Re: [DUG] access memory as a file

Phil Middlemiss Sun, 09 Jul 2006 13:30:24 -0700

I think it is possible if the DLL is using the Windows multimedia file I/O services. There is a component floating around called TMediaPlayerMemoryExtension, or TMediaPlayerMemoryFile which does the job. But you have to use a pretend extension which you register to a callback with mmioInstallIOProc and append a "+" to the end of the file. When the DLL calls the mciSendCommand function with mci_open on the file (eg, "SomeFile.MMM+") the callback you register with mmioInstallIOProc will be called and allow you to pass the memory data.

If you have trouble tracking the component down then let me know and I will have a hunt on my hard drive. This was discussed not so long ago on the list so a search of the list archive should provide all you need.

Cheers,
Phil.

Ross Levis wrote:

I doubt this is possible but I thought I would ask anyway.

I have a 3rd party DLL which opens a file that I specify. Specially it is an audio decoder plugin which decodes MP3 to PCM.

What I would like to do is use this plugin to access a memory location which contains MP3 data instead of a file.

Is it possible to set up something in Windows where you specify a filename but actually accesses memory instead.

This will be used with encrypted mp3 files so they are not accessible to anyone to steal for their own use. I am currently opening the file, decrypting, and then saving a temporary file to disk. But this has 2 disadvantages. It is very slow, so lots of latency between asking a track to play and hearing it. And also, while the file is decrypted on disk, someone can steal it.

The DLL cannot be modified. Is there any solution?

Thanks,
Ross.
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