Film-mode (3:2/2:2 Pulldown) detector, method and video device
View Patent ↗A film mode detector detects film mode of a series of fields of video by comparing pixels in a field adjacent the current field, with corresponding pixels directly above and directly below the pixels in an adjacent field. The number of pixels in the adjacent in time to the current field having (or not having) a value approximately between values of the pixels above and below in the current field is assessed. Film mode for a current field may be detected by monitoring the assessment from field to field. Alternatively or additionally, the detector may detect film mode by assessing for each current field, whether a relatively large or relatively small number of pixels in the immediately previous field have values outside a specified distance of values of a corresponding pixel in the immediately subsequent field, for at least a portion of the immediately previous and subsequent fields. Again, film mode may be detected by monitoring this second assessment from field to field.
1. A method of detecting film mode of a series of fields of video, said method comprising:
for each current field, assessing, in a circuit, whether a relatively large or relatively small number of pixels in a field immediately previous to said current field are outside a specified distance of a corresponding pixel in a field immediately subsequent to said current field, for at least a portion of said field immediately previous and said field immediately subsequent;
monitoring said assessing from current field to current field to detect that said series of fields of video represent video encoded in film mode, wherein assessing further comprises calculating the distance between the pixel and the corresponding pixel.
2. The method of claim 1 , wherein said film mode is detected for the Xth of said current fields if said assessing assesses a relatively small number of pixels for said X.th current field;
and relatively large number of pixels for the immediately preceding four current fields.
3. The method of claim 2 , wherein said film mode is detected for fields subsequent to said Xth field, until said assessing assesses a relatively large number of pixels for five or more current fields.
4. The method of claim 2 , wherein said film mode is detected for fields subsequent to said Xth field until said assessing assesses a relatively small number of pixels for two or more fields.
5. The method of claim 1 , further comprising maintaining for each current field a plurality of counts, each of said plurality of counts counting the number of pixels in said field immediately previous whose value is outside an associated offset of the value of a corresponding pixel in said field immediately subsequent, for at least a portion of said field immediately previous and immediately subsequent.
6. The method of claim 2 , wherein said film mode is signaled by an indicator to form a current frame by weaving said current field and said immediately previous field.
7. The method of claim 2 , wherein said film mode is signaled by an indicator to form a current frame by weaving said current field and said immediately subsequent field.
8. A non-transitory computer readable medium storing processor readable instructions, that when loaded at a computing device operable to decode video into a plurality of video fields, adapt said computing device to detect film mode of said series of video fields in accordance with the method of claim 1 .
9. A film mode detector for detecting a film mode recording of a series of fields of video comprising:
at least one like field comparator for assessing whether a pixel in a field immediately previous to said current field is outside a specified distance of a corresponding pixel in a field immediately subsequent to said current field;
at least one counter connected to said at least one like field comparator, wherein the comparator receives the signal indicating the specified distance.
10. The detector of claim 9 , further comprising a processor monitoring said at least one counter from current field to current field to detect that said fields represent video encoded in film mode.
11. The detector of claim 9 , wherein the comparator calculates the distance between the pixel and the corresponding pixel.
12. The detector of claim 9 , wherein the counter is incremented if the pixel and the corresponding pixel are within the specified distance, and wherein the counter is not incremented if the pixel and the corresponding pixel are not within the specified distance.
13. A video device including the film mode detector of claim 9 .
14. A film mode detector for detecting a film mode recording of a series of fields of video comprising:
at least one like field comparator for assessing whether a pixel in a field immediately previous to said current field is outside a specified distance of a corresponding pixel in a field immediately subsequent to said current field;
at least one counter connected to said at least one like field comparator, wherein the comparator calculates the distance between the pixel and the corresponding pixel.
15. The detector of claim 14 , further comprising a processor monitoring said at least one counter from current field to current field to detect that said fields represent video encoded in film mode.
16. The detector of claim 14 , wherein the counter is incremented if the pixel and the corresponding pixel are within the specified distance, and wherein the counter is not incremented if the pixel and the corresponding pixel are not within the specified distance.
17. A video device including the film mode detector of claim 14 .
18. A film mode detector for detecting a film mode recording of a series of fields of video comprising:
at least one like field comparator for assessing whether a pixel in a field immediately previous to said current field is outside a specified distance of a corresponding pixel in a field immediately subsequent to said current field;
at least one counter connected to said at least one like field comparator, wherein the comparator calculates the distance between the pixel and the corresponding pixel, wherein the counter is incremented if the pixel and the corresponding pixel are within the specified distance, and wherein the counter is not incremented if the pixel and the corresponding pixel are not within the specified distance.
19. The detector of claim 18 , further comprising a processor monitoring said at least one counter from current field to current field to detect that said fields represent video encoded in film mode.
20. A video device including the film mode detector of claim 18 .