dbpoweramp wav>shn>wav problem

[hippienerd]

I have worked a ton with shn and am now exploring FLAC, and as a result installed dBpowerAMP convert so I can directly convert between different formats without having to decode to wav, like with mkw 0.97.

So I have been doing some testing to convince myself that using dbpoweramp 10 (installed from dMC-r10.exe) and mkw 0.97 is interchangable. I installed the shn codec from dbpoweramp's site (dBpowerAMP-codec-shorten.exe) So I ripped a CD with EAC. Then I used mkw and dbpower amp to convert to seperate shn files.

Problem #1: shns don't match. I used md5sum command line tool to created md5s, and the two shn's md5s do not match.

So next I decided to convert back to wav and compare files. The crcs for the original wavs and the wavs run through dbpoweramp do not match. mkw gives back the same wavs as the originals. If I use mkw to convert the dbpoweramp shns back to wavs, and I still don't get the original wavs.

Then i tested the FLAC codec, and got back the same wavs. This would seem to indicate that there is a problem with the shorten codec in dbcpoweramp. I have tons of shn files and want to convert my archive henceforth to FLAC, but I don't trust the shn side of dbpoweramp.

Problem #2: Shn codec does not return the same wave in dbpoweramp.

I know I am kinda anal about this, but i don't want to use a tool that is not converting properly, since I do not know what it is changing, I just know the two files are different.

If it matters, I am running W98SE. More info about my systems is available upon request.

Anybody else had problems with dbpoweramp shn codec? Any idea what is happening here?

[hippienerd]

Re: dbpoweramp wav>shn>wav problem

OK. To follow up, I rebooted my PC and tried again. Now dbpoweramp I get the same wavs when I use the dbpoweramp forntend for the shn codec.

However I still get two different shns depending on whether or not I use mkw or dbpoweramp. Also if I compress the shns with dbpoweramp and decompress with mkw, then I get a different wav file. Interstingly if I convert to shn with mkw and convert back to wav with dbpoweramp, I get the same wav file

So are mkw and dbpoweramp just incomaptible? Then I would need to keep track of which one I used when compressing, which would be a pain.

Any insight would be appreciated.

[xoas]

Re: dbpoweramp wav>shn>wav problem

Up front, let me say that I am nowhere near as technically hip as you. Still, I don't see why you feel that mkw and dBpowerAMP Music Converter (dMC) are incompatible on the basis that they produce different size shn files. In fact your experiment converting a wav to shn with mkw and from shn to wav with dMC (which reulted in a wav identical to the original) would seem to confirm that they ARE compatible.

It seems to me possible that dMC may use a different version of the shn codec than mkw does (which might account for the difference in file sizes) or perhaps the programs themselves encode in a slightly different fashion. The mkw site also does have the following discussion on this topic which seems relevent:

Note that WAV files may contain non-audio data blocks, which are typically used only by the creating application and ignored by other applications. mkwACT will ignore such data blocks without issuing a warning. Thus, WAV files containing such extra information will not be byte-identical after compressing and uncompressing, although the audio data contained will be identical.

This seems to suggest that the differences you are seeing may well be limited to non-audio information. And this is what I very strongly suspect. It seems to me that if the difference between the two programs were substantive dMC would not be able to decode your mkw shn files and I don't think the resulting wav would be playable. What was the extent of the differences you are talking about (between shn files from wav produced by mkw and by dMC)?

[Spoon]

Re: dbpoweramp wav>shn>wav problem

You cannot compare compressed (even lossless) audio files, shorten might have unique stream serial numbers, the only way is to compare uncompressed wave files (and even then you have to convert a wave file to wave file because somewave files can have different wave headers which would give wrong md5 even though the data is identical).

[hippienerd]

Re: dbpoweramp wav>shn>wav problem

OK, but why wouldn't the wave header be the same?

Is there a utility for viewing the wav header and/or comparing data and wave header?

Or perhaps someone can direct me towards a site where I can learn more about what is contained in the wav header?

My point is that I want the exact wav file back that went into the codec process. If I have compressed with dbc and decompressed with mkw, then I don't get the same wavs based on the crc. Perhaps the wav data is the same and perhaps it's not, but how would I know from a user level perspective? Is there a way to verify that the data is the same without crc?

Also I am wondeirng if shn has a header and if so what info is contained in addition to the data?

Anyway thanks for the help so far.

[Spoon]

Re: dbpoweramp wav>shn>wav problem

Some programs write a WAVEFORMAT header, some a WAVEFORMATEX - both are correct.