timestamp

Contents:

• Introduction
• Compiling
• Running
• Example
• Download

Introduction

DV files do not come with an understanding of the milliseconds since epoch time standard. However, milliseconds since epoch (hereafter referred to as ms/epoch) is useful to researchers as it provides them a single piece of data that useful because it is unique between frames, and leads to easy calculations of time, for such math as velocity calculation, or similar.

Compiling

timestamp is compiled by running gnu make in the src directory.

Running

Try running the timestamp binary by cd'ing to the directory the binary is located, and typing ./timestamp. You should get something that looks like this:

		Usage: ./timestamp <btf_dir>
		Where <btf_dir> is the BTF main directory.

Example

For this example, the following invocations were used:
./timestamp ANTBTF/ produces:

		Opening ANTBTF//reltimestamp.btf ... Success!
		Opening ANTBTF//recordtime.btf ... Success!
		Opening ANTBTF//framestamp.btf ... Success!
This btf seems to be 30fps
The seconds change 14 frames in.
Analysis:
The Date of the first Second change is '02/05/2003-18:18:54' (or 1046906334ms since epoch)
This date is (14frames * (1000ms/s / 30fps)) = 466ms in the future from the beginning of the file
Therefore, this movie starts at 1046905868ms since epoch
Opening ANTBTF//timestamp.btf ... Success!
Adding timestamp for frame    299

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