METHOD AND APPARATUS FOR DETERMINING REPRODUCTION ACCURACY OF DECOMPRESSED VIDEO

• US 20110158309A1
• Filed: 12/28/2009
• Published: 06/30/2011
• Est. Priority Date: 12/28/2009
• Status: Abandoned Application

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: TINE, STEVEN D., ISHTIAQ, FAISAL, BEKIARES, TYRONE D.
• Application Number:
  US12/648,274
• Publication Number:
  US 20110158309A1
• Time in Patent Office: Days
• US Class Current: 375/240.01
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30168 Image quality inspection
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: H04N 17/004 for digital television systems
• CPC Class Codes: H04N 19/154 Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion use of rate-distortion criteria H04N19/147
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/85 using pre-processing or post-processing specially adapted for video compression

Abstract

A video decoder receives compressed video and processes the video to generate decompressed video comprising a plurality of pixels in a sequence of frames. For at least some of the pixels, the video decoder further determines, on a pixel by pixel basis, motion vector and quantizer values used to perform compression of the pixels and determines a quality value for each corresponding pixel using the motion vector and quantizer values, wherein the quality value provide a measure of reproduction accuracy of the decompressed video with respect to corresponding uncompressed video.

Claims

1. A method for determining reproduction accuracy of decompressed video, the method comprising:

at a decoder;

receiving compressed video;

processing the video to generate decompressed video comprising a plurality of pixels in a sequence of frames;

for at least some of the pixels, determining, on a pixel by pixel basis, motion vector and quantizer values for the pixels and determining a quality value for each corresponding pixel using the motion vector and quantizer values, wherein the quality values provide a measure of reproduction accuracy of the decompressed video with respect to corresponding uncompressed video.

2. The method of claim 1, wherein the quality value determined for each pixel comprises at least one of a relative quality value or an absolute quality value.

3. The method of claim 2 further comprising correlating the quality values in time with the corresponding decompressed pixels.

4. The method of claim 3 further comprising displaying a representation of the quality values correlated in time with the corresponding decompressed pixels.

5. The method of claim 4, wherein the displaying comprises overlaying the representation of the quality values over the corresponding decompressed pixels.

6. The method of claim 5, wherein the representation visually distinguishes the relative quality values.

7. The method of claim 2 further comprising:

writing the quality values to a storage medium contemporaneously with the corresponding decompressed pixels; and

correlating the quality values in time with the corresponding decompressed pixels on the storage medium.

8. The method of claim 7 further comprising performing a compression technique on the quality values before writing them to the storage medium.

9. The method of claim 8, wherein the compression technique comprises a lossless compression technique.

10. The method of claim 1, wherein the quality values are relative quality values, and wherein determining the relative quality value for each corresponding pixel using the motion vector and quantizer values comprises:

determining whether the decompressed pixel was spatially encoded or temporally compensated;

upon determining that the decompressed pixel was spatially encoded, the method further comprising;

recording the quantizer value, which comprises a quantizer value for a macroblock that includes the pixel;

recording the motion vector value, which comprises a zero magnitude;

recording a delta frame count of a zero value since the pixel was last spatially encoded;

upon determining that the decompressed pixel was temporally compensated, the method further comprising;

recording the quantizer value, which comprises a quantizer value for the pixel when it was last spatially encoded;

recording the motion vector value, which comprises a non-zero magnitude;

recording a non-zero delta frame count value since the pixel was last spatially encoded; and

sorting the pixels based on the recorded quantizer values, motion vector values and delta frame counts, and assigning the relative quality values to the sorted pixels.

11. The method of claim 10, wherein upon determining that the decompressed pixel was temporally compensated, the method further comprising:

computing the motion vector value by summing all motion vector magnitudes used to encode the pixel since the pixel was last spatially encoded.

12. The method of claim 10, wherein the sorting comprises ranking the decompressed pixels and assigning the relative quality values based on the relative rankings.

13. The method of claim 11, wherein the ranking comprises:

performing a primary sort based on the recoded motion vector values;

performing a secondary sort based on the recorded quantizer values; and

performing a tertiary sort based on the recorded delta frame counts.

14. The method of claim 1, wherein the quality values are relative quality values, the method further comprising generating absolute quality values, for the corresponding decompressed pixels, from the relative quality values.

15. The method of claim 14, wherein generating the absolute quality values comprises:

setting a plurality of absolute quality reference values; and

mapping the relative quality value to the corresponding absolute quality value using interpolation based on the plurality of absolute quality reference values.

16. A computer-readable storage element having computer readable code stored thereon for programming a computer to perform a method for determining reproduction accuracy of decompressed video in a decoder upon receiving compressed video and processing the video to generate decompressed video comprising a plurality of pixels in a sequence of frames, the method comprising:

for at least some of the pixels, determining, on a pixel by pixel basis, motion vector and quantizer values for the pixels; and

determining a quality value for each corresponding pixel using the motion vector and quantizer values, wherein the quality values provide a measure of reproduction accuracy of the decompressed video with respect to corresponding uncompressed video.

17. A video decoder comprising:

an interface that receives compressed video; and

a processor that;

processes the video to generate decompressed video comprising a plurality of pixels in a sequence of frames; and

for at least some of the pixels, determines, on a pixel by pixel basis, motion vector and quantizer values for the pixels and determines a quality value for each corresponding pixel using the motion vector and quantizer values, wherein the quality values provide a measure of reproduction accuracy of the decompressed video with respect to corresponding uncompressed video.