Contributions:WebcamLogger - Revision history

Mellinger: /* See also */

2025-06-04T13:54:31Z

Mellinger: /* Format of the Video File */

2025-06-04T13:53:52Z

Format of the Video File

← Older revision		Revision as of 13:53, 4 June 2025
Line 101:		Line 101:

	'''Note''': Do not expect nominal framerate and/or nominal duration of the video file to correspond to the camera's actual framerate or duration. Also, in case of variable framerate cameras, video display may be jerky when playing back the video in a standard video player such as VLC. This is ''not'' an error but an artifact of how video frames are stored.		'''Note''': Do not expect nominal framerate and/or nominal duration of the video file to correspond to the camera's actual framerate or duration. Also, in case of variable framerate cameras, video display may be jerky when playing back the video in a standard video player such as VLC. This is ''not'' an error but an artifact of how video frames are stored.

			For a strategy how to synchronize video with brain signal data, and possibly audio data, see [[User_Reference:BCI2000Viewer#AV_Synchronization_Strategies\|this page]].

	==Troubleshooting==		==Troubleshooting==

Mellinger: /* Functional Description */

2025-06-03T16:19:11Z

Functional Description

← Older revision		Revision as of 16:19, 3 June 2025
Line 37:		Line 37:

	The video file bears the name of the BCI2000 data file, with the extension removed and <tt>_M_video.mp4</tt> appended where <tt>M</tt> is the index of the camera in question.		The video file bears the name of the BCI2000 data file, with the extension removed and <tt>_M_video.mp4</tt> appended where <tt>M</tt> is the index of the camera in question.
	For the format of the video file, see the notes below.		For the format of the video file, see [[Contributions:WebcamLogger#Format_of_the_Video_File\|the notes below]].

	'''NOTE:''' This module can also be used to perform screen capture with a virtual screencast webcam driver.		'''NOTE:''' This module can also be used to perform screen capture with a virtual screencast webcam driver.

Mellinger: /* Format of the Video File */

2025-06-03T16:16:27Z

Format of the Video File

← Older revision		Revision as of 16:16, 3 June 2025
Line 101:		Line 101:

	'''Note''': Do not expect nominal framerate and/or nominal duration of the video file to correspond to the camera's actual framerate or duration. Also, in case of variable framerate cameras, video display may be jerky when playing back the video in a standard video player such as VLC. This is ''not'' an error but an artifact of how video frames are stored.		'''Note''': Do not expect nominal framerate and/or nominal duration of the video file to correspond to the camera's actual framerate or duration. Also, in case of variable framerate cameras, video display may be jerky when playing back the video in a standard video player such as VLC. This is ''not'' an error but an artifact of how video frames are stored.


	==Troubleshooting==		==Troubleshooting==

Mellinger: /* Troubleshooting */

2025-06-03T16:15:49Z

Troubleshooting

@@ Line 92: / Line 92: @@
 ===WebcamFrame<0-n>===
 The frame number of the video recorded on camera with index i. i must be less than or equal to n due to the nature of event declarations. The default value of n is 3, allowing for the recording of up to 4 cameras. To record from more cameras, change the <code>NUM_OF_WEBCAM_EVENTS</code> macro in WebcamLogger.cpp to the number of cameras you want to record from and recompile. Event values can be used to synchronize the video with the recorded neural data. It is a 32-bit value, allowing 4294967295 frames before overflowing. If the webcam can capture at 30 frames/sec, this allows more than four years of video before it will go back to frame 0. In other words, this should not be an issue for most users.
 ==Troubleshooting==

Mellinger: /* Functional Description */

2025-06-03T15:54:06Z

Functional Description

← Older revision		Revision as of 15:54, 3 June 2025
Line 35:		Line 35:
	==Functional Description==		==Functional Description==
	For many experiments, visual information about how a subject is behaving during an experiment is desired. This extension acquires video from most webcams, and writes to an MP4 video file. It also records the current frame number as a state variable, so that the video can be synchronized with brain data at sample resolution (max. 1ms). Other options include the ability to overlay the date and time directly on the video (useful for long-term monitoring), and time decimation (i.e., save every Nth frame).		For many experiments, visual information about how a subject is behaving during an experiment is desired. This extension acquires video from most webcams, and writes to an MP4 video file. It also records the current frame number as a state variable, so that the video can be synchronized with brain data at sample resolution (max. 1ms). Other options include the ability to overlay the date and time directly on the video (useful for long-term monitoring), and time decimation (i.e., save every Nth frame).

			The video file bears the name of the BCI2000 data file, with the extension removed and <tt>_M_video.mp4</tt> appended where <tt>M</tt> is the index of the camera in question.
			For the format of the video file, see the notes below.

	'''NOTE:''' This module can also be used to perform screen capture with a virtual screencast webcam driver.		'''NOTE:''' This module can also be used to perform screen capture with a virtual screencast webcam driver.

Mellinger: /* Usage */

2025-06-03T15:41:49Z

Usage

← Older revision		Revision as of 15:41, 3 June 2025
Line 44:		Line 44:

	==Usage==		==Usage==
	Webcams should be installed and configured per the device instructions. ~~The~~ Webcam logger uses the Windows Media Foundation (WMF) library for display and saving. Desired resolution may be chosen per webcam, and will be matched agains available resolutions.		Webcams should be installed and configured per the device instructions. On Windows, the Webcam logger uses the Windows Media Foundation (WMF) library for display and saving. Desired resolution may be chosen per webcam, and will be matched agains available resolutions.

	Camera options are found in the ''Source'' tab of the Configuration window.		Camera options are found in the ''Source'' tab of the Configuration window.

Swiftj: /* Troubleshooting */

2024-04-16T20:12:11Z

Troubleshooting

← Older revision		Revision as of 20:12, 16 April 2024
Line 93:		Line 93:
	You may experience an error code stating that the remote procedure call failed when trying to launch the webcam logger. This is likely a driver issue. To fix this, try rolling back the camera driver in the device manager by following this [https://support.microsoft.com/en-us/windows/camera-doesn-t-work-in-windows-32adb016-b29c-a928-0073-53d31da0dad5 tutorial].		You may experience an error code stating that the remote procedure call failed when trying to launch the webcam logger. This is likely a driver issue. To fix this, try rolling back the camera driver in the device manager by following this [https://support.microsoft.com/en-us/windows/camera-doesn-t-work-in-windows-32adb016-b29c-a928-0073-53d31da0dad5 tutorial].

	~~[[File:WebcamDriverError.png\|alt="Webcam driver error"\|~~Webcam Driver Error]]		Webcam Driver Error

	[[File:WebcamRollbackDriver.png\|alt="Webcam rollback driver"\|Webcam Rollback Driver]]		[[File:WebcamDriverError.png\|400px\|alt="Webcam driver error"\|Webcam Driver Error]]

			Roll Back Driver

			[[File:WebcamRollbackDriver.png\|400px\|alt="Webcam rollback driver"\|Webcam Rollback Driver]]

	==See also==		==See also==

Swiftj: /* Troubleshooting */

2024-04-16T20:03:22Z

Troubleshooting

← Older revision		Revision as of 20:03, 16 April 2024
Line 92:		Line 92:
	==Troubleshooting==		==Troubleshooting==
	You may experience an error code stating that the remote procedure call failed when trying to launch the webcam logger. This is likely a driver issue. To fix this, try rolling back the camera driver in the device manager by following this [https://support.microsoft.com/en-us/windows/camera-doesn-t-work-in-windows-32adb016-b29c-a928-0073-53d31da0dad5 tutorial].		You may experience an error code stating that the remote procedure call failed when trying to launch the webcam logger. This is likely a driver issue. To fix this, try rolling back the camera driver in the device manager by following this [https://support.microsoft.com/en-us/windows/camera-doesn-t-work-in-windows-32adb016-b29c-a928-0073-53d31da0dad5 tutorial].

			[[File:WebcamDriverError.png\|alt="Webcam driver error"\|Webcam Driver Error]]

			[[File:WebcamRollbackDriver.png\|alt="Webcam rollback driver"\|Webcam Rollback Driver]]

	==See also==		==See also==

Swiftj at 19:20, 16 April 2024

2024-04-16T19:20:16Z

← Older revision		Revision as of 19:20, 16 April 2024
Line 89:		Line 89:
	===WebcamFrame<0-n>===		===WebcamFrame<0-n>===
	The frame number of the video recorded on camera with index i. i must be less than or equal to n due to the nature of event declarations. The default value of n is 3, allowing for the recording of up to 4 cameras. To record from more cameras, change the <code>NUM_OF_WEBCAM_EVENTS</code> macro in WebcamLogger.cpp to the number of cameras you want to record from and recompile. Event values can be used to synchronize the video with the recorded neural data. It is a 32-bit value, allowing 4294967295 frames before overflowing. If the webcam can capture at 30 frames/sec, this allows more than four years of video before it will go back to frame 0. In other words, this should not be an issue for most users.		The frame number of the video recorded on camera with index i. i must be less than or equal to n due to the nature of event declarations. The default value of n is 3, allowing for the recording of up to 4 cameras. To record from more cameras, change the <code>NUM_OF_WEBCAM_EVENTS</code> macro in WebcamLogger.cpp to the number of cameras you want to record from and recompile. Event values can be used to synchronize the video with the recorded neural data. It is a 32-bit value, allowing 4294967295 frames before overflowing. If the webcam can capture at 30 frames/sec, this allows more than four years of video before it will go back to frame 0. In other words, this should not be an issue for most users.

			==Troubleshooting==
			You may experience an error code stating that the remote procedure call failed when trying to launch the webcam logger. This is likely a driver issue. To fix this, try rolling back the camera driver in the device manager by following this [https://support.microsoft.com/en-us/windows/camera-doesn-t-work-in-windows-32adb016-b29c-a928-0073-53d31da0dad5 tutorial].

	==See also==		==See also==

← Older revision		Revision as of 13:54, 4 June 2025
Line 116:		Line 116:

	==See also==		==See also==
	[[User Reference:Logging Input]], [[Contributions:Extensions]], [[Programming Reference:Events]]		[[User Reference:Logging Input]], [[Contributions:Extensions]], [[Programming Reference:Events]], [[User Reference:BCI2000Viewer]]

	[[Category:Contributions]][[Category:Extension]]		[[Category:Contributions]][[Category:Extension]]