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Old 29th October 2011, 04:44   #41  |  Link
Asmodian
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Sorry I took a long time editing my above post to add command line and didn't see your request, I wouldn't have edited if there had been a reply.

Any ideas for 32 bit audio? I think I just don't know how to get raw 32 bit out of eac3to. Sorry I think my issue is with the wrong tool for this thread.

Last edited by Asmodian; 29th October 2011 at 05:50.
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Old 29th October 2011, 13:02   #42  |  Link
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Maybe with:
eac3to.exe in.mp2 stdout.wav | qaac.exe -o out.m4a --tvbr 127 --ignorelength -

24 bits (default for eac3to) is enough for a mp2 source.
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Last edited by tebasuna51; 29th October 2011 at 13:04.
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Old 29th October 2011, 21:41   #43  |  Link
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Thanks.

Yes, I have learned that for this source (and many other sources) I will not get anything by going above 24 bit. eac3to is smart enough to not give me extra useless bit depth.
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Old 26th March 2013, 21:11   #44  |  Link
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Average bitrate -vs- Constrained Variable bitrate

Can anyone explain to me what is the difference between --abr and --cvbr modes when encoding at the same target bitrate, 80kbps for instance?
I know that both output files will have ~80kbps variable bitrate so what would be the reason to pick one in favor of the other mode?
Does ABR allow bigger fluctuations of actual bitrate throughout the file?
Does CVBR mode apply narrow bitrate limits in which the average (desired) bitrate can fluctuate?

==EDIT==
Found this Technical Note TN2237 where different encoding strategies are explained in detail:
Quote:
Encoding Strategy

These encoding strategies (a.k.a bit rate control modes) are used with the -s parameter in afconvert and the kAudioCodecPropertyBitRateControlMode (AudioUnit/AudioCodec.h) property.

Constant Bit Rate (CBR) kAudioCodecBitRateControlMode_Constant - Recommended for live streaming.

This mode achieves a constant target bit rate and is completely compliant to the CBR mode specified in the MPEG-4 standard. This mode is suitable for constant-bit-rate network transmission when decoding in real-time with a fixed end-to-end audio delay. However, due to the strict constant bit rate constraint, this mode offers the lowest audio quality and highest complexity among all the encoding modes offered.

Average Bit Rate (ABR) kAudioCodecBitRateControlMode_LongTermAverage - Default Mode, recommended for controlling file size.

A target bit rate is achieved over a long term average (typically after the first few seconds of encoding). Unlike the CBR mode, this mode does not provide constant delay when using constant bit rate transmission, but provides best overall quality while still being able to strictly control the resulting file size with less complexity than the CBR mode.

Variable Bit Rate (VBR) kAudioCodecBitRateControlMode_Variable - Recommended for controlling audio quality.

The audio signal is encoded with constant (and settable) quality and virtually no bit rate constraints. This is the best mode to achieve consistent audio quality across many files and the smallest file size to achieve that quality. It also has the lowest complexity of all the encoding modes.

Variable Bit Rate But Constrained (VBR Constrained) kAudioCodecBitRateControlMode_VariableConstrained - Recommended as a compromise between VBR and ABR.

This mode is similar to VBR but limits the average bit rate variation. The lower limit is the user-selected bit rate. Higher bit rate is adapted for difficult tracks and can generate larger files than the ABR mode.
I seem to go with ABR then when more predictable bitrate/filesize is required for my purposes.

Last edited by kypec; 26th March 2013 at 21:33.
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Old 8th September 2014, 10:37   #45  |  Link
kotuwa
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Quote:
Originally Posted by the_weirdo View Post
q=2 is highest quality. It's also default value.
Why is 2 the highest quality?
Usually Other encoders use lower values for high quality and higher value for lower quality neh!
Like Lame, x264, x265, Xvid etc...
If I did not see this, without knowing I was going to use -q 0
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Old 8th September 2014, 11:31   #46  |  Link
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Because Apple set it that way. Qaac only follows what Apple Coreaudio uses. And you shouldn't really change default values if you don't know what those values mean or you didn't read manual, right?

BTW, with x264/5, Xvid ect... only CRF/QP scale uses lower values for higher quality. Every other setting uses higher value for higher quality (me, subme).
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Old 8th September 2014, 22:14   #47  |  Link
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Quote:
Originally Posted by detmek View Post
BTW, with x264/5, Xvid ect... only CRF/QP scale uses lower values for higher quality. Every other setting uses higher value for higher quality (me, subme).
More close related with LAME vbr quality and encoding quality as it is audio...
in x264 etc most of those things u mention related to number or number range, not quality, so it is being literal...
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Old 8th September 2014, 22:19   #48  |  Link
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hey BTW...
After converting AC3 5.1 into AAC 5.1 M4A using QAAC
it shows
Code:
Channel count                            : 2 channels
Original Channel count                   : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Why it show 2 channels
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Old 8th September 2014, 22:21   #49  |  Link
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Quote:
Originally Posted by kotuwa View Post
hey BTW...
After converting AC3 5.1 into AAC 5.1 M4A using QAAC
it shows
Code:
Channel count                            : 2 channels
Original Channel count                   : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Why it show 2 channels
What application gave you that information?
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Old 8th September 2014, 22:25   #50  |  Link
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MediaInfo, probably. We had a discussion about that recently:
http://www.hydrogenaud.io/forums/ind...dpost&p=867076
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Old 12th September 2014, 19:02   #51  |  Link
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Thanks...
another question, how to swap Left and Right Channels when encoding?
what are the switches?
Is there any way or any tool that can do this in AAC tracks without reencoding?
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Old 12th September 2014, 19:12   #52  |  Link
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Quote:
Originally Posted by kotuwa View Post
another question, how to swap Left and Right Channels when encoding?
what are the switches?
This is specifically mentioned in the documentation, read it!
--chanmap 2,1
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Old 13th September 2014, 03:11   #53  |  Link
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Quote:
Originally Posted by dansrfe View Post
What are the benefits v.s. Nero AAC Encoder?
Well, for one, that it doesn't depend on a 10-year-old Nero 7 package that I just never been able to get working in Windows 7.
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Old 13th September 2014, 09:31   #54  |  Link
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Quote:
Originally Posted by asarian View Post
Well, for one, that it doesn't depend on a 10-year-old Nero 7 package that I just never been able to get working in Windows 7.
What!?
As I know last NeroAACEncoder is released in 2009.
And no need of a nero package... unlike QAAC, single EXE can be downloaded and no extra setup is needed in NeroAACEnc. Nero used to give that exe, but not anymore I think... But easily downloadable from many other websites...
QAAC would be better, but not fro the reasons you mentioned
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Old 13th September 2014, 10:30   #55  |  Link
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QAAC is better than NeroAacEnc at low bitrates (there are test until ~ 96 Kb/s for stereo), with more bitrate the difference can be negligible.
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Old 16th October 2014, 14:21   #56  |  Link
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Quality 96 !!!

Did a QAAC encode using MeGUI. HE-AAC CVBR.
mediainfo shows this
Code:
Writing application                      : qaac 2.44, CoreAudioToolbox 7.9.8.3, AAC-HE Encoder, CVBR 40kbps, Quality 96
What us the Quality 96 part?
What are the other values of this quality?
I know that there is a --quality switch that has 0,1,2 values..
Is this related to it?... probably not...
any switch related to this quality?
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Old 22nd May 2015, 17:13   #57  |  Link
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qaac 2.49

Reminder: Apple was a winner (highest audible quality) amongst AAC encoders according to blind tests. http://listening-tests.hydrogenaud.i...96-a/index.htm

qaac 2.49

Changelog:
Code:
[qaac] release 2.49
posted 2 hours ago by nu 774
Fixed issues on MP4Source:
Fixed handling of Nero style chapters starting from non-zero timestamp (typically inserted by fb2k and old neroaacenc).
Fixed handling of reading MP4 files with multiple elst entries.


[qaac] release 2.48 (refalac 1.48)
posted 10 hours ago by nu 774
Fixed an issue on MP4Source: trailing samples were discarded under certain conditions.


[qaac] release 2.47 (refalac 1.47)
posted 58 minutes ago by nu 774
Large file (>= 4GB) output is now supported. Very long duration (beyond 32bit limit) is also supported, but the latter is not compatible with QuickTime 7.
On very large files, container optimization can take several minutes. You can disable it by --no-optimize.


[qaac] release 2.46 (refalac 1.46)
posted an hour ago by nu 774
Fixed an issue on DLL loading: when a DLL qaac tries to load depends on other missing DLLs, OS was showing a modal dialog which effectively stopped the process until it is closed.
Allow -A option for refalac to be compatible with qaac.


[qaac] release 2.45 (refalac 1.45)
posted 40 minutes ago by nu 774
Added qaac64.exe that works with iTunes 64bit (ver 12.1).
Switched to static C runtime linking. Now you don't need msvcr120.dll and msvcp120.dll anymore.
Minor bug fixes.

Last edited by IgorC; 22nd May 2015 at 17:15.
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Old 22nd May 2015, 21:08   #58  |  Link
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Great to see qaac updated, it is an excellent tool and I use it regularly.
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Old 23rd May 2015, 10:02   #59  |  Link
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Quote:
Originally Posted by IgorC View Post
Reminder: Apple was a winner (highest audible quality) amongst AAC encoders according to blind tests.
At 96 kbps.
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Old 24th May 2015, 11:46   #60  |  Link
foxyshadis
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Quote:
Originally Posted by IgorC View Post
Reminder: Apple was a winner (highest audible quality) amongst AAC encoders according to blind tests. http://listening-tests.hydrogenaud.i...96-a/index.htm
FDK is considered higher quality now. Still, Apple AAC is extremely close, no harm using it, especially at 128 and up.
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