HydrogenAudio

Lossless Audio Compression => Lossless / Other Codecs => Topic started by: Marino13 on 2003-10-20 14:06:23

Title: What lossless format should I use? I am confused
Post by: Marino13 on 2003-10-20 14:06:23
I am getting ready to rip my 1,000+ CD collection and I am very confused about which lossless format to use.  Some of them support tags, some don't.  Some of them say they compress 4:1 and some 2:1.  Some say the decoding process takes a lot of cpu juice.  Here is what I want to accomplish...

1.  I am using EAC to rip so the format must be compatible.  A command line would help also.

2.  I want some kind of tags with the songs so when I convert them to another format it creates the tags itself.

3.  Although disc space is not my primary concern, I would like it to compress as much as possible.

4.  I would like it to be somewhat fast for encoding and decoding.

I must say after reading that I am leaning towards FLAC but Monkey's Audio also seems to be very popular.  Any help is appreciated.
Title: What lossless format should I use? I am confused
Post by: dev0 on 2003-10-20 14:41:13
You've already mentioned the two top contenders for your needs: FLAC and APE.
In the end it boils down to personal preference and compatibility with the software you use. Just be sure to use APEv2 tags as explained here (http://www.saunalahti.fi/~cse/EAC/) with APE.

dev0
Title: What lossless format should I use? I am confused
Post by: sthayashi on 2003-10-20 14:44:44
1st, any codec that claims to get 4:1 compression ratios is lying to you.  Roughly 50-60% is the norm, give or take 10% depending on style.

Given your needs, I would suggest going with Monkey's Audio.  It fits what you want out of it better than FLAC does.  The biggest advantages of FLAC are that it can be used on virtually any platform, whereas Monkey's Audio doesn't have as much support outside Windows.

FLAC is also much faster, but if you have a modern computer, the difference won't be painful.

If space is REALLY a concern for you and speed isn't, you might wish to consider OptimFROG, since I've read it has some of the best compression ratios, but I don't know too much more about it since I've never really used it.
Title: What lossless format should I use? I am confused
Post by: ailean on 2003-10-20 14:46:58
I went thru the same thing recently when I decided to re-rip everything lossless. In the end I went with FLAC, mainly for it's bigger support on OSes and hardware (waiting for a 80GB Rio Karma!    )

EAC was fairly easy to set up, all tags filled (I've done a few mass convertions to AAC/MP4 without missing anything), I'm not sure what my ratio is but most say about 2:1 and encoding and decoding are said to be faster then APE at max ratio.

Certainly playback doesn't even wake my CPU, not seen more then 2% but then it is a 3GHz P4 (upgraded from a Cely to help speed up convertions).

Compression at max isn't blindingly fast, but it normally keeps up with the slow EAC ripping with sometimes 1-2 tracks left to compress by the end of the CD read.

I'd certainly stick with the popular APE or FLAC formats, more chance of other software supporting them. If you use non Windows machines or are interested in hardware players then FLAC is probably your best bet. But give them both a go and see how you get on, if you go for FLAC I can post the EAC commandline I use (not on that PC at the moment).
Title: What lossless format should I use? I am confused
Post by: sony666 on 2003-10-20 14:57:43
don't forget to consider WavPack
Title: What lossless format should I use? I am confused
Post by: Jojo on 2003-10-20 16:17:25
I'd still use WMA9 PRO Lossless!
Title: What lossless format should I use? I am confused
Post by: chinaLi on 2003-10-20 17:36:19
Quote
I am getting ready to rip my 1,000+ CD collection and I am very confused about which lossless format to use.  Some of them support tags, some don't.  Some of them say they compress 4:1 and some 2:1.  Some say the decoding process takes a lot of cpu juice.  Here is what I want to accomplish...

1.   I am using EAC to rip so the format must be compatible.  A command line would help also.

2.   I want some kind of tags with the songs so when I convert them to another format it creates the tags itself.

3.   Although disc space is not my primary concern, I would like it to compress as much as possible.

4.  I would like it to be somewhat fast for encoding and decoding.

I must say after reading that I am leaning towards FLAC but Monkey's Audio also seems to be very popular.  Any help is appreciated.

So WMA9 Lossless may suit you.
Title: What lossless format should I use? I am confused
Post by: Moneo on 2003-10-20 18:22:51
Quote
So WMA9 Lossless may suit you.

Compared to Monkey's Audio and FLAC, it's the slowest of the bunch, in terms of both encoding and decoding, and it also has the lowest compression ratio.

To add insult to injury, both the encoder and the decoder are closed-source.

Hardware support is nonexistent at the moment, and to my knowledge, no announcements of upcoming devices supporting WMA9 lossless have been made.

I wouldn't recommend using this format for anything.
Title: What lossless format should I use? I am confused
Post by: Jojo on 2003-10-20 19:45:44
Quote
Quote
So WMA9 Lossless may suit you.

Compared to Monkey's Audio and FLAC, it's the slowest of the bunch, in terms of both encoding and decoding, and it also has the lowest compression ratio.

To add insult to injury, both the encoder and the decoder are closed-source.

Hardware support is nonexistent at the moment, and to my knowledge, no announcements of upcoming devices supporting WMA9 lossless have been made.

I wouldn't recommend using this format for anything.

When I compared WMA 9 Pro Lossless to FLAC, WMA had a slightly better compression rate! It also was a bit faster on my machine. However, I have to admit that I only compared 10 songs and finally switched over to WMA 9 Pro Lossless
Title: What lossless format should I use? I am confused
Post by: bidz on 2003-10-20 19:58:45
Quote
When I compared WMA 9 Pro Lossless to FLAC, WMA had a slightly better compression rate! It also was a bit faster on my machine. However, I have to admit that I only compared 10 songs and finally switched over to WMA 9 Pro Lossless


There is no such thing as WMA9 Pro Lossless. WMA9 Pro doesn't have a Lossless option. Just so you know it, its Windows Media 9 Lossless (WMA9 Lossless), not Pro (Pro/Std/Lossless doesn't need more confusion mixed into it than it already has).
Title: What lossless format should I use? I am confused
Post by: ScorLibran on 2003-10-20 20:19:43
Quote
I am getting ready to rip my 1,000+ CD collection and I am very confused about which lossless format to use.  Some of them support tags, some don't.  Some of them say they compress 4:1 and some 2:1.  Some say the decoding process takes a lot of cpu juice.  Here is what I want to accomplish...

1.   I am using EAC to rip so the format must be compatible.  A command line would help also.

2.   I want some kind of tags with the songs so when I convert them to another format it creates the tags itself.

3.   Although disc space is not my primary concern, I would like it to compress as much as possible.

4.  I would like it to be somewhat fast for encoding and decoding.

I must say after reading that I am leaning towards FLAC but Monkey's Audio also seems to be very popular.  Any help is appreciated.

My $0.02 on each of your points.  As others have pointed out, there a many good alternatives for lossless compression, especially since "artifacting" is not an issue, and the remaining issues are more easily quanitified (compression ratios, performance, tagging, other features) .  But considering for a moment only FLAC and Monkey's (which were my two primary considerations as well when deciding my own preferred lossless format)...

1.  Either FLAC or APE....EAC can call and pass parameters to any compressor with a CLI (command line interface).

2.  Monkey's has better tagging.  APEv2 is a popular, well-standardized and well-supported tag format.

3.  Monkey's gives slightly better compression ratios, but the numbers are really close (differences are often less than 1%).

4.  FLAC has great decoding performance, but encoding speed is not so stellar.

First, isolate your hardware/software compatibility requirements (which you've probably already done).  For me, the only lossless format I can currently use on more than one of my platforms is FLAC, so my decision's easy.  When there's more compatibility with Monkey's Audio, I'll have to re-evaluate.

When looking at tagging features, test the compatibility of your platforms not only with certain encoding formats, but also with certain tag types.  For instance, the Kenwood Music Keg and PhatNoise PhatBox play FLAC files just fine, but their head unit firmware will not interpret FLAC tags.  I had to use ID3v2 on my FLACs.   
Title: What lossless format should I use? I am confused
Post by: CyberInferno on 2003-10-20 21:48:52
One of the easiest solutions is to use EAC with APE 3.98a with the Monkey's Audio DLL.  It automatically writes the tags in APEv2 format and you don't have any command line to deal with.  In EAC's compression options, uncheck "Use external program for compression" under the "External Compression" tab, then select "Monkey's Audio Lossless Encodes v3.98 DLL" (be sure to have Monkey's Audio installed already).  I dont' know if it has any effect, but I also uncheck all the options under the "ID3 Tag" tab.
Title: What lossless format should I use? I am confused
Post by: phwip on 2003-10-20 23:07:17
The differences in encoding speed and size are not really that big between FLAC and Monkeys unless disk space is really tight.  Also, you can transcode to other formats and carry over the tags from either format if you use the diskwriter component in foobar2000 to do this.  Both formats can be set up with EAC using command line parameters.  I don't really think there is any significant advantage in the tagging formats used: both apev2 and vorbis comments (in FLAC) are versatile.

This is not like comparing lossy formats where quality issues are involved, so in the end it will probably come down to some little difference which suits you better.  For example, when I was making this decision I wanted to use Replay Gain on my files and at the time I was using Winamp, so I had to go with FLAC.  This is because the FLAC winamp plugin supports Replay Gain and the Monkeys one doesn't.  If you play around with the two formats you will probably find some small reason why one suits you better than the other.
Title: What lossless format should I use? I am confused
Post by: MadXviD on 2003-10-20 23:34:37
I was having some problems with APE files, cuz BAO won't load them, that's an issue I don't understand, cuz I made a MAC.exe copy in the BAO dir  .

I loaded FLAC files and everything's perfect  .

I can say I'm pretty much sure about this:

1. If you want compatibility, go on with FLAC.

2. If you care about file sizes, you have to give MA a try...

^^
Title: What lossless format should I use? I am confused
Post by: Moneo on 2003-10-21 00:51:46
Quote
When I compared WMA 9 Pro Lossless to FLAC, WMA had a slightly better compression rate! It also was a bit faster on my machine. However, I have to admit that I only compared 10 songs and finally switched over to WMA 9 Pro Lossless

I stand corrected, wma lossless does compress better than flac.

Here's some speed/perfomance tests featuring wma9 lossless:

http://web.inter.nl.net/users/hvdh/lossles...ss/lossless.htm (http://web.inter.nl.net/users/hvdh/lossless/lossless.htm)

http://home.wanadoo.nl/~w.speek/comparison.htm (http://home.wanadoo.nl/~w.speek/comparison.htm)
Title: What lossless format should I use? I am confused
Post by: jcoalson on 2003-10-21 05:24:35
more info:

http://www.hydrogenaudio.org/forums/index....showtopic=11853 (http://www.hydrogenaudio.org/forums/index.php?showtopic=11853)

Josh
Title: What lossless format should I use? I am confused
Post by: den on 2003-10-21 06:11:06
I believe Wavpack, Optifrog, Monkey's or FLAC will suit your requirements. Wavpack is certainly quick.

At the end of the day though, it doesn't really matter if you are retaining this stuff on HD. If you pick one and don't like it later, simply transcode to another format, as it is lossless anyway...  B)

Just do it ™
Title: What lossless format should I use? I am confused
Post by: Volcano on 2003-10-21 19:25:29
I've played around with WavPack, FLAC and APE a lot in recent months, and I think I would be using WavPack now if it weren't for the ridiculously slow seeking during playback. (Other than that, it rocks - fast encoding and decoding, good compression ratio, and ReplayGain support even outside of foobar2000.) I stuck with APE finally, being a Windows-only user at the moment... but I'd really have no problem with FLAC either. The compression ratio isn't too much of an issue - once you get up to album sizes of ~400 MB, those few megabytes don't matter much.
Title: What lossless format should I use? I am confused
Post by: Marino13 on 2003-10-26 03:33:13
Quote
One of the easiest solutions is to use EAC with APE 3.98a with the Monkey's Audio DLL.  It automatically writes the tags in APEv2 format and you don't have any command line to deal with.  In EAC's compression options, uncheck "Use external program for compression" under the "External Compression" tab, then select "Monkey's Audio Lossless Encodes v3.98 DLL" (be sure to have Monkey's Audio installed already).  I dont' know if it has any effect, but I also uncheck all the options under the "ID3 Tag" tab.

I have tried this and it seems to be faster.  I know this is 3.98a.  Is there any problems with this alpha?  I have used this with a couple of test albums and everything seems fine.  Is there any reason why I could not use this over Case's "User Defined" option with wapet and MAC 3.97?
Title: What lossless format should I use? I am confused
Post by: Marino13 on 2003-10-26 03:53:48
A big thank you to everyone for their help in this post.  I cannot express how much I appreciate your input.  I still have not made my final decision, but maybe you can answer a couple more questions and I will convince myself that FLAC is better than Monkey's or Monkey's is better than FLAC for my purposes.

1    I have decided that my sole purpose for doing this is archiving.  I do not want to have to rip my 1,000+ CD collection ever again.  I have already done it four times and it takes way too long.  I want to be able to transcode all of the files at any time to any new format that comes out.  I am not worried about hardware or software compatibility (with the exception of software that will be able to transcode into another format).  Which one would you use?  Size of the resulting files are so close that I have thrown this out as a parameter of which one to choose.  I will purchase however many Hard Drives I need to and also back them up to DVD's to be safe.

2    Both formats seems to tag fine with one exception.  I realize that this has to do with the software but when I transcode ape files to mp3's with dBpowerAMP Music Converter the tags do not transfer to the mp3's id3 tags but with flac they do.  Is there any certain reason for this?  I can just use my tag editor software to fix this, but that is one extra step I would like to avoid.

3    I use Tag & Rename for my mp3's and I love it.  What is the best tag editor that will do mp3's, flac and monkey's?

4    In my last post I stated that it seems faster using the Monkey's 398 dll (to make sure v2 tags are written) in the waveform setting in EAC rather than using Case's user defined settings with wapet and Monkey's 397 exe since it does not convert to wav and then to ape.  Should I just go this route or is there some reason not to?  Are there any known issues with 398a?

Thanks for any help!
Title: What lossless format should I use? I am confused
Post by: floyd on 2003-10-26 03:58:42
hmm..  this question would be easier to answer if you stated what target media you are going to archive to.  cds?  dvds?  hds?

for optical media, I'd prefer ape for the following reason: ape compresses better than FLAC (in my experience usually more than the 1-2% previously stated in the thread), and on unreliable optical media, every byte counts as I use the extra space on the disk for PAR2 parity files to protect against data loss.

OTOH, FLAC is supposed to be more resistant to errors.  If the bitstream is corrupted, it still plays.  To me, this is near worthless as such a file with glitches would be unnacceptable anyway.

If you are backing up to a huge HD, you might as well use FLAC, since its much faster to encode and decode (using best compression is usually a waste of time with FLAC) and you generally don't worry about data loss - or if you do you use RAID.

edit: posted as you were posting.  if you are using both HDs and dvds to archive I'd say data security is a non-issue.  I'd use FLAC to save yourself time.
Title: What lossless format should I use? I am confused
Post by: indybrett on 2003-10-26 04:37:08
I use FLAC. It just works. And there are good tools to encode directly to Ogg thanks to John33.  You can never really go wrong using any lossless compression, be it FLAC, APE, SHN, or something else.
Title: What lossless format should I use? I am confused
Post by: Volcano on 2003-10-26 12:05:13
Quote
2 Both formats seems to tag fine with one exception. I realize that this has to do with the software but when I transcode ape files to mp3's with dBpowerAMP Music Converter the tags do not transfer to the mp3's id3 tags but with flac they do. Is there any certain reason for this?

This happens because the current stable Monkey's Audio component for dBpowerAMP doesn't read APEv2 tags from Monkey's Audio files, it only reads APEv1. The component compiled against Monkey's Audio 3.98 Alpha sources does this, but I haven't used it yet (I couldn't get it to work at all in Win98, but according to Spoon, this is actually a problem with the Monkey's Audio encoder itself).

foobar2000 will do the job just as well.


Quote
3 I use Tag & Rename for my mp3's and I love it. What is the best tag editor that will do mp3's, flac and monkey's?

I use Tagger (http://tagger.boereck.de/) (a frontend for the command-line tool Tag (http://www.saunalahti.fi/~cse/html/tag.html)) because it supports all formats I currently need and allows me to enter lots of metadata very quickly. foobar2000's masstagger supports more formats (AAC/MP4 for instance) and can rename files from any metadata included (whereas Tag can only use the standard Artist, Album, Title etc. fields for this), but entering large bunches of metadata with it isn't as comfortable as with Tagger. The only serious problem with Tag/Tagger is the lack of ID3v2 support for MP3.


Quote
4 In my last post I stated that it seems faster using the Monkey's 398 dll (to make sure v2 tags are written) in the waveform setting in EAC rather than using Case's user defined settings with wapet and Monkey's 397 exe since it does not convert to wav and then to ape. Should I just go this route or is there some reason not to?

I've never used the MAC DLL, I always stick to the command-line tool with wapet, but since nobody here has reported an issue with it so far, I'd think it's fine. In fact I'll give it a try for my next rip, now that you said it's faster.


Quote
Are there any known issues with 398a?

Not to my knowledge.


As for which format to use... even though I use Monkey's Audio myself, I'd recommend FLAC. It works just as well as APE (and decodes a lot faster), and the Rio Karma plays it which is a big bonus.


Quote
OTOH, FLAC is supposed to be more resistant to errors. If the bitstream is corrupted, it still plays.

Monkey's Audio and OptimFROG also have this feature. WavPack unfortunately hasn't.
Title: What lossless format should I use? I am confused
Post by: buzzy on 2003-10-31 21:39:44
Use flac.

Another thread on WMA
http://www.hydrogenaudio.org/forums/index.php?showtopic=4827 (http://www.hydrogenaudio.org/forums/index.php?showtopic=4827)

What about the longevity of the encoder and (much more importantly) decoder?  MS has a support time frame of about  5 years for an OS.  It's true that you can shift out of the format by transcoding everything to the appropriate format in a few years.  But the availability of source code and 'nix foundation of flac would suggest an indefinite lifetime for a flac decoder, wouldn't it?

Though presumably MS has it's eye on become the ubiquitous lossless compression standard, across all electronics.  Maybe the question is more whether they have a long term format here, or whether they will abandon it if a better encoding approach emerges.

Not to mention the proprietary aspect of WMA.  It's not just MS bashing, objectively speaking they will only allow to happen what is in their business interest.  Sometimes that will coincide with your interests, and sometimes it will not.  Look at the history of decoding the WMA lossy format, for example.
Title: What lossless format should I use? I am confused
Post by: buzzy on 2003-10-31 22:17:20
Quote
for optical media, I'd prefer ape for the following reason: ape compresses better than FLAC (in my experience usually more than the 1-2% previously stated in the thread), and on unreliable optical media, every byte counts as I use the extra space on the disk for PAR2 parity files to protect against data loss.

OTOH, FLAC is supposed to be more resistant to errors.  If the bitstream is corrupted, it still plays.  To me, this is near worthless as such a file with glitches would be unnacceptable anyway.

My reaction was similar to yours - if you can't recover an exact copy of the file, that's of limited use.  But to be honest, there may well be more errors when you play a pressed CD - CD Audio is an error-tolerant format, designed to interpolate or mask it's way through errors as much as correct them.  So a disc missing a few dozen flac frames (~0.1 seconds each) might be tolerable to listen to until you get a replacement.

You're not getting something for nothing with APE's smaller file sizes.  As I understand it, part of the reason flac has larger files sizes is because it has an internal  frame structure.  (Not sure how much of the difference this accounts for.  You can adjust the block size and relax some of the format restrictions to reduce the overhead, to some degree - though I never do.) This allows streamability - chunks of the file make sense to, and are verifiable by, a hardware or software decoder in and of themselves.  It also provides the robustness against corrupt files.

I'm still wondering exactly how that compares to MAC, as my experience with ape is limited.  As I gather the MAC decoder won't decode a file that's at all corrupt, but you can to some degree still force the bitstream to play through errors and output that to recover some of the file.
Title: What lossless format should I use? I am confused
Post by: torok on 2003-11-01 20:40:30
Yea, but how often does a file just corrupt itself while sitting on your drive? Don't hard drives have error data built into them?
Title: What lossless format should I use? I am confused
Post by: Volcano on 2003-11-03 18:00:33
Quote
Yea, but how often does a file just corrupt itself while sitting on your drive? Don't hard drives have error data built into them?

The discussion was about storage on optical media such as DVD-/+R and CD-R, where data corruption is always a possibility.
Title: What lossless format should I use? I am confused
Post by: Chiller on 2003-11-05 18:18:00
I am also trying to decide btw the FLAC and APE, to re-encode 500 albums.  I am leaning towards ape for 1 reason.  I have 3 planned uses for my archive. Output to transcoder to current and future formats, Output to CD to get perfect image, and distant third is hardware support in the form of a Digital audio reciever.  Ease of converting entire collection to new formts with tag info is a must

To make a perfect copy of the CD you need gaps. You only get this if you rip a whole album with a cue sheet.  Both FLAC and APE can do this but..

With ape you can make APL so that you can store individual tagging information for use in audioplayers, transcoders and possibly DAR in the future (I think you might be able to do this now with mediacenter and TIVO2 but it requires extensive computer recorces and $200 TIVo, $200 regular tivo service and $200 TIVO computer service!!!!!!.)

FLAC developer says that with its metadata you can save the cue in the same file (nice), but without any tags.  His answer is that with this info in the future someone will develop software that can read this info and get tag info from Freedb, but this does not exist at this time.  If this were available it would sway me to FLAC because I think hardware support is more likly to come sooner. However even if this software were developed, would a hardware DAR or portable support its output - unlikly unless it produces files similar to APL's? Can anyone think of a senario where I would be able to play back individual songs through a DAR from the DAR interface with a whole album and cue? 

I keep hearing murmurs about a FLAC front end, but have seen nothing.  If flac is to hit main stream I think a front end that makes encoding, transcoding with optimal use of its metadata is in need.  This is still in the realm of us techies.
Title: What lossless format should I use? I am confused
Post by: dewey1973 on 2003-11-06 00:30:37
Quote
I keep hearing murmurs about a FLAC front end, but have seen nothing.  If flac is to hit main stream I think a front end that makes encoding, transcoding with optimal use of its metadata is in need.  This is still in the realm of us techies.

Uhhhh...  Am I missing something.  There is a FLAC front end included in the installer from The FLAC download page! (http://flac.sourceforge.net/download.html)  The same front end is available at Speek's front end site (flac). (http://home.wanadoo.nl/~w.speek/flac.htm)

There is also a mulitcodec front end at Speek's front end site (multi) (http://home.wanadoo.nl/~w.speek/multi.htm) that makes easy work of transcoding.
Title: What lossless format should I use? I am confused
Post by: Chiller on 2003-11-06 01:22:33
I am sorry I miss spoke, I have seen the front end, but while simple for you (and have been able to use it myself). I would not as much a user friendly GUI like MA.  here are links to threads on discusions on a possible native GUI from the FLAC developer and the metadata issues.

http://www.hydrogenaudio.org/forums/index....ic=10953&st=50& (http://www.hydrogenaudio.org/forums/index.php?showtopic=10953&st=50&)

http://www.hydrogenaudio.org/forums/index....ac,and,cuesheet (http://www.hydrogenaudio.org/forums/index.php?act=ST&f=19&t=8178&hl=flac,and,cuesheet)

http://www.hydrogenaudio.org/forums/index....ac,and,cuesheet (http://www.hydrogenaudio.org/forums/index.php?act=ST&f=20&t=4646&hl=flac,and,cuesheet)

There was also mention in one of the threads about the posibility of making a hack for FLAC to use APL.  This would be a nice solution.
Title: What lossless format should I use? I am confused
Post by: jcoalson on 2003-11-07 04:23:58
FUI is on the shelf until I get some significant free time again.

FLAC + APL works in foobar2000 I think, but there's no way a DAR is going to support APL (unless maybe you count a media center PC as a DAR).

Also, you can get a perfect copy by ripping to multiple files.

Josh
Title: What lossless format should I use? I am confused
Post by: phong on 2003-11-07 04:39:57
Writing a front end to do the freedb thing you suggest is almost trivial.  Many libraries exist that make accessing the freedb very easy and likewise, storing the freedb ID or cuesheet (from which the ID can be generated) in a comment tag a the time of encoding is quite simple.  In fact, I may try to whip something up if I ever get time.

Also, FLAC has hardware support right now (Rio Karma), and it's likely to get more in the future (the decoder is both free and very fast).
Title: What lossless format should I use? I am confused
Post by: kiwi on 2003-11-10 09:05:08
I'd go with APE or FLAC. 

Those were the two that I considered.  I decided to go with APE because I wanted to use MediaCenter for my organization and playback.

One thing to consider for backup purposes is to just get a duplicate HDs.  Cost/Time wise, it will probably be quite competitive with DVD options.  Say you compress your albums to about 300MB or so per album, you can get 12-13 CDs per DVD.  That gives you 75 or so DVDs.  I've gone with HDs in removable trays that are inserted into an external USB/Firewire enclosure for backup purposes, and then removed completely from the system.

kiwi