Aborting a foreach loop containing a stabilisation effect

Jack S wrote on 3/13/2025, 6:38 AM

@jetdv Edward, I wonder if you can help me with this. I'm not sure if it's even possible. I have a batch stabilisation module in my application extension. It processes selected video events using a foreach loop. I want to have the ability to abort the process if necessary. I have an 'Abort' button that sets an abort boolean to true and this boolean is tested at the start of the foreach loop. If the boolean is true, I invoke a return command to exit the function. The problem is, during the process, it's impossible to activate the button. I've searched the API to see if I can access the 'Cancel' function on the stabilisation progress UI which I could use to intercept the loop, but I can't find anything. Do you have any ideas?

Comments

jetdv wrote on 3/13/2025, 8:25 AM

I'm assuming the "abort" button just gives a windows beep indicating it's not available to click? That would probably be because "VEGAS" is working so the extension isn't accepting input. You might be able to put it on a separate thread but then the current process would probably still need to finish unless you manually click on the "Cancel" button too.

Jack S wrote on 3/13/2025, 8:48 AM

No, there's no Windows beep when I attempt to click it. It just isn't responsive because the pointer is a hourglass. I don't mind having to click the Cancel button for the current iteration if I could then get the Abort button to accept an input. I don't know what you mean by 'put it on a separate thread'. Can you explain please?

bvideo wrote on 3/13/2025, 10:39 AM

Does this scenario match your stabilize loop and can you use it to exit the loop:

Somewhere in your loop, your code does "ParameterChanged" to the "AnalyzeMotion" parameter. At your next statement, the analyze has finished. You can then test the "HasMotionData" parameter. If it is true, the analyze completed. If you hit [Cancel] during the stabilize dialog, "HasMotionData" will be false. Then you can quit your loop. (I presume you have done OpenVideoEffectUI() so you can watch the stabilize operation running and see the cancel button.)

Aside from that, it's not clear that multithreaded code could intercept your own "quit" button and safely terminate the analyze process.

Jack S wrote on 3/13/2025, 10:48 AM

@bvideo Thanks for that. I think I know what you mean. I'll give it a go and report back.

Jack S wrote on 3/14/2025, 11:23 AM

@bvideo OK. After many hours of trying to figure this out, I'm stumped. I can usually muddle my way through after being given some hints, but this time I'm lost. This is what I have at the moment after your advice.

                                        OFXParameter myOFXParameterAlt = myOFXEffect.FindParameterByName("AnalyzeMotion");  //Define the parameter
                                        myOFXParameterAlt.ParameterChanged();                                               //Acivate stabilisation
                                        OFXParameter myOFXParameterRes = myOFXEffect.FindParameterByName("HasMotionData");  //Define the parameter
                                        myOFXParameterRes.ParameterChanged(contProcess);                                    //Load the result into the boolean 'contProcess'
                                        MessageBox.Show("contProcess = " + contProcess);                                    //Display the state of the 'HasMotionData' parameter
                                        if (!contProcess)                                                                   //If it is false ...
                                        {
                                            return;                                                                         //... break out of the calling procedure.
                                        }

Unfortunately, clicking cancel results in 'HasMotionData' being true. It is never false, so the foreach loop continues. Am I doing this correct? Thanks in advance.

jetdv wrote on 3/14/2025, 2:34 PM

That is now how you would check the value of the boolean parameter. Convert it to a boolean parameter:

OFXBooleanParameter fit = (OFXBooleanParameter)ofx.FindParameterByName("HasMotionData");

and then just read the value:

Boolean HasMotionData = fit.Value;

bvideo wrote on 3/14/2025, 2:59 PM

@Jack S Another thought: when I want to analyze motion data, I first check to see if "HasMotionData" is already true. If it is true, either I don't run the analyze (not needed) or I do the "ParameterChanged" operation on the "CLearMotionData" (crazy spelling) pushbutton parameter first to erase the preexisting motion data. I don't know what would happen if the "AnalyzeMotion" parameter is pushed when there is already motion data present. Would it run the analyze or not? And if so, would [Cancel] restore the previous motion data or leave it cleared?

Sorry I have not written this in clear C++ & scripting API language. Thanks to @jetdv for spelling things out clearly, as always!

Jack S wrote on 3/15/2025, 6:59 AM

@jetdv Thanks Edward, that did it. I had to make a small change to suit my code, replacing ofx.FindParameterByName to myOFXEffect.FindParameterByName, but that was all.
The foreach loop now exits when I click the cancel button. I've marked your answer as the solution.

@bvideo Before activating stabilisation, I check whether it's already in the chain. If it is, I remove it. This has worked for me since I introduced the module into my application extension, so I'm not going to change that.

Thanks to you both for your input, it's most appreciated.