Unified approach to film mode detection
A method for film mode detection is disclosed. The method generally includes the steps of (A) detecting if a plurality of fields in a video signal are in a 3:2 pull-down pattern to control a plurality of first flags based on a plurality of statistics gathered from the fields, (B) detecting if the fields contain moving interlaced text to control a second flag based on both (i) the statistics and (ii) a repeat-field flag of the first flags that indicates repeating consecutive same polarity fields and (C) deciding among a plurality of inverse telecine processes to de-interlace the fields based on all of (i) a 3:2 mode flag of the first flags, (ii) a 3:2 direction flag of the first flags and (iii) the second flag.
1. A method for film mode detection, comprising the steps of:
(A) gathering a plurality of statistics from a plurality of fields in a video signal using a circuit;
(B) detecting if said fields are in a 3:2 pull-down pattern to control a plurality of first flags based on said statistics;
(C) detecting if said fields contain moving interlaced text to control a second flag based on both (i) said statistics and (ii) a repeat-field flag of said first flags that indicates repeating consecutive same polarity fields; and
(D) deciding among a plurality of inverse telecine processes to de-interlace said fields based on all of (i) a 3:2 mode flag of said first flags, (ii) a 3:2 direction flag of said first flags and (iii) said second flag, wherein said 3:2 direction flag distinguishes between (a) both a current field and a next field originating from a frame and (b) both said current field and a previous field originating from said frame.
2. The method according to claim 1 , further comprising the step of:
detecting if said fields are in a 2:2 pull-down pattern based on said statistics to control a plurality of third flags, wherein the deciding step is further based on (i) a 2:2 mode flag of said third flags and (ii) a 2:2 direction flag of said third flags.
3. The method according to claim 2 , wherein said statistics of said current field comprise (i) a vertical activity, (ii) a first row sum of absolute differences between said current field and said previous field, (iii) a second row sum of absolute differences between said current field and said next field and (iv) a third row sum of absolute differences between said previous field and said next field.
4. The method according to claim 1 , wherein the step of deciding comprises the sub-step of:
deciding none of said inverse telecine processes if no telecine mode was detected.
5. The method according to claim 1 , wherein the step of deciding comprises the sub-step of:
deciding a non-weave process of said inverse telecine processes if said second flag indicates that said moving interlace text is detected in said fields.
6. The method according to claim 1 , wherein the step of deciding comprises the sub-step of:
deciding a weave process of said inverse telecine processes between said current field and one of (i) said previous field and (ii) said next field based on said both said 3:2 mode flag and said 3:2 direction flag.
7. The method according to claim 1 , further comprising the step of:
de-interlacing a first portion of said fields lacking said moving interlaced text using a weave process of said inverse telecine processes while said second flag indicates that said moving interlaced text is present.
8. The method according to claim 7 , further comprising the step of:
de-interlacing a second portion of said fields having said moving interlaced text using a spatial filter process of said inverse telecine processes.
9. The method according to claim 8 , further comprising the step of:
de-interlacing a third portion of said fields between said first portion and said second portion using a gradual blend of said weave process and said spatial filter process.
10. A method for film mode detection, comprising the steps of:
(A) gathering a plurality of statistics from a plurality of fields in a video signal using a circuit;
(B) detecting if said fields are in a 2:2 pull-down pattern to control a plurality of first flags based on said statistics;
(C) detecting if said fields contain moving interlaced text to control a second flag based on said statistics; and
(D) deciding among a plurality of inverse telecine processes to de-interlace said fields based on all of (i) a 2:2 mode flag of said first flags, (ii) a 2:2 direction flag of said first flags and (iii) said second flag, wherein said 2:2 direction flag distinguishes between (a) both a current field and a next field originating from a frame and (b) both said current field and a previous field originating from said frame.
11. The method according to claim 10 , further comprising the step of:
detecting if said fields are in a 3:2 pull-down pattern based on said statistics to control a plurality of third flags, wherein the deciding step is further based on (i) a 3:2 mode flag of said third flags and (ii) a 3:2 direction flag of said third flags.
12. The method according to claim 11 , wherein control of said second flag is further based on a repeat-field flag of said third flags that indicates repeating consecutive same polarity fields.
13. The method according to claim 10 , wherein the step of deciding comprises the sub-step of:
deciding none of said inverse telecine processes if no telecine mode was detected.
14. The method according to claim 10 , wherein the step of deciding further comprises the sub-step of:
deciding a non-weave process of said inverse telecine processes if said second flag indicates that said moving interlace text is detected in said fields.
15. The method according to claim 10 , wherein the step of deciding comprises the sub-step of:
deciding a weave process of said inverse telecine processes between said current field and one of (i) said previous field and (ii) said next field based on said both said 2:2 mode flag and said 2:2 direction flag.
16. A system comprising:
a memory configured to store a plurality of fields from a video signal; and
a first processor configured to (A) gather a plurality of statistics from said fields, (B) detect if said fields are in a 3:2 pull-down pattern to control a plurality of first flags based on a said statistics, (C) detect if said fields contain moving interlaced text to control a second flag based on both (i) said statistics and (ii) a repeat-field flag of said first flags that indicates repeating consecutive same polarity fields and (D) decide among a plurality of inverse telecine processes to de-interlace said fields based on all of (i) a 3:2 mode flag of said first flags, (ii) a 3:2 direction flag of said first flags and (iii) said second flag, wherein said 3:2 direction flag distinguishes between (a) both a current field and a next field originating from a frame and (b) both said current field and a previous field originating from said frame.
17. The system according to claim 16 , wherein said first processor is further configured to detect if said fields are in a 2:2 pull-down pattern based on said statistics to control a plurality of third flags, wherein the deciding step is further based on (i) a 2:2 mode flag of said third flags and (ii) a 2:2 direction flag of said third flags.
18. The system according to claim 16 , wherein said first processor comprises a video capture module configured to detect if said fields are in said 3:2 pull-down pattern.
19. The system according to claim 16 , further comprising a second processor configured to detect if said fields are in said 3:2 pull-down pattern.
20. The system according to claim 16 , further comprising a second processor configured to de-interlace said fields according to a particular one of said inverse telecine processes decided upon by said first processor.
21. The system according to claim 16 , wherein step (D) decides none of said inverse telecine processes if no telecine mode was detected.
22. The system according to claim 16 , wherein step (D) decides a non-weave process of said inverse telecine processes if said second flag indicates that said moving interlace text is detected in said fields.
23. The system according to claim 16 , wherein step (B) asserts said second flag as true in response to said statistics indicating vertically moving interlaced text.
24. A system comprising:
a memory configured to store a plurality of fields from a video signal; and
a first processor configured to (A) gather a plurality of statistics from said fields, (B) detect if said fields are in a 2:2 pull-down pattern to control a plurality of first flags based on said statistics, (C) detect if said fields contain moving interlaced text to control a second flag based on said statistics and (D) decide among a plurality of inverse telecine processes to de-interlace said fields based on all of (i) a 2:2 mode flag of said first flags, (ii) a 2:2 direction flag of said first flags and (iii) said second flag, wherein said 2:2 direction flag distinguishes between (a) both a current field and a next field originating from a frame and (b) both said current field and a previous field originating from said frame.
25. The system according to claim 24 , wherein said first processor is further configured to generate an output signal conveying said fields in an interlaced format in response to no telecine being detected.
26. The system according to claim 24 , further comprising a second processor configured to de-interlace said fields according to a particular one of said inverse telecine process decided upon by said first processor.
27. The system according to claim 24 , wherein step (D) decides none of said inverse telecine processes if no telecine mode was detected.
28. The system according to claim 24 , wherein step (D) decides a non-weave process of said inverse telecine processes if said second flag indicates that said moving interlace text is detected in said fields.
29. The system according to claim 24 , wherein step (B) asserts said second flag as true in response to said statistics indicating vertically moving interlaced text.