Multi Ch. AAC in Quicktime

[rtjnyoface]

Is it possible to export multi-channel aac in quicktime pro? My source is 5 channel and every time I export all the multi-channel options are greyed out.

Wav-> Export-> movie to QT movie-> options-> sound settings:

AAC format-> (only mono and stereo, all other options greyed out)-> AAC VBR

Any help is appreciated. I tried looking for answers but maybe the rest of you are using nero_aac who knows. I was just testing out QT encoding.

:thanks:

[juGGaKNot]

testing out QT encoding.


Why do you need audio for that ?

render wav/aac and try to mux if it is allowed.

[Skelsgard]

What can be done with Quicktime in Windows:
- you can open a QT movie with multichannel (mc) aac and play mc if it was made by a Mac (awesome, right?)
- you can open a QT movie with mc aac and "Save as" another .mov and file will play mc
- you can open a QT movie with mc aac and "Export" to .mov with 5.1 AAC options and file will play mc
- you can open an ADTS AAC file in QT and "Save as" MOV and it will play mc
- you can open a multichannel WAVE_EXT wav file and encode to 5.1 AAC in MOV and this file will play mc

What can NOT be done:
- you can't mux multichannel AAC into MP4 and play in QT
- you can't mux multichannel AAC into MP4, export to MOV with QT and then play that MOV in QT (there will be no sound)
-- basically, no mc support for MP4 files. Go figure...
- you can't open a multichannel PCM wav file and encode to mc AAC in MOV (it doesn't let you choose 5.1 aac)
- you can't mux raw h.264 and raw aac to "Save as" to MOV, there's no multiplexing capacity in QT.

neroaacenc is the best choice for AAC encoding anyway

[rtjnyoface]

neroaacenc is the best choice for AAC encoding anyway
Are those results posted somewhere that I've yet to see? Even at VBR?
I thought we were supposed to stay away from such defining statements?

you can open a multichannel WAVE_EXT wav file and encode to 5.1 AAC in MOV and this file will play mc

So is wave_ext wav different from a pcm wave file? If that is the case can I somehow demux my original vob's to wave_ext? I don't think so but maybe you know of a way.

My goal is to take my original ac3 file (typically demuxed from the vob's in wav but doesn't have to be) and encode it via quicktime 5.1 AAC. Is that possible? If it's not I don't mind I just wish to know.

It would be great to see those results if they are posted somewhere as encoding in QT I would certainly reconsider.

Thanks for the replies guys.

[Skelsgard]

Are those results posted somewhere that I've yet to see? Even at VBR?
I thought we were supposed to stay away from such defining statements?

You're right, "best" is a cursed word around this parts.
Let's say that it offers more features than others, (FAAC can't encode HE and it hasn't been optimized for a while, just some minor bug fixes), I don't know if ppl are stil using Winamp's CT encoder which was suppossed to be good too, and Quicktime is a pain in the ass to use (it supports no piping so you have to have the file in your HDD (4 Gb for a 2hs 6ch track), has very limited options for source like I said: only WAVE_EXT files).
It's only my opinion, nothing objective I can provide for you.

Yes, it can be done, you'll have to decode the AC3 track to an interleaved 6ch WAV, then make sure is a WAVE_EXT file, or if not, process it to be one, and then load it into QT for encoding.
For most ppl it would be a hassle as with piping you can chain a good ac3 decoder with neroaacenc and it all get done on the fly, without a huge intermediate WAV file (in case of movies of course).
PCM has no header information for multichannel whereas WAVE_EXT allows for setting which type of channel mapping the file has: L-R-C-LFE-SL-SR, L-R-C-LFE-BL-BR, L-R-C-LFE-SL-SR-BL-BR (in 7.1 files), etc, etc (I believe it also allows for wav files to be bigger than 4Gb without hack but I'm not sure about that)
But if your interested you can decode the ac3 track with eac3to which will produce a WAVE_EXT compatible file that you can load into QT for AAC 531 encoding.

[rtjnyoface]

Wow. I apparently seem incompetent to the lot of you who've answered my question. Yes I did use the search (as well as using google to search doom9) and I came up with pretty much nothing. I did it again today and I still only came up with 1 real result and it was this thread. Maybe it was the way I was typing it in though (dvd-audio).

Anyhoo, thanks for the responses guys, regardless of how condescending may have been

[Skelsgard]

Wow. I apparently seem incompetent to the lot of you who've answered my question. Yes I did use the search (as well as using google to search doom9) and I came up with pretty much nothing. I did it again today and I still only came up with 1 real result and it was this thread. Maybe it was the way I was typing it in though (dvd-audio).

Anyhoo, thanks for the responses guys, regardless of how condescending may have been

Uhh... what?

[SeeMoreDigital]

What can NOT be done:
- you can't mux multichannel AAC into MP4 and play in QT
- you can't mux multichannel AAC into MP4, export to MOV with QT and then play that MOV in QT (there will be no sound)
-- basically, no mc support for MP4 files. Go figure...
- you can't open a multichannel PCM wav file and encode to mc AAC in MOV (it doesn't let you choose 5.1 aac)Actually.... "you can" do these things!

Here's a QT sample with 6Ch AAC audio: -

http://www.one.seemoredigital.net/Downloads/MPEG-4_with_6Ch_AAC-LC_in_MOV.7z


Cheers

[rtjnyoface]

Uh...what?

Sorry skelgard, maybe I should have added a smiley or something. Didn't mean to sound as though I really didn't appreciate the help. The whole internet thing really takes away a lot of what we miss during face to face communication. I really do appreciate the time you've taken to respond and the length at which you have responded. :)

[Skelsgard]

Actually.... "you can" do these things!

Here's a QT sample with 6Ch AAC audio: -

http://www.one.seemoredigital.net/Downloads/MPEG-4_with_6Ch_AAC-LC_in_MOV.7z


Cheers

Edited: my bad, apparently my version of QT was buggy or something cause after I updated to the latest version (7.6.2), MP4 files are playing properly with multichannel AAC audio.
Still, no multichannel PCM WAV are accepted for 5.1 encoding.
So it should be like this:
What can NOT be done:
- you can't open a multichannel PCM wav file and encode to mc AAC in MOV (it doesn't let you choose 5.1 aac)
- you can't mux raw h.264 and raw aac to "Save as" to MOV, there's no multiplexing capacity in QT.
- you can't export audio as AAC 5.1 when exporting to MP4 in QT.

[rtjnyoface]

Unsure if I should start another thread for this but when we encode 5.1 audio to 5.1 AAC how the heck do we choose a bit rate? I would like to have a bit rate of around 250 but I'll enter .66 ( vbr ~250) and I'll get some outrageous bit rate. Alright.

So then I then thought I would have to divide 250/6 (with an assumption that the bit rate set would be the bit rate of one channel) but that doesn't give me an av. bit rate of 250 either.

I've used belight, megui, and another small program specifically designed for using nero aac. I assume this is user error but I am unsure. And for the record, I've used the search function ;).

[b66pak]

use neroaacenc:

http://forum.doom9.org/showthread.php?t=141380


Usage:
neroaacenc [options] -if <input-file> -of <output-file>
Where:
<input-file> : Path to source file to encode.
The file must be in Microsoft WAV format and contain PCM data.
Specify - to encode from stdin.
Note that multiple input files can be specified, they will be
encoded together into a single output file with chapter marks
indicating source file divisions.
<output-file> : Path to output file to encode to, in MP4 format.

==== Available options: ====

Quality/bitrate control:
-q <number> : Enables "target quality" mode.
<number> is a floating-point number in 0...1 range.
-br <number> : Specifies "target bitrate" mode.
<number> is target bitrate in bits per second.
-cbr <number> : Specifies "target bitrate (streaming)" mode.
<number> is target bitrate in bits per second.
When neither of above quality/bitrate options is used,
the encoder defaults to equivalent of -q 0.5

Multipass encoding:
-2pass : Enables two-pass encoding mode.
Note that two-pass more requires a physical file as input,
rather than stdin.
-2passperiod : Overrides two-pass encoding bitrate averaging period,
<number> : in milliseconds.
: Specify zero to use least restrictive value possible (default).

Advanced features / troubleshooting:
-lc : Forces use of LC AAC profile (HE features disabled)
-he : Forces use of HE AAC profile (HEv2 features disabled)
-hev2 : Forces use of HEv2 AAC profile
Note that the above switches (-lc, -he, -hev2) should not be
used; optimal AAC profile is automatically determined from
quality/bitrate settings when no override is specified.
-ignorelength : Ignores length signaled by WAV headers of input file.
Useful for certain frontends using stdin.


example: 2pass encoding@256kb/sec

neroaacenc -2pass -br 256000 -ignorelength -if audio.wav -of audio.mp4

example: 1pass quality encoding

neroaacenc -q 0.66 -ignorelength -if audio.wav -of audio.mp4
_

[rtjnyoface]

Use neroaacenc.

Ya. I have been. And I understand the process of using it but I don't see how your reply answers my question.

[b66pak]

Unsure if I should start another thread for this but when we encode 5.1 audio to 5.1 AAC how the heck do we choose a bit rate?


answer:

-br <number> : Specifies "target bitrate" mode. <number> is target bitrate in bits per second.
_

[rtjnyoface]

Ah. I understand what part of the question you are answering (sorry if it seemed like there were more than one question).

My dilemma is that I want to encode 5.1 CA3 to 5.1 aac. Now, yes I understand how to physically choose a bit rate but I should say that my intended question/dilemma is:

I choose a bit rate say... in megui. If I choose that bit rate I get an insanely larger bit rate in the final file and a large file. So if I choose 250 I would end up with a file that has a bit rate of around 900 or something. SO... that's why I was wondering if the bit rate is just for one channel by itself or something strange like that.

So, my expected process is to choose a vbr and have the bit rate for the final file be around that br. BUT....what I get is a file that has a bit rate of like 5x the bit rate I entered and is insanely large.

Have I been clear enough cuz I'm still unsure?

[tebasuna51]

To recode ac3 to aac y suggest you use -q 0.31 to -q 0.35
Less than 0.31 the SBR part is used (HHE can be NOT compatible with some players) and more than 0.35 you can obtain bigger size than original ac3.

[rtjnyoface]

To recode ac3 to aac y suggest you use -q 0.31 to -q 0.35

I used .47 and got the results I wanted. Problem is I had to encode about 5 times to get it right.

Less than 0.31 the SBR part is used (HHE can be NOT compatible with some players)

Won't be using it on a hardware player if that's what you are suggesting (wouldn't use HE anyways).

more than 0.35 you can obtain bigger size than original ac3.

Used .47 and got a file the same bit rate but a 30% smaller file. Explain that I guess. That's what my confusion is about. For one I have to encode, adjust, reencode, adjust, reencode, etc. What I would like is to enter the br that I want and get a file near the br I specified instead of playing this crazy guessing and reconfiguring game. I could swear it must be something that I'm doing. No one else seems to have this issue.

[SeeMoreDigital]

- you can't open a multichannel PCM wav file and encode to mc AAC in MOV (it doesn't let you choose 5.1 aac)You can. But the 6Ch PCM in WAV source has to be QT7 friendly. Here's a compatible 6Ch PCM in WAV sample (http://www.one.seemoredigital.net/Downloads/6Ch_PCM_in_WAV_5sec).

- you can't mux raw h.264 and raw aac to "Save as" to MOV, there's no multiplexing capacity in QT.Yep... This is correct.

- you can't export audio as AAC 5.1 when exporting to MP4 in QT.You can. QT7 does however produce some confusing info: -

http://i25.tinypic.com/1zewapz.png

Never-the-less, the resulting .MP4 file does contain 6Ch AAC. Try it yourself using the sample in my previous post.


Cheers