Video Data Compression

• US 20110235720A1
• Filed: 01/05/2011
• Published: 09/29/2011
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Alan Chalmers, Alessandro Artusi, Francesco Banterle, Gavin John Edwards, Gerhard Bonnet, Kurt Debattista, Patrick Ledda
• Inventors: Edwards, Gavin John, Debattista, Kurt, Banterle, Francesco, Artusi, Alessandro, Chalmers, Alan, Ledda, Patrick, Bonnet, Gerhard
• Granted Patent: US 9,406,112 B2
• Time in Patent Office: Days
• US Class Current: 375/240.25
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20028 Bilateral filtering
• CPC Class Codes: G06T 5/90 Dynamic range modification of images or parts thereof
• CPC Class Codes: G06T 5/92 based on global image properties
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/33 in the spatial domain
• CPC Class Codes: H04N 19/34 Scalability techniques involving progressive bit-plane based encoding of the enhancement layer, e.g. fine granular scalability [FGS]
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A method of producing a compressed video data stream (12) by compressing a stream of relatively high dynamic range video frames (2). A bilateral filter (3) extracts a base frame (4) with luminance information. The base frame (4) and the original frame (2) are used to provide a detail frame (5) with chroma information. A tone mapping operation (6) is selected (7, 11) and applied to the base frame to generate a relatively low dynamic range base frame (8), which is then compressed (9). The detail frame (5) is compressed separately. Final frame data (12) is then created, consisting of the compressed relatively low dynamic range base frame, the compressed detail frame, and stored information in respect of the tone mapping operation that had been applied to the base frame.

Claims

1. A method of producing a compressed video data stream by compressing a stream of relatively high dynamic range video frames, wherein for at least some original video frames in the stream, the method comprises the steps of:

(a) from the original frame in the stream, using a filter to extract a base frame;

(b) using the base frame and the original frame to provide a detail frame relating to fine details in the original frame;

(c) generating a tone mapping operation for the base frame and applying the tone mapping operation to the base frame to generate a relatively low dynamic range base frame;

(d) storing information in respect of the tone mapping operation applied to the base frame;

(e) subjecting the relatively low dynamic range base frame to temporal compression, and subjecting the detail frame to temporal compression;

(f) creating final frame data consisting of the compressed relatively low dynamic range base frame, the compressed detail frame, and the information in respect of the tone mapping operation applied to the base frame; and

(g) including the final frame data in the compressed video data stream.

2. A method as claimed in claim 1, wherein generating a tone mapping operation for a base frame comprises selecting a tone mapping function from a plurality of predefined tone mapping functions.

3. A method as claimed in claim 2, wherein the tone mapping operation applied to the base frame is obtained by altering an initial tone mapping function selected from the plurality of predefined tone mapping functions, by reference to stored properties of at least one previous tone mapping function obtained for a previous base frame of the same scene.

4. A method as claimed in claim 3, wherein if the difference between the initial tone mapping operation determined for a given base frame and the at least one previous tone mapping function is too large, the initial tone mapping operation is corrected to a tone mapping operation which corresponds more closely to the at least one previous tone mapping function.

5. A method as claimed in claim 2, wherein generating a tone mapping operation for a base frame further comprises selecting parameters associated with the selected tone mapping function.

6. A method as claimed in claim 1, wherein the detail frame (5) is obtained by subtraction of the base frame (4) from the original frame (2) and/or by division of the original frame (2) by the base frame (4).

7. A method as claimed in claim 1, wherein the compression of the relatively low dynamic range base frame and the compression of the detail frame are carried out separately.

8. A method as claimed in claim 1 wherein the base frame contains the luminance of the original frame.

9. A method as claimed in claim 8, wherein the filter used to extract the base frame from the original frame is a bilateral filter.

10. A method as claimed in claim 1, which is carried out for all original video frames in the stream of relatively high dynamic range video frames.

11. A method as claimed in claim 1, characterised in that luminance information relating to a frame is included in the compressed video data stream separately from the information in respect of the tone mapping operation applied to the base frame.

12. A method as claimed in claim 2, wherein the plurality of predefined tone mapping functions comprises at least one fixed and/or at least one user defined tone mapping function.

13. A method as claimed in claim 1, wherein the relatively high dynamic range video frames are arranged as a plurality of different scenes each comprising a plurality of the video frames, and the tone mapping operations applied to some frames in the same scene differ from one another.

14. A method as claimed in claim 1, wherein the relatively high dynamic range video frames are arranged as a plurality of different scenes each comprising a plurality of the video frames, and the tone mapping operations applied to frames in one of the plurality of scenes differ from the tone mapping operations applied to frames in another of the plurality of scenes.

15. A method as claimed in claim 14, wherein the tone mapping operations applied to some frames in the same scene differ from one another.

17. A method of decoding a compressed video data stream obtained by carrying out a method as claimed in claim 1 wherein, using the final frame data in the video data stream, the relatively low dynamic range base frame is obtained from the compressed relatively low dynamic range base frame, the detail frame is obtained from the compressed detail frame, using the information in respect of the tone mapping operation applied to the base frame, the base frame is reconstructed via inverse tone mapping;

and the base frame is combined with the detail frame to obtain a relatively high dynamic range frame to be reproduced.

18. A method as claimed in claim 17 wherein it is possible to amend an initial tone mapping function so as to take into account the particular properties of a device for displaying the video frame data.

19. A method as claimed in claim 18 wherein there are look-up-tables for different display devices which relate to different inverse tone mapping functions for a given look-up-table entry.

16. A computer software product comprising instructions stored on a non-transitory medium which when carried out by data processing apparatus will cause the apparatus to be configured to carry out a method of producing a compressed video data stream by compressing a stream of relatively high dynamic range video frames, wherein for at least some original video frames in the stream, the method comprises the steps of:

(a) from the original frame in the stream, using a filter to extract a base frame;

(b) using the base frame and the original frame to provide a detail frame relating to fine details in the original frame;

(c) generating a tone mapping operation for the base frame and applying the tone mapping operation to the base frame to generate a relatively low dynamic range base frame;

(d) storing information in respect of the tone mapping operation applied to the base frame;

(e) subjecting the relatively low dynamic range base frame to temporal compression, and subjecting the detail frame to temporal compression;

(f) creating final frame data consisting of the compressed relatively low dynamic range base frame, the compressed detail frame, and the information in respect of the tone mapping operation applied to the base frame; and

(g) including the final frame data in the compressed video data stream.