Methods and apparatus to monitor audio/visual content from various sources
View Patent ↗Methods and apparatus to monitor audio/visual content from various sources are disclosed. Example methods disclosed herein to monitor a media presentation include generating a plurality of interpixel differences associated with a plurality of video samples of a video signal corresponding to a video frame of the media presentation. Such example methods also include processing the plurality of interpixel differences to determine whether the video frame exhibits macroblocking. Such example methods further include eliminating a first source from a plurality of possible sources of the media presentation when the video frame exhibits macroblocking.
1. A method to monitor a media presentation, the method comprising:
generating a plurality of interpixel differences associated with a plurality of video samples of a video signal corresponding to a video frame of the media presentation;
processing the plurality of interpixel differences to determine whether the video frame exhibits macroblocking; and
eliminating a first source from a plurality of possible sources of the media presentation when the video frame exhibits macroblocking.
2. A method as defined in claim 1 , wherein processing the plurality of interpixel differences includes:
determining a first power spectral density associated with the plurality of interpixel differences;
filtering the first power spectral density to determine a second power spectral density; and
determining a value based on a difference between the first power spectral density and the second power spectral density.
3. A method as defined in claim 2 , further including comparing the value to a threshold to determine whether the video frame exhibits macroblocking.
4. A method as defined in claim 2 , further including determining that the media presentation corresponds to compressed video when the difference is greater than a threshold.
5. A method as defined in claim 2 , further including determining that the media presentation corresponds to a video game when the value is substantially equal to zero.
6. A method as defined in claim 1 , further including determining whether an audio signal corresponding to the media presentation is muted.
7. A method as defined in claim 6 , wherein determining whether the audio signal is muted includes:
counting zero crossings associated with a plurality of audio samples of the audio signal; and
determining whether the audio signal is muted when a number of zero crossings satisfies a first threshold.
8. A tangible computer readable storage device or storage disk including computer readable instructions which, when executed, cause a processor to at least:
generate a plurality of interpixel differences associated with a plurality of video samples of a video signal corresponding to a video frame of a media presentation;
process the plurality of interpixel differences to determine whether the video frame exhibits macroblocking; and
eliminate a first source from a plurality of possible sources of the media presentation when the video frame exhibits macroblocking.
9. A tangible computer readable storage device or storage disk as defined in claim 8 , wherein to process the plurality of interpixel differences, the instructions, when executed, further cause the processor to:
determine a first power spectral density associated with the plurality of interpixel differences;
filter the first power spectral density to determine a second power spectral density; and
determine a value based on a difference between the first power spectral density and the second power spectral density.
10. A tangible computer readable storage device or storage disk as defined in claim 9 , wherein the instructions, when executed, further cause the processor to compare the value to a threshold to determine whether the video frame exhibits macroblocking.
11. A tangible computer readable storage device or storage disk as defined in claim 9 , wherein the instructions, when executed, further cause the processor to determine that the media presentation corresponds to compressed video when the value is greater than a threshold.
12. A tangible computer readable storage device or storage disk as defined in claim 9 , wherein the instructions, when executed, further cause the processor to determine that the media presentation corresponds to a video game when the value is substantially equal to zero.
13. A tangible computer readable storage device or storage disk as defined in claim 8 , wherein the instructions, when executed, further cause the processor to determine whether an audio signal corresponding to the media presentation is muted.
14. A tangible computer readable storage device or storage disk as defined in claim 13 , wherein to determine whether the audio signal is muted, the instructions, when executed, cause the processor to:
count zero crossings associated with a plurality of audio samples of the audio signal; and
determine whether the audio signal is muted when a number of zero crossings satisfies a first threshold.
15. An apparatus comprising:
a macroblock detector to:
generate a plurality of interpixel differences associated with a plurality of video samples of a video signal corresponding to a video frame of a media presentation; and
process the plurality of interpixel differences to determine whether the video frame exhibits macroblocking; and
a decision processor to eliminate a first source from a plurality of possible sources of the media presentation when the video frame exhibits macroblocking.
16. An apparatus as defined in claim 15 , wherein the macroblock detector is further to:
determine a first power spectral density associated with the plurality of interpixel differences;
determine a second power spectral density by filtering the first power spectral density; and
determine a value based on a difference between the first power spectral density and the second power spectral density.
17. An apparatus as defined in claim 16 , wherein the macroblock detector is further to compare the value to a threshold to determine whether the video frame exhibits macroblocking.
18. An apparatus as defined in claim 16 , wherein the decision processor is further to determine that the media presentation corresponds to compressed video when the value is greater than a threshold.
19. An apparatus as defined in claim 16 , wherein the decision processor is further to determine that the media presentation corresponds to a video game when the value is equal to zero.
20. An apparatus as defined in claim 15 , further including a mute detector to determine whether an audio signal corresponding to the media presentation is muted.
21. An apparatus as defined in claim 20 , wherein the mute detector is further to:
count zero crossings associated with a plurality of audio samples of the audio signal; and
determine whether the audio signal is muted when a number of zero crossings satisfies a first threshold.