Fast fade operation on MPEG video or other compressed data

• US 6,633,673 B1
• Filed: 06/17/1999
• Issued: 10/14/2003
• Est. Priority Date: 06/17/1999
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Shen, Bo
• Primary Examiner(s): Do, Anh Hong
• Application Number:
  US09/335,462
• Time in Patent Office: 1,580 Days
• Field of Search: 382/232, 382/236, 382/238, 382/251, 382/250, 382/235, 348/595, 375/240.04, 375/240.2, 345/629, 345/634
• US Class Current: 382/232
• CPC Class Codes: H04N 19/126 Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/179 the unit being a scene or a shot
• CPC Class Codes: H04N 19/48 using compressed domain processing techniques other than decoding, e.g. modification of transform coefficients, variable length coding [VLC] data or run-length data motion estimation in a transform domain H04N19/547; processing of decoded motion vectors H04N19/513
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/87 involving scene cut or scene change detection in combination with video compression
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals

Abstract

A method and apparatus for receiving and processing compressed data, such as video or audio data, in a compressed domain. An exemplary preferred embodiment of the method and apparatus is embodied in a digital video editor programmed to determine appropriate sizes of amplitude adjustment steps to be directly applied to the compressed data in consideration of temporal dependencies of the compressed data. For a fade-out operation, DC coefficients are stepped down such that pixels of an image reproduced from the compressed data fade in a uniform manner; at the end of the DC fade-out, AC coefficients are then disabled. A preferred embodiment of the method and apparatus also provides compensation for quantization variations and operates in consideration of syntax particular to a compression standard with which the compressed data are compliant.

Claims

1. A process for modifying characteristics of a sequence of data representing compressed data including temporal dependencies between elements of the data, the process comprising the steps of:

receiving a sequence of data representing compressed data, including a selected characteristic to be modified, wherein the compressed data includes information representing motion estimation for purposes of compressing data;

assigning at least one adjustment for modifying the selected characteristic as a function of the temporal dependencies of the compressed data; and

applying the at least one adjustment to the selected characteristic, wherein the step of receiving a sequence of data includes the step of receiving a sequence of digital video data wherein information representing motion estimation includes coded video blocks, the step of receiving further includes the step of receiving MPEG video blocks wherein the selected characteristic is a characteristic representing a DC component of the video information and the step of assigning at least one adjustment includes the step of calculating a plurality of fade step sizes to be applied to the DC component of the video information in the order in which the video blocks are stored wherein the step of calculating a plurality of fade step sizes includes the step of calculating a plurality of fade step sizes having a magnitude which varies as a function of the relative order in which the video blocks are displayed.

2. The process of claim 1 wherein the step of calculating includes the step of calculating a plurality of fade step sizes as a function of whether the video block is independent, predicted or bidirectional.

3. The process of claim 2 wherein the step of calculating includes the step of calculating a reference distance.

4. The process of claim 3 wherein the step of calculating includes the step of calculating a plurality of fade step amounts as a function of a quantization table.

5. The process of claim 4 wherein the step of calculating further includes the step of rounding off.

6. The process of claim 1 wherein the step of assigning at least one adjustment includes the step of determining the difference between a calculated adjustment for a video block and a desired adjustment applied to the video block.

7. The process of claim 6 wherein the step of determining the difference includes the step of determining a difference between a calculated adjustment for a video block and a desired adjustment applied to a video block and using the difference for calculating an adjustment for a corresponding video block in a subsequent frame.

8. The process of claim 7 further comprises the step of identifying a reference block and identifying a predicted block and calculating an error correction as a function of a relationship between the reference block and the predicted block.

9. The process of claim 8 wherein the step of identifying a reference block includes the step of identifying a plurality of reference blocks and identifying a relationship between the plurality of reference blocks and a predicted block, and wherein the step of calculating an error includes the step of calculating a weighted error correction as a function of the relationship of the predicted block to each of the plurality of reference blocks.

10. The process of claim 1 wherein the step of receiving a sequence includes the step of receiving data representing video blocks of more than one type and the step of assigning includes the step of assigning a plurality of adjustments for modifying the selected characteristic as a function of the types of coded video blocks.

11. The process of claim 10 wherein the step of receiving a sequence of digital video data includes the step of receiving digital video data having digital video picture information stored in a first sequence, for display of the picture information in a second sequence different from the first sequence, and wherein the step of assigning a plurality of adjustments includes the step of assigning adjustments as a function of the first sequence.