On Fri, 2005-11-11 at 16:47 -0800, Jack Coates wrote: > Pat Farrell wrote:... > >I proposed that we only consider the music part of the file, > >and skip all the metadata tags. I think that changing > >one of the tags within a song, say Genre from Pop to House > >does not change the essence of the music. So I proposed > >that we read the whole file, ignore the tags, headers, and > >assorted BS, and put the music bytes thru the hash function. > >And store the resulting hash. > > I kinda agree with this in theory, but the practice is not something I > imagine going well.
Can you elaborate? Seems pretty straight forward to me. It will be kinda slow, but it is an ideal thing to do in a background thread. The code I wrote to grab cover art had to be able to read the tags and dictionary data in MP3 and Flac/Ogg files. > >WMA and AAC are great examples of why using tags is not sufficient. > >The internal format of these files are proprietary. You may > >be able to reverse engineer the format for any specific version, > >but you will have to repeat it for each modification that Microsoft > >or Apple make. > wouldn't the DRM versions of these songs have different checksums on > every device they're copied too? I think this is impossible to answer this. You'd have to know a lot more about the DRM from the assorted vendors than I know. I would expect, if they did it "properly" that you could not access the raw PCM data, so you couldn't calculate the crypto-hash. Mostly because if I can get access to the raw PCM data to calculate the hash, I probably could figure out how to write them to a file without the DRM. > I'd guess because the tags are often already there, and/or already being > maintained. One could even call them the "standard" since they're the > primary way to get data about songs from one computer music player to > another (even though they all seem to make a database of their own these > days, they're all starting from the tags). I see it more as when all you have is a hammer, all the world's problems look like nails. Clearly if you focus on moving tunes to low-brain components, you have to have minimal common subset approaches, such as tags. But those same components are not likely to understand or properly handle any extension or "non-standard" tags. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html _______________________________________________ Discuss mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/discuss
