Project announcement : New opensource AAC DirectShow filter, hosted on corecodec.org

[Nic]

I remember the old days when I even had my name on the developers list of FAAC and was discussing improving its huffman bugs, and Ivan was barely releasing more than an improved ISO reference version of AACEnc? Do you reckon, I could get one with thoughts of nostalgia?....

...Nah, I didn't think so either.lol.

-Nic

[bond]

now the sbr code is here (under gpl )!!!

go toff go


read menno's post on ha here (down atm)
johnv's announcement on doom9 is here

[Wilbert]

Roberto compiled a new FAAC (still without sbr code I guess, but with the channel remapping bug corrected): http://64.246.62.80/~hydrogenaudio.o...howtopic=11494
Guess he didn't update the version number on the RareWares site

[bond]

Originally posted by Wilbert
still without sbr code I guess

the sbr code will only be available for the decoder side!

[[Toff]]

The CoreAAC code is now in CVS and support SBR.
It's not tested a lot (for example channel remapping) and so probably not bug proof

a temporary experimental build is available here

CoreAAC_1.0b4_20030729-1.exe
CoreAAC_1.0b4_20030729-1.zip

[bond]

great!

downmix to stereo works great
sbr decoding seems to work also

the bitrate isnt shown correctly -> 220kbps although sbr file at 65kbps...
the zip file isnt downloadable

sorry i cant say anything about channel remapping

[[Toff]]

Originally posted by bond

the bitrate isnt shown correctly -> 220kbps although sbr file at 65kbps...
the zip file isnt downloadable
sorry i cant say anything about channel remapping

Thanks,
Yes, bitrate display is wrong for sbr, i will fix that later, i still collect bug .
Thz zip link should be fixed now.

[bond]

just some small "optical" things:

1) perhaps it would look better if you the downmix option would show up under a "settings sub-headline" in the info tab like in corevorbis
i dont know if there is also postgain available for aac like for vorbis?
2) under about tab, after faad2 2.0 rc1 there seem to be too much spaces before the "-"
3) it seems that the info and the about tab dont have the same height, you can see that when you switch between the two

as i said nothing really important...

[rjamorim]

Winamp plugin and command line decoder, for anyone interested:

http://pessoal.onda.com.br/rjamorim/in_mp4.exe
http://pessoal.onda.com.br/rjamorim/faad.zip

[hans-jürgen]

Originally posted by Wilbert
Roberto compiled a new FAAC (still without sbr code I guess, but with the channel remapping bug corrected): http://64.246.62.80/~hydrogenaudio.o...howtopic=11494
Guess he didn't update the version number on the RareWares site

The related bugfix happened on July 21, 2003 and the current FAAC version is still 1.18, because knik didn't update the number. This means that direct transcoding from AC-3 when combined with foobar2000 is possible now, and the -I switch is not needed, because foo_ac3.dll already reorders the channels to a 5.1 WAV layout which is the default mapping in FAAC 1.18. See also this thread:

http://forum.doom9.org/showthread.ph...0&pagenumber=3

SBR won't be implemented in FAAC (the open source encoder) as long as no one takes a look at the ISO reference software and specifications for MPEG-4 HE AAC (when available) and tries it...

[bond]

one more thing about the info tab:

i mentioned that when the downmix option is ticked it is always shown that the aac streams have 2 channels (even if they have 6 channels)
i think it would be better if always 6 channels are shown under the info tab when a 6 channel file is used (even if they get downmixed)...

[Herske]

Hello all,

I read this thread carefully but I still do not know how to extract the *correct* HE .aac out of mp4 container.

I have tried:
-mp4ui 0.95 - the extracted HE .aac file is recognised as LC in foobar2k and winamp

-mp4creator60 (v0.9.8.6 ) - the same problem.

I'm using the SBR decoders for both winamp and foobar, the .mp4 file plays perfectly; I've also tried forcing mpeg-4 conversion, in mp4creator and mp4ui: still no luck.

Thanks in advance for any help,
/herske.

[rjamorim]

MPEG4ip still doesn't recognize HE AAC. That's why it doesn't work well with this profile.

[CruNcher]

@Herske

Nero has buildin .aac creation you have to activate the checkbox that says Export to ISO AAC file and then also a .aac file is created.

[Herske]

Thanks for the replies.

Cruncher, I tried this, and the .aac file is still reported (in foobar 2k) as being LC instead of HE.

So, is it any way to mux HE files in mkv?

Thanks,
/herske.

[tiki4]

Hi there,

I got a serial for Nero 6 some days ago and have the same problem. It seems that even Nero exports a LC AAC file and just strips off the SBR part of the file (Menno?). However, there is a rather simple way to mux your files if you are a little bit experienced with Graphedit. Just install the 3ivx codec from 3ivx.com. This codec comes with a MP4 splitter filter (I think this was mentioned before). Now render your HE-AAC-MP4 files in Graphedit, remove the CoreAAC and DirectSound output filters and connect the pin of the MP4 splitter with Gabest's MatroskaMuxer and that one with the FileWriter. I tried this with the Ogg Muxer from Tobias and it plays perfectly. This is not the most newbie friendly solution at the moment, but I think Koepi and Nic will come up with a solution shortly.

Regards,

tiki4

[[Toff]]

Don't forget that HE AAC is still backward compatible.
A decoder that can't handle the SBR part will still decode the AAC LC part of the file. So make sure that the decoder you use support SBR or you file will be seen as a classic AAC LC file.

Also it's not possible to detect if a .aac file has SBR information or not in it without decoding it (there is no information in the headers about SBR). So if foobar display the file information before decoding it will probably show AAC LC.

About matroska, there is the same problem at the muxer level, currently mkvmerge makes no difference between AAC LC and HE AAC. It use the same ID. The current version of CoreAAC will not handle that correctly (dshow need to know the output sample rate before decoding). I have now a version that works using a little tricks but we are still discussing the use of a different ID.

[Nic]

@Toff: Could you please state some more info on this (the tricks your using, etc)? Else ill catch you on IRC and talk more about it (when you say ID are you refering to the same kind of ID you get in ADTS headers?) (Thanks alot )

@Tiki: At worst, ill have to wait to see how mkvmerge does it, then do it the same way, but ill look into it tonight

-Nic

[Herske]

Toff: I was using the correct SBR decoders, it was the first thing I checked.


Great advice, tiki, it worked perfectly. The resulting .aac files plays ok with CoreAAC, which recognises it corectly as having SBR.

PS. Foobar 2k and winamp can't play the resulting file, error: "Max number of scalefactor bands exceeded" and mkvmerge doesn't recognise the resulting .aac file, but I have finally managed to mux everything correctly using Graphedit and MatroskaMuxer filter form Gabest.

[tiki4]

@[Toff]:

Now I'm a little bit confused:

Does that mean that Nero 6 exports AAC files with MPEG-2 ADTS headers (where high efficiency profile isn't defined) that still contain the SBR information but e.g. the new Winamp 2 plugin compiled by John33 doesn't see the SBR content of the file because, well, because of what? I tried to mux such a file that was exported by Nero but the resulting video wasn't decoded with SBR by CoreAAC. Really confusing

However, the Graphedit method is working, we'd just need a MP4 parser filter independent from 3ivx, so that CVS OggMux just has to build a filter graph. As I said, it works perfectly when demuxed with the MP4 splitter and muxed into OGM or Matroska via DirectShow.

Regards,

tiki4