Windows 下使用 C 语言加密和播放视频文件

在 Windows 下，可以使用 Microsoft 提供的 Windows Media Foundation 库来加密和播放视频文件的加密数据。以下是一个示例代码，用于加密和播放视频文件的加密数据。

#include <windows.h>
#include <mfapi.h>
#include <mfidl.h>
#include <mfreadwrite.h>
#include <mferror.h>

// 加密视频文件
HRESULT EncryptVideoFile(LPCWSTR inputFile, LPCWSTR outputFile, LPCWSTR encryptionKey)
{
    IMFSourceReader* pSourceReader = NULL;
    IMFAttributes* pAttributes = NULL;
    IMFTransform* pTransform = NULL;
    IMFMediaSink* pSink = NULL;
    IMFSinkWriter* pSinkWriter = NULL;

    HRESULT hr = S_OK;

    // 创建源读取器
    hr = MFCreateSourceReaderFromURL(inputFile, NULL, &pSourceReader);
    if (FAILED(hr))
    {
        goto done;
    }

    // 创建转换器
    hr = MFCreateTransformNode(MFT_CATEGORY_VIDEO_EFFECT, CLSID_CMSAESDecryption, IID_PPV_ARGS(&pTransform));
    if (FAILED(hr))
    {
        goto done;
    }

    // 设置加密密钥
    hr = pTransform->SetInputParameter(0, &MF_TRANSFORM_CRYPTO_AES128_KEY, encryptionKey, sizeof(encryptionKey));
    if (FAILED(hr))
    {
        goto done;
    }

    // 创建输出文件
    hr = MFCreateSinkWriterFromURL(outputFile, NULL, NULL, &pSinkWriter);
    if (FAILED(hr))
    {
        goto done;
    }

    // 设置输入流格式
    hr = MFSetAttributeSize(pSinkWriter, MF_MT_FRAME_SIZE, 1920, 1080);
    if (FAILED(hr))
    {
        goto done;
    }

    // 添加视频流
    hr = pSinkWriter->AddStream(NULL, &pAttributes);
    if (FAILED(hr))
    {
        goto done;
    }

    // 设置输出流格式
    hr = pAttributes->SetGUID(MF_MT_MAJOR_TYPE, MFMediaType_Video);
    if (FAILED(hr))
    {
        goto done;
    }

    hr = pAttributes->SetGUID(MF_MT_SUBTYPE, MFVideoFormat_H264);
    if (FAILED(hr))
    {
        goto done;
    }

    // 设置流加密
    hr = pAttributes->SetUINT32(MF_MT_ALL_SAMPLES_INDEPENDENT, TRUE);
    if (FAILED(hr))
    {
        goto done;
    }

    // 设置流加密转换器
    hr = pAttributes->SetUnknown(MF_TRANSFORM_OBJECT_ID, pTransform);
    if (FAILED(hr))
    {
        goto done;
    }

    // 将输入流连接到加密转换器
    hr = pSourceReader->SetOutputMediaType((DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM, pAttributes, NULL);
    if (FAILED(hr))
    {
        goto done;
    }

    // 将输出流连接到输出文件
    hr = pSinkWriter->SetInputMediaType(0, pAttributes, NULL);
    if (FAILED(hr))
    {
        goto done;
    }

    // 开始转换和写入
    hr = pSinkWriter->BeginWriting();
    if (FAILED(hr))
    {
        goto done;
    }

    DWORD streamIndex, flags;
    LONGLONG timeStamp;
    IMFSample* pSample = NULL;

    // 读取源文件并写入输出文件
    while (SUCCEEDED(hr))
    {
        hr = pSourceReader->ReadSample((DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM, 0, &streamIndex, &flags, &timeStamp, &pSample);
        if (FAILED(hr))
        {
            goto done;
        }

        if (flags & MF_SOURCE_READERF_ENDOFSTREAM)
        {
            break;
        }

        hr = pSinkWriter->WriteSample(0, pSample);
        if (FAILED(hr))
        {
            goto done;
        }

        SafeRelease(&pSample);
    }

    // 完成写入
    hr = pSinkWriter->Finalize();

done:
    SafeRelease(&pSourceReader);
    SafeRelease(&pTransform);
    SafeRelease(&pSink);
    SafeRelease(&pSinkWriter);
    SafeRelease(&pAttributes);
    SafeRelease(&pSample);

    return hr;
}

// 播放加密视频文件
HRESULT PlayEncryptedVideo(LPCWSTR inputFile, LPCWSTR encryptionKey)
{
    IMFMediaSource* pSource = NULL;
    IMFMediaSession* pSession = NULL;
    IMFVideoDisplayControl* pDisplayControl = NULL;
    IUnknown* pUnknown = NULL;

    HRESULT hr = S_OK;

    // 创建媒体源
    hr = MFCreateSourceResolver(NULL)->CreateObjectFromURL(inputFile, MF_RESOLUTION_MEDIASOURCE, NULL, &pUnknown);
    if (FAILED(hr))
    {
        goto done;
    }

    hr = pUnknown->QueryInterface(IID_PPV_ARGS(&pSource));
    if (FAILED(hr))
    {
        goto done;
    }

    // 创建会话
    hr = MFCreateMediaSession(NULL, &pSession);
    if (FAILED(hr))
    {
        goto done;
    }

    // 设置会话源
    hr = pSession->SetTopology(0, NULL);
    if (FAILED(hr))
    {
        goto done;
    }

    // 创建视频显示控制器
    hr = MFGetService(pSession, MFNETSOURCE_VIDEO_PRESENT_SERVICE, IID_PPV_ARGS(&pDisplayControl));
    if (FAILED(hr))
    {
        goto done;
    }

    // 设置加密密钥
    hr = pDisplayControl->SetVideoWindow(NULL, MFVideoPresenter_MirrorImage, 0);
    if (FAILED(hr))
    {
        goto done;
    }

    hr = pDisplayControl->SetEncryptionKey(encryptionKey, sizeof(encryptionKey));
    if (FAILED(hr))
    {
        goto done;
    }

    // 开始播放
    hr = pSession->Start(&GUID_NULL, NULL);
    if (FAILED(hr))
    {
        goto done;
    }

    // 等待播放结束
    hr = pSession->WaitForEnd();
    if (FAILED(hr))
    {
        goto done;
    }

done:
    SafeRelease(&pSource);
    SafeRelease(&pSession);
    SafeRelease(&pDisplayControl);
    SafeRelease(&pUnknown);

    return hr;
}

int main()
{
    LPCWSTR inputFile = L"input.mp4";
    LPCWSTR outputFile = L"output.mp4";
    LPCWSTR encryptionKey = L"encryption_key";

    HRESULT hr = S_OK;

    // 加密视频文件
    hr = EncryptVideoFile(inputFile, outputFile, encryptionKey);
    if (FAILED(hr))
    {
        // 处理错误
        return hr;
    }

    // 播放加密视频文件
    hr = PlayEncryptedVideo(outputFile, encryptionKey);
    if (FAILED(hr))
    {
        // 处理错误
        return hr;
    }

    return 0;
}

注意：在运行代码前，请确保已经安装了 Windows Media Foundation 库，并在项目中添加了相应的库文件。代码中的 input.mp4 是输入视频文件，output.mp4 是输出加密后的视频文件，encryption_key 是加密密钥。