Windows Issues

[kmsquire]

From https://groups.google.com/d/msg/julia-dev/we55cgrenl0/d5IOUh7fBp8J:

• without video="ThinkVantage Virtual Camera" I only got "malformed dshow input string". for folks who are not familiar with ffmpeg, this command will list the available devices:

  shell> ffmpeg -list_devices true -f dshow -i dummy

• there are continuous "frame full"-related error messages that make the REPL unusable, as soon as opencamera is called. ctrl^C doesn't work.

• the ImageView window gets stuck from time to time, and starts updating again as soon as I move the window. Probably a Tk thing, haven't tried Gtk version lately.

Cc: @ihnorton

[ihnorton]

... I'll see if I can get any more info on 2 and 3. The first one is (probably?) just documentation.

[kmsquire]

This wasn't meant to shame you!

For 1, I'm planning to make a call to ffmpeg for now. If it's installed through BinDeps, can you give me the install path of the program? It's installed with the zip, but I don't know exactly where that's unpacked.

Not sure the best route if someone already has the libraries installed elsewhere. How likely is that, and do you have any suggestions?

[ihnorton]

For me it is in %HOME%\.julia\v0.3\VideoIO\deps\ffmpeg-2.2.3-win64-shared\bin.

I tried using an API function like this:

using VideoIO
ctx = [AVFormat.avformat_alloc_context()]
infolist = [convert(Ptr{Ptr{AVDevice.AVDeviceInfo}}, C_NULL)]
AVDevice.avdevice_list_devices(pointer(ctx),pointer(infolist))

but ended up segfaulting (again and again..and then got distracted by backtrace issues on Windows).

Am I doing something obviously wrong there?

[ihnorton]

Not sure the best route if someone already has the libraries installed elsewhere. How likely is that, and do you have any suggestions?

If it's in the PATH then calling it should just work. Otherwise the user probably has to set a config variable anyway, and the bin/ path should be inferrable.

[kmsquire]

Thanks Isaiah.

Regarding AVDevice.avdevice_list_devices, from the source, it looks like the iformat field of the AVFormatContext needs to be set first, although I don't know to what. I'll try to look into it when I have the time.

In the mean time, I'll check in something which shells out to the binary.

[kmsquire]

#26 should address the first issue, although I haven't tested it. Actually, I merged that pretty quickly, and probably should make more of an effort to find the binary if it isn't installed by WinRPM.

Regarding the call to AVDevice.avdevice_list_devices (which in theory is nicer than #26), I think that will be dependent on #27 for proper implementation.

[kmsquire]

Covered by more recent issues (#146, #152)