On Wed, Sep 9, 2009 at 3:29 PM, Jean-Daniel Dupas<
email@hidden> wrote:
> I Never dev for iPhone but isn't it possible to simply uncompress the data
> using the ExtAudioFile API ?
>
>
http://developer.apple.com/iphone/library/documentation/MusicAudio/Reference/ExtendedAudioFileServicesReference/Reference/reference.html
>
>
> Le 10 sept. 2009 à 00:11, Steven Winston a écrit :
>
>> Howdy KappA,
>>
>> The best solution I've found is to use AudioQueueOfflineRender. The
>> only problem with it, is it's next to impossible to, for me at least,
>> get the timing right between the various formats that AudioQueue
>> supports. See you have to have one AudioQueue to do an offline
>> render, then change the PCM you receive in the buffer, then send that
>> back out all while staying ahead of the file being played. My problem
>> comes from the fact that some files & formats play at different speeds
>> through the offline render than others.
>> The only other solution I have come up with that solves this problem
>> is to port a MP3Library / OggLibrary and do things entirely in
>> software. It's not as fast as there's no benefit from the hardware
>> for speed, but at least the rate of decompressing is uniform.
>> Ofcourse there's probably a trick I'm missing here.
>>
>> Thanks,
>> Steve
>>
>> On Wed, Sep 9, 2009 at 1:48 PM, KappA<
email@hidden> wrote:
>>>
>>> Hi All,
>>>
>>> I am hoping this is a somewhat simple question. I am using Audio Queue's
>>> for
>>> audio playback (iPhone OS3), and I would like to add some simple EQ
>>> effects
>>> to the audio output... I am supporting MP3 and AAC playback, so I will
>>> need
>>> my solution to still be able to support these formats.
>>>
>>> I'd basically like to use this EQ function:
>>>
http://musicdsp.org/archive.php?classid="">
>>>
>>> Which takes an audio sample input of type "double", and returns a
>>> modified
>>> sample output, of type "double"
>>>
>>> I can actually see where we copy the audio bytes to the audio buffer data
>>> structure, in the Audio Queue Services callbacks... but I am not sure how
>>> to
>>> convert the raw audio bytes to audio samples, where I can manipulate
>>> them...
>>>
>>> Is this even possible? Am totally off base here?
>>>
>>> If it is not possible, any other ideas to acheive something similar with
>>> Audio Queues?
>>>
>>> If I cannot do it with Audio Queues, is there something else I can use
>>> for
>>> playback, that will support MP3's and AAC etc?
>>>
>>> I can share more info if needed.
>>>
>>> Any help appreciated.
>>>
>>> Thanks,
>>> KappA
>>>
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>
> -- Jean-Daniel
>
>
>
>
>