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Topic: MP3 settigs for preserving old recordings (Read 5602 times) previous topic - next topic
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MP3 settigs for preserving old recordings

I maintain a sort of public audio archive that has a good deal of old recordings (1960-x and before) reissued on CDs or digitized from tape/vinyl. I don't own the CDs myself: recordigs get contributed by other people and sent me over the net.

This is a long-term project and I need to set guidelines for quality preservation of the recordings, such that I don't regret setting too low a quality standard in, say, ten or twenty years in the future. At the same time, I need to be reasonably practical about contributing the songs and keeping the collection on the web (i.e. a requirement like "send me lossless WAV only" will hinder the growth of the collection).

So far I came up with the standard to rip recent recordings from CDs into MP3 at 256 kbps, CBR, joint stereo, and keep them in the collection in the same format. The choice of MP3 format and CBR has been made for compatibility. The choice of 256 kbps bitrate has been made based on the results of listening tests I read on the web as providing no perceptible quality loss for most of the recordings (please remember I can't set exotic requirements on the format and file size, or the collection won't get contributions).

My question is whether 256 kbps is necessary for OLD recordigs, or lower bitrate will be sufficient with older recordings to provide no perceptible loss in quality. Are there MP3 listening tests that use old recordings reissued on CDs?

If lower bitrate is sufficient, another question is: where do I draw the line for the contributors to consider something an 'old' recording? E.g. shall I say "one originally recorded before 1970"? Other year?

I am not an audiophile and don't have good equipment myself, but some users of my collection are. I want to make reasonable effort to cater to them and to professional users. When a manager of a large sport event writes "I can't playback your MP3s of Russian anthem in a sports hall", this is no good. When a film producer wants to include an old recording into the soundtrack, but compression artifacts in the recording in my archive are audible by the standards of modern film production, this is no good. At the same time, I want to stop exactly where these requirements are satisfied, and don't waste unnecessary effort beyond that point. Hence the question about bitrate for old recordings.

http://www.vad1.com/anthems/

MP3 settigs for preserving old recordings

Reply #1 –
Well, truthfully --alt-preset standard will most likely do as well (probably better than) as 256k CBR and will most likely be loads smaller.  VBR is part of the mp3 standard so you wouldn't be breaking it by using VBR.  If you insist on CBR I'm not sure what would be enough without listening to the material you're encoding.
Nero AAC 1.5.1.0: -q0.45

MP3 settigs for preserving old recordings

Reply #2 –
Since you've got to accept the best that you can get, why not stay with anything at or ABOVE 192kbps.  Better to get the recordings you are looking to post than get to bogged down with the integrity of the sound since they are not modern recordings anyway.

BTW....Great site you've created.  It is great that you are sharing your interest with others.

MP3 settigs for preserving old recordings

Reply #3 –
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When a film producer wants to include an old recording into the soundtrack, but compression artifacts in the recording in my archive are audible by the standards of modern film production, this is no good.
[a href="index.php?act=findpost&pid=259348"][{POST_SNAPBACK}][/a]

I doubt that a film producer will be interested in whatever quality MP3's from you.
Only uncompressed or lossless should be enough for them, IMHO...
Sorry for my poor English, I'm trying to get better... ;)
"The greatest trick the Devil ever pulled, was convincing the world he didn't exist."

MP3 settigs for preserving old recordings

Reply #4 –
Quote
I doubt that a film producer will be interested in whatever quality MP3's from you.
Only uncompressed or lossless should be enough for them, IMHO...
[a href="index.php?act=findpost&pid=259656"][{POST_SNAPBACK}][/a]

Film producers were interested (admittedly, they didn't complain about MP3 quality, but rather asked about proper licensing of old recordings).

I suppose at some point MP3 becomes in reality "good enough" as a distribution format for professional use or finished songs (just as JPEG at sufficiently low compression is used now by professional photographers to sell stock images to publishing and advertising agencies for further editing and use). Some audiophiles may be more demanding, but I'm more interested in use of MP3 in professional practice. I want to know that point, err, bitrate. That's what the question is mostly about, and specifically for old recordings if someone has tested them.

I suppose it's something between 192 and 256 kbps in reality? Or am I mistaken?

MP3 settigs for preserving old recordings

Reply #5 –
makarov:

Given the fact you have this site for this purpose I think ultimately you should check out the 'FLAC' format because its lossless compression.  Thereis no loss in quality at all but smaller than typcial WAV files. 

Mp3 on the other hand is lossy meaning no matter what you going to have to throw away something to compress it. The trick is to try to get it encoded so eventho stuff has been "thrown away"  you cant tell.  For this listening tests etc etc etc etc (so many threads on it) use:

lame 3.90.3 with --alt-preset standard (which is vbr)

No more ... no less will be needed for best quality mp3 encoding. VBR > CBR generally. Doing cbr 256 or even 320 is a bit overkill I'd say usually. Wasted bitrate. APS will give you the best mp3 can get. And I will bet u see avg VBR bitrates less than 256 but sounding the same if not better. The presets have special tweaks internal  to make it sound even better than normal hand switches.

hope this helps. 

MP3 settigs for preserving old recordings

Reply #6 –
I have to agree that while high bitrate MP3 is a good format for final listening, if you're going to be doing ANY further processing of the sound at all, you should keep the audio as close to the original as possible. That means lossless.

MP3 settigs for preserving old recordings

Reply #7 –
Quote
I have to agree that while high bitrate MP3 is a good format for final listening, if you're going to be doing ANY further processing of the sound at all, you should keep the audio as close to the original as possible. That means lossless.
[a href="index.php?act=findpost&pid=259792"][{POST_SNAPBACK}][/a]

Yeah! That's why I've written that film producers won't be interested in MP3...
Sorry for my poor English, I'm trying to get better... ;)
"The greatest trick the Devil ever pulled, was convincing the world he didn't exist."

MP3 settigs for preserving old recordings

Reply #8 –
Quote
Quote
I have to agree that while high bitrate MP3 is a good format for final listening, if you're going to be doing ANY further processing of the sound at all, you should keep the audio as close to the original as possible. That means lossless.
[a href="index.php?act=findpost&pid=259792"][{POST_SNAPBACK}][/a]

Yeah! That's why I've written that film producers won't be interested in MP3...
[a href="index.php?act=findpost&pid=259887"][{POST_SNAPBACK}][/a]
i agree, however in certain situations lossy format will do just fine (but it is best to avoid that if you do not want to be 'situation limited' )
PANIC: CPU 1: Cache Error (unrecoverable - dcache data) Eframe = 0x90000000208cf3b8
NOTICE - cpu 0 didn't dump TLB, may be hung

MP3 settigs for preserving old recordings

Reply #9 –
If you absolutely don't want to go lossless, then LAME preset standard (or perhaps extreme) will be a good choice. Being vbr, the perceived quality will be about the same, while the bitrate will vary depending on how demanding the input is. You won't be wasting bits that way.

It is worth noting that while an old recording might be of low fidelity to the ear, it does not mean it will be easy to encode. Noise, crackle and pops pose considerable problems for mp3 and many other lossy formats.

Personally I would suggest lossless for different reasons other than fidelity alone. As I understand you want to create an archive with a long lifetime in mind. Perhaps in 20 years mp3 will be almost dead and people will be asking you for files in some new lossy format. Your only option then is to transcode from your lossy source loosing more quality as you go. I think you can be assured, that PCM audio will be available for a very long time and should FLAC, or whatever lossless codec you choose now, be outdated, you could easily reencode to the currently en vogue lossless format.

The things to look out when choosing a lossless format now is usability and especially focud on tagging capabilities since it will make maintaining (and reencoding if need be) a large archive much easier.

MP3 settigs for preserving old recordings

Reply #10 –
sadly, i know for a fact that a lot of sound houses will use mp3 as a matter of course when doing mixes, even for movies.

so a producer may be all hoity-toity about not using lossy, but the fact remains they probably will be anyway.

if you're having stuff contributed from the community, you surely could accept many formats?  you could have a "recommended" format (like FLAC or even wavepack lossy, as it transcodes well and is transparent at 320kbps), and a "minimum requirement" of mp3 above say, 160, or ideally --preset standard.

anyway, the last time i went to the movies, the sound system was about the worst i'd ever heard - the amps were completely blown up, there was insane clipping, and the overall sound level was way too low, such that people unconsciously didn't laugh for fear of disturbing others (it was a comedy).  if that's the end format, then 128kbps Blade would do

MP3 settigs for preserving old recordings

Reply #11 –
Here is how it ended up.

I have bought half-decent headphones (i.e. not $5 crap) and have been listening to quite a bit of pieces lately, mostly to classical music, both from CDs and from MP3 files. The firm conclusion is: with MP3, anything less than 256 CBR distinctly distorts the sound and hampers critical listening to me. This is apparent when I listen to symphonic and brass orchestra recordings: background percussion sounds lose clarity and get distorted, stereo echoes lose "volume", loud places in the piece when many instruments are playing simultaneously become sounding somewhat like bubbling watery noise, and so on. I think, I could even hear the difference in one case when I compared 256 and 320 kbps.
Other kinds of music (not symphonic and brass) appear to be less demanding, but any good recording encoded at less than 192 kbps will very noticeable suffer in audio quality.

Most recordings in the collection the question was about are made with orchestras. My standard for contributions ripped from CDs is now MP3 320 kbps joint stereo (with lame 3.96.1, that would be "lame --preset insane") or 256 kbps (--preset cbr 256). I will accept any files of course if they are needed for the collection, but that's the standard for those cases I'm in control.

I've listened to some classical music in VBR, downloaded from emusic.com, and VBR just doesn't sound right to me. Quieter passages are "mudded" and almost-silent parts are real crap, unlike CBR where you still hear little live sounds and noises the orchestra produces there. Maybe also my ears have difficulty adapting to changing quality throughout the piece, I don't know. It's a bit annoying for me to listen to, perhaps worse than CBR at the same average bitrate. This was enough a turnoff not to consider VBR again. Besides, it looks like 320 kbps is the maximium bitrate and is only available as CBR for standard MP3s.

MP3 settigs for preserving old recordings

Reply #12 –
Quote
I've listened to some classical music in VBR, downloaded from emusic.com, and VBR just doesn't sound right to me. Quieter passages are "mudded" and almost-silent parts are real crap, unlike CBR where you still hear little live sounds and noises the orchestra produces there. Maybe also my ears have difficulty adapting to changing quality throughout the piece, I don't know. It's a bit annoying for me to listen to, perhaps worse than CBR at the same average bitrate. This was enough a turnoff not to consider VBR again. Besides, it looks like 320 kbps is the maximium bitrate and is only available as CBR for standard MP3s.
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Well 320 CBR is technically the best mp3 can do but I honestly doubt you can hear bitrate changes in VBR material.  This sounds like placebo to me, but if you could back this up with ABX tests that would be good.

[a href="http://www.hydrogenaudio.org/forums/index.php?showtopic=3974#]http://www.hydrogenaudio.org/forums/index....showtopic=3974#[/url] You might want to read that, especially number 8.  They're really strict about that here
Nero AAC 1.5.1.0: -q0.45

MP3 settigs for preserving old recordings

Reply #13 –
I'm sorry I didn't want to violate the forum code. What I've said above about VBR is indeed a very subjective impression not backed up by any controlled testing. I'll keep it in mind do better testing if I encounter it again.
 

MP3 settigs for preserving old recordings

Reply #14 –
Some people have a policy to ask for lossless, but accept whatever they get.

However, true archives really will only consider lossless - they know that it's pointless to archive a lossy format, unless it really is the only source available.


As for trying to ensure the quality of an mp3, it's not enough to specify the bitrate - the choice of the encoder is also very important. Avoiding ripping errors is even more important.

It's very difficult to get other people to do this job properly. On balance, getting them to rip straight to 320kbps mp3 (using whatever they normally use) is probably the best you can do - unless your audience are particularly tech aware, which is unlikely to be the case.

Cheers,
David.