C Sharp Webcam

近日正在研究.Net Framework的webcam擷取方法，我想利用熟悉的C#程式語言來操作，可是卻發現.Net Framework中沒有這樣的Class可以使用，因此在Google與Jasper的協助之下，找到.Net Framework可以擷取的方法，其解決方案如下：

1. Microsoft® Video for Windows® (VFW)
2. Microsoft DirectShow API
3. Windows Image Acquisition (WIA)
4. Microsoft Media Foundation SDK

如果想要用DirectShow API的人，可以參考Windows SDK(自行到微軟網站免費取得)中的graphedt.exe這個程式(路徑通常是C:\Program Files\Microsoft SDKs\Windows\v6.1\Bin\graphedt.exe)，可以先玩玩看了解DirectShow的觀念，不過好像DirectShow較難上手，優點是效果跟效能較佳。

目前研讀的結果是這些大多以C++語言開發為主，若你是用C#語言開發，可能需要使用DllImportAttribute 類別的功能，參考

1. DllImportAttribute Class：http://msdn.microsoft.com/zh-tw/library/system.runtime.interopservices.dllimportattribute.aspx
2. Interoperating with Unmanaged Code：http://msdn.microsoft.com/en-us/library/sd10k43k.aspx
3. Platform Invoke Examples：http://msdn.microsoft.com/en-us/library/42b9ea93.aspx
4. Consuming Unmanaged DLL Functions：http://msdn.microsoft.com/en-us/library/26thfadc.aspx
5. Platform Invoke Data Types：http://msdn.microsoft.com/en-us/library/ac7ay120.aspx

就目前而言，最簡單且便利的方式是使用Microsoft® Video for Windows® (VFW)，這是Windows API，所以直接呼叫就可以囉！可以參考Video Capture Reference：http://msdn.microsoft.com/en-us/library/dd757696(VS.85).aspx

Basic Capture Operations

• capCreateCaptureWindow
• WM_CAP_ABORT
• WM_CAP_DRIVER_CONNECT
• WM_CAP_SEQUENCE
• WM_CAP_STOP

Capture Windows

• CAPSTATUS
• capGetDriverDescription
• WM_CAP_DRIVER_CONNECT
• WM_CAP_DRIVER_DISCONNECT
• WM_CAP_GET_STATUS

Capture Drivers

• CAPDRIVERCAPS
• WM_CAP_DRIVER_GET_CAPS
• WM_CAP_DRIVER_GET_NAME
• WM_CAP_DRIVER_GET_VERSION
• WM_CAP_GET_AUDIOFORMAT
• WM_CAP_GET_VIDEOFORMAT
• WM_CAP_SET_AUDIOFORMAT
• WM_CAP_SET_VIDEOFORMAT

Capture Driver Preview and Overlay Modes

• WM_CAP_SET_OVERLAY
• WM_CAP_SET_PREVIEW
• WM_CAP_SET_PREVIEWRATE
• WM_CAP_SET_SCALE
• WM_CAP_SET_SCROLL

Capture Driver Video Dialog Boxes

• WM_CAP_DLG_VIDEOCOMPRESSION
• WM_CAP_DLG_VIDEODISPLAY
• WM_CAP_DLG_VIDEOFORMAT
• WM_CAP_DLG_VIDEOSOURCE

Audio Format

• WM_CAP_GET_AUDIOFORMAT
• WM_CAP_SET_AUDIOFORMAT

Video Capture Settings

• CAPTUREPARMS
• WM_CAP_GET_SEQUENCE_SETUP
• WM_CAP_SET_SEQUENCE_SETUP

Capture File and Buffers

• CAPTUREPARMS
• WM_CAP_FILE_ALLOCATE
• WM_CAP_FILE_GET_CAPTURE_FILE
• WM_CAP_FILE_SAVEAS
• WM_CAP_FILE_SET_CAPTURE_FILE

Directly Using Capture Data

• WM_CAP_SEQUENCE_NOFILE

Capture from MCI Device

• WM_CAP_SET_MCI_DEVICE

Manual Frame Capture

• WM_CAP_SINGLE_FRAME
• WM_CAP_SINGLE_FRAME_CLOSE
• WM_CAP_SINGLE_FRAME_OPEN

Still-Image Capture

• WM_CAP_EDIT_COPY
• WM_CAP_FILE_SAVEDIB
• WM_CAP_GRAB_FRAME
• WM_CAP_GRAB_FRAME_NOSTOP

Advanced Capture Options

• WM_CAP_FILE_SET_INFOCHUNK
• WM_CAP_GET_USER_DATA
• WM_CAP_SET_USER_DATA

Working with Palettes

• WM_CAP_EDIT_COPY
• WM_CAP_PAL_AUTOCREATE
• WM_CAP_PAL_MANUALCREATE
• WM_CAP_PAL_OPEN
• WM_CAP_PAL_PASTE
• WM_CAP_PAL_SAVE

Yielding to Other Applications

• WM_CAP_GET_SEQUENCE_SETUP
• WM_CAP_SET_CALLBACK_YIELD
• WM_CAP_SET_SEQUENCE_SETUP

AVICap Callback Functions

• capControlCallback
• capErrorCallback
• capStatusCallback
• capVideoStreamCallback
• capWaveStreamCallback
• capYieldCallback
• WM_CAP_SET_CALLBACK_CAPCONTROL
• WM_CAP_SET_CALLBACK_ERROR
• WM_CAP_SET_CALLBACK_FRAME
• WM_CAP_SET_CALLBACK_STATUS
• WM_CAP_SET_CALLBACK_VIDEOSTREAM
• WM_CAP_SET_CALLBACK_WAVESTREAM
• WM_CAP_SET_CALLBACK_YIELD

另外一篇有用的資料：

Visual Studio C++ .NET Express: Using DirectShow in a Webcam Capture Application By bjhamltn_BJH Using DirectShow in a Webcam Capture Application