System for editing compressed image sequences
First Claim
1. A method of editing a compressed input image sequence and producing therefrom a compressed output image sequence, the input sequence including at least one group of images (that does not depend upon any other images for reconstruction from a compressed format), the group of images having at least one compressed dependent frame that contains data for reconstructing one image based upon data from a second image in the group of images, said method using a computing device and comprising:
- receiving with the compressed input image sequence;
using the computing device to convert a dependent frame to a compressed data format that does not depend upon the second image without decompressing all images in the group of images to an image domain;
editing data using the computing device, by altering temporal order of an image represented by the dependent frame with respect to at least one other image in the sequence; and
using the computing device to produce the compressed output image sequence from the data which has been edited by the computing device.
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Accused Products
Abstract
This disclosure provides for an image editing system that permits manipulation of compressed image formats without full decompression to the image domain. In particular, an editor manipulates discrete cosine transform ("DCT") coefficients for a dependent frame in a compressed image sequence to incorporate DCT representations of anchor frames upon which the dependent frame depends. Once converted, the frame can simply be reordered in the compressed domain without violating temporal dependencies, subject to bit rate matching. In one embodiment, an image sequence can be cut to leave remaining image frames which are then altered, so as to eliminate temporal dependencies upon eliminated frames. In another embodiment, an image sequence can be processed in the compressed domain for reverse-play. The editor provided by this disclosure permits real-time compressed domain editing applications, with reduced requirements for computational bandwidth.
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Citations
22 Claims
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1. A method of editing a compressed input image sequence and producing therefrom a compressed output image sequence, the input sequence including at least one group of images (that does not depend upon any other images for reconstruction from a compressed format), the group of images having at least one compressed dependent frame that contains data for reconstructing one image based upon data from a second image in the group of images, said method using a computing device and comprising:
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receiving with the compressed input image sequence; using the computing device to convert a dependent frame to a compressed data format that does not depend upon the second image without decompressing all images in the group of images to an image domain; editing data using the computing device, by altering temporal order of an image represented by the dependent frame with respect to at least one other image in the sequence; and using the computing device to produce the compressed output image sequence from the data which has been edited by the computing device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus that converts an input sequence of compressed input images into an output sequence of compressed images, the input sequence including at least one group of images (that does not depend upon any other images for reconstruction from a compressed format), the group of images having at least one compressed dependent frame that contains data for reconstructing one image based upon data from a second image in the group of images, said apparatus comprising:
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memory that receives the input sequence; and an editor that receives user commands to edit the input sequence and that, responsive to user commands, alters the temporal order of at least one image from the compressed image sequence (including an image represented by the dependent frame) with respect to another image in the input sequence, the editor including one of firmware, hardware and software that converts the dependent frame to a compressed data format that does not depend upon the second image, without decompressing all images in the group of images to an image domain, alters the temporal order of at least one image in the sequence (including an image represented by the dependent frame), and formats the compressed output image sequence to reflect the altered temporal order. - View Dependent Claims (10, 11, 12)
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13. An apparatus, comprising:
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means for receiving a compressed input image sequence; means for manipulating the compressed input image sequence in a compressed domain, without decompressing any image in the input image sequence to a image domain, including one of means for cutting the compressed input image sequence and splicing remaining images of the compressed image sequence to a second image sequence and means for reversing play-order of images represented by the input image sequence; and means for producing a compressed output image sequence.
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14. An apparatus operative to receive compressed image data complying with a Moving Pictures Experts'"'"' Group (M.P.E.G.) Standard and including information representing a sequence of independent (I) frames, prediction (P) frames and bidirectional (B) frames, to edit temporal order of images represented by the sequence in response to a set of one or more commands, and to provide an output of image data that is compressed and compliant with a MPEG Standard, said apparatus comprising:
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machine readable media; and instructions stored on the machine readable media that instruct a machine to receive data representing I, P and B frames, perform, with respect to a particular frame selected in response to the set of one or more commands, a conversion including one of (a) conversion of a P frame to an I frame by removing dependence of the P frame upon data from any other frame, (b) conversion of a B frame to a B frame having no dependence upon data from future frames, such that the B frame as converted only depends upon one or more prior frames in the sequence of data, and (c) conversion of a B frame to a B frame having no dependence upon data from prior frames, such that the B frame as converted only depends upon one or more future frames in the sequence of data, and alter temporal order of at least one image represented by the sequence (including an image represented by the dependent frame) with respect to another image in response to the commands, and produce therefrom the output of compressed data, wherein the conversion is automatically selected (in response to the set of one or more commands and in response to whether the particular frame is an I, P or B frame) to eliminate a temporal dependency between any frame representing the at least one image which is to be altered in temporal order with respect to another image. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification