This is not a code writing service. I'll just give you the central part of a possible algorithm and leave it to you to fill the gaps (opening the files, closing them, etc.). This is just the basic idea, untested:

my ($current_frame, $count);
while (<$INFILE>) {
    if (/^(Frame:\s+\d+)/) {
        print "$current_frame $count \n" if defined $current_frame;
        $current_frame = $1;
        $count = 0;
    elsif (/^C\d+) {
        $count ++;
    }
}
print "$current_frame $count \n"; # prints last group
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