[StainlessS]

#2 and #3 updated. Added BorderColor and ATM args to function.
Added BorderColor to comply with your Border color requirement (was black only).
Default ATM added/changed in RT_QueryBorderCrop, would fail to find any croppings as had not been added/updated in this script.

Here also a client script to get you going (will update script in RT_Stats next update).

import("ImageSplicer.avs")

FN =  "Base Photos\*.BMP"
SZLIMIT     =   -768        # Height=Abs(SZLIMIT)
FAR         =   4.0/3.0
AUTOCROP    =   TRUE
STRENGTH    =   0.66
SHOWAL      =   False
SHOWBORD    =   False
SUBS        =   False
CROPTHRESH  =   -0.5
FPS         =   1.0
WMOD        =   4
HMOD        =   4
DEBUG       =   TRUE
IGNORE      =   0.4
BORDCOL     =   $001144     # Added for goorawin
ATM         =   0.5         # Added, arg to QueryborderCrop

Anim = ImageSplicer(FN,SzLimit=SZLIMIT,Far=FAR,AutoCrop=AUTOCROP,AutoLevelStrength=STRENGTH,ShowAutoLevel=SHOWAL,ShowBorder=SHOWBORD,
                \ Subs=SUBS,CropThresh=CROPTHRESH,Fps=FPS,Wmod=WMOD,Hmod=HMOD,Debug=DEBUG,IGnore=IGNORE,BorderColor=BORDCOL,ATM=ATM)

anim.AssumeFPS(1).ChangeFPS(45) #repeat each frame 45 times (1 sec + 0.5 sec overlap)        
Vid = Trim(15, -30)           # first second
GScript("""
    for (f=45, Framecount-45, 45) {
    next = Trim(f, -45) # next second, incl overlap
    vid = Dissolve(vid, next, 15)
}
""")
Return Vid.AssumeFPS("pal_video")

EDIT: In actual fact, ATM would have made no difference, only pertinent if using RT_QueryBorderCrop default AutoThresh (-32.0).
I forgot how it works.