Faulty handling of file: protocol on Windows

[Hendrik Schreiber]

Summary of the bug:

In the dev documentation it is mentioned that one can open resources either via a filename, a URL or some other form of custom AVIOContext.

But in its current form FFmpeg does not seem to support well formed Windows file URLs.

On Windows, the scheme part (file:) is always followed by a bunch of slashes, usually three (file:///), before the drive designator.
A correct local file URL is e.g.:

file:///C:/somePath/someFile.mp3

A more complete explanation can be found at ​http://blogs.msdn.com/b/ie/archive/2006/12/06/file-uris-in-windows.aspx

Contrary to this, in libavformat/file.c (static int file_open(URLContext *h, const char *filename, int flags), line 112) FFmpeg simply cuts off "file:" in line 119 and thinks it is done.

Unfortunately,

open("///C:/somePath/someFile.mp3", access, 0666); // line 135 

leads to EINVAL/Invalid Argument. This function is called via avio_open2, which is called by avformat_open_input.

This bug was already discussed on libav-user: ​http://libav-users.943685.n4.nabble.com/Libav-user-Faulty-handling-of-file-protocol-on-Windows-td4657921.html

[Carl Eugen Hoyos]

Please either provide a failing command line (if the ticket is reproducible with the ffmpeg executable) together with the complete, uncut console output or add sample code that allows to reproduce the problem.

[Hendrik Schreiber]

int res = 0;
AVFormatContext **format_context;
res = avformat_open_input(format_context, "file:///C:/somePath/someFile.mp3", NULL, NULL);
...
// res must *not* be EINVAL, if the file is valid and exists.