Filter
Top Products
www.ti.com
n
n
n
140
2
60
n
1440
Active Video
124
Y 2
Blanking Data
1
721
779
843
VCOUNT
VCOUNT
EXC=1
HRST=1
EXC=1
HRST=0
HCOUNT
720
HCOUNT
VCOUNT
0
AVID
EXC=1
HRST=0
EXC=1
HRST=1
HCOUNT
842
HCOUNT
VCOUNT
778
HSYNC
79
799
857
63
n−1
15
735722
2
736
n−1
16
793
857844
780
n−1
0
794
136
856855800
80 135
857 10
138137 139
56
12011964
0 55
121 123122
5857 59
Blanking
80.0
VCLKIN
VDIN[9−2]
80.0
10.0
10.0
80.0
80.0
10.0
10.0
10.0
80.0
80.0
10.0
10.0
80.0
10.0
80.0
Y 0
10.0
80.0
Cb 0
Cb 1
Y 1
Cr 0
n+1
1
721
779
843
720719718
857856 0
842842840
777776 778
722
2
844
780
10.0
Cb 0
80.0
Y 719
Cr 359
Y 718
10.0
80.0
10.0
80.0
276
3.4.4FieldIdentification
BT.656andY/CModeFieldandFrameOperation
Figure3-6.HCOUNTOperationExample(EXC=1)
Inordertoproperlysynchronizetothesourcedatastreamandcapturethecorrectfields,field
identificationneedstobeperformed.Fieldidentificationismadeusingoneofthreemethods:EAV,field
indicatorinput,orfielddetectlogic.ThefieldidentificationmethodisdeterminedbytheEXC,FLDD,and
FINVbitsinVCxCTL.
Table3-9.FieldIdentificationProgramming
VCxCTLBit
EXCFLDDFieldDetectMethod
00EAVcode
01EAVcode
10UseFIDinput
11Usefielddetect(fromHSYNCandVSYNCinputs)
IntheBT.656standardandinmanyY/Cstandards,afieldidentification(F)bitiscontainedinEAVand
SAVcodesembeddedinthedatastream.IntheEAVfielddetectmethod,theFbitintheEAVofthefirst
lineofeveryfieldischecked.IfF=0,thenthecurrentfieldisdefinedasfield1.IfF=1,thenthecurrent
fieldisdefinedasfield2.Dependingonhowthefirstlineofafieldisdefined(asdeterminedbytheVRST
bitinVCxCTL)andthevideostreambeingcaptured,theFvalueatthestartofafieldmaynotreflectthe
actualfieldbeingsupplied.TheFINVbitinVCxCTLallowsthedetectedfieldvaluetobeinverted.(For
example,inBT.656525/60operation,theFbitchangesto0toindicatefield1onthefourthlineofthe
field.IftheVRSTbitissetsothelinecounterbeginscountingatline1ofthefield(thefirstEAVwhereV
is1),thentheFbitstillindicatesfield2(F=1)andneedstobeinverted.IftheVRSTbitissettostart
countinglinesbeginningwiththefirstactiveline(thefirstEAVwhereVis0),theFvaluewillhavealready
changedtoindicatefield1(F=0)andnoinversionisnecessary.)
56VideoCapturePortSPRUEM1–May2007
SubmitDocumentationFeedback