Thank you for your quick response... > In this instance, it seems to me that a hash that only samples the input data would be just as useful as one that runs o

Thank you for your quick response... > In this instance, it seems to me that a hash that only samples the input data would be just as useful as one that runs over the whole set. So if I understand this correctly, hashing a set of bytes of a percentage of the file size would be a possible approach that could work. In your suggestion 1/128th of the file size, so a little less that 1 percent? But the difference is, that you instead of one chunk would hash a set of bytes always skipping a fixed amount? > or you could put your metadata into your audio files so it sticks with them when they move. That is already the case. The audio files are casual files like in every library. But I know, where the metadata starts and ends, so I can build a only-audio hash, that does not change, if the metadata changes. That is the point of this whole feature...