How to programmatically convert .rm (RealPlayer Media) file to MP3 or another format?

Question

I would like to convert .rm (RealPlayer Media) file to MP3 or another format? First, I successfully managed that using VLC but the quality was not good. Then I tried the Real Alternative codec with DirectShow, this also worked ok, but then I found that the codec is no longer developed because RealNetworks sued the developer.

Now, I have installed the RealPlayer and I am trying to use it's DirectShow filters to convert .rm to .mp3 but without success:( (Actually after adding RealPlayer Transcode filter and choosing a file the GraphStudio crashes.)

Is there a legal way to programmatically convert .rm file to another format? How to make RealPlayer to programmatically convert files? Do you have any hints or examples, how to use RealPlayer Transcode filter? (I am new to DirectShow.)

UPDATE to make the question more concrete: How can I list implemented interfaces and its members of RealPlayer Transcode filter? I have not found any documentation:( (The GraphStudio says it has 0 pins and just common properties.)

Answer 1

You need to build a DirectShow graph to read and decode .rm, then compress audio into MP3 and write it into a file. This is similar to recompressing an AVI file, described in some detail on MSDN: Recompressing an AVI File. You just have audio without video there, and the container formats are different.

UPDATE: There is no way to reliably list implemented interfaces in COM. Sometimes you can find this out by checking the type library, however a lot of DirectShow filters are coming without it. Typically, you need an SDK header file from the filter vendor to get a definition of implemented so called 'private' interfaces.