Question

可以实现IMFTransform接口来编码或解码H264或AAC数据，还是应该使用FFmpeg或OpenH264。

Answer 1

对媒体进行编码或解码时，IMFTransform是Media Foundation API中公开的接口编解码器。也就是说，你没有实现它 - 你利用了现有的编解码器实现（当你想扩展API并提供额外的编解码器时实现它）。

Stock Windows为您提供：

AAC Decoder - CLSID_CMSAACDecMFT
AAC Encoder - CLSID_AACMFTEncoder
H.264 Video Decoder - CLSID_CMSH264DecoderMFT，在适用的情况下利用DXVA硬件辅助解码
H.264 Video Encoder - CLSID_CMSH264EncoderMFT，软件（后备）编码器

可能会为其他硬件加速编码器提供硬件驱动程序。上面提到的所有内容都以IMFTransform的形式提供，可以直接使用或使用更高级别的Media Foundation API。

Answer 2

您可以实现CLSID_CMSH264DecoderMFT接口来解码和编码H264和AAC。请参阅CLSID_CMSAACDecMFT和CLSID_CMSH264EncoderMFT解码H264和ACC，同时解析CLSID_AACMFTEncoder和IUnknown *_transformUnk; IMFTransform *_encoder; HRESULT MediaEncoder::InitialiseEncoder(EncoderType encoder) { HRESULT hr = S_OK; // Has the encoder been init. if (!_isOpen) { _encoderType = encoder; // Init the COM. CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); // Create a new close event handler. _hCloseEvent = CreateEvent(NULL, FALSE, FALSE, NULL); // If event was not created. if (_hCloseEvent == NULL) { // Get the result value. hr = __HRESULT_FROM_WIN32(GetLastError()); } // If successful creation of the close event. if (SUCCEEDED(hr)) { // Start up Media Foundation platform. hr = MFStartup(MF_VERSION); _isOpen = true; } if (SUCCEEDED(hr)) { // Select the encoder. switch (encoder) { case Nequeo::Media::Foundation::EncoderType::H264: // Create the H264 encoder. hr = CreateEncoder(CLSID_CMSH264EncoderMFT); break; case Nequeo::Media::Foundation::EncoderType::AAC: // Create the AAC encoder. hr = CreateEncoder(CLSID_AACMFTEncoder); break; case Nequeo::Media::Foundation::EncoderType::MP3: // Create the MP3 encoder. hr = CreateEncoder(CLSID_MP3ACMCodecWrapper); break; default: hr = ((HRESULT)-1L); break; } } if (SUCCEEDED(hr)) { // Query for the IMFTransform interface hr = _transformUnk->QueryInterface(IID_PPV_ARGS(&_encoder)); // Encoder has been created. _created = true; } } // Return the result. return hr; } HRESULT MediaEncoder::CreateEncoder(const CLSID encoder) { HRESULT hr = S_OK; // Create the decoder. hr = CoCreateInstance(encoder, NULL, CLSCTX_INPROC_SERVER, IID_IUnknown, (void**)&_transformUnk); // Return the result. return hr; }以对H264和ACC进行编码。

编码器示例：初始化编码器。

    IUnknown    *_transformUnk;
    IMFTransform    *_decoder;

    HRESULT MediaDecoder::InitialiseDecoder(DecoderType decoder)
        {
            HRESULT hr = S_OK;

            // Has the decoder been init.
            if (!_isOpen)
            {
                _decoderType = decoder;

                // Init the COM.
                CoInitializeEx(NULL, COINIT_APARTMENTTHREADED);

                // Create a new close event handler.
                _hCloseEvent = CreateEvent(NULL, FALSE, FALSE, NULL);

                // If event was not created.
                if (_hCloseEvent == NULL)
                {
                    // Get the result value.
                    hr = __HRESULT_FROM_WIN32(GetLastError());
                }

                // If successful creation of the close event.
                if (SUCCEEDED(hr))
                {
                    // Start up Media Foundation platform.
                    hr = MFStartup(MF_VERSION);
                    _isOpen = true;
                }

                if (SUCCEEDED(hr))
                {
                    // Select the decoder.
                    switch (decoder)
                    {
                    case Nequeo::Media::Foundation::DecoderType::H264:
                        // Create the H264 decoder.
                        hr = CreateDecoder(CLSID_CMSH264DecoderMFT);
                        break;

                    case Nequeo::Media::Foundation::DecoderType::AAC:
                        // Create the AAC decoder.
                        hr = CreateDecoder(CLSID_CMSAACDecMFT);
                        break;

                    case Nequeo::Media::Foundation::DecoderType::MP3:
                        // Create the MP3 decoder.
                        hr = CreateDecoder(CLSID_CMP3DecMediaObject);
                        break;

                    case Nequeo::Media::Foundation::DecoderType::MPEG4:
                        // Create the MPEG4 decoder.
                        hr = CreateDecoder(CLSID_CMpeg4sDecMFT);
                        break;

                    default:
                        hr = ((HRESULT)-1L);
                        break;
                    }
                }

                if (SUCCEEDED(hr))
                {
                    // Query for the IMFTransform interface 
                    hr = _transformUnk->QueryInterface(IID_PPV_ARGS(&_decoder));

                    // Decoder has been created.
                    _created = true;
                }
            }

            // Return the result.
            return hr;
        }

        HRESULT MediaDecoder::CreateDecoder(const CLSID decoder)
        {
            HRESULT hr = S_OK;

            // Create the decoder.
            hr = CoCreateInstance(decoder, NULL, CLSCTX_INPROC_SERVER, IID_IUnknown, (void**)&_transformUnk);

            // Return the result.
            return hr;
        }

解码器示例：初始化解码器。

DataFrame.all()

实施＆＃39; IMFTransform＆＃39;编码或解码H264或AAC

2 个答案: