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Research and Technology - Forensic Science Communications - July 2006

Table 2: An example of the representative video, audio, and control-track times, lengths, and frames for a 10.00-second overrecording with the following characteristics: (1) the underlying recording is at SP speed, (2) the overrecording is at SP speed, and (3) the underlying recording and overrecording VCRs have flying erase and hi-fi audio heads. The distance from the full-track erase head to the video-recording head has been designated as 80.00 mm, the frame numbers have been rounded to the nearest whole number, all lengths are in mm, and all times are in seconds.

 

Playback Video Sequence

Hi-Fi Audio

Linear Audio

Control Track

Segment

Time

Length

     Time     

      Length      

 Frames 

 

 

 

O

10.00

333.50

0–10.00

0–333.50

1–300

Yes

Yes

Yes

E

2.40

80.00

10.00–12.40

333.50–413.50

301–372

No

No

No

UNP

2.89

96.30

12.40–15.29

413.50–509.80

373–458

No

No

No

UN

2.38

79.24

15.29–17.67

509.80–589.04

459–530

Yes

No

No