aac directshow

[ivan_alias]

What does it take to write a directshow filter for aac? Is anyone working on this?

[DSPguru]

Originally posted by ivan_alias
What does it take to write a directshow filter for aac? Is anyone working on this? it's (somewhere, in the middle) in my to-do list.

AAC have become my favorite compression standard and i plan to release more and more tools related to this.
first tool would be AACGain (soon;)).
then, with the help of good friends (:)), a DSF.

[ivan_alias]

Cool - I look forward to that.

What else is on your to-do list? Or is it a secret or a surprise ;)

[DSPguru]

it's endless :D

[bbq@KL]

http://arbor.ee.ntu.edu.tw/~jackei/projectbsd/index.html

AAC Directshow Filter & WAV Wrapper
http://arbor.ee.ntu.edu.tw/~jackei/projectbsd/AAC2WAV.zip

[Nic]

I wrote the AAC stuff hosted at Jackei's & it is not recommended at the moment...

...Im giving the sourcecode (if I can find it ;) ) to DSPguru, & hopefully he will have better luck :)

-Nic

[tiki4]

@Nic, DSPguru:

You give me a happy day :D

I'm looking forward...

Regards,

tiki4

[ivan_alias]

"Nudge"

Guys, has this one gone onto the back burner? There is so much great development going on here with all the fantastic tools talked about on these forums, I'm sure it can get lost. :(

Is anyone working on a new aac directshow filter? If all is to believed aac should be able to bring some really good 5.1 sound to even 1 CD rips soon :)

[iago]

I totally share the same feelings as tiki4! ;)
Go Nic and DSPguru! ;)

regards,
iago

[symonjfox]

I made some testing with FAAC 2 and Psytel AAC encoders, but I have to say that the output files weren't better than the same files encoded with LAME (same input and some settings).

I think that first should be a COOL ENCODER (as LAME is for MP3), and then a cool decoder, don't you think so? If MP3 quality is better than the same in AAC, why should I use it?

I know that AAC is just at its beginning and there are many many things to do before it become the best audio format.

[ivan_alias]

I was thinking of AAC because of its multi-channel support. MP3 is limited to 2 channels really. (I know you can get DPL2 downmix etc..)

[symonjfox]

Yes, me too.

I'd like to use AAC to create MPEG4 files (I know that MP3 is supported too).
I think we must wait some time before using AAC multichannel muxed in MPEG4 file, because I tried make some, but there's no MPEG4 player that works fine.

I created Xvid or DivX video files, nowadays player just support MPEG 4 SIMPLE PROFILE (so no B-frames, no QPEL GMC or other).

Then I created the AAC sound file, many problems: 90% plays correctly the LOW COMPLEXITY AAC (only) and 10% the NORMAL profile. Where is the Long Time Prediction (which is supposted to give better quality)?

Then some MP4 files are played/opened only by some applications, while other MP4 are played/opened by other applications having the same proprieties-settings. A mistery of my computer :scared:

I hope future filters/players will play everything :)

[BoNz1]

@symonjfox, have you tried the 3ivx mp4 filters? I have made number of files using b-frames, gmc, 1/4 pixel, and 2ch aac that played back fine with their filters. Right now it is probably the best solution for this kind of thing IMHO. There is no support for multichannel aac yet, but I am told that in future releases that they plan to support it. I would use LC when creating your aac files, LTP prediction is less complex than the main profile but offers about the same quality however it isn't widely supported, better to stick with LC, IMO.

[symonjfox]

I installed 3ivx just for evaluate the video quality (that is nice just at low bitrates, else Xvid is better). I haven't tried it yet for MP4 files.

Then I can't mux 3ivX files in MP4 container because MP4UI doesn't accept it.

Do you really think that Main AAC is better than LTP AAC?
I read somewhere that first standalone AAC players will just support Low complexity, is it true? So is it better to use LC instead of Main?

[tiki4]

@symonjfox:

Have a look over to hydrogenaudio.org about your questions regarding LowComplexity and Main Profile. The author of Psytel AAC Encoder and now the Nero MP4 Plugin, Ivan Dimkovitch, states there that there is no real advantage of things like Long Term Prediction and other fancy stuff. I can't give you a direct link but just do a short search in the AAC forum. For now it seems best to stick with LC profile until something like SBC comes to AAC (-> AAC+). Maybe one day we see encoders and decoders for that. Otherwise, I'm only interested in AAC when there will be a multichannel decoder. Maybe on the long term Ogg Vorbis is faster to implement channel coupling, so the need for AAC will vanish. However one can have MC AAC with aacenc.exe and AACMachine. You just cannot decode it. So what is the point of having it? DSPGuru himself said somewhere that AAC is at the moment the best format for MC audio, but for the moment it is just not possible to make use of that:(

Cheers,

tiki4

[symonjfox]

ok, thanks you very much :D

[rjamorim]

Originally posted by symonjfox
Do you really think that Main AAC is better than LTP AAC?

Not in Psytel AACenc. Psytel's main profile is very buggy, and should NEVER be used.

[rjamorim]

Originally posted by tiki4
However one can have MC AAC with aacenc.exe and AACMachine. You just cannot decode it. So what is the point of having it?

You can decode AAC MC with MPEG4ip player.

But only that, ATM. :(

It would be great if someone made a directshow AAC filter with FAAD2. I'm not sure if Nic's (made with FAAD1) supports MC.

Regards;

Roberto.

[acki]

Hi all, this is my first post.


I'm one of those that coudln't play AAC MC files.
The main reason in my case, was that I have a regular
stereo card, so I started writting my own player.

Copy-pasting here, ripping code there, and adding
some more code of my own I came up with a small
*alfa* player for AAC MC for stereo soundcards (via
channel downmix, of course)

It works, but it's still _VERY_ alpha.

Also, a DS filter is in its way...

If someone is interested I'll post a link for D/L



Acki.

[rjamorim]

Originally posted by acki
Copy-pasting here, ripping code there, and adding
some more code of my own I came up with a small
*alfa* player for AAC MC for stereo soundcards (via
channel downmix, of course)

It works, but it's still _VERY_ alpha.

Is it based on FAAD2?

Also, a DS filter is in its way...

Great!
Maybe you can try to merge this filter with Valex's ac3 filter (http://ac3filter.sourceforge.net/)?

I believe it would be great to have one filter that handles most used audio formats. (I'm still wishing for MAD implementation in that filter too)

If someone is interested I'll post a link for D/L

Yes, I would love to check it out. Thanks. :)

Regards;

Roberto.

[MaTTeR]

Originally posted by rjamorim
(I'm still wishing for MAD implementation in that filter too) Indeed that would be an excellent idea:) Has this idea been mentioned to Valex yet?

Having a "super filter" of sorts that supported all these codecs (in some fashion) would be a wish come true.

[rjamorim]

Originally posted by MaTTeR
Indeed that would be an excellent idea:) Has this idea been mentioned to Valex yet?

http://forum.doom9.org/showthread.php?s=&threadid=39351

[ak]

There (http://www.borgtech.org/aacdec) is one.
Although, naturally, they don't distribute binaries and:
The decoder is actually a wrapper to a faad2 decoding library.
[...]
This program is released under GNU license.
[...]
Please note that this filter is designed to cooperate with mpx project.
It probably will not work with AVIs, even if there was a way to put an AAC audio in AVI files, which generally is not a good idea (waste of space, just like VBR MP3). [:D]

[Nic]

There's an installer in the source code download :)

-Nic

ps
3ivx's AAC mpeg-4 audio dshow filter is also a wrapper around faad.

pps
And id never heard of the mpx file format until I saw that either.
(good link :) )

[ak]

Originally posted by Nic
There's an installer in the source code download :)

There is, lol... Never thought they dare to put it in package.

And id never heard of the mpx file format until I saw that either.
Me either, in fact I was looking for TV app there.:D

[acki]

I've tried that filter myself... couldn't get a single
"mpx" file with aac audio to work. No sound at all.

Acki.

[rjamorim]

Originally posted by ak
There is, lol... Never thought they dare to put it in package.

It seems to me that Dolby doesn't cares that much about AAC decoder binaries anymore.

It's been almost an year since I last got something like this (http://www.inf.ufpr.br/~rja00/Dolby.txt)

I've heard that even the AAC licensing now allows license-free usage on freeware players/decoders. But I didn't check that.

[The Link]

I don´t use AAC yet but perhaps there are some people who are interested in this: http://www.borgtech.org/aacdec/

It was said that this one is different from Nic´s filter (not on that page). Perhaps some people want to test it.
If this is nothing new to you, please excuse this post!

Regards,

The Link

P.S.: On the same site there´s a new file format called mpx (including a dshow filter) I´ve never heard about ...