Using DLLs

[Boereck]

Hello,
I want to use the dBpowerAmp-encoding-DLLs in my program, but I have some problems. I thought that the ExampleCompression-Source from the website could help me, but I write in Delphi, so I don't understand everything in the ExampleCompression-Code.
Well, here are my questions:
How is the type / class (?) "WAVEFORMATEX" defined?
With which parameters/variables do I call the "SetProfile"-function? And what does it do?
Do I have to stream the data of the wave-file through "ANewDataBlockArrived" or is there a way to encode directly from a file on harddisk?

Thanks you,
Max

[donny]

Re: Using DLLs

you should try importing some of the dlls in Delphi...

I think it is done tru import types, or define new types... I can look it up if you can't fin it...
anyway I think you shuld get new components installed and then you can see their properties and it should be logic enough....

I did this for QueMaster (components amp and multiplayer...)

[Spoon]

Re: Using DLLs

WFX is from Windows API.

[Boereck]

Re: Using DLLs

Allright, I found WAVEFORMATEX in Delphi's Windows SDK-Help.
I can use "SetProfile" as a function without parameters and output (at least It doesn't cause an access-violation), but I still don't know what it actually does.
I think before I can use the encoder-DLLs I have to learn how to get WAVEFORMATEX-Information from a WAVE-file, and how to read blocks of a WAVE-file that I can send to ANewDataBlockArrived.
I Already found a WAV-file component. I hope it helps me.

Thanks,
Max

[Boereck]

Re: Using DLLs

When I try to use the "CreateNewCompressionObject"-function, I always get this access-violation error:

Project C:\Eigene Datein\Delphi\DLL Loader\DllLoader.exe faulted with message: 'access violation at 0x00431c54: read of address 0x00000000'. Process Stopped. Use Step or Run to continue.

Here are some code-extracts (taken from several units). I get the message when I use "Start" with correct WavInfo from 'C:\test.wav'.

interface

type TWaveFormatEX = record
    wFormatTag: Word;         { format type }
    nChannels: Word;          { number of channels (i.e. mono, stereo, etc.) }
    nSamplesPerSec: DWORD;  { sample rate }
    nAvgBytesPerSec: DWORD; { for buffer estimation }
    nBlockAlign: Word;      { block size of data }
    wBitsPerSample: Word;   { number of bits per sample of mono data }
    cbSize: Word;           { the count in bytes of the size of }
end;

 type ENCompressionOpenResult = (COROk, CORFileError, CORMemoryError, CORCodecError);

 procedure CreateNewCompressionObject(FileName:ShortString; var ReturnError: ENCompressionOpenResult; WFXOutputFormat: TWaveFormatEX); cdecl; external 'Mp3 (Lame).dll';

 procedure Start(WavInfo: TWaveFormatEX);

implementation

 procedure Start(WavInfo: TWaveFormatEX);
 var
   ReturnError: ENCompressionOpenResult;
 begin
  CreateNewCompressionObject('C:\test.wav',ReturnError,WavInfo);
 end;

[Boereck]

Re: Using DLLs

If I use an "Array of Char" inistead of a "ShortString" in "CreateNewCompressionObject" and call it with an "Array [0..255] of Char" the program doesn't crash totaly, I but still get an access-violation:

Project DllLoader.exe raised exception class EAccessViolation with message 'Access violation at address 1000AC44 in module 'Mp3 (Lame).dll'. Write of address 000000FF'. Process stopped. Use Step or Run to continue.

I don't get it. How can I call this function?? I even tried to send a pointer to the Filename. I'm trying it for hours now. I thing I'm going mad soon. o_O

[Spoon]

Re: Using DLLs

I would like to help but don't program in delphi.

"type ENCompressionOpenResult = (COROk, CORFileError, CORMemoryError, CORCodecError);"

Possibly delphi handles enums differently to C++

[Spoon]

Re: Using DLLs

Plus everything in that function will be passed as a pointer to it, filename, WFX and result.

[donny]

Re: Using DLLs

I don't know if this helps but I used to have a lot of similar errors before... In my case I had to "create" an tamp component first, before using it .... something like:

amp:= tamp.create;

maybe that is your problem too... you don't "reserve" the memory before using it...

I remeber I had those errors about some other issues, but can't remeber what ... :(

[Boereck]

Re: Using DLLs

Thanks, anyway.
I'll better ask in a Delphi-Forum. I think the people there have some exprience in using DLLs written in C++.

[donny]

Re: Using DLLs

yeah, there are a lot of delphi forums, and poeple do need to to cross-over c++ and delphi...

[Bert]

Re: Using DLLs

Boereck, did you have success in unsing the dll with delphi?
It would be interesting for me too.