Author Topic: Bit Rate and Frequency Conversion  (Read 1728 times)

dlmckain

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Bit Rate and Frequency Conversion
« on: November 18, 2021, 02:36:12 PM »
I made the mistake of recording at 24 bit 192 kHz from a Behringer UMC204HD where Windows was configured to use 24 bit 96 kHz.

I don't expect it really makes a difference except maybe the audio file will have double samples (two samples for each "real" sample) which would double the file size.

Vinyl Studio has the "Convert File Format" option but it appears to only be to go from one format to another (eg. FLAC to WAV) leaving the sample rate unchanged.

Is there a way to downsample the frequency to save some disk space?

I know that 24 bit 192 kHz is a bit overkill, subjectively, for audio files. Yes, you preserve as much as information as possible for future post-processing but at the cost of disk space.

Additionally, I'm assuming the higher frequency recordings put a higher demand on Vinyl Studio during processing for noise and other operations.

A conundrum.

Paul Sanders (AlpineSoft)

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Re: Bit Rate and Frequency Conversion
« Reply #1 on: November 18, 2021, 09:08:45 PM »
Hi,

VinylStudio can't change the sample rate of a recording I'm afraid, but it can save your tracks with a lower sample rate if that helps at all.  However, the higher sample rate shouldn't increase processing times noticeably.

How many recordings did you make in this way?  Is disk space a major issue here?

dlmckain

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Re: Bit Rate and Frequency Conversion
« Reply #2 on: November 19, 2021, 10:42:14 AM »
Too many files.

I did open one of the 192 kHz files in Audacity and was surprised to see that the waveform was contiguous with a sample every ^5x10^-6 seconds which is 1/192K.

I had expected to see doubling of samples, that is, the amplitude "stepping" every two samples. Audacity's "resample" from 192 to 96 kHz just removed every other sample, which was expected as 192 / 2 = 96.

Maybe Windows is lying to me and the ADC is actually running at 192 kHz.

Sorry to be exacting - I worked with data acquisition for most of my career, mostly at 10 Hz but for hundreds of data channels.

Maybe just need to suck it up and buy more hard disk space to store my recordings.

Also need to study Nyquist frequencies and the like.

So, the answer is that you can resample in Audacity. Not sure about the bit depth as, on import, it takes the supposed 24 bit and shows it at 36 float which is a bit confusing.

Paul Sanders (AlpineSoft)

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Re: Bit Rate and Frequency Conversion
« Reply #3 on: November 19, 2021, 01:54:03 PM »
Sounds like Audacity's resampling algorithm is very poor.  VinylStudio is smarter than that.

Steve Crook

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Re: Bit Rate and Frequency Conversion
« Reply #4 on: December 03, 2021, 11:47:28 AM »
Disk is cheap. 4Tb of USB3 rust for <100ukp. I have two and a 2Tb SSD. Rips go onto the SSD and robocopy /mir /mt:8 onto the rust and I have one backup kept off site. I have all my rips (CD and LP) ,VS files, recorded radio and images from album covers on the SSD (about 2000 albums so far) and there's 500Gb left. LPs are all at 24/192 but stored as FLAC, CDs are 16/44.1.

I wouldn't trust SSD for long term storage where it's unpowered for more than a few weeks because of the potential for bit rot.


Paul Sanders (AlpineSoft)

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Re: Bit Rate and Frequency Conversion
« Reply #5 on: December 03, 2021, 12:16:39 PM »
Taking things seriously then :)

Steve Crook

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Re: Bit Rate and Frequency Conversion
« Reply #6 on: December 03, 2021, 12:27:07 PM »
Ripping is a means to an end. I hate redoes and I've been bitten by bit rot once and hard disk failure more recently. I had single backups but it made me think much more seriously about a formal backup routine. The 4TB discs are cheap and a simple backup script does the hard work for my rips and for other data I can't afford to lose, even if the house burns down! I made sure to buy discs from different manufacturers in the hope this is some security against simultaneous failure.

I have the good fortune to have a friend who will keep the (encrypted) off site disc for me in exchange for free PC related advice :)

Paul Sanders (AlpineSoft)

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Re: Bit Rate and Frequency Conversion
« Reply #7 on: December 03, 2021, 01:57:16 PM »
Yes, that all makes excellent sense.

Thanks for the tip about bit rot, I'll keep my eyes open for that.  I've recently moved (or, rather, copied) a lot of stuff to SSD because it's so much faster so I will need to be careful about that.  Makes my machines fly, tho :)

Lewis

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Re: Bit Rate and Frequency Conversion
« Reply #8 on: December 08, 2021, 07:31:41 AM »


I wouldn't trust SSD for long term storage where it's unpowered for more than a few weeks because of the potential for bit rot.
No way. My simple experience says SSDs are good for the longest time of storage.
Way back in 2009 when I bought my NoName SSD (1Tb) it's been in service (no power supply) for 10+ years.
R-W cycles are endless.

Paul Sanders (AlpineSoft)

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Re: Bit Rate and Frequency Conversion
« Reply #9 on: December 08, 2021, 09:43:27 AM »
That's reassuring.  Quite honestly I'm not sure what to think, there seems to be a lot of contradictory information / opinions floating around.

I did read somewhere (forget where, sorry) that someone hammered an SSD with several years' worth of read / write cycles (especially write) with no ill-effects.  YMMV, as they say.

Lewis

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Re: Bit Rate and Frequency Conversion
« Reply #10 on: December 08, 2021, 09:54:55 AM »
Paul,
loads of opinions exist.
TTYTT, I've got a netbook branded AsusTEK eeePC 900 (15Gb SSD), my first instance of SSD being out-of-box,
imagine my surprise, its SSD (praise the Savior) serves me right, nowadays it is destined for sharing files via p-2-p connectivity (circa 2014 when this netbook became useless for up-to-date communications.)
I am unable to figure out by counting how many data chunks/bites/bits have been sent/received from that SSD since that time.
Roughly, 12-14Tbs, I guess.

Steve Crook

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Re: Bit Rate and Frequency Conversion
« Reply #11 on: December 08, 2021, 01:14:54 PM »
No way. My simple experience says SSDs are good for the longest time of storage.
Way back in 2009 when I bought my NoName SSD (1Tb) it's been in service (no power supply) for 10+ years.
R-W cycles are endless.

We're probably at crossed purposes.

I'm talking about drives being unused (without any power) for a period. Depending on the type SSD they can have bits change state from 1 to 0 in a matter of weeks. Drives made for, and sold as data storage use different memory to those used for (for example) boot drives on PC and could be expected to hold storage for at least months and, probably, years.

I've had this happen to an SSD I was using to store data on my music server. It remained unused and powered off for around three months. It had damaged files when powered back up. My practice now is to have the OS do a sanity check on any SSD that's been off for months. Almost always files are reparable because the file systems have error correction/CRC checks etc. But, eggs and baskets...

What I think you're talking about is disk 'wear' when cells can only be deleted/written to a limited number of times, so that a drive that has lots of delete and write operations starts to have cells fail, and, gradually, the capacity of the drive declines. Data is never lost. Modern disc controllers manage this very well, and the memory itself has improved a lot over the years to the extent that, for most domestic situations it's not an issue.

Personally, I'd not use SSDs for long term backup. Anything where you wouldn't plug the drive in and use it for several months at a time.

Lewis

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Re: Bit Rate and Frequency Conversion
« Reply #12 on: December 08, 2021, 02:02:14 PM »

I'm talking about drives being unused (without any power) for a period. Depending on the type SSD they can have bits change state from 1 to 0 in a matter of weeks. Drives made for, and sold as data storage use different memory to those used for (for example) boot drives on PC and could be expected to hold storage for at least months and, probably, years.
My point is storing your data for future reference.
E.g. DWG files (a bunch of them) containing gygabytes of data say 2018-2021 (three years AFAICR.)
Nevertheless, if I put away my SSD drive for a couple of years, I will surely retrieve the data.

As for my SSD 'tiniest' 15Gb drive, R-W cycling is underway and goes on on and on even when I'm typing these characters O, N right here.