?
Solved

AIFF file header fields

Posted on 2001-06-12
2
Medium Priority
?
277 Views
Last Modified: 2010-04-06
I'm trying to add support for AIFF files (Apple's native PCM audio file format) to a windows program. It works fine in different ways, but other programs which have this support seem to work with a slightly different structure. (Eg: Cool Edit, AWave, Gold Wave). There appear to be 2 less bytes in the COMM chunk before the sampling rate field, and two extra in the SSND field before the sound data.
 The structure I'm using adheres strictly to Apple's AIFF v1.3 documentation, but these other programs concurr on their own structure. I'm using Delphi 3, and here's what I'm doing...
 To write a file, I assign all the field values for the FORM, COMM and SSND chunks to fields in records, byte-reverse each numeric field, and then write the 2 records to disk. To read a file, I read X bytes to a buffer, assign its address to typed pointers, byte-reverse the fields, and get all the info from the records.
 If v1.3 of the format is ancient, or if I'm just stupid and wrong, then can someone please either tell me where to find the docs on the latest version, or fill me in on the proper structure. Following are the record types that I use...

 TrecAIFF_TOF = record
   HeaderCkID : Tarr4CC; { array of 4 char's }
   FileSize   : longint;
   FormatID   : Tarr4CC;
   FmtCkID    : Tarr4CC;
   FmtSize    : longint;
   NmbrChnls  : smallint;
   NmbrFrms   : cardinal;
   NmbrBits   : smallint;
   SmplRate   : extended;
 end;
 PrecAIFF_TOF = ^TrecAIFF_TOF;

 TrecAIFFSgnlHDR = record
   SgnlCkID   : Tarr4CC;    
   SgnlCkSize : longint;
   Offset     : longint;
   BlockSize  : longint;    
 end;                        
 PrecAIFFSgnlHDR = ^TrecAIFFSgnlHDR;


 A thousand thanks (and 50 points) to whoever is able to help!
0
Comment
Question by:HorridMan
2 Comments
 
LVL 11

Accepted Solution

by:
robert_marquardt earned 200 total points
ID: 6181167
I would guess that the records are all packed record.

Is "SmplRate: extended;" really correct? Extended is a 10 Byte type whereas Double is a 8 Byte type.
0
 

Author Comment

by:HorridMan
ID: 6189457
 Packed records work perfectly! I would never have thought of that myself. Incidentally, I tried at first using a longint for the SmplRate field, but strangely extended type does work. Goodness knows why they designed it that way.
0

Featured Post

Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Objective: - This article will help user in how to convert their numeric value become words. How to use 1. You can copy this code in your Unit as function 2. than you can perform your function by type this code The Code   (CODE) The Im…
In my programming career I have only very rarely run into situations where operator overloading would be of any use in my work.  Normally those situations involved math with either overly large numbers (hundreds of thousands of digits or accuracy re…
Are you ready to place your question in front of subject-matter experts for more timely responses? With the release of Priority Question, Premium Members, Team Accounts and Qualified Experts can now identify the emergent level of their issue, signal…
As many of you are aware about Scanpst.exe utility which is owned by Microsoft itself to repair inaccessible or damaged PST files, but the question is do you really think Scanpst.exe is capable to repair all sorts of PST related corruption issues?
Suggested Courses

840 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question