Topic: .st5 vs. .md5 - ?

[acidjack]

I see now that, for example, xAct allows you to do an "ST5" style checksum file.  My understanding is that this type of checksum is preferable and basically eliminates the need for .ffp files to the extent one believes they are warranted.  I feel like I don't see many tapers using .st5, but maybe I'm not looking very carefully.  Thoughts?

From TradersDen's FAQ:

The main reason is that when you double-click a .ffp for testing using TLH, it extracts the checksums hidden in each FLAC file's header and compares that to what is in the .ffp file to see if it matches (takes about three seconds). Using the .ffp this way for testing does not test the audio content whatsoever (which could be corrupt after a successful .ffp verification). A second stage of testing is necessary in this case, it is "test" mode, which decompresses the audio to a temp file and generates a fresh hash from this and compares that to the the checksum hidden in the header. So, only after the two-stage test the files are verified. Double-clicking on a .st5 for verification using TLH results in the audio content of the files to be tested being decompressed to a temp file (temporarily) while a fresh hash is generated and compared to the corresponding checksums contained in the .st5 file. So the .st5 test is only one step and verifies both (a) that the files will decompress properly (as with "test" mode) and (b) that the checksums contained in the .st5 file match hashes freshly generated from that decompressed audio. When a .st5 verifies 100% okay everything is tested except the header isn't looked at, thus the .ffp. The .ffp is admittedly a little superfluous, but since it is only 1k and takes about three seconds to generate and verify its not really much to ask.

[hi and lo]

.st5 is definitely my preferred checksum and what I include in a text file.

[twatts (pants are so over-rated...)]

Interesting...  I may make the switch...

I always used FLAC FFPs instead of FLAC MD5s with my seeds b/c it didn't matter if you added tags.  With MD5s, any change to tagging will create an error...  But I didn't realize FFPs didn't actually test the files... 

Terry

[hi and lo]

Md5's still have their place. Useful to identify a file-set as an unmodified original release or when doing ftp file transfers.

I do generate all three (st5/md5/ffp) when making file sets, but the ffp really has no advantage or purpose if an st5 is present.

[twatts (pants are so over-rated...)]

Md5's still have their place. Useful to identify a file-set as an unmodified original release or when doing ftp file transfers.

I do generate all three (st5/md5/ffp) when making file sets, but the ffp really has no advantage or purpose if an st5 is present.

I generate a WAV MD5 and an FLAC FFP now...  I'm going to start adding a FLAC ST5 in there as well... 

Thanks for this!

Terry

[JasonSobel]

an st5 is redundant, as the checksum is identical to the FFP checksum.
it can be useful for SHN files, particularly when converting SHN to FLAC.  because you can create an st5 checksum on the SHN files, and then an FFP on the FLAC files, and verify visually that the audio data is the same.

and in regards to the trader's den quote, saying that the FFP verification in Trader's Little Helper doesn't actually check the audio data.  that is not true.  the FFP checksum data is included in the header of each FLAC file.  so when you create an FFP file, and it's almost instantaneous, it's just grabbing the FFP data from the header of each file.  but when you verify an FFP, it is not an almost instantaneous process.  and that is because it is decoding the file and re-creating the audio data checksum, and then comparing it with the data in the FFP file.  so the FFP verification does indeed check the FLAC file and decodes it to a temp file.

[macdaddy]

St5 ignores header data. So if your workstation changes header info, like samplitude does, an st5 of the raw wav is a good idea cos u can always check the files after a while if you decide to go back and remaster, u know u are working with the same exact wav file u originally recorded. An st5 is also good when checking files transferred from hd to hd, since an md5 of the original transfer/save is useless if the header data changes due to the way your wav editor works (found the latter out the hard way)...

Furthermore, when mastering to redbook, since st5 hashes wav data, you can st5 your final wav tracks, and compare to the ffp from the final flac files, and know your encode went flawlessly prior to seeding. Simarly, when Joe Downloader makes his CDs, he can make his own st5 (or use the one I include in the seeded fileset); if it matches the downloaded ffp, then the flac > wav conversion went right, and the files are ready to be burned to standard.

Ymmv