Question

I would like to encode a date/time stamp in each frame of a video in a way that it can be easily read back by a computer. On my system the frame rate is variable, so counting frames does not seem like a good solution. I have it displaying the date and time in human readable form (text) on the frame, but reading that back into the computer doesn’t appear to be as trivial as I would like. The recorded videos are large (10s of GB) and long so writing a text file also seems to be troublesome besides being one more file to keep track of. Is there a way to store frame-by-frame information in a video?

Answer 1

There are several ways you can do this.

1. If your compression is not very strong, you may be able to encode the time-stamp in the top or bottom row of your image. These may not contain too much valuable info. You can add some form of error correction (e.g. CRC) to correct any corruptions done by the compressor.
2. A more general solution (which I used in the past) is to have the video file, e.g. AVI, contain another separate text stream. Besides AVI most formats support multiple streams, since these are used for stereo-audio streams, subs etc. The drawback here is that there aren’t many tools that allow you to write these streams, and you’ll have to implement this yourself (using the relevant APIs) for each video format you want to support. In a way this is similar to keeping a text file next to your video, only this file content is multiplexed inside the same video file as a separate stream.