[carltonh]

So I have some albums in 24 bit, 96 KHz in my collection. My thought is that encoding down to 500 Kbs OGG from this might be better than 16/44 FLAC or CD quality. But I'm not a pro enough to trust my judgement. Any opinions?

 

[spruce music]

My opinion is to down sample to 44.1 FLAC.  FLAC can stay 24 bit and you are only removing ultrasonic information.  FLAC files sizes will be somewhere around 50% of 44.1/24 and those will be less than half of 96/24.  Still that will be double OGG at 500 kbps.  The FLAC downsampling and encode is pretty close to lossless for below 20 khz content.  OGG is always a lossy encoding. 

What is the goal of downsampling?  To save storage space, play on portable players or what?

 

[carltonh]

  My opinion is to down sample to 44.1 FLAC.  FLAC can stay 24 bit and you are only removing ultrasonic information.  FLAC files sizes will be somewhere around 50% of 44.1/24 and those will be less than half of 96/24.  Still that will be double OGG at 500 kbps.  The FLAC downsampling and encode is pretty close to lossless for below 20 khz content.  OGG is always a lossy encoding. 

What is the goal of downsampling?  To save storage space, play on portable players or what?

Yes, the goal is to save space for portable players. However, I think you misunderstand the concept of lossless encoding in this context. If you downsample from 24/96 flac to 24/44.1 flac, you have still lost information, even if it is still above CD quality by being 24 bit.
 
So the information that is lost going from 24/96 to CD quality flac, for instance, is going to be processed in a different way than OGG or MP3, each is based on a different subjective measure of what humans here as important. Whereas FLAC, and all lossless encoding methods are designed upon a design for a 1 to 1 equivalence of not losing information while minimizing file size.
 
To my knowledge with encoders I use, the MP3 max limit is 320 Kbps, but OGG is 500 Kbps, and bit for bit, OGG is usually considered better than MP3. Given that these are designed for maximize the most important information in downcoding. I think it might be reasonable to consider an original ~2900 Kbps 24/96 FLAC, downcoded to 500 Kbps OGG vs. 1411 Kbps WAV equivalent to lossless ~1000 Kbps FLAC. The 1411 WAV or ~1000 Kbps FLAC are already lossy in this case.

 

[spruce music]

  Yes, the goal is to save space for portable players. However, I think you misunderstand the concept of lossless encoding in this context. If you downsample from 24/96 flac to 24/44.1 flac, you have still lost information, even if it is still above CD quality by being 24 bit.
 
So the information that is lost going from 24/96 to CD quality flac, for instance, is going to be processed in a different way than OGG or MP3, each is based on a different subjective measure of what humans here as important. Whereas FLAC, and all lossless encoding methods are designed upon a design for a 1 to 1 equivalence of not losing information while minimizing file size.
 
To my knowledge with encoders I use, the MP3 max limit is 320 Kbps, but OGG is 500 Kbps, and bit for bit, OGG is usually considered better than MP3. Given that these are designed for maximize the most important information in downcoding. I think it might be reasonable to consider an original ~2900 Kbps 24/96 FLAC, downcoded to 500 Kbps OGG vs. 1411 Kbps WAV equivalent to lossless ~1000 Kbps FLAC. The 1411 WAV or ~1000 Kbps FLAC are already lossy in this case.

Do you plan to let OGG keep the ultrasonic content?  You have that option in OGG.  I don't think ultrasonic content adds anything audible.  If I were doing this for a portable player that would do OGG, I would use it.  On most portable players variable bit rate 320 kbps MP3 is not audibly different.  So OGG set to 320 kbps is going to be inaudible or very nearly so.  That lets you use the least space for excellent sound quality.
 
Now about lossy, non-lossy etc.  Yes, downsampling is lossy, but only for ultrasonic content.  OGG is always lossy in some ways beyond just ultrasonic content.  It does an excellent job, but is lossy.  For content below 20 khz there will be less difference between a 44/24 FLAC and the original than is the case with a 500 kpbs OGG file.  The OGG could still hold ultrasonic content, but I consider that useless.
 
So considering your goal, use on a portable player, I would go with 320 kpbs OGG.  Least space of all and minimal sound quality difference for simple listening.

 

[castleofargh]

as a pretty intense DAP user (not a collector at all but I can't seem to be able to get less than 5 DAPs at a time to do all I like), I'd tell you to stay away from OGG. some gears won't play OGG(even less so if you start using custom settings). and for the DAPs I've had that did play OGG, several had some matter of trouble with it that weren't always corrected with newer firmwares.
so you can do it if you know that your actual DAP is fine with it, but what about the next one?
in my opinion, AAC is the go to lossless format when it comes to efficiency, and if you do care about still having as much data as you can, then flac is the logical answer at 16/44. but it uses so much space compared to even max AAC or max mp3.  I still use mp3 max vbr instead simply because I'm lazy and that's what I've had for some time.