Methods and apparatus are disclosed to index digital frames. An example method includes identifying channel types associated with a plurality of image frames, splitting each one of the plurality of image frames into a respective color channel based on the identified channel types, applying a local binary pattern to each of the respective color channels to generate a respective pattern number, generating a spatial representation of each respective pattern number to determine transition probabilities for each channel type, and identifying a degree of similarity between the plurality of image frames based on the transition probabilities.