[Ffmpeg-devel] Re: Using avcodec.dll and avformat.dllmeansthatoutput_example.c would not work?

Martin Boehme boehme
Thu Dec 15 10:47:49 CET 2005

Lars Blumberg wrote:
> Hello Martin,

Please don't top-post...

> I am using the API function LoadLibrary to connect to methods in the DLLs. 
> That all works fine. It is the same way as you would use dynamic loading in 
> C++.

Well, in C++ you actually have two choices: Use an import library or use 
LoadLibrary(). The latter choice is much more painful, though, which is 
why most people use import libraries...

> And I did not know before, that are "linked against each other" at 
> runtime when loaded within the same application. Is that really true?

Huh? Not sure what you're trying to say here... but yes, any DLL that 
has dependencies on other DLLs brings those in automatically (if that's 
what you're asking).


> "Martin Boehme" <boehme at inb.uni-luebeck.de> schrieb im Newsbeitrag 
> news:438C0ADE.9070707 at inb.uni-luebeck.de...
> Lars Blumberg wrote:
>> I am using ffmpeg functionality via the libraries "avcodec.dll" and 
>> "avformat.dll", which  i have built before. To examine how to use both 
>> DLLs (in Delphi) I am translating the example code "output_example.c" 
>> given with the ffmpeg distribution.
>> The first code which is run is "av_register_all" to register all necessary 
>> things. When I have a look into the implementation of this method, I see 
>> that "avcodec_register_all" is called there at first.
>> But as you know, both methods are in different DLLs. That means, that 
>> "av_register_all" cannot call "avcodec_register_all". When I only call the 
>> first function I cannot use any codec. That's why I have to call 
>> "avcodec_register_all" by myself after calling "av_register_all".
> Hm... don't have any idea how loading DLLs works in Delphi... all I can
> say is that "it works for me" under MinGW. My understanding was that
> when a DLL has dependencies on further DLLs, those DLLs also get loaded
> as part of the process.
> Are you calling LoadLibrary() yourself (i.e. loading the DLLs
> explicitly) or does Delphi do that for you?
> Martin

Martin B?hme
Inst. f. Neuro- and Bioinformatics
Ratzeburger Allee 160, D-23538 Luebeck
Phone: +49 451 500 5514
Fax:   +49 451 500 5502
boehme at inb.uni-luebeck.de

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