Abstract: A method, medium, and apparatus for deleting and/or restoring time-series contents stored in a recording medium. When the time-series contents are stored in the recording medium, deleting of data that is present in a first area of a recording medium includes periodically inserting a time stamp into the contents, generating deletion data positional information based on the time stamp, the deletion data positional information representing a relative position of the deletion data within the contents, storing the deletion data positional information and the deletion data in a second area of the recording medium, and designating the first area as overwritable on the recording medium. Even if the recording medium is reloaded in another disk drive and under another operating system, data deleted from the recording medium can be easily restored.

Abstract: An apparatus, method, and medium for video synchronization are provided. The apparatus may include a PTS register storing a presentation time stamp (PTS) of a picture to be reproduced and skip enable flag information indicating whether the picture can be skipped, by using a position of the picture in a video decoder buffer in which pictures to be decoded are stored; and a controller controlling the picture reproduction by skipping, repeating, or reproducing the picture with reference to the PTS and the skip enable flag information stored in the PTS register.

Abstract: A method of hierarchical image indexing which extracts representative images of a TV program and generates a hierarchical index image guide of the representative images, and an apparatus therefor. Respective images at predetermined times are extracted from a predetermined program. A hierarchical index is allocated to each extracted image and the indexes are mapped to locations of transport stream packets. A tree of images having the allocated indexes is constructed as a hierarchically indexed Image guide (HIIG). When a stored program is to be reproduced, a location desired to be watched is selected in the HIIG, and from the selected location, reproducing and trick plays (FF, rewind) are enabled such that a user easily searches the program and begins viewing the program at the searched for location.

Abstract: An apparatus and a method of changing a bit rate of a compressed image bit stream by changing a codeword so as to easily change the bit rate and reduce a changing loss. The apparatus for changing a bit rate, in which an input bit stream generated by an image compression encoding method is changed into an output bit stream having a desired bit rate, includes a changing codeword determiner which selects codewords to replace the codewords of the input bit stream, and a codeword changer which changes the codewords of the input bit stream into the codewords selected by the changing codeword determiner. The method and the apparatus can be applied to image services provided through the Internet and receiving apparatuses supporting the Personal Video Recorder (PVR) function. Particularly, the method of changing the bit rate of a compressed image bit stream changes the codewords of input transform coefficients so as to easily change the bit rate and reduce the changing loss.

Abstract: A security method and a security apparatus are disclosed which use a self-generated encryption key. The security method includes the steps of: generating an encryption key; decrypting pre-encrypted data using a pre-stored manufacturer key; and re-encrypting the decrypted data using the encryption key. The security method and apparatus minimize external leakage of data by self-generating the unique encryption key. Since the encryption keys are unique in each set, set binding is possible.

Abstract: An apparatus, method, and medium for video synchronization are provided. The apparatus may include a PTS register storing a presentation time stamp (PTS) of a picture to be reproduced and skip enable flag information indicating whether the picture can be skipped, by using a position of the picture in a video decoder buffer in which pictures to be decoded are stored; and a controller controlling the picture reproduction by skipping, repeating, or reproducing the picture with reference to the PTS and the skip enable flag information stored in the PTS register.

Abstract: A method, medium, and apparatus for deleting and/or restoring time-series contents stored in a recording medium. When the time-series contents are stored in the recording medium, deleting of data that is present in a first area of a recording medium includes periodically inserting a time stamp into the contents, generating deletion data positional information based on the time stamp, the deletion data positional information representing a relative position of the deletion data within the contents, storing the deletion data positional information and the deletion data in a second area of the recording medium, and designating the first area as overwritable on the recording medium. Even if the recording medium is reloaded in another disk drive and under another operating system, data deleted from the recording medium can be easily restored.

Abstract: A method of hierarchical image indexing which extracts representative images of a TV program and generates a hierarchical index image guide of the representative images, and an apparatus therefor. Respective images at predetermined times are extracted from a predetermined program. A hierarchical index is allocated to each extracted image and the indexes are mapped to locations of transport stream packets. A tree of images having the allocated indexes is constructed as a hierarchically indexed Image guide (HIIG). When a stored program is to be reproduced, a location desired to be watched is selected in the HIIG, and from the selected location, reproducing and trick plays (FF, rewind) are enabled such that a user easily searches the program and begins viewing the program at the searched for location.

Abstract: A method of transcoding an input image bit stream into an output image bit stream having a different bit rate. The method includes determining a cut area of an input image to be removed, cutting the input image according to the cut area, and generating an output image of the output image bit stream corresponding to the input image after the cutting. In the present method, image areas of not interest to a user are removed so as to lower the bit rate. In addition, removed bits are reassigned to concern areas so as to improve a picture quality.

Abstract: An apparatus and a method of changing a bit rate of a compressed image bit stream by changing a codeword so as to easily change the bit rate and reduce a changing loss. The apparatus for changing a bit rate, in which an input bit stream generated by an image compression encoding method is changed into an output bit stream having a desired bit rate, includes a changing codeword determiner which selects codewords to replace the codewords of the input bit stream, and a codeword changer which changes the codewords of the input bit stream into the codewords selected by the changing codeword determiner. The method and the apparatus can be applied to image services provided through the Internet and receiving apparatuses supporting the Personal Video Recorder (PVR) function. Particularly, the method of changing the bit rate of a compressed image bit stream changes the codewords of input transform coefficients so as to easily change the bit rate and reduce the changing loss.