Methods for encoding an image

• US 8,731,314 B1
• Filed: 10/17/2012
• Issued: 05/20/2014
• Est. Priority Date: 07/28/2005
• Status: Active Grant

• Current Assignee: Teradici Corporation (HP Inc.)
• Original Assignee: Teradici Corporation (HP Inc.)
• Inventors: Hobbs, David Victor, Ratto, Patrick
• Primary Examiner(s): Alavi, Amir
• Application Number:
  US13/653,841
• Time in Patent Office: 580 Days
• Field of Search: 382/164, 382/173, 382/232, 382/233, 382244-246, 375/240.01, 375/240.12, 375/240.16, 375/240.24, 375/240.27, 375/E7.264, 345/2.1, 345/3.1, 345/329, 341/63, 341/65, 341/106, 709/247, 709/250, 713/171, 714/E11.173
• US Class Current: 382/244
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/149 by estimating the code amount by means of a model, e.g. mathematical model or statistical model
• CPC Class Codes: H04N 19/166 concerning the amount of transmission errors, e.g. bit error rate [BER]
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/196 being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters processing of motion vectors H04N19/513
• 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 19/507 using conditional replenishment

Abstract

An image encoding apparatus. In one embodiment, the apparatus comprises an encoding engine coupled to a source of a block of pixel data, the encoding engine enabled to encode the block of pixel data to a quality level, the encoding engine coupled to a network interface; and a state sequencer, the state sequencer enabled to obtain an indication of scan block persistence, build state information and encoding parameters to control the quality level.

Claims

1. A method for encoding an image, comprising:

(a) generating, by a computer, an initial quality encoding of a portion of a plurality of portions of an image spatially divided into the plurality of portions, wherein the initial quality encoding is generated based on determining the portion has changed;

(b) generating a quality improvement encoding of the portion based on determining the portion (i) is unchanged since being previously encoded and (ii) has been encoded to less than a pre-determined quality; and

(c) generating a lossless encoding of the portion based on determining the portion (i) is unchanged since being previously encoded and (ii) has been encoded to the pre-determined quality.

2. The method of claim 1, further comprising selectively repeating, for each portion of the plurality of portions and based on change state and encoded state information associated with each portion of the plurality of portions, the steps of (a) generating an initial quality encoding, (b) generating a quality improvement encoding, and (c) generating a lossless encoding.

3. The method of claim 2, wherein selectively repeating, for each portion of the plurality of portions, the steps of (a) generating an initial quality encoding, (b) generating a quality improvement encoding and (c) generating a lossless encoding, is further based on image type information associated with each portion of the plurality of portions, the image type information identifying image encoding requirements and determined by analyzing a corresponding image of each portion of the plurality of portions.

4. The method of claim 1, wherein generating the lossless encoding comprises performing a spatial domain encoding and generating the quality improvement encoding comprises performing a transform domain encoding.

5. The method of claim 1, wherein generating the lossless encoding comprises performing a sequence of residual encodings.

6. The method of claim 1, wherein the plurality of portions comprises a computer display image, the computer display image comprising a plurality of asynchronously changing regions.

7. The method of claim 1, further comprising transmitting encodings to a remote computer, the encodings comprising the initial quality encoding, the lossless encoding and the quality improvement encoding.

8. The method of claim 7, wherein transmitting the encodings comprises scheduling transmission of the encodings based on at least one of latency constraints, available bandwidth or build states of the plurality of portions.

9. The method of claim 8, wherein a first portion of the encodings is transmitted immediately while a second portion of the encodings is delayed until at least one of a defined network bandwidth is available or a defined period of time has elapsed.

10. The method of claim 1, further comprising maintaining state information identifying an encoded quality of each portion of the plurality of portions.

11. The method of claim 10, wherein the state information comprises, for each portion of the plurality of portions, image type information determined by analyzing a corresponding image of each portion, the image type information identifying, for a corresponding portion of the plurality of portions, an encoding sequence selected from a list comprising (I) a direct to lossless encoding sequence or (II) an encoding sequence of bit planes.

12. The method of claim 1, wherein generating the quality improvement encoding and generating the lossless encoding are further based on at least one of (I) available network bandwidth, (II) network bandwidth consumption preferences, (III) area of the image unchanged since being previously encoded and encoded to less than the pre-determined quality or (IV) a pre-determined progressive build sequence.

13. The method of claim 1, wherein generating the quality improvement encoding comprises repeatedly encoding the portion with progressive quality improvements until the portion is encoded to the pre-determined quality.

14. The method of claim 13, wherein repeatedly encoding the portion with progressive quality improvements comprises pausing between encodings at one or more of a desired quality level or a perceptually lossless quality level.

15. The method of claim 1, wherein generating the lossless encoding comprises one of (I) generating a residual encoding comprising a difference between the portion and a decoding of a previous encoding of the portion, or (II) generating an initial lossless encoding of the portion.

16. A method for encoding an image, comprising:

(a) generating, by a computer, an initial quality encoding of a portion of a plurality of portions of an image spatially divided into the plurality of portions, wherein the initial quality encoding is generated based on determining the portion has changed;

(b) generating a quality improvement encoding of the portion based on determining the portion (i) is unchanged since being previously encoded and (ii) has been encoded to less than a pre-determined quality; and

(c) selectively repeating, for each portion of the plurality of portions based on change state and encoded state information associated with each portion of the plurality of portions, the steps of (a) generating an initial quality encoding and (b) generating a quality improvement encoding.

17. The method of claim 16, further comprising maintaining state information identifying an encoded state of each portion of the plurality of portions, the encoded state identifying, for each corresponding portion of the plurality of portions, an encoding sequence selected from a list comprising (I) a direct to lossless encoding sequence or (II) lossy encoding followed by a lossless encoding.

18. A method for encoding an image, comprising:

(a) generating, by a computer, an initial quality encoding of a portion of a plurality of portions of an image spatially divided into the plurality of portions, wherein the initial quality encoding is generated based on determining the portion has changed;

(b) generating a lossless encoding of the portion based on determining the portion is unchanged for a predetermined time since being previously encoded; and

(c) selectively repeating, for each portion of the plurality of portions based on change state and encoded state information associated with each portion of the plurality of portions, the steps of (a) generating an initial quality encoding and (b) generating a lossless encoding.

19. The method of claim 18, further comprising maintaining state information identifying an encoded state of each portion of the plurality of portions, the encoded state identifying, for each corresponding portion of the plurality of portions, an encoding sequence selected from a list comprising (I) a direct to lossless encoding sequence or (II) lossy encoding followed by a lossless encoding.