×

Discussion Board

Results 1 to 8 of 8
  1. #1
    Registered User
    Join Date
    Dec 2008
    Posts
    12

    Vorbis Decoder, DevSound

    hi!

    Is the Vorbis Decoder used by Ogg controller a software or hardware decoder?

    thanks!

  2. #2
    Nokia Developer Moderator
    Join Date
    Feb 2006
    Location
    Oslo, Norway
    Posts
    28,674

    Re: Vorbis Decoder, DevSound

    Software. If it would be supported by the hardware, you would not have to install it...

  3. #3
    Registered User
    Join Date
    Dec 2008
    Posts
    12

    Re: Vorbis Decoder, DevSound

    Thanks a lot!

    The reason why i had this doubt was because Ogg controller initialises Devsound using FourCC code and the documentation says:

    --------------------------------------------------------------
    void InitializeL(MDevSoundObserver &aDevSoundObserver, TFourCC aDesiredFourCC, TMMFState aMode);

    Initializes DevSound object for the mode aMode for processing audio data with hardware device supporting FourCC aDesiredFourCC.
    ----------------------------------------------------------------

    i was confused by "hardware device".

    Can i use CMMFDevSound::InitializeL(MDevSoundObserver &aDevSoundObserver, TUid aHWDev, TMMFState aMode);
    with TUid of a software decoder even though documentation says that this would "Initialize DevSound object for the mode aMode for processing audio data with hardware device aHWDev"

    Thanks!!!

  4. #4
    Nokia Developer Moderator
    Join Date
    Feb 2006
    Location
    Oslo, Norway
    Posts
    28,674

    Re: Vorbis Decoder, DevSound

    Even the newest devices on http://www.forum.nokia.com/devices do not list .ogg as supported format, for example http://www.forum.nokia.com/devices/5800_XpressMusic has a really impressive list of supported formats (just compare to others), and .ogg is just not amongst them. So it is not there by default, and everything you install is certainly a software.
    In theory it could happen that an installable codec uploads some DSP code in runtime and executes it, but you would obviously notice that in an open-source codec. And it would be device-specific, while the codec in question is not bound to a certain set of devices.

  5. #5
    Registered User
    Join Date
    Dec 2006
    Posts
    2,280

    Re: Vorbis Decoder, DevSound

    Hi,

    There are two confusions here. First is that a HwDevice may actually be implemented in software, it is just the way a component in the Media Device Framework is named that would normally be implemented with hardware acceleration of some kind. Second, check which FourCC code the DevSound layer is initialised with. I think you'll find it's PCM16 and that is in fact played directly by a hardware device, the software decode from the ogg vorbis format has already been done at this point.

    The ogg player project provides an MMF controller plug-in. You can't use that plug-in UID with DevSound, although you could load it directly with RMMFController and add a data source (file). The Vorbis decoder, tremor is not a plug-in and doesn't have a UID.

    What is your use-case? What do you want to do with Ogg?

    Hope that helps,
    Sorcery

  6. #6
    Registered User
    Join Date
    Dec 2008
    Posts
    12

    Re: Vorbis Decoder, DevSound

    thanks wizard_hu_ and Sorcery!

    i am trying to write an audio controller plugin (for mp3) and i was doin so on the same lines as the ogg controller.

    This is my problem:

    In ogg controller, in PrimeL, Devsound is initialised with KMMFFourCCCodeVORB. On similar lines, I initialised with KMMFFourCCCodeMP3, but got returned a KErrNotFound.

    So i tried an alternative of initialising with Uid of the software decoder plugin (inbuilt Nokia mp3's). but this initializeL function isnt completed successfully (it doesnt return from this function) and it hangs. (Note that the decoder::Newl is called and done successfully)
    (i hv disabled the inbuilt Nokia mp3 controller plugin).

    So i just wanted to know if my approach was correct in intialising DevSound using the UID of a Software Decoder.

    Thanks Again!!

  7. #7
    Registered User
    Join Date
    Dec 2006
    Posts
    2,280

    Re: Vorbis Decoder, DevSound

    Hi,

    I think you must be referring to an update to the Symbian Ogg controller example that I haven't seen, presumably using a HwDevice plug-in (software one) for the Ogg codec.

    The Ogg Player project has an older controller plug-in that uses CMMFAudioOutput rather than DevSound directly and in PrimeL() it simply calls:
    iAudioOutput->SinkPrimeL();
    to initialize the audio.

    It sounds like you need to read my book for some background.

    It also sounds like you are working for a device manufacturer? If you're using Symbian OS v9.4 or earlier then you're probably going about things the right way (HwDevice plug-in and send the data direct to DevSound - you won't be able to initialize with KMMFFourCCCodeMP3 until you've installed an appropriate plug-in for that). If you're using v9.5 (or later) then you should almost certainly be using the new architecture and writing plug-ins for the OpenMAX IL interface.

    You should probably get some tech support/consulting from Symbian (although I know that is very expensive!).

    Sorcery

  8. #8
    Registered User
    Join Date
    Dec 2008
    Posts
    12

    Re: Vorbis Decoder, DevSound

    Thanks for your help Sorcery!
    Yes I am working for a device manufacturer. Btw I'm using 9.5.
    Cheers!

Similar Threads

  1. Video decoder
    By ominolego in forum Symbian Media (Closed)
    Replies: 122
    Last Post: 2009-11-23, 04:40
  2. Using Paltform provided H.264 decoder on S60 3.0 ( N95 )
    By ravinder007 in forum Symbian Media (Closed)
    Replies: 2
    Last Post: 2008-10-22, 11:25
  3. How devSound load hwDevice
    By pprasad in forum Symbian Tools & SDKs
    Replies: 0
    Last Post: 2007-05-03, 09:57
  4. multiple threads access to devsound
    By pavankrishnamurthy in forum Symbian Media (Closed)
    Replies: 3
    Last Post: 2006-10-18, 10:18
  5. DevSound internal buffer (AKA Latency with streaming)
    By Rocco77 in forum Symbian Media (Closed)
    Replies: 4
    Last Post: 2006-01-25, 21:59

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
×