Data transmission apparatus and data transmission method

This application is a divisional of U.S. patent application Ser. No. 10/344,957, filed on Jul. 16, 2003, which is a national phase application under 35 U.S.C. § 371 of International Application No. PCT/JP02/06089 filed Jun. 19, 2002, which claims priority from Japanese Patent Application No. P2001-189744, filed on Jun. 22, 2001, the disclosures of which are hereby incorporated by reference herein.

1. Technical Field

The present invention relates generally to a data transmission apparatus and a data transmission method and, more particularly, to a data transmission apparatus and a method thereof and further a data processing apparatus and a method thereof for properly managing data contents and reproduction information recorded to a recording medium even after the editing of the recorded data contents.

2. Background Art

Recently, various types of optical disks are being proposed as disk-type information recording media which are for use on recording/reproducing apparatuses in a detachable manner. These recordable optical disks are being proposed as mass storage media of several gigabytes, which are highly expected as media for recording AV (Audio Visual) signals such as video signals. The sources (or the supply sources) of digital AV signals to be recorded on recordable optical disks include CS digital satellite broadcast and BS digital broadcast signals and, in the future, digital ground-based television broadcast signals.

Generally, the digital video signals supplied from these sources are image-compressed by MPEG2 (Moving Picture Experts Group 2). Each recording apparatus has its unique recording rate. When the digital video signals of digital broadcasting are recorded by use of conventional consumer video storage media, the digital video signals are decoded to perform band limitation before being recorded in the case of analog recording. Alternatively, in the case of digital recording such as MPEG1 Video, MPEG2 Video, and DV (Digital Video), the digital video signals are decoded once and encoded again with the device-unique recording rate and encoding algorithm before being recorded.

However, the above-mentioned recording schemes involve the degradation in picture quality because the supplied bit streams are decoded once and then band-limited and encoded again before being recorded. When picture-compressed digital signals are recorded, if the transfer rate of the inputted digital signals does not exceed the recording rate of the recording/reproducing apparatus used, a recording method in which the supplied bit streams are directed recorded without decoding and re-encoding least degrades the picture quality. However, if the transfer rate of the picture-compressed digital signals exceeds the recording rate of a disk of recording medium, it is required for the recording/reproducing apparatus to re-encode the digital signals for recording so that the transfer rate after the decoding on the recording/reproducing apparatus becomes less than the upper limit of the disk recording rate.

If a digital signal is transmitted by a variable rate scheme in which the bit rate of an inputted digital signal goes up and down with time, a disk recording apparatus in which data are stored once in its buffer for burst recording can use the disk capacity less wasteful as an information recording medium than a tape-recording apparatus in which the recording rate is fixed because the rotary head has a fixed rotational speed.

Thus, in the future in which the digital broadcasting becomes the mainstream broadcasting, such recording/reproducing apparatuses using disks as recording media will be required as recording broadcast signals as they are digital without decoding and re-encoding like data streamers.

As described above, as the storage capacity of recording media increases, each recording medium will be able to recording lots of data (for example, video data and audio data associated with programs) to record many programs to a single disk. In such a situation, each user is required to perform operations such as copying of desired data selected from among many programs recorded to a disk to another disk.

However, if a copy operation is performed, it becomes difficult to properly managing the contents of the recorded data and the reproduction information.

In carrying out the invention and according to one aspect thereof, a first data transmission apparatus comprises: a read section operable to read a data stream and its management information from a recording medium; a control section operable to determine partial management information corresponding to a partial data stream necessary for reproducing a specified reproduction interval in the data stream; and a transmission section operable to transmit the partial data stream and partial management information determined by the control section.

The above-mentioned transmission section can transmit the partial management information in an asynchronous manner.

The above-mentioned control section can select one of asynchronous transmission and synchronous transmission of the partial data stream.

The above-mentioned data stream can be an AV stream and the management information can include address information of a discontinuity point of encoded information in the AV stream, information for relating time information in the AV stream with address information, and time information of a characteristic image in the AV stream.

The above-mentioned management information can be Clip Information, the address information of the discontinuity point can be a SequenceInfo and a ProgramInfo, the information for relating the time information with the address information can be a CPI, and the time information of the characteristic image can be a ClipMark.

The above-mentioned management information can further include a PlayList which is information for specifying a reproduction interval of the AV stream.

The above-mentioned transmission section can further transmit information for specifying a reproduction interval of the AV data stream as the partial data stream.