ASIO and Video on Windows

General JUCE discussion
1

Using JUCE 3.0.8

When I choose the ASIO driver (ASIO4All) and playback a video in Windows, a EC_ERRORABORT error is produced in the graphEventProc() routine. This error closes the vide and sets mediaEvent to null which causes a crash on the next instructions.

    void graphEventProc()
    {
        LONG ec;
        LONG_PTR p1, p2;
        jassert (mediaEvent != nullptr);
        while (SUCCEEDED (mediaEvent->GetEvent (&ec, &p1, &p2, 0)))
        {
            switch (ec)
            {
            case EC_REPAINT:
                component.repaint();
                break;
            case EC_COMPLETE:
                if (component.isLooping())
                    component.goToStart();
                else
                    component.stop();
                break;
            case EC_USERABORT:
            case EC_ERRORABORT:
            case EC_ERRORABORTEX:
               component.closeMovie(); //This causes mediaEvent to be set to null
                break;
            default:
                break;
            }
            mediaEvent->FreeEventParams (ec, p1, p2);
        }
    }

This also occurs in the JUCE demo.

All is fine using Windows Audio.

HELP!

2

OK.. well, we can't stop the DirectShow class from failing, but we can at least avoid the crash!

I think the best non-leaky fix would be to just move the FreeEventParams call up to the top, e.g.

        while (SUCCEEDED (mediaEvent->GetEvent (&ec, &p1, &p2, 0)))
        {
            mediaEvent->FreeEventParams (ec, p1, p2);

            switch (ec)
            {

..as the parameters don't actually seem to be needed at all. Does that work for you?

3

Thanks, that is what I had to do. Are you saying one can not have video and ASIO at the same time?

If I comment out the closing of the video, it runs but has no sound.

Is it possible to fix this or what do you recommend I do to show video while using ASIO?

4

That doesn't have anything to do with JUCE - it sounds like Windows components or drivers fighting with each other. Can't really help with that..

5

I wonder how other DAWS do it!

You also need to place a return; after the component.closeMovie() to avoid the crash.

6

You also need to place a return; after the component.closeMovie() to avoid the crash.

No, I suggested moving the line up to there. Not copying it, otherwise the memory would be freed twice. I've already pushed this fix to master BTW.