qtaacenc: a command-line QuickTime AAC encoder for Windows Options

[UPollaehne]

Can you implmenet access to HE-AAC encoder as well?

Unfortunately, HE-AAC encoder is not available in QT for Windows.

So if I do get AAC SBR as Codec Profile for a file encoded with --tvbr 12 --highest - %d with foobar I have to assume that Quicktime Pro enables HE?

[nao]

So if I do get AAC SBR as Codec Profile for a file encoded with --tvbr 12 --highest - %d with foobar I have to assume that Quicktime Pro enables HE?

No, maybe the player misrecognizes it or QT intentionally appends the SBR flag at low samplerates for some reason. Actually SBR isn't used at all. The same thing happens to AAC files created by iTunes with low samplerates.

[wkmax]

Thank you so much for this contribution nao!!!
Works fine, QuickTime True VBR AAC rules!

Are these bitrates values correct for qtaacenc?:

Target Quality - True VBR AAC (Powered by QuickTime & CoreAudio):
Q0 - Q4 = ~40 kbps
Q5 - Q13 = ~45 kbps
Q14 - Q22 = ~75 kbps
Q23 - Q31 = ~80 kbps
Q32 - Q40 = ~95 kbps
Q41 - Q49 = ~105 kbps
Q50 - Q58 = ~115 kbps
Q59 - Q68 = ~135 kbps
Q69 - Q77 = ~150 kbps
Q78 - Q86 = ~165 kbps
Q87 - Q95 = ~195 kbps
Q96 - Q104 = ~225 kbps
Q105 - Q113 = ~255 kbps
Q114 - Q122 = ~285 kbps
Q123 - Q127 = ~320 kbps

Thanks again!

This post has been edited by wkmax: Jan 24 2010, 12:51

[nao]

One question: XLD Q&CA True VBR AAC bitrates are the same in qtaacenc?:

Yes if XLD runs on OSX 10.5/10.6 with QT 7.6.4/7.6.3.

[wkmax]

One question: XLD Q&CA True VBR AAC bitrates are the same in qtaacenc?:

Yes if XLD runs on OSX 10.5/10.6 with QT 7.6.4/7.6.3.

Thank you nao

This post has been edited by wkmax: Jan 24 2010, 12:56

[Mix3dmessagez]

tested it out, got a file with 10.1MB with it, knew something was wrong...

proceeeded to encode file manually with quicktime vbr, got 5.76MB file..

I have it at it's highest setting...

[Steve Forte Rio]

Why iTunes (v9.0.2.25) and qtaacenc produce files with different bitrates while thay use the same (QuickTime) Encoder and configured equally?

iTunes AAC 320 VBR mode - 341 kbps

QTAACEnc 20100124 --cvbr 320 - 342 kbps

This post has been edited by Steve Forte Rio: Jan 29 2010, 20:38

[lvqcl]

Try qtaacenc --cvbr 320 --normal.

[Steve Forte Rio]

Duration : 6:35.613 (17446548 samples)
Sample Rate : 44100 Hz
Channels : 2
Bitrate : 336 kbps
Codec : AAC
Codec Profile : AAC LC
Encoding : lossy
Tool : iTunes 9.0.2.25, QuickTime 7.6.5
Track Peak : 0.964269

Duration : 6:35.613 (17446548 samples)
Sample Rate : 44100 Hz
Channels : 2
Bitrate : 336 kbps
Codec : AAC
Codec Profile : AAC LC
Encoding : lossy
Tool : qtaacenc 20100124, QuickTime 7.6.5
Track Peak : 0.964269


Differences found: 29983105 sample(s), starting at 0.0000000 second(s), peak: 0.0234758 at 306.0978005 second(s), 2ch

added:

huh, the differences was due to some metadata. After removing tags:

No differences in decoded data found.

Thanks.

This post has been edited by Steve Forte Rio: Jan 30 2010, 09:09

[C.R.Helmrich]

So for extra clarification: Does that mean that iTunes uses "normal quality" (which cannot be changed), while QuickTime uses "high quality" by default?

Chris

[nao]

So for extra clarification: Does that mean that iTunes uses "normal quality" (which cannot be changed), while QuickTime uses "high quality" by default?

I set the default quality to "high" in qtaacenc, but the default in QT is normal.

[clintb]

You are my audio transcoding hero! I HATE having to go out of foobar to do any FLAC > AAC conversions, and wanted badly to use true VBR of Quicktime and here's the thread on how to do it!

A big thank you!

[richard123]

I've been encoding a song from Abbey Road. At q68, I get 150kps. At every q value from 69-76, I get 168kps. I would have expected each additional q value to add a small amount to bit rate, rather than a jump between two values and then no change over a number of values.

Is this typical behavior?

[clintb]

I've been encoding a song from Abbey Road. At q68, I get 150kps. At every q value from 69-76, I get 168kps. I would have expected each additional q value to add a small amount to bit rate, rather than a jump between two values and then no change over a number of values.

Is this typical behavior?

Check out post 28, and it does seem to be normal...in my limited testing.

[richard123]

Check out post 28, and it does seem to be normal...in my limited testing.

Aha!

I had thought #28 was just lumping things together for ease of presentation

It is odd behavior.

[wkmax]

Check out post 28, and it does seem to be normal...in my limited testing.

Aha!

I had thought #28 was just lumping things together for ease of presentation

It is odd behavior.

This is the approx. target quality for QuickTime True VBR AAC, confirmed by nao. Works on QuickTime 7.6.5 (Windows OS - qtaacenc), QuickTime 7.6.4 (Mac OS X 10.5 Leopard - XLD) and QuickTime 7.6.3 (Mac OS X 10.6 Snow Leopard - XLD):

Target Quality - True VBR AAC (Powered by QuickTime & CoreAudio)
Q0 - Q4 = ~40 kbps
Q5 - Q13 = ~45 kbps
Q14 - Q22 = ~75 kbps
Q23 - Q31 = ~80 kbps
Q32 - Q40 = ~95 kbps
Q41 - Q49 = ~105 kbps
Q50 - Q58 = ~115 kbps
Q59 - Q68 = ~135 kbps
Q69 - Q77 = ~150 kbps
Q78 - Q86 = ~165 kbps
Q87 - Q95 = ~195 kbps
Q96 - Q104 = ~225 kbps
Q105 - Q113 = ~255 kbps
Q114 - Q122 = ~285 kbps
Q123 - Q127 = ~320 kbps

Regards

[richard123]

Any idea why Apple would do levels in this stepwise fashion, rather than a smoother increase? In other words, why doesn't adding one to the Q value add a bit to bitrate, rather than having bands of Q values leading to the same bitrate?

These posts found Q60-65 to lead to 127-129 kbps, which is close to what you're reporting: http://www.hydrogenaudio.org/forums/index....mp;#entry682937

This post has been edited by richard123: Jan 31 2010, 02:33

[kornchild2002]

tested it out, got a file with 10.1MB with it, knew something was wrong...

proceeeded to encode file manually with quicktime vbr, got 5.76MB file..

I have it at it's highest setting...

It sounds like QuickTime Pro is encoding at 128kbps TVBR. I have yet to find a way to change the encoding setting (other than enabling true VBR and setting quality to high) in the latest version of QuickTime Pro under Windows, it always results in files that are at 128kbps TVBR. So the setting you used with qtaacenc was why you had a 10.1MB file. There was nothing wrong. Using Q values of 105 and above can result in large files. It sounds like you were using Q105 or somewhere around there to produce a file with an overall average bitrate of 256kbps.

[singaiya]

I just noticed that for Q values <59, output is resampled to 32 kHz. For me, Q 59 results in 139 kbps on average. Isn't resampling done at much lower bitrates with mp3?.

Thanks nao for this program.

[lvqcl]

Quick test:

lame -V 6.248: 126 kbps
lame -V 6.249: 115 kbps

qtaacenc --tvbr 59: 135 kbps
qtaacenc --tvbr 58: 105 kbps

(and qtaacenc --tvbr 58 --samplerate keep: 114 kbps)

I cannot say that 126 is 'much lower' than 135 kbps.

This post has been edited by lvqcl: Feb 1 2010, 16:41

[matt_t]

Thanks nao for your program.

Could you possibly give an illustration of how to use qtaacenc with dBpoweramp's CLI encoder, as you already have with foobar? That would be great.

[redsandvb]

Thank you nao

[punkrockdude]

I notice that the output files sometimes are almost 1 dB quieter that the file it encodes. How does this happen? I calculated it with Foobar 1.0 ReplayGain Scanner and the AAC quality is 127.

[b66pak]

ok...i have done some tests...here are the results...

the qtaacenc encoder accepts wav's up to 32float (mono or stereo ONLY)...

if found that is limited (an old apple flaw!!!) to maximum 186 minutes for a 32float@48000hz wav or 279 minutes for a 24bit@48000hz wav and 327 minutes for a 16bit@48000hz wav!!!

the 4gb limit is on apple side of the encoder...i test it using the STDIN input by feeding a +8hrs .ac3 file with 16, 24, 32, 32float bits...
_

OT: @nao considering your expertise in windows iTunes libraries do you think a CLI raw (or full) mp4 muxer can be done? (.h264 + .acc + softsubs [apple style] + chapters [apple style])

something like subler for mac...

http://code.google.com/p/subler/
_

This post has been edited by b66pak: Feb 2 2010, 21:35

[Steve Forte Rio]

I notice that the output files sometimes are almost 1 dB quieter that the file it encodes. How does this happen? I calculated it with Foobar 1.0 ReplayGain Scanner and the AAC quality is 127.

Maybe it is special technology to reduce/prevent clipping?

the qtaacenc encoder accepts wav's up to 32float (mono or stereo ONLY)...

It accepts, but in fact we have conversion to 16 bit fixed point which results in clipping in some cases

This post has been edited by Steve Forte Rio: Feb 2 2010, 21:39