Re: Which Audio Formats are supported directly by CoreAudio
Re: Which Audio Formats are supported directly by CoreAudio
- Subject: Re: Which Audio Formats are supported directly by CoreAudio
- From: William Stewart <email@hidden>
- Date: Wed, 21 Sep 2005 14:56:15 -0700
On 21/09/2005, at 2:14 PM, Jens Alfke wrote:
On Sep 21, 2005, at 12:09 PM, William Stewart wrote:
What afconvert is doing here is using both the AudioFormat and
AudioFileGlobal APIs to find out:
What file types are installed on the system
- AudioFile and AudioFileComponents
What codecs are installed on the system
- AudioCodec components (with bridging to *some* SM codecs)
What file types support what data formats
However, not all the built-in codecs support encoding; in
particular there is no MP3 encoder:
Quite true.
The data format list for CAF for instance, is based on the decoder
components that we find - so:
'caff' = Apple CAF File (.caf)
data_formats: '.mp3' 'MAC3' 'MAC6' 'QDM2' 'QDMC'
'Qclp' 'Qclq' 'aac ' 'agsm' 'alac'
'alaw'
'drms' 'dvca' 'dvi ' 'ima4' 'lpc '
BEI8
BEI16 BEI24 BEI32 BEF32 BEF64 LEI16
LEI24 LEI32 LEF32 LEF64 'ms\x00
\x02' 'ms\x00\x11'
'ms\x001' 'ms\x00U' 'samr' 'ulaw'
'vdva'
mp3 is listed as a supported format.
However, there is only an adec version of mp3 on the system (this is
the decoder component) - there is no aenc (encoder) as described below.
Of course, if a developer were to say make available the LAME mp3
encoder as an audio codec, then it would just show up to all the
users of these APIs
Bill
From: Brad Ford <email@hidden>
Date: July 7, 2005 9:49:36 AM PDT
To: + Kennedy Kok + <email@hidden>
Cc: email@hidden
Subject: Re: converting quicktime sound track to mp3
QuickTime/CoreAudio do not ship an mp3 encoder. We have an mp3
decoder, thus we can play mp3's, but if you want to encode mp3's,
you'll either need to install a third party provided mp3 audio
encoder component, or do it in iTunes.
-Brad Ford
QuickTime Engineering
--Jens
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