Determining the optimal frame extraction rate for indexing depends on a few key factors: the content type, the goals of your indexing system, and the computational resources available. Generally, the frame extraction rate refers to how many frames are taken from a video over a specific period. For example, you might choose to extract one frame per second, or perhaps ten frames per second, depending on the requirements of your project.
First, consider the content of the video. If the video has a lot of movement or changes quickly—like an action scene in a movie—you may want to extract more frames to capture critical moments. In this case, capturing ten frames per second might provide a more detailed index, letting your system identify changes in the scene more effectively. Conversely, for a static video, such as a lecture recording where not much changes, a lower extraction rate, say one frame per second, could suffice without sacrificing quality.
Second, analyze the goals of your indexing system. If the main objective is to generate a searchable database of video content, extracting frames at higher rates could be beneficial since those frames will be tagged with metadata for easier access. However, higher rates also mean more data to process, store, and manage, which might strain your resources. So, you must balance the rate of extraction with the speed of index-building and the amount of storage available. Testing different rates and observing their effects on indexing performance should guide you to the optimal solution.