Embedding Timestamp information in a captured video frames

Hello,

I want to be able to embed some binary information (a time stamp) into each frame of a video file as I capture it. I can embed the information by modifying the data in the frame using the callback filter, but I think the data will be altered when the file is run through a codec and saved to disk. Is there a way to keep this data from being altered without saving the file uncompressed?

Thanks,

-Ray 

Ray,
If you use any type of lossy compression, the data will be modified in a way that does not guarantee reversing when it is decompressed.
You could try a lossless compression format, but generally the size reduction is not close to the good lossy formats such as H264 and MPEG4.
You could come up with an approach that's 'loss-resistant'. The idea is to set certain pixel values to represent the numbers you want, and make different number values fairly distinct from each other. A lossy compression algorithm usually makes limited to changes the color and/or intensity information, so if your chosen values are far apart enough, you should be able to retrieve them correctly even if they are shifted during encoding/decoding.