DATA STRUCTURE OF MULTIMEDIA FILE FORMAT, ENCRYPTING METHOD AND DEVICE THEREOF, AND DECRYPTING METHOD AND DEVICE THEREOF

• US 20130301831A1
• Filed: 07/15/2013
• Published: 11/14/2013
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: SATO, Jun, Terauchi, Toru
• Granted Patent: US 9,729,828 B2
• Time in Patent Office: Days
• US Class Current: 380/236
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 21/41407 embedded in a portable device, e.g. video client on a mobile phone, PDA, laptop constructional details of equipment or arrangements specially adapted for portable computer application G06F1/1626; arrangements specially adapted for mobile receivers in broadcast systems H04H20/57
• CPC Class Codes: H04N 21/4325 by playing back content from the storage medium reproduction of recorded television signals H04N5/76; reproduction of recorded television signals H04N9/79
• CPC Class Codes: H04N 21/440281 by altering the temporal resolution, e.g. by frame skipping television signal recording using magnetic recording on tape for reproducing at a rate different from the recording rate H04N5/783
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 5/783 Adaptations for reproducing at a rate different from the recording rate
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 7/167 Systems rendering the television signal unintelligible and subsequently intelligible

Abstract

In a data structure of a multimedia file format, a movie box and a media data box are provided. In each box, a non-encrypted size field, a non-encrypted type field and box data field are provided. In box data of the movie box, information data regarding multimedia data is stored. The multimedia data is encrypted and stored in box data of the media data box. The information data is obtained by referring to the container in the movie box. This information data is held as encryption and encoding information data. By referring to the information data, a data unit of the encrypted multimedia data in the media data box is obtained, and the unit data is decrypted.

Claims

1-8. -8. (canceled)

9. A method of reproducing a multimedia file including attribution information and a sequential array of chunks, each of the chunks including at least one of encoded audio frames or encoded video frames, the encoded audio frames and/or the encoded video frames being encrypted, the method comprising:

decrypting the multimedia file, which comprises;

obtaining chunk offset information from the attribution information in the multimedia file, wherein the chunk offset information indicates respective start positions of the chunks from a head of the file;

referring to one of the start position of the chunks, and extracting the chunks from the multimedia file based on the one of the start positions of the chunks; and

decrypting the encrypted audio frames and/or the encrypted video frames in the extracted chunks into the encoded audio frames and/or the encoded video frames with referring to the one of the start positions of the chunks and successively outputting the encoded audio frames and/or the encoded video frames;

decoding an audio stream extracted from the encoded audio frames into an audio signal and/or a video stream extracted from the encoded video frames into a video signal; and

displaying a moving picture based on the video signal.

10. The method according to claim 9, wherein the multimedia file includes a first box and a second box, the attribution information is contained in the first box and the chunks are contained in the second box.

11. The method according to claim 9, further comprising:

storing the multimedia file in a memory to decrypt the multimedia file.

12. The method according to claim 9, further comprising storing the encoded audio frames and/or the encoded video frames in a memory to decode the audio stream.

13. A method of reproducing a multimedia file including attribution information and a sequential array of chunks, each of the chunks including at least one of samples, each of the samples including an encoded audio frame or encoded video frame, the encoded audio frame or the encoded video frame being encrypted, the method comprising:

decrypting the multimedia file, which comprises;

obtaining first offset information and sample information from the attribution information in the multimedia file, wherein the first offset information indicates respective start positions of the chunks from a head of the file, and the sample information indicates a number of samples and respective sample sizes of the samples in each of the chunks;

calculating second offset information from the first offset information and the sample information, wherein the second offset information indicates respective start positions of the samples;

referring to one of the start position of the chunks, and extracting one of the samples from the multimedia file based on the one of the start positions of the samples;

decrypting the encrypted audio frame and/or the encrypted video frame in the extracted sample into the encoded audio frame and/or the encoded video frame with referring to the one of the start positions of the samples and successively outputting the encoded audio frames and/or the encoded video frames; and

decoding an audio stream extracted from the encoded audio frames into an audio signal and/or a video stream extracted from the encoded video frames into a video signal; and

displaying a moving picture based on the video signal.

14. The method according to claim 13, wherein the multimedia file includes a first box and a second box, the attribution information is contained in the first box and the samples are contained in the second box.

15. The method according to claim 14, wherein the multimedia file includes a first box and a second box, the attribution information is contained in the first box and the chunks are contained in the second box.

16. The method according to claim 14, further comprising storing the encoded audio frames and/or the encoded video frames in a memory to decode the audio stream.