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Re: ExtAudioFileCreateNew questions
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Re: ExtAudioFileCreateNew questions


  • Subject: Re: ExtAudioFileCreateNew questions
  • From: "Kevin Dixon" <email@hidden>
  • Date: Mon, 31 Mar 2008 20:45:43 -0400 (EDT)
  • Importance: Normal

Thanks, that was enlightening.
Also, I discovered the error I was getting earlier was 'fmt?' and is
directly related to this...
The problem was I was using the StreamDescription from the input file, and
then trying to force it into a different file format's context --I should
have guessed this wouldn't work.

Thanks all,

-Kevin

> AudioFileGetGlobalInfo
>
> has a property to return a list of formats that are supported for a
> given file format - if you just enter in terminal "afconvert" you'll
> see this property in action
>
> Bill
>
> On Mar 29, 2008, at 7:17 PM, Brian Willoughby wrote:
>> On Mar 29, 2008, at 19:02, Kevin Dixon wrote:
>>> Also, I was originally hoping to use the same output file format
>>> (e.g. WAV
>>> in WAV out) as the input, but I couldn't see an easy way to map
>>> AudioStreamBasicDescription.mFormatID or something to an
>>> AudioFileTypeID.
>>> I realize that more varieties of formats can be read than can be
>>> written,
>>> but if both are available, I would prefer to use the same in/out
>>> format.
>>> Any suggestions to this end?
>>
>> I suggest that you segregate lossless from lossy formats in this
>> step.  You can map any format to lossless without repercussion.
>> However, if you read lossy and write lossy, then you take the risk
>> of compounding the loss.  e.g. Read MP3 and write MP3, depending
>> upon what you do to the data in between, could produce awful
>> results.  I don't think both are available to ExtAudioFile without
>> additions, but you get the idea.  I would say that you should narrow
>> your choices for this automated step to include only the lossless
>> options.  The user can always override if you provide for this.
>>
>> With regard to the programming details, you might just have to hard-
>> code your list of supported output formats, or perhaps read them
>> from an XML configuration file which can be updated as you learn
>> more supported formats.
>>
>> Brian Willoughby
>> Sound Consulting
>>
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References: 
 >ExtAudioFileCreateNew questions (From: "Kevin Dixon" <email@hidden>)
 >Re: ExtAudioFileCreateNew questions (From: Brian Willoughby <email@hidden>)
 >Re: ExtAudioFileCreateNew questions (From: William Stewart <email@hidden>)

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