Method and apparatus for simplifying the decoding of data

• US 8,195,622 B2
• Filed: 04/29/2010
• Issued: 06/05/2012
• Est. Priority Date: 01/07/2007
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Albert, Eric J., Begeman, Nathaniel, Gies, Sean
• Primary Examiner(s): Nguyen, Phong
• Assistant Examiner(s): Ly, Anh
• Application Number:
  US12/770,417
• Publication Number:
  US 20100211553A1
• Time in Patent Office: 768 Days
• Field of Search: 707/678, 707/694, 707/697, 707/699, 707/701, 386/27, 386/33, 386/354, 386/355, 386/356, 345/549, 345/606, 345/613
• US Class Current: 707/678
• CPC Class Codes: H04N 1/41 Bandwidth or redundancy reduction by scanning H04N1/17 ; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00

Abstract

The various methods and devices described herein relate to devices which, in at least certain embodiments, may include a method of decoding data or a data stream in a file, which may include checking for a first data portion of a plurality of data portions in the file, the first data portion having a first data value, reading in data from another data portion of the plurality of data portions, decoding or decompressing the data, performing a checksum operation on the decoded data if the first data portion having the first data value is not detected, and skipping a checksum operation on the decoded data if the first data portion having the first data value is detected. In the embodiment, a checksum operation on encoded data may also be skipped. In an embodiment, the first data value may include information or instructions about how a decoder may decode the data and may also include a tag or identifier.

Claims

1. A computer implemented method, comprising:

encoding data, by a data processing system, into a first data section of a plurality of data sections in a file, the first data section including a first data value of a first type or a second type; and

encoding data into a second data section of the plurality of data sections in the file, the second data section to include information to allow a decoder to perform a data check operation to verify the data of the second data section if the first data section includes the first data value of the first type, the first data section to include information to allow the decoder to determine whether to perform the data check operation to verify the data of the second data section, the decoder to skip the data check operation without verifying the data of the second data section if the first data section includes a first data value of the second type, wherein when the first data value is of the first type in the first data section, the encoding data in the first data section includes encoding information into a critical data chunk in an image data that indicates to the decoder that the data check operation will be performed.

2. The method of claim 1 wherein the image data file is a PNG (Portable Networks Graphics) file.

3. The method of claim 2 wherein encoding data into the second data section includes encoding a data check value appended to the data in the second data section.

4. The method of claim 1 wherein encoding data into the first data section including a first data value of the second type includes encoding information into a critical data chunk in a PNG file that indicates to a decoder that a computation of a checksum will not be performed.

5. The method of claim 4 wherein encoding data into the second data section includes encoding data without a data check value appended to the data in the second data section.

6. The method of claim 1 wherein encoding data into the first data section includes encoding an indication to a decoder that a scan line of an image represented by the file has been filtered with a same filter as another scan line of the image represented by the file.

7. An apparatus, comprising:

means for encoding data into a first data section of a plurality of data sections in a file, the first data section including a first data value of a first type or a second type; and

means for encoding data into a second data section of the plurality of data sections in the file, the second data section to include information to allow a decoder to perform a data check operation to verify the data in the second data section if the first data section includes the first data value of the first type, the first data section to include information to allow the decoder to determine whether to perform the data check operation to verify the data of the second data section, the decoder to skip the data check operation without verifying the data of the second data section if the first data section includes a first data value of the second type, wherein when the first data value is of the first type in the first data section, the encoding data in the first data section includes encoding information into a critical data chunk in an image data that indicates to the decoder that the data check operation will be performed.

8. A computer-readable non-transitory storage medium storing executable program instructions which when executed cause a computer to perform a method comprising:

encoding data into a first data section of a plurality of data sections in a file, the first data section including a first data value of a first type or a second type; and

encoding data into a second data section of the plurality of data sections in the file, the second data section including information to allow a decoder to perform a data check operation to verify the data in the second data section if the first data section includes the first data value of the first type, the first data section including information to allow the decoder to determine whether to perform the data check operation to verify the data of the second data section, the decoder to skip the data check operation without verifying the data of the second data section if the first data section includes a first data value of the second type, wherein when the first data value is of the first type in the first data section, the encoding data in the first data section includes encoding information into a critical data chunk in an image data that indicates to the decoder that the data check operation will be performed.

9. The computer-readable non-transitory storage medium of claim 8 wherein said image data file is a PNG (Portable Networks Graphics) file.

10. The computer-readable non-transitory storage medium of claim 9 wherein said encoding of data into the second data section includes encoding a data check value into an image data (IDAT) chunk.

11. The computer-readable non-transitory storage medium of claim 8 wherein said encoding of data into the first data section including a first data value of the second type comprises encoding information into a critical data chunk in a PNG file that indicates to a decoder that a computation of a checksum will not be performed.

12. The computer-readable non-transitory storage medium of claim 11 wherein said encoding of data into the second data section comprises encoding data without a data check value into an image data chunk (IDAT).

13. The computer-readable non-transitory storage medium of claim 8 wherein said encoding of data into the first data section includes encoding information to inform a decoder that each scan line of an image represented by the file has been filtered by a same filter.

14. The computer-readable non-transitory storage medium of claim 8 wherein said encoding of data into the first data portion includes encoding information to inform a decoder that an image has been encoded with an arbitrary ordering of components for a pixel.

15. The computer-readable non-transitory storage medium of claim 14 wherein said encoding of data into the second data section includes encoding data representing an image with an arbitrary ordering of components for a pixel.

16. The computer-readable non-transitory storage medium of claim 8 wherein said encoding of data into the second data section includes encoding a premultiplied alpha channel into the second data section.

17. A computer implemented method, comprising:

encoding data, by a data processing system, into a first data section of a plurality of data sections in a file, the first data section including a first data value of a first type or a second type; and

encoding data into a second data section of the plurality of data sections in the file, the first data section to include information to allow a decoder of the data of the second data section to determine whether to perform a data check operation to verify the data of the second data section, the second data section to include information for the decoder to perform the data check operation to verify the data of the second data section if the first data section includes the first data value of the first type, the second data section to exclude the information if the first data section includes a first data value of the second type for the decoder to skip the data check operation without verifying the data of the second data section, wherein the decoder is capable of computations involving a portion of the data of the second data section, and wherein the encoding of data into the second data section includes encoding already computed data to allow the decoder to skip the computations involving the portion of the data of the second data section, wherein the already computed data is pre-computed via the computations.

18. A computer-readable non-transitory storage medium storing executable program instructions which when executed cause the computer to perform a method comprising:

encoding data into a first data section of a plurality of data sections in a file, the first data section including a first data value of a first type or a second type; and

encoding data into a second data section of the plurality of data sections in the file, the first data section to include information to allow a decoder of the data of the second data section to determine whether to perform a data check operation to verify the data of the second data section, the second data section to include information for the decoder to perform thee data check operation to verify the data of the second data section if the first data section includes the first data value of the first type, the second data section to exclude the information if the first data section includes a first data value of the second type for the decoder to skip the data check operation without verifying the data of the second data section, wherein the decoder is capable of computations involving a portion of the data of the second data section, and wherein the encoding of data into the second data section includes encoding already computed to allow the decoder to skip the computations involving the portion of the data of the second data section, wherein the already computed data is pre-computed via the computations.