在Go中直接调用Win32 API进行视频捕获确实比较复杂,但可以通过syscall和golang.org/x/sys/windows包实现。以下是使用Media Foundation API捕获视频的基本示例:
package main
import (
"fmt"
"syscall"
"unsafe"
"golang.org/x/sys/windows"
)
var (
mfplat = windows.NewLazySystemDLL("mfplat.dll")
mf = windows.NewLazySystemDLL("mf.dll")
mfreadwrite = windows.NewLazySystemDLL("mfreadwrite.dll")
mfStartup = mfplat.NewProc("MFStartup")
mfShutdown = mfplat.NewProc("MFShutdown")
mfCreateSourceReaderFromMediaSource = mfreadwrite.NewProc("MFCreateSourceReaderFromMediaSource")
mfCreateMediaSource = mf.NewProc("MFCreateMediaSourceFromURL")
)
func main() {
// 初始化Media Foundation
hr, _, _ := mfStartup.Call(0x00020070, 0) // MF_VERSION
if hr != 0 {
panic(fmt.Sprintf("MFStartup failed: 0x%X", hr))
}
defer mfShutdown.Call()
// 创建视频捕获设备源
var mediaSource uintptr
devicePath, _ := syscall.UTF16PtrFromString("video=") // 默认视频设备
hr, _, _ = mfCreateMediaSource.Call(
uintptr(unsafe.Pointer(devicePath)),
0,
0,
uintptr(unsafe.Pointer(&mediaSource)),
)
if hr != 0 {
panic(fmt.Sprintf("Create media source failed: 0x%X", hr))
}
// 创建Source Reader
var sourceReader uintptr
hr, _, _ = mfCreateSourceReaderFromMediaSource.Call(
mediaSource,
0,
uintptr(unsafe.Pointer(&sourceReader)),
)
if hr != 0 {
panic(fmt.Sprintf("Create source reader failed: 0x%X", hr))
}
fmt.Println("Video capture initialized successfully")
// 这里可以添加帧读取和处理逻辑
// ...
}
对于更完整的实现,需要添加以下功能:
// 定义必要的GUID和接口
var (
IID_IMFSourceReader = windows.GUID{0x70ae66f2, 0xc809, 0x4e4f, [8]byte{0x89, 0x15, 0xbd, 0xcb, 0xbd, 0x94, 0x11, 0x50}}
MFMediaType_Video = windows.GUID{0x73646976, 0x0000, 0x0010, [8]byte{0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}}
)
// 设置视频输出格式(示例:RGB32)
func setVideoFormat(sourceReader uintptr) error {
var mediaType uintptr
hr, _, _ := mfCreateMediaType.Call(uintptr(unsafe.Pointer(&mediaType)))
if hr != 0 {
return fmt.Errorf("CreateMediaType failed: 0x%X", hr)
}
// 设置媒体类型为视频
setGUID, _, _ := mfSetGUID.Call(
mediaType,
uintptr(unsafe.Pointer(&MFMediaType_Video)),
0,
)
// 设置子类型为RGB32
mfSubTypeRGB32 := windows.GUID{0x00000016, 0x0000, 0x0010, [8]byte{0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}}
setGUID, _, _ = mfSetGUID.Call(
mediaType,
uintptr(unsafe.Pointer(&mfSubTypeRGB32)),
uintptr(unsafe.Pointer(&MF_MT_SUBTYPE)),
)
// 应用到Source Reader
hr, _, _ = mfSetCurrentMediaType.Call(
sourceReader,
0,
0,
mediaType,
)
return nil
}
// 读取视频帧
func readVideoFrame(sourceReader uintptr) ([]byte, error) {
var flags, actualStreamIndex, timestamp uint32
var sample uintptr
hr, _, _ := mfReadSample.Call(
sourceReader,
0, // Stream index
0,
uintptr(unsafe.Pointer(&flags)),
uintptr(unsafe.Pointer(&actualStreamIndex)),
uintptr(unsafe.Pointer(×tamp)),
uintptr(unsafe.Pointer(&sample)),
)
if hr != 0 {
return nil, fmt.Errorf("ReadSample failed: 0x%X", hr)
}
// 从sample中获取缓冲区数据
// ... 需要实现IMFSample接口方法
return nil, nil
}
注意:完整实现需要定义更多Win32接口和常量,上述代码展示了基本框架。实际使用时需要处理COM接口、内存管理、错误处理等细节。