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Topic: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR? (Read 5288 times) previous topic - next topic

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  • LTP
  • [*]
Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
I've just finished ripping my 600+ album collection using XLD on my Mac, all stored in a lossless format on an external hard drive (and further backed up on another kept off-site because there is simply no way I'm doing all that work again for anything).

Now I'd like to play all my music on my MacBook with a modest speaker set-up while i work, ideally while not having an external hard drive hogging the USB port, and since 600GB worth of tunes is likely to choke up my machine I thought it sensible I convert to a lossy format to general play.

Now my question is this, what should be the highest quality AAC encode I should aim for? While I know it's entirely subjective and a lot of people are saying that the iTunes Plus (256kbs VBR) option is a good enough compromise between sound quality and size but I have a 700GB+ hard drive in my Mac so would it be worthwhile going the full hog with 320kbs and should I go with the VBR option with that bit rate? Would that make any difference? I apologise in advance if I am treading old and unwelcome ground but I haven't been able to find anything that helpful so far online about the differences and/or benefits between 320kbs and 320kbs VBR AAC files so your recommendations would be very valuable.

I don't want to have to re-encode everything in a couple of years so until a Mac can comfortably hold a decent sized lossless library then essentially I want the highest quality lossy format to tide me over for the foreseeable future.

So, 256kbs VBR, 320kbs or 320kbs VBR?

  • lithopsian
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #1
Maybe you should have used a compressed lossless format.  1GB per album would seem to be about three times larger than necessary.

  • LedHed8
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #2
Good morning.  Here's what I would do as it seems you are in the Apple Eco-system:  Spend the $24.99/year to subscribe to iTunes Match and upload all of your lossless files to the Cloud.  The Cloud will accept Apple Lossless, AIFF, or WAV; as well as lossy MP3 or AAC.  I'd go with lossless as your 1st option for uploads.  In most cases, iTunes will match your music with AAC iTunes Plus files.  In the cases there aren't matches, iTunes will transcode the lossless files to AAC iTunes Plus files.  AAC iTunes Plus is Constrained Variable Bit Rate 256kbps files.

If you have other Apple devices you can use iTunes Match to download or stream your Cloud music as you see fit.  They will all be available across your devices in the iTunes Plus format.  This is also a great time-saver once you get through the initial uploads.  Make sure your metadata is how you want it before you start because it's easier to do it right the 1st time rather than fix it later.

For what it's worth, bitrates above 160kbps are generally overkill with a good AAC encoder like iTunes or FhG AAC.

Hope this helps.  Best regards, LedHed8

P.S.- Added Bonus -- You won't have to use local storage on any devices if you don't want, and the iTunes Cloud will do the lossy encoding for you.
  • Last Edit: 20 January, 2016, 10:52:29 AM by LedHed8

  • LTP
  • [*]
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #3
Maybe you should have used a compressed lossless format.  1GB per album would seem to be about three times larger than necessary.

I probably have a fair few more than 600 albums but I have a ton of external storage so size isn't really an issue (or so I have been told). Even keeping to Apple Lossless however I would still consume an uncomfortable amount of hard drive space on my Mac which is why I'd like to find the best compromise with the best AAC bit rate. I'm playing from iTunes on my Macbook so while I am a great believer in lossless formats it wouldn't be being played to its full potential here anyway.

Good morning.  Here's what I would do as it seems you are in the Apple Eco-system:  Spend the $24.99/year to subscribe to iTunes Match and upload all of your lossless files to the Cloud.  The Cloud will accept Apple Lossless, AIFF, or WAV; as well as lossy MP3 or AAC.  I'd go with lossless as your 1st option for uploads.  In most cases, iTunes will match your music with AAC iTunes Plus files.  In the cases there aren't matches, iTunes will transcode the lossless files to AAC iTunes Plus files.  AAC iTunes Plus is Constrained Variable Bit Rate 256kbps files.

If you have other Apple devices you can use iTunes Match to download or stream your Cloud music as you see fit.  They will all be available across your devices in the iTunes Plus format.  This is also a great time-saver once you get through the initial uploads.  Make sure your metadata is how you want it before you start because it's easier to do it right the 1st time rather than fix it later.

For what it's worth, bitrates above 160kbps are generally overkill with a good AAC encoder like iTunes or FhG AAC.

Hope this helps.  Best regards, LedHed8

P.S.- Added Bonus -- You won't have to use local storage on any devices if you don't want, and the iTunes Cloud will do the lossy encoding for you.

I don't really want to fork out more than I already have to our mighty overlords in Cupertino, especially as I can easily set my Mac to encode my lossless library into 256kbs or higher AAC overnight and while I think 600-700 lossless albums might choke my Mac, it would probably cope with having the same library 2-3 times smaller.

I'm mostly confused about the VBR part, as I vaguely remember a while back people were saying there was no point having 320kbs as a variable bit rate because 320kbs was as high as it could go anyway, I don't think AAC could even do 320kbs VBR at one point in time?

From what I can understand, when iTunes does VBR it basically sets the chosen bit rate as the minimum and from there it goes higher depending on the track (except for silence when it goes lower) is that right? So a track encoded at 256kbs could go up to 275kbs or something like that? Thus VBR is superior to CBR in that regard, which is why iTunes Plus uses VBR for its encoding.

Would that mean then that in theory 320kbs VBR AAC is superior to 320kbs CBR AAC because the VBR would encoded the track at 320kbs as a minimum and only go higher or is there nowhere for it to go after 320kbs and thus it's just wasted space? A couple of tracks I encoded with both were obviously slightly bigger encoded using 320kbs VBR but I couldn't tell any noticeable difference (nor would I expect to).

I literally just want to encode at what would be the highest quality AAC bit rate and while I can find enough arguments about whether 256kbs is good enough for most people and that you can or cannot tell the difference when tested, and a few arguments from some about 320kbs being detectably better than 256kbs, I can't find anything at all about 320kbs being theoretically or audibly better using VBR or not. In fact a lot of the information is out of date now as some sites say AAC won't even DO VBR at 320kbs.

I'd really appreciate it if someone could run me through this, even if it's to appease my own curiosity.

  • yourlord
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #4
I don't really want to fork out more than I already have to our mighty overlords in Cupertino

Then  you picked the wrong platform.

Disregarding that point, you'd honestly probably be fine at 128kbps VBR.

Also, your computer has a network. Attach that external drive to a machine which is always on and have that machine host the files on your network (As a last resort, most wifi routers these days offer this feature). You can play them on your laptop or any other machine on the network directly; no transcoding, and no wasting hundreds of GB of storage on every machine you plan to listen on. 

  • greynol
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  • Global Moderator
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #5
Would that mean then that in theory 320kbs VBR AAC is superior to 320kbs CBR AAC because the VBR would encoded the track at 320kbs as a minimum and only go higher or is there nowhere for it to go after 320kbs and thus it's just wasted space?
You've already long passed the point of wasted space.

I'd really appreciate it if someone could run me through this, even if it's to appease my own curiosity.
https://hydrogenaud.io/index.php/topic,16295.0.html
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

  • shadowking
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #6
600 albums lossless would be around 200GB .  This would be 25% off the total HDD capacity. Assuming you don't have too much HD videos / pics etc, then that should be fine.  Maybe a waste of time transcoding. Especially to such high rates like 256~320. You may end up with the worst of everything - inefficiency.

I would suggest AAC / vorbis / mpc @ 160..190.. Even mp3 can be just fine in most cases [ V3 / V2 settings]
OR even lower like 130k AAC / vorbis
  • Last Edit: 21 January, 2016, 04:37:33 AM by shadowking
wavpack 4.8 -b4x4s0.75c

  • 2Bdecided
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #7
600 albums lossless would be around 200GB.
That matches what I see in my collection.

The sound quality difference between 256kbps and 320kbps AAC is vanishingly small almost all of the time. You are far more likely to imagine a difference than hear a real one. You are also quite likely to get annoyed at having to maintain two collections in sync every time you rip a new disc, or correct a problem you find in the metadata when playing the tracks. Of course if you want to load everything on to a lower capacity portable player, you'll have to do this, but it's nice if it can be avoided.

Cheers,
David.

  • Nichttaub
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #8
A few years ago I did a very critical ABX of three different albums, 2-3 samples each at 128K AAC vs. AIFF.  Each sample trial took about 1/2 hour and was very stress-inducing because of the intense concentration I needed to identify the samples.  I was just barely able to do 15/15 on the comparisons, but I'm not at all sure I could put the differences into words.  I abandoned higher bit rate comparisons at this point, because if identifying 128K samples was that much work...

This convinced me that if I ripped at 256K I was so far beyond my ability to discern differences that it literally doesn't matter.  Whatever decision you make, you should at least do an ABX of some very demanding music before committing.  It might save you a tremendous amount of space and stress.

  • shadowking
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #9
If 128k tests are stress inducing then in real life listening it should be perfect or very close. IMO no reason for 256k which may fail on other critical sample. If people cannot handle the risk of some minor difference then maybe forget lossy compression. For small collections you can have as much or even more music compared to 128..192 of 10yrs ago.
wavpack 4.8 -b4x4s0.75c

  • Nichttaub
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #10
Yes, I actually convert to 128k for car audio now, based on that.  My collection on the main audio system at 256K is still approaching 300GB, so it's manageable but won't fit on a portable player yet...

  • shadowking
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #11
 A decade ago or so , ripping into mp3 128~192:  600 cd's = 35GB.   No compatibility issue or transcoding. Sound quality is near transparent. With mirror backup = 70GB.

Today with lossless + multi collections:  200GB lossless + 100GB (additional HQ lossy libs for pc / phone).  With backup = 600GB. 

If using many formats, it seems a new problem is emerging worse than 1 lossy or lossless. It may also involve a lot of work esp if you can't transcode directly into a device and have to maintain multi collections.
  • Last Edit: 22 January, 2016, 07:43:13 AM by shadowking
wavpack 4.8 -b4x4s0.75c

  • ZakiSayed
  • [*]
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #12
I've just finished ripping my 600+ album collection using XLD on my Mac, all stored in a lossless format on an external hard drive (and further backed up on another kept off-site because there is simply no way I'm doing all that work again for anything).

Now I'd like to play all my music on my MacBook with a modest speaker set-up while i work, ideally while not having an external hard drive hogging the USB port, and since 600GB worth of tunes is likely to choke up my machine I thought it sensible I convert to a lossy format to general play.

Now my question is this, what should be the highest quality AAC encode I should aim for? While I know it's entirely subjective and a lot of people are saying that the iTunes Plus (256kbs VBR) option is a good enough compromise between sound quality and size but I have a 700GB+ hard drive in my Mac so would it be worthwhile going the full hog with 320kbs and should I go with the VBR option with that bit rate? Would that make any difference? I apologise in advance if I am treading old and unwelcome ground but I haven't been able to find anything that helpful so far online about the differences and/or benefits between 320kbs and 320kbs VBR AAC files so your recommendations would be very valuable.

I don't want to have to re-encode everything in a couple of years so until a Mac can comfortably hold a decent sized lossless library then essentially I want the highest quality lossy format to tide me over for the foreseeable future.

So, 256kbs VBR, 320kbs or 320kbs VBR?

VBR is better than CBR because it doesn't waste bits in encoding unnecessary parts like silence, and the only way to know if you want 256/320 Kbps is by taking an ABX test. But then there's CVBR (constrained) and TVBR (true) for AAC, the latter is more efficient, but is "slightly" inferior in quality than CVBR, based on this: http://forum.doom9.org/showthread.php?t=161957.
Now as you can see, the difference is negligible, I'd highly recommend TVBR instead for better space savings.

From my personal experience, it's REALLY hard to tell "properly" encoded 256 Kbps TVBR AAC from lossless, except on killer samples with expensive audio equipment, quiet environment, and exceptional hearing. I have a very good pair of ears :) but I cannot ABX 256k TVBR AAC from lossless only rock-heavy music collection with my JBL headphones. Maybe with a better set of cans and on classical/opera music...

I'm also new to using AAC files (preferred MP3 VBR v0 before), and all this knowledge I've gained is only from a few months of experience, so excuse me if anything is off.
Rap is NOT music

  • kadet
  • [*]
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #13
Thanks for this topic and all answers, I'm just before digitization of my CD's archive, really a lot of CD's, I would like to ask one last follow up question related to this thread.

Lossless compression would be still overkill for me - SD cards space capacity is limited, I bought 256 GB, with FLAC I would have to drastically limit my digital collection and omit many of great CD's so I'm going to go lossy way and AAC/M4A as this is popular currently and used in iTunes as well so I would stick to one format, but...

Encoding of so much CD's is a lot of work, If I'm going to do it, I would like to keep as insane quality as possible, even if there is completely no reason for that now (maybe in next ~10 years there will be better audio equipment available with more affordable prices). Thus I would like to encode my CD's to lossy format, but with insane quality to save as much quality as possible.

As far as I understand - qaac.exe wrapper for iTunes encoder gives probably the best quality. But highest possible bitrate for it is 320 kbps.
With --cbr 0 --quality 2 --no-optimize it is producing nice files, fast and without any Hz cutoff.
I have tested fdkaac.exe, but no matter what encoding options I will set - I see cutoff at 20 kHz.

Finally I give a try with neroAacEnc.exe and I see that with VBR it can go up to 400 kbps also no cutoff, but in other hand Nero AAC Encoder is not updated for last 6 years and I'm afraid that maybe there is risk for some bugs there.

The question is:
Despite that it is probably stupid anyway - if I would choose between
- qaac --cbr 0 --quality 2 --no-optimize (320 kbps)
- neroAacEnc with VBR quality 1.0 (400 kbps)
I should go with option 1 or option 2 (despite that Nero is not updated anymore) to save as much quality as possible?

PS: Please don't be mad - I really want to save as much data as possible and I would go lossless, but SD cards capacity is still too low for my CD's collection ;)

  • greynol
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  • Global Moderator
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #14
(maybe in next ~10 years there will be better audio equipment available with more affordable prices).
That won't make a difference.

Quote
Hz cutoff
This is not a valid metric for assessing encoding quality.

Quote
PS: Please don't be mad - I really want to save as much data as possible and I would go lossless, but SD cards capacity is still too low for my CD's collection ;)
No one is mad, although it's annoying to see steadfast irrationality and/or ignorance regarding the use of lossy codecs.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

  • kadet
  • [*]
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #15
@greynol - thanks for answer, fully understand You and I know that in fact I could even go with lower bitrate and I still wouldn't be able to point on which file is encoded with what bitrate in blind test ;)

Generally my point is just to preserve as much audio data as it is possible when going lossy way and it's just because I can't go lossless way ;)

Encoding file with 320 kbps gives bigger size that in 256 kbps - of course this even says less about real encoding quality, but is this mean that some more of audio data is preserved? I don't want to irritate anybody, just asking - to be sure that I will encode my collection once and I won't have to do that ever again ;) You know - a lot of work ;) Maybe even few months...
  • Last Edit: 15 April, 2017, 12:07:21 PM by kadet

  • greynol
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #16
Encoding file with 320 kbps gives bigger size that in 256 kbps - of course this even says less about real encoding quality, but is this mean that some more of audio data is preserved?
Nope.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

  • Case
  • [*][*][*][*][*]
  • Developer (Donating)
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #17
Do yourself a favor, kadet, and use lossless codec to encode the CDs you extract. Keep the lossless files on your computer or external hard drive and convert from those to portable use as needed. The CD extraction process is the most time consuming part of your project and it makes no sense to have to redo it.

You can easily re-encode the collection with new codec or bitrate without quality loss in case your requirements change. If you want to include more music per SD card just re-encode with a lower bitrate. AAC has great quality even at 128 kbps.

Higher bitrate usually means that frequency cutoff is higher and psychoacoustic threshold for audibility is lowered so that more of the less important parts are included. But this isn't a guarantee that higher bitrate file has better quality if they are from different encoders or they are encoded with some custom encoding parameters. Different encoders have different psychoacoustic models, they may not utilize all the features of the format and they can have bugs.

For example Nero encoder has tremendous trouble with the beginnings and endings of tracks and it gives audible artifacts even at ridiculously high bitrates with some gapless tracks.

  • shadowking
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #18
Consider Wavpack lossy, lossywav/Flac @ 450..550k . Both have good support and friendly on hardware players. A restoration file can be produced optionally to allow restoration to full-lossless. Flac is more popular but more complex to setup and in regard to restoration files.. Wavpack uses its own binary for all processing .

The wavpack setting of -b6x5 yields 540k for cd-audio .  You can also use fractional values like b5.5.  This should produce archival quality while reducing usage on sdcard up to a factor of 2 for some genres.

For lossywav/Flac, you can use a setting of  --high or --extreme

For **PC only** usage, Optimfrog DS can be used around --quality 5 ~ 6 (400..500k). There -may be- an Android port in the near future. This encoder is more cpu-intensive on hardware decoding. The --mode fast command use less resources for decoding which may be important is ever portable hardware support is established.

Basically, Just use such settings for both your PC and portable without any transcoding to other formats. This is what I do. If re-encoding to mp3 /aac  is needed it can be done with very high confidence too.

Recent Android devices support flac and 3rd party players like PowerAmp support many formats inc flac  / wavpack.

  • Last Edit: 16 April, 2017, 01:50:45 AM by shadowking
wavpack 4.8 -b4x4s0.75c

  • greynol
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #19
Higher bitrate usually means that frequency cutoff is higher and psychoacoustic threshold for audibility is lowered so that more of the less important parts are included. But this isn't a guarantee that higher bitrate file has better quality if they are from different encoders or they are encoded with some custom encoding parameters.
You mean the threshold of audibility is raised, not lowered. Regardless, if the threshold of audibility is not reached with a lower bitrate then the quality of the encode is not any worse than if it was made with a higher bitrate.
  • Last Edit: 16 April, 2017, 03:59:09 AM by greynol
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

  • kadet
  • [*]
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #20
I'm very thankful for all Your answers and help. I decided to change my idea and to go with lossless way like Case said - I got also not enough HDD space, but HDD's are much cheaper :) I will just buy few additional TB to keep it just for music from my CD's saved in lossless format :) Somehow I believe that damaging music quality would be a disgrace and disregard to artists who created that music ;)

For mobile usage quality won't be so crucial in this situation as I will always have lossless copies to roll back to them at some point in future :D But I will try also shadowking idea - I even didn't knew that there is something between lossless and classic lossy way, it's worth to give this a try :D And in future when Micro SD business will grow - I just replace lossy copies with lossless originals :)

Also thanks to greynol for important explanations :)

For sure I'm not going to rush and I'll check all possibilities so I will do whole operation of digitalisation once and I won't have to do that ever again, better to read, learn and test than do something badly and waste a lot of time ;)

Thanks for Your help :D
  • Last Edit: 20 April, 2017, 09:23:19 AM by kadet

  • Porcus
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Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #21
I just don't see the point of not going lossless with CD rips. You would anyway need an offsite backup, and a larger hard drive does not cost that much (for most music collections).

And lossless rips can be repaired ... of course that only matters if they were erroneous. I uploaded a badass sample: https://hydrogenaud.io/index.php/topic,113978.new.html

  • greynol
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  • Global Moderator
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #22
It's pretty idiotic not to keep a lossless backup for a variety of reasons, including playing around with silly 450kbit non psychoacoustic pet formats that will never receive ubiquitous support.

However, ignorant placebo-based BS like this isn't one if them...
Somehow I believe that damaging music quality would be a disgrace and disregard to artists who created that music
Now if you can pass an ABX test, then fine, but most people have no clue what an ABX test is.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

  • ziemek.z
  • [*]
Re: Converting my lossless rips to AAC, do I go with 256kbs, 320kbs or 320kbs VBR?
Reply #23
LTP, if you *really* want to stick with AAC, choose 256 kbps VBR. Higher bitrates would be waste of space because it's not so likely for you to hear any difference between 256 kbps and 320 kbps. Just do an ABX test ;)
I can recommend you WavPack. If you set encoder to hybrid mode, you can get 2 files: one high-quality lossy file (it can go down to around 200-300 kbps) and second, correction file. These 2 files combined in decoder produce lossless music restoration, however lossy WavPack file's quality is enough (at least for me  :) )
sox -e float -b 32 -V4 -D gain -1 rate -v 48000 norm -1
opusenc --bitrate 128