gorodoe
Posts: 1
Joined: Fri Jul 22, 2016 9:44 pm

Higher AAC Bitrate?

Fri Jul 22, 2016 9:52 pm

I've been searching and not yet found anybody asking this, why AAC for MP4 are limited only up to 192 kbps. Shouldn't at least, at the very least it goes up to 256, or even 320. I know above 192 AAC are to most indistinguishable and yes bandicam can export .WAV tracks. But it's just something that keeps me wondering why don't options for up to 320kbps are given.

GameTipsAndMore Blog
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Joined: Thu May 17, 2012 12:39 am
Location: Canada
Contact: Website

Re: Higher AAC Bitrate?

Sat Jul 23, 2016 7:08 am

I've been searching and not yet found anybody asking this, why AAC for MP4 are limited only up to 192 kbps. Shouldn't at least, at the very least it goes up to 256, or even 320. I know above 192 AAC are to most indistinguishable and yes bandicam can export .WAV tracks. But it's just something that keeps me wondering why don't options for up to 320kbps are given.
If I may pop in on this, I myself wondered why this is [in many applications in the recent past], as I purposely used to utilize 320kbps when I used MP3 compression in the more distant past [in an attempt to maintain audio fidelity]. I wondered why some applications seemed to 'default' or 'go up to' 192kbps with AAC encoding. So, I looked it up - and I'll share what I found, hopefully it will help you out:

Around the year 2000, the European Broadcasting Union did actual testing of human hearing, in double-blind tests, to see where people could no longer 'hear the difference' between the various [commonly-used] levels of audio bitrate compression, using Advanced Audio Coding (AAC). What they found was, that 192kbpsAAC was a 'sweet spot', whereas with higher bitrates, the majority of people couldn't really tell the difference (although I am sure there are many Audiophiles that, with the right headphones, could tell a difference beyond that). I believe this is why Apple feels it can state something to the effect of '192kbpsAAC being "CD Quality Audio" ' [something I read somewhere in the past] which is quite a statement, considering CD Audio is essentially a 1400kbps WAV-format audio source...

Regardless, 192kbps, for AAC, became an 'acceptable substitute' for high-quality ("CD Quality") audio (remember that AAC is more advanced than MP3, requiring less bitrate to simulate the same apparent audio quality). Thus, I assume this is why Bandicam (and other apps that use audio) settled on ~192kbps for AAC recording [I am not 100% sure of course, I do not work for Bandisoft]. If you want higher audial fidelity, you can always switch to AVI and use MPEG-1 Layer 2 format (up to 384kbps) and can also record in WAV format, if you desire - and then if your sound adapter is capable of it, you can even record in 24-bit at 96kHz with Bandicam (with their "Save as Original Format" option) - which, with those settings, is somewhere in the realm of 4600kbps! :geek:

Edit:
I found some Technical Data for the EBU Listening Tests that were done, if you (or anyone else) are interested - https://tech.ebu.ch/docs/techreview/trev_283-kozamernik.pdf
("Hope That Helps!") ~ Troy

bandicam user
Posts: 1
Joined: Sun Oct 11, 2020 5:39 am

Re: Higher AAC Bitrate?

Sun Oct 11, 2020 5:59 am

Yes, I have blind test myself of the two files that were recorded by bandicam.
One was H264 AVI mp3 256kbps, another one was H264 MP4 aac 192kbps,
Their sound quality are different. I can easily pick out the file of mp3 256kbps in the blind test.

The 256kbps MP3 has better sound than 192kbps AAC.
Due to the limiting of 192kbps of AAC of recording,
I need to switch to AVI instead of MP4 when
I need to record video with higher quality audio.

Because of only AVI format has the option to choose 256kbps MP3.
I think 256kbps is enough, so I choose 256kbps instead of 320kbps.

The highest quality of MP3 is 320kbps,
is the hightest quality of AAC is 192kbps?

Is this a bad idea to let the MP4 file to have an
option to choose mp3 format?

I think AVI is older and mp4 is newer, so I prefer to use MP4.
However the highest sound quality of MP4 is limited as AAC 192kbps.
Is this a good idea to use AVI instead of MP4 in the "Generation Alpha"?

GameTipsAndMore Blog
Posts: 449
Joined: Thu May 17, 2012 12:39 am
Location: Canada
Contact: Website

Re: Higher AAC Bitrate?

Tue Oct 13, 2020 6:24 am

Yes, I have blind test myself of the two files that were recorded by bandicam.
One was H264 AVI mp3 256kbps, another one was H264 MP4 aac 192kbps,
Their sound quality are different. I can easily pick out the file of mp3 256kbps in the blind test.

The 256kbps MP3 has better sound than 192kbps AAC.
Due to the limiting of 192kbps of AAC of recording,
I need to switch to AVI instead of MP4 when
I need to record video with higher quality audio.

Because of only AVI format has the option to choose 256kbps MP3.
I think 256kbps is enough, so I choose 256kbps instead of 320kbps.

The highest quality of MP3 is 320kbps,
is the hightest quality of AAC is 192kbps?

Is this a bad idea to let the MP4 file to have an
option to choose mp3 format?

I think AVI is older and mp4 is newer, so I prefer to use MP4.
However the highest sound quality of MP4 is limited as AAC 192kbps.
Is this a good idea to use AVI instead of MP4 in the "Generation Alpha"?
If I may pop back in to try give an answer to a couple ideas you presented:

» The "highest quality of AAC" is not technically 192kbps (as a technological absolute limitation), but as Apple has stated (and enforced it seems), not many programs/applications will go above that, as it has become an accepted 'standard'. Apple has put out an iOS specification that shows the limit they present for Bluetooth/iOS devices as just above 256kbps (linked just below if I can add it, or at the bottom of this posting):

https://discussions.apple.com/content/a ... /857005040
(see bottom of posting)


As you have observed, above about 256kbps (using MPEG2/MP3 as an example), the fidelity starts to become 'lost' to most of us – I too think that about 256kbps (MPEG-2 audio) is pretty much fine [and it seems that testing and other sources agree with us, according to the Apple.com graphic/table above, as their specification is only just above that].

I only use 320kbps, as one day getting large, over-the-ear headphones as a gift, I started to notice the differences in [what I was using at the time] 128kbps and 320kbps audio encodes/archives I was doing - I essentially 'gave up on' 128kbps music archiving of my CDs and switched to 320kbps (as it seems many of the music community was doing at that time / talking about). Other than ever-so-slight fidelity differences I noticed, I leave the overhead (using 320kbps over 256kbps) for expected further compression loss. Overall though, Apple, the tests that the European Broadcasting Union did (and other tests no doubt), are enough to make companies (and program developers) 'limit' their bandwidth usage for audio, to about 192kbps for AAC, as a standard. This also allows more Bitrate for other uses (Video, etc) for things like Bluetooth and other medium with potential Bitrate limitations.

So, Bandicam (and others) use 192kbps AAC (for audio) as it is an accepted standard and for general use purposes (general public, etc), it seems fine. If you were doing Official Broadcasting of some kind (eg. News, Sports, National News, etc) then you’d likely want something more for fidelity, but you’d probably be using something in-house (provided by the network) anyway, heh.

» It is not really a ‘bad’ idea to use MP4 with MP3 audio [techncially, ‘any’ “container” can have almost ‘any’ “format” inside of it] - it is just something avoided as some editing programs do not ‘like’ certain formats or containers. To explain, try to think of multimedia files as two different ‘parts’: “Containers” are things like MP4, AVI, MKV, etc. - and these can be ‘filled’ with different formats of audio/video, like MP3, AAC, MPEG-2 video, MPEG-4 video, and others. These also change slightly over time. In the past, many used say, AVI with MPEG-4 (simple) video with MP3 audio, while today many use say, MP4 with MPEG-4 (advanced) video with AAC audio. [To further confuse things, most of these are just various types of MPEG formats (MP2, MP3, MP4, AAC, are all “MPEG-4” standards)].

Some video editing applications are more ‘fussy’ than others, refusing to open/recognize one format or another, or some container or another (for example, Sony’s Vegas Video editors used to not like MP3 audio very much, and many video editors still won’t open the MKV container). Of course, a lot of this technically depends on the Codecs and Splitters and Filters that are installed on the system. These are the formats that are installed/understood by the system, allowing Media Players and Video Editors to open them and use them. If one type or another is not installed, they may not be recognized by the system (some ‘general use’ codecs are installed in Windows by Default, that can open many different formats at once); so to get around this limitation, it is possible to just install the desired codec you wish to use. Bandicam works quite well with this, as they have included a “EXTERNAL CODEC” option, under their AVI container section (AVI is a more ‘general use’ container, able to hold a number of various formats, as is others like MKV).

So, the problems that can arise [with editing programs] make most programs avoid ‘mixing’ the formats that don’t normally go together [as generally accepted standards], so that’s why some combinations/choices are not readily available in recording/editing applications.


» You can use with AVI or MP4 if you wish, either one works great for recording with Bandicam, the only issues you might run into is that your preferred video editor (whatever that may be) may not ‘like it’ (recognize/be compatible with it as readily) – do some testing of short clips, to make sure whatever editing program you are using, can open the output recordings – and you’ll be fine.

HTH a bit
~T
Attachments
aac ios decives specification.jpg
AAC audio spec from Apple for iOS devices
aac ios decives specification.jpg (16.72 KiB) Viewed 999 times
("Hope That Helps!") ~ Troy

vulc
Posts: 7
Joined: Tue Sep 09, 2014 7:18 am

Re: Higher AAC Bitrate?

Tue Nov 10, 2020 6:33 pm

You can use with AVI or MP4 if you wish, either one works great for recording with Bandicam, the only issues you might run into is that your preferred video editor
Yeah, that's it. And this is not the only reason, but one of many reasons. AVI should be used only for outdated software (and outdated devices). In all other cases, problems can (and sometimes) arise.
It's bad that the developers don't give users the minimum audio codec settings. I also tried to draw attention to this in this topic.
The minimum requirements for audio codec settings:
  • independent choice of any codec for any multimedia-container (instead of aac only for mp4. And mp3 only for avi :shock: :? :? )
  • switching modes encoding: VRB or CBR (ABR is little demand)
  • of course quality up to 320 kbps for any codec. :?
  • channel encode settings: mono/stereo/joint stereo

High-quality audio recording (encoding) is also important when capturing media-content. Especially if it contains high quality music. Don't you think?
Apologize for my low level of English.

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