Multimedia dedicated weblog.


April 20th, 2008 Posted in Free Software


yet another small fix. Thanks goes to clsid for reporting this bug. Output of the decoder got screwed when output mixing was active and you switched audio streams with different number of channels.

Download : (280 KB)


  1. 51 Responses to “MONOGRAM AAC Decoder”

  2. By Paul Kendall on Apr 23, 2008

    Will you be posting the source to this wrapper.
    I would like to convert it to a simple faad2 wrapper for linux so it can be used my the MythTV project for DVB-T in New Zealand & Norway etc.


  3. By Igor Janos on Apr 23, 2008

    Sure. The filter is available in the SVN repository. You can either access it via web interface by clicking the “SVN Repository” link in the right sidebar or check out the source with

    svn co svn://


  4. By Paul Kendall on Apr 23, 2008

    Awesome, thanks Igor.
    I have taken the 0.9.0 and hacked it up into a simple filter that can be used by MythTV and it seems to be working great.
    What I have to do now is get it to auto-detect LATM and unwrap or ignore.


  5. By Sina™ on May 7, 2008

    What’s the version of FAAD?

  6. By Igor Janos on May 7, 2008

    The latest from
    I think it says 2.6.1.

  7. By Sina™ on May 8, 2008

    OK, do you have a public email?

  8. By Igor Janos on May 8, 2008

    Sure. should be quite simple to figure out - my surname $a-t@ monogram !@#4 sk

  9. By Sina™ on May 8, 2008

    What’s this mail?
    Did you checked your Hydrogen Audio ID?

  10. By Igor Janos on May 9, 2008

    I did not receive any mails from hydrogen. I suppose it’s directed to some of my old email addresses. Gonna go check for that.

    My current mail is janos -#2# monogram !@# sk

  11. By Sina™ on May 9, 2008

    [Edited by Janos]
    Yes. The mail is correct. but I would not like to have it this way on the web. I’m really glad I don’t receive much spam :)

    Your products is good.
    So, could you please help Adobe Audition users?
    I bought Audition 3 & it’s very expensive.
    Audition doesn’t support AMR file format.
    It suffer all Audition users.

    Could you please develop AMR plug-in base on these sources?:

    VoiceAge Open AMR Implementation

    Audition 3.0 SDK (ZIP, 421.5 KB)

    Audition SDK ReadMe (PDF , 15k )

  12. By Igor Janos on May 9, 2008

    I’ve downloaded the trial version of Audition. If it’s not very complicated I think I could do it.

  13. By Sina™ on May 9, 2008


  14. By Sina™ on May 9, 2008

    Sorry for email.☺☺
    Also, Audition is a high-end audio editor/converter.

  15. By Igor Janos on May 10, 2008

    Hey. AMR decoding works now with audition. Do you also need encoding support ?

  16. By Sina™ on May 10, 2008

    You did it?
    You R♂cks…
    I don’t need to encoding, but some people needs it.☺
    It can be great if it support encoding like all filters in Audition.☺
    Did you used VoiceAge Open AMR Implementation?

  17. By Igor Janos on May 10, 2008

    I’ve added also encoding support. Follow this link to get the plugin :

    No. I did not use the Open AMR implementation.

  18. By sdxy on Jul 7, 2008

    When decoding AAC 5.1 and mixing to 2 channels, this aac decoder seems not work very well.
    most of the person sound is out from the left speaker.

  19. By Francesco on Sep 27, 2008

    Using your AAC Decoder, I can’t get audio decoded from a DVB-T stream with H264 video & Raw AAC with ADTS.
    I can give you a link on such video if you’re interested in fixing it.

  20. By Russell B on Oct 8, 2008

    Hello Igor,

    I am trying to use the “x264vfw - H.264/MPEG-4 AVC” codec which is a directshow filter.I need to programmatically configure this filter. So I was wondering if you knew what the COM interface of this filter looks like, something that I can use a CoCreateInstance function on? I know your GraphStudio tool knows how to code it.

    Thank you very much in advance for your time and help.

    Russell B.

  21. By Igor Janos on Oct 9, 2008

    VFW codecs are not “real directshow filters”. They are used as “plugins” in a VFW wrapper filter. GraphStudio cannot really control them in a direct way. It can only display the property page of the VFW-wrapped codec and let it configure itself. There are also no interfaces that you could use to configure specific parameters such as bitrate or keyframe interval directly to a VFW-wrapped codec.

  22. By Russell B on Oct 9, 2008

    Thanks. That’s good to know. I noticed the VFW codec has a DriverProc() and a Configure() entry point which I can probably call using refelction to set it up.

  23. By Sergio on Oct 18, 2008

    I have some capture streams of ISDB-Tb 1seg Brazil digital television. TS with h264 and LATM/LOAS AAC. I´m using elecard demuxer (outputs the AAC stream as LATM AAC stream), elecard LATM demuxer and elecard aac decoder to output audio. With the mpeg demuxer/latm demuxer combination of elecard, any aac decoder works, except the monogram decoder. Without the latm demuxer, the monogram decoder also refuses to connect. What´s worng?

    Test stream:

  24. By Skelsgard on Nov 6, 2008

    I’ve tested your AAC decoder with an 8-channel speaker test encoded with Neroaacenc and although the decoding is flawless, the mapping is incorrect.
    As of latest version (9.0.5 beta), to get the right mapping the wav source must have this order: FR-FC-FL-SR-RL-RR-LFE-SL.
    Mappings are also wrong for 5.1 audio, but I haven´t tested what channel order is necessary. Is not an encoder problem as ffdshow and others decode 5.1 without mapping problems.
    I hope your still working on this decoder as it is a great answer to the hassle of getting and installing crappy Nero-9-ultra-heavy-all-in-one-bundle-of-bloatware just for the dec filters.

  25. By Skelsgard on Nov 6, 2008

    Sorry, right order for 8-channel wav is this: FR-FC-FL-SR-RR-SL-LFE-RL.

  26. By Skelsgard on Nov 6, 2008

  27. By Igor Janos on Nov 6, 2008

    Thanks for the info. I’ll try to make it work. However I’m quite busy with lot of things. Best thing you can do is to buzz me from time to time if the update doesn’t come in the next few days :)

  28. By Nathan Plez on Dec 16, 2008

    I am also interested in a version which can properly decode 8 channel aac audio encoded with nero’s encoder. The current version is so close… please let me know when the update is made.

  29. By Nick on Dec 30, 2008

    How does this compare with CoreAAC? Does it have feature parity?

  30. By Igor Janos on Dec 30, 2008

    Basically this filter can do all CoreAAC can and also something more - mainly it can decode LATM encapsulated streams. Also CoreAAC appears not to be in development anymore.

  31. By MatMaul on Jan 13, 2009

    hello !
    I think I found a bug.
    When I use your decoder with MPC and his audio switcher activated the audio sounds bad.
    I don’t have this problem with other aac decoders (ffdshow, elecard).
    it works if I put the ffdshow audio processor between your decoder and the audio switcher.

    thanks in advance !

  32. By Igor Janos on Jan 13, 2009

    Is it possible for you to upload a small sample video for me where this problem appears?

  33. By MatMaul on Jan 13, 2009

    here is a sample :
    this sample have 3 aac audio tracks, one 6ch sbr, one 6ch lc and one 2ch sbr+ps.
    same wrong accelerate audio for the 3 tracks.

    seems like the problem comes from 6ch because if I remux it and keep only the 2ch track it works fine but if I switch to the 2ch track in the multitrack sample I have the problem.

    and using the internal mixer of your filter to downmix to 2ch fix the problem too.

    the type of audio is also wrongly reported (LC instead of HE) but it is not a big deal.

  34. By Igor Janos on Jan 13, 2009


    I’m having problems downloading the file. The server appears not responding.

    I have also received several more reports regarding the AAC decoder so I’m hoping for a new release sometime during the next week.

  35. By MatMaul on Jan 13, 2009

    sorry, the server was down (first time in a month, you are lucky :P )
    Should be ok now

    I can’t wait to test the new version :)

  36. By leon58 on Jan 19, 2009

    Hello Igor:
    I downloaded your AAC-Decoder and tried to compile on MS2008, however, I encountered linking error as below
    Error 2 error LNK2001: unresolved external symbol _FilterDllMain decoder_aac

    could you give me a help ? thx

  37. By Igor Janos on Jan 19, 2009

    That’s because I’m using my own build of the baseclasses library.
    Follow this link :

  38. By leon58 on Jan 19, 2009

    Got it. thx

  39. By leon58 on Jan 20, 2009

    Hi Igor:
    I successfully compiled aac_dec project through ms2008 by adding FilterDllMain as your article above. unfortunately, when I tried to decode HE-AAC audio (TS, MS-DEMUX), it failed. As this reason, I was wondering whether this problem is caused by my compliation. so, I used the ax file resided in you binaries folder to replace the one I generated. But the result is the same (failed). The problem can be fixed by the ax file you provided in this article.
    Is there any different between these 2 filters ?

    thx, for you reading anyway :)

  40. By leon58 on Jan 20, 2009

    BTW, I used Rlease-MFC-Static version

  41. By Igor Janos on Jan 20, 2009

    It might be possible that I have commited several minor revisions when compared to the version. But I believe your problem is caused by either a bug/not-implemented-feature or by the format of the extradata. In any case I’m about to do a major update so if you can upload the problematic file for me I would be thankful.

  42. By leon58 on Jan 20, 2009

    Okay, The transport stream is mpeg-2, video format is H.264, Audio is HE-AAC. but the file is about 30 MB. where should I upload to ?


  43. By Igor Janos on Jan 20, 2009

    Perhaps zip it into several smaller files and email them to me. use janos $@! monogram $$.dot.#@ sk

  44. By leon58 on Jan 20, 2009

    Hi Igor:
    The e-mail address u posted above cannot be displayed properly. what displayed on my monitor is janos $@! monogram $$.dot.#@ sk

    it seemes to be some problem with it :(

  45. By Igor Janos on Jan 20, 2009

    Yes that’s exactly my point. I don’t want spambots to flood my server. You should be able to assemble my email address easily.

  46. By leon58 on Jan 20, 2009

    Ha ! I got it. I will sent you immediately.
    BTW, I have traced the source code on your svc. where the problem is probably occured in PayloadLengthInfo function. U might take a look. or could you plz release the source code of aac decoder the same in this article ?I used the decoder in this article can work with my TS.
    Actually, what I want to implement is a filter can take LATM header off. As this reason, I may modify your decoder or create a new one but add your function in my new filter. anyway, you website really helpful for me :)

  47. By Medp7060 on Jan 22, 2009

    To decode aac LATM is much appreciated and looking forward to you new release.

  48. By Skelsgard on Mar 3, 2009

    Any updates on the mapping issue? Or a new version with a fix?

  49. By Cheng on Mar 8, 2009

    Hi,I used “KMPlayer” including
    “MONOGRAM AAC Decoder″ to play the file:
    When I played the file and pushed “Tab” button to see the message of it, input audio format was 2ch 44100Hz, output audio format was still 2ch 44100Hz.

    But if I played the file:
    Input audio format is 6ch 44100Hz, but output audio format became 6ch 48000Hz.


  50. By Igor Janos on Mar 8, 2009

    Hi guys, there’s a new release of the AAC decoder. Can you do some testing for me ?

  51. By Cheng on Mar 8, 2009

    I can test my own media files with your new release of the AAC decoder. You can E-MAIL it to me.

  52. By Igor Janos on Mar 8, 2009

    It’s available on the front page.

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