Environment commands for Enabling/Disabling audio and video?

General Development
#1

I see that there are no standard ways to tell a core that video or audio is disabled, so I’d like to add that in. What would be the best way to standardize this?

Edit: just made this up:

#define RETRO_ENVIRONMENT_GET_AUDIO_VIDEO_ENABLE (47 | RETRO_ENVIRONMENT_EXPERIMENTAL)

      case RETRO_ENVIRONMENT_GET_AUDIO_VIDEO_ENABLE:
      {
         int result = 0;
         if (!audio_driver_is_suspended())
         {
            result |= 2;
         }
         if (video_driver_is_active())
         {
            result |= 1;
         }
         if (data != NULL)
         {
            int* result_p = (int*)data;
            *result_p = result;
         }
      }
      break;

Then I made this change to Snes9x:

   int result = -1;
   bool okay = environ_cb(RETRO_ENVIRONMENT_GET_AUDIO_VIDEO_ENABLE, &result);
   if (okay && result != -1)
   {
	   bool audioEnabled = 0 != (result & 2);
	   bool videoEnabled = 0 != (result & 1);

	   IPPU.RenderThisFrame = videoEnabled;
	   S9xSetSoundMute(!audioEnabled);
   }

During times when audio and video were suspended, I got a performance boost. Nice.