Re: Audio data format and file type - how to match?
Re: Audio data format and file type - how to match?
- Subject: Re: Audio data format and file type - how to match?
- From: William Stewart <email@hidden>
- Date: Mon, 24 Jul 2006 17:41:53 -0700
Would this be something like:
@constant kAudioFileGlobalInfo_AvailableFormatIDs
Specifier is a pointer to a AudioFileTypeID containing a file type.
Returns a array of format IDs for formats that can be read.
Which is a property that is used with AudioFileGetGlobalInfo its one
call (well actually a couple because first of all you have to find
out how big the property is), and it does exactly what you describe
below.
This code is what is used in the code that Doug referred you too
Thanks
Bill
On 22/07/2006, at 2:39 PM, tahome izwah wrote:
Thanks... but... isn't there a simpler way to determine a
compatibility matrix?
Something like...
CAGetCompatibleFileTypesFromStreamType(char *fileType, AudioFileTypeID
*type, long *numTypes);
...or CAGetCompatibleStreamTypesFromFileType() for doing the reverse?
In my humble opinion, this whole CoreAudio business seems overly
complicated and has a pretty steep learning curve. ExtAudioFile is a
step in the right direction, but some things (like matching file type
and stream format) are still very inconvenient and require a lot of
coding...
Thanks for listening,
--th
2006/7/21, Doug Wyatt <email@hidden>:
On Jul 20, 2006, at 23:13 , tahome izwah wrote:
> Hi all,
>
> I have a question about the four char codes describing the audio
data
> format and the actual file types of the files that can hold such
> data... is there any call that tells me from such a four char code
> what the right file type(s) should/can be?
>
> For instance, if I let the user select from a list of encoding
options
> in a save-as dialog box and he selects "MPEG-4
AAC" (corresponding to
> the four char code kAudioFormatMPEG4AAC in an
> AudioStreamBasicDescription that I set up), how do I know what file
> type I have to pass to ExtAudioFileCreateNew() to create the
correct
> audio file (in this case kAudioFileM4AType)?
>
> To be future-proof, I'd not like to go through all the available
file
> types manually so I guess there must be an option/call that I can
> use...?
Have a look at /Developer/Examples/CoreAudio/PublicUtility/
CAAudioFileFormats.cpp
Also in /Developer/Examples/CoreAudio/PublicUtility/Services/
AudioFileTools, try the "audioformats" tool.
Doug
--
Doug Wyatt
Core Audio, Apple
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