition to the encoded data of the encoded data in the second encoding mode that can use the additional encoding and decoding tools, Decryption means for decrypting the encrypted data and outputting the encoded data of the second encoding mode;
A buffer memory for temporarily storing encoded data from the decryption means;
Additional tool usage determining means for determining whether the encoded data read from the buffer memory uses the additional encoding tool;
When the additional tool usage determining means determines that the additional encoding tool is not used, the encoding mode of the encoded data is changed from the second encoding mode to the first encoding mode, Encoding mode changing means for converting into encoded data of one encoding mode and outputting the encoded data;
An encoded data conversion apparatus comprising: encryption means for outputting data obtained by encrypting encoded data in the first encoding mode. In addition to the encoding and decoding tools that can be used in the first encoding mode, in addition to the encoded data of the encoded data in the second encoding mode that can use the additional encoding and decoding tools, Decryption means for decrypting the encrypted data and outputting the encoded data of the second encoding mode;
Additional tool usage determining means for determining whether the encoded data is using the additional encoding tool, with the encoded data from the decryption means as an input,
When the additional tool usage determining means determines that the additional encoding tool is not used, the encoding mode of the encrypted data is changed from the second encoding mode to the first encoding mode, An encoded data conversion apparatus comprising: an encoding mode changing unit that converts encoded data of the first encoding mode into encrypted data and outputs the encrypted data.

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