使用 C++ 流式传输到 Windows Media Player

Question

I have to read encrypted music or video from USB drive, decrypt it on the fly as a stream, and send it to mp3 player.

I can already read the file from the USB and decrypt it on the fly in chunks, but now I need to send the chunked data somewhere to play it, for example windows media player (WMP).

WMP requires a URL to the music/video source, so I figure I would create a stream in memory and give that to WMP as the URL. Then when WMP starts reading from the stream, it would somehow call my function which would then read a chunk of data from the USB, decrypt it, and put it to the stream to be played by WMP.

Anybody knows how to create a URL stream, and then get notified when the stream wants data?

Im using Visual C++ MFC/Win32.

Thanks

Answer 1

The WMP requires an URL, which can be the name of a file or a HTTP(S) URL that delivers the file data. In your case, the HTTP option would seem a good choice so you get notified when data is needed. For this to work you have to implement your own tiny HTTP server, preferably on an ephemeral port. So, you have your music file in memory and set up a HTTP server to deliver the file data. The URL for example will be something like http://127.0.0.1:5432/MusicFile.mp3 , which you specify to WMP. Your web server will then receive a request for the file and you can start sending it.

As a note, using a (non-persisted) memory-mapped file should also work. However, you indicate that you want to be notified and it's not clear if that's just to be able to deliver data.