| 摘要 |
The present invention teaches a variety of methods and apparatus for providing reduced bit rate digital video formats. Generally speaking, the present invention decodes digital video data stored in a first, higher bit rate format and then encodes the digital video data into a second fixed bit rate digital video format that is less than the first fixed bit rate digital video format. Several different compression techniques are contemplated. For example, in one embodiment the dc and header information is preserved intact, higher ac frequency information is deleted, and new macroblocks are created for the decoded video segments. The new macroblocks are then assembled into shorter length video segments. Another technique involves quantizing the DC and AC frequency information. Of course, both the high frequency "lopping" and the quantizing techniques can be combined for even further compression. A separate aspect of the present invention teaches a computer implemented method for editing digital video data. According to this aspect, digital video information encoded according to a faster bit rate format is converted into a reduced bit rate digital video format which is then used for the interactive editing process. During the interactive editing process, the computer maintains an edit list of all desired edits. Then, the edit list can be used to automatically implement an editing session upon the digital video information encoded according to the first fixed bit rate data format.
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