ATEM Audio Interface

I have been trying to work with the ATEM SDK and am have some difficulty, mostly because I am trying to learn how to work with ‘COM’ in the C# environment. While doing research on ‘COM’ with Microsoft documents, and working with the ATEM samples, I thought I had figured it out. So I have been trying to make a connection (get a pointer) to the IBMDSwitcherAudioMixer interface and control the Program Output Gain.
In the development environment I have no errors, and it compiles without any problems. Yet when the app is run it exits citing an ‘Access Violation’. The code in question is:
IBMDSwitcherAudioMixer mxIterator = null;
IntPtr mxIteratorPtr;
Guid mxIteratorIID = typeof(IBMDSwitcherAudioMixer).GUID;
m_switcher.CreateIterator(ref mxIteratorIID, out mxIteratorPtr);

with the last line where the ‘Access Violation’ occurs. The ‘m_switcher’ object is the switcher object gotten through;
m_switcherDiscovery.ConnectTo(address, out m_switcher, out failReason)
from the C# example included with the SDK.
Can someone point me in the right direction?

Funny, I have just spent the last couple of nights trying to get it working and cracked it when I woke up this morning.
I was using the switcher iterator rather than the mixer iterator to get the audio inputs.
switcher is my existing switcher object.

Code: Select all

IBMDSwitcherAudioMixer m_audiomixer;
            m_audiomixer = (BMDSwitcherAPI.IBMDSwitcherAudioMixer)switcher;

            IBMDSwitcherAudioInputIterator audioIterator = null;

            IntPtr audioIteratorPtr;
            Guid audioIteratorIID = typeof(IBMDSwitcherAudioInputIterator).GUID;
           
            m_audiomixer.CreateIterator(ref audioIteratorIID, out audioIteratorPtr);             if (audioIteratorPtr != null)
            {
                audioIterator = (IBMDSwitcherAudioInputIterator)Marshal.GetObjectForIUnknown(audioIteratorPtr);
            }
            int audioinputnum = 1;
           
            IBMDSwitcherAudioInput audioInput;
            audioIterator.Next(out audioInput);


audioInput.xxx will give you level, balance etc.
Regards,
Ian

Video of the audio interface used in PowerShell with Midi device

Ian,

Thanks for the info, although it was not exactly what I was looking for which was to control the output gain of the ATEM mixer. I had reviewed the input and found that it looked a lot like the video selection interface, which you have just confirmed.

I did however realize from your information that the program gain was a single interface gotten directly through the BMDSwitcherAPI as shown in the lines below.

IBMDSwitcherAudioMixer m_AudioMixer;
m_AudioMixer = (BMDSwitcherAPI.IBMDSwitcherAudioMixer)m_switcher;
m_AudioMixer.AddCallback(m_PgmAudioMixer);

Sorry, missed that. Yes, output is much simpler.
I add the following to my switcher class...

Code: Select all

        private double _gain;
        private double _balance;
        private int _FollowFTB;
        public double ProgramOutGain
        {

            get
            {
                BMDSwitcherAPI.IBMDSwitcherAudioMixer m_params =
               (BMDSwitcherAPI.IBMDSwitcherAudioMixer)switcher;
                m_params.GetProgramOutGain(out _gain);
                return _gain;
            }
            set
            {
                BMDSwitcherAPI.IBMDSwitcherAudioMixer m_params =
               (BMDSwitcherAPI.IBMDSwitcherAudioMixer)switcher;
                m_params.SetProgramOutGain(value);
            }
        }
        public double ProgramOutBalance
        {

            get
            {
                BMDSwitcherAPI.IBMDSwitcherAudioMixer m_params =
               (BMDSwitcherAPI.IBMDSwitcherAudioMixer)switcher;
                m_params.GetProgramOutBalance(out _balance);
                return _balance;
            }
            set
            {
                BMDSwitcherAPI.IBMDSwitcherAudioMixer m_params =
               (BMDSwitcherAPI.IBMDSwitcherAudioMixer)switcher;
                m_params.SetProgramOutBalance(value);
            }
        }
        public int ProgramOutFollowFTB
        {

            get
            {
                BMDSwitcherAPI.IBMDSwitcherAudioMixer m_params =
               (BMDSwitcherAPI.IBMDSwitcherAudioMixer)switcher;
                m_params.GetProgramOutFollowFadeToBlack(out _FollowFTB);
                return _FollowFTB;
            }
            set
            {
                BMDSwitcherAPI.IBMDSwitcherAudioMixer m_params =
               (BMDSwitcherAPI.IBMDSwitcherAudioMixer)switcher;
                m_params.SetProgramOutBalance(value);
            }
        }