When should call GC.Collect()?

Question

I'm using BitmapSource to draw frames as video that get from IP Camera. The below is summary code.

while(true)
{
    char* rgbBuffer = GetFrameFromCamera();
    BitmapSource^ bitmapSource = BitmapSource::Create(resX, resY, 96, 96, PixelFormats::Bgr24, nullptr, (IntPtr)rgbBuffer, rgbBufferLength, linesize);
    wpfVideoControl.Draw(bitmapSource); 
    delete []rgbBuffer;
}

The problem is, the memory usage that watched from Task Manager is very large. And after along time, when the memory usage about 1300MB, the application is not responding.

My application is 32bit, and the resolution of IP Camera is 1280x960, frame per second is 25 and there are 4 cameras. Each bitmap frame is about 3,5 MB. It mean the velocity allocation memory for this case about 3,5*25*4 = 350 MB/second.

So the memory is increased very fast and seem the GC can not cover it. Therefore that caused "The application is not responding".

I have tried to call GC.Collect() in each while loop as below code. And the application was worked fine. But this caused the CPU consuming.

while(true)
{
    GC::Collect();
    GC::WaitForPendingFinalizers();
    char* rgbBuffer = GetFrameFromCamera();
    BitmapSource^ bitmapSource = BitmapSource::Create(resX, resY, 96, 96, PixelFormats::Bgr24, nullptr, (IntPtr)rgbBuffer, rgbBufferLength, linesize);
    wpfVideoControl.Draw(bitmapSource); 
    delete []rgbBuffer;
}

To avoid the CPU consuming, I have tried to call GC.Collect() after 1s by the timer thread below

void TimerThread()
{
    while(true)
    {
        GC::Collect();
        GC::WaitForPendingFinalizers();     
        Sleep(1000);
    }
}

This way was solved the CPU consuming issue. But the problem very large memory usage still exist.

Someone can show me the best way to solve my problem.