transcoding and tagging, FLAC, ALAC, WMA, etc Options

[thanirs]

All,

OK we all agree that your choice of lossless compresser/encoder depends on what your personal needs are. However I have one question:

Say I picked a format today (ALAC for example), and then I later realize I want the files in a different lossless format. Is it easy to transfer the tags to the new format?

Every document I read says not to worry too much about which lossless format you pick today because its not a big deal to change it to a different format tomorrow.

My main concern is about tags. Is there a chance that I would end up with files with no tagging if I don't pick the correct codec? What do I watch out for?

My personal situation is that I am extracting audio CDs with EAC but I have not decided on the codec. I don't have a portable player so I don't care for lossy formats. I want to stream the lossless format via a device (say Squeezebox) to my high end audio system. Each codec seems to use different tags. Why can't they all use one standard tag? :-) This last question is more rhetorical, I know the answer.

Sorry this is long but I want to make sure if I pick a codec today, I won't be screwed a year from now.

Thanks

[ozmosis82]

Personally, I'd avoid ALAC and stick with either FLAC or WavPack. I originally archived my music with FLAC, and have recently switched to WavPack and, with the advent of a new version of FLAC, I'm probably going to go back to FLAC (encoding/decoding reasons, as well as support).

As for tags, if you're using foobar2000 to transcode, it copies all the tags over when transcoding, regardless of the tagging system.

So basically, use fb2k and you'll pretty much be safe. You can always test format transcoding by decompressing to WAV and verifying that the MD5 checksum matches the original file.

[thanirs]

Hi there,

just curious what made you go with FLAC and switch to WavPack? Thanks

Personally, I'd avoid ALAC and stick with either FLAC or WavPack. I originally archived my music with FLAC, and have recently switched to WavPack and, with the advent of a new version of FLAC, I'm probably going to go back to FLAC (encoding/decoding reasons, as well as support).

As for tags, if you're using foobar2000 to transcode, it copies all the tags over when transcoding, regardless of the tagging system.

So basically, use fb2k and you'll pretty much be safe. You can always test format transcoding by decompressing to WAV and verifying that the MD5 checksum matches the original file.

[Klyith]

As for tags, if you're using foobar2000 to transcode, it copies all the tags over when transcoding, regardless of the tagging system.

* As long as it can write and fully support the tagging standard in question. I've never touched an ALAC file, but for WMA lossless Foobar is fairly limited when dealing with WMA (actually ASF) tags. No custom tag types, no replaygain, etc.

[ozmosis82]

Hi there,

just curious what made you go with FLAC and switch to WavPack? Thanks

I originally went with FLAC (after WMA Lossless) because I was a fan of Vorbis files (I used to have my music Ogg'ed). I figured I might as well be consistent.

I started looking around and found WavPack (this was over a year ago), but only just recently transcoded my archives into WavPack from FLAC after discovering that 80% of my archived music was NOT losslessly backed up. I don't know how I did it, but discovered it when the new iPod firmware allowing gapless playback was released. I was testing the gaplessness out, but my tracks weren't sounding gapless. I went back to listen to my FLACs and there were clicks and pops in between tracks. I found the original CD and ripped it and it played back without the clicks/pops. Somewhere along the way I managed to completely screw up however I was transcoding when I initially went to FLAC (I started off with WMA Lossless--yikes).

Anyway, I went to WavPack because of the MD5 checksum that it stores and uses to check against when decoding. I realise that FLAC stores the MD5 checksum in the compressed file's metadata, but I wasn't sure if it actually checks against it when decoding. Basically, I was paranoid and after ending up having to buy back something like 200+ CDs to make up for my earlier mishap, I didn't want to have to worry about it again.

Honestly, I don't know where I went wrong the first time. I was using Speek's multifrontend to encode the files, and I'm pretty sure I used Microsoft's own WMA Lossless decoder to decode the original WMA Lossless files. Regardless, it was a very painful experience that I don't want to have to repeat again. I'm now using foobar2000 to do all of my encoding which seems to be infinitely more reliable than the setup I was using before. I've tested the transcoding between WavPack straight to FLAC via pipe, and the MD5 hashes for both WAVs are identical. Once the new FLAC encoder comes out I'll probably bring everything back to FLAC.

As for tags, if you're using foobar2000 to transcode, it copies all the tags over when transcoding, regardless of the tagging system.

* As long as it can write and fully support the tagging standard in question. I've never touched an ALAC file, but for WMA lossless Foobar is fairly limited when dealing with WMA (actually ASF) tags. No custom tag types, no replaygain, etc.

Right... my bad.

[jcoalson]

Anyway, I went to WavPack because of the MD5 checksum that it stores and uses to check against when decoding. I realise that FLAC stores the MD5 checksum in the compressed file's metadata, but I wasn't sure if it actually checks against it when decoding.

FLAC was the first codec to have the MD5 sum (it was there from the beginning) and it checks it when decoding.

http://flac.sourceforge.net/documentation.html
"In test mode, flac acts just like in decode mode, except no output file is written. Both decode and test modes detect errors in the stream, but they also detect when the MD5 signature of the decoded audio does not match the stored MD5 signature, even when the bitstream is valid. "

http://flac.sourceforge.net/documentation...._options_decode
-d, --decode Decode (flac encodes by default). flac will exit with an exit code of 1 (and print a message, even in silent mode) if there were any errors during decoding, including when the MD5 checksum does not match the decoded output. Otherwise the exit code will be 0.

Josh

[ozmosis82]

Awesome Josh, thanks for that. I swear I've read that page a ton of times, and still managed to miss that crucial piece of text. Wow... gotta slow down.

I just wonder how fb2k decodes files, and whether its conversion tool also checks the file's stored MD5 tag whenever decoding a lossless file to WAV. Or does its conversion tool use the proper codec's decoder in order to convert from compressed to WAV?

This post has been edited by ozmosis82: Oct 21 2006, 20:36

[Egor]

I just wonder how fb2k decodes files, and whether its conversion tool also checks the file's stored MD5 tag whenever decoding a lossless file to WAV. Or does its conversion tool use the proper codec's decoder in order to convert from compressed to WAV?

Foobar2000 has its own FLAC decoder built into foo_input_std component. Besides an MD5 sum, FLAC has a stream error checking function, and foobar2000 utilizes that (I don't think fb2k checks against MD5). There is also an optional File Integrity Verifier component.