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• How to fill an AVFrame structure in order to encode an YUY2 video (or UYVY) into H265

  22 avril, par Rich Deng

  I want to compress a video stream in YUY2 or UYVY format to, say H265. If I understand the answers given this thread correctly, I should be able use the function av_image_fill_arrays() to fill the data and linesize arrays of an AVFrame object, call avcodec_send_frame(), and then avcodec_receive_packet() to get encoded data :

  


  bool VideoEncoder::Init(const AM_MEDIA_TYPE* pMediaType)
{
    // we should have a valid pointer
    if (pMediaType)
    {
        m_mtInput.Empty();
        m_mtInput.Set(*pMediaType);
    }
    else
        return false;

        // find encoder
    m_pCodec = m_spAVCodecDlls->avcodec_find_encoder(AV_CODEC_ID_HEVC);
    m_pCodecCtx = m_spAVCodecDlls->avcodec_alloc_context3(m_pCodec);
    if (!m_pCodec || !m_pCodecCtx)
    {
        Log.Log(_T("Failed to find or allocate codec context!"));
        return false;
    }

    AVPixelFormat ePixFmtInput = GetInputPixelFormat();
    if (CanConvertInputFormat(ePixFmtInput) == false)
    {
        return false;
    }

    // we are able to convert
    // so continue with setting it up
    int nWidth = m_mtInput.GetWidth();
    int nHeight = m_mtInput.GetHeight();

    // Set encoding parameters

    // Set bitrate (4 Mbps for 1920x1080)
    m_pCodecCtx->bit_rate = (((int64)4000000 * nWidth / 1920) * nHeight / 1080);  

    m_pCodecCtx->width = nWidth;  
    m_pCodecCtx->height = nHeight;


    // use reference time as time_base
    m_pCodecCtx->time_base.den = 10000000;  
    m_pCodecCtx->time_base.num = 1;

    SetAVRational(m_pCodecCtx->framerate, m_mtInput.GetFrameRate());
    //m_pCodecCtx->framerate = (AVRational){ 30, 1 };
    m_pCodecCtx->gop_size = 10;  // GOP size
    m_pCodecCtx->max_b_frames = 1;

    // set pixel format
    m_pCodecCtx->pix_fmt = ePixFmtInput;  // YUV 4:2:0 format or YUV 4:2:2

    // Open the codec
    if (m_spAVCodecDlls->avcodec_open2(m_pCodecCtx, m_pCodec, NULL) < 0)
    {
        return false;
    }

        return true;
}

bool VideoEncoder::AllocateFrame()
{

    m_pFrame = m_spAVCodecDlls->av_frame_alloc();
    if (m_pFrame == NULL)
    {
        Log.Log(_T("Failed to allocate frame object!"));
        return false;
    }

    m_pFrame->format = m_pCodecCtx->pix_fmt;
    m_pFrame->width = m_pCodecCtx->width;
    m_pFrame->height = m_pCodecCtx->height;

    m_pFrame->time_base.den = m_pCodecCtx->time_base.den;
    m_pFrame->time_base.num = m_pCodecCtx->time_base.num;


    return true;
}

bool VideoEncoder::Encode(IMediaSample* pSample)
{
    if (m_pFrame == NULL)
    {
        return false;
    }

    // get the time stamps
    REFERENCE_TIME rtStart, rtEnd;
    HRESULT hr = pSample->GetTime(&rtStart, &rtEnd);
    m_rtInputFrameStart = rtStart;
    m_rtInputFrameEnd = rtEnd;


    // get length
    int nLength = pSample->GetActualDataLength();

    // get pointer to actual sample data
    uint8_t* pData = NULL;
    hr = pSample->GetPointer(&pData);

    if (FAILED(hr) || NULL == pData)
        return false;

    m_pFrame->flags = (S_OK == pSample->IsSyncPoint()) ? (m_pFrame->flags | AV_FRAME_FLAG_KEY) : (m_pFrame->flags & ~AV_FRAME_FLAG_KEY);

    // clear old data
    for (int n = 0; n < AV_NUM_DATA_POINTERS; n++)
    {
        m_pFrame->data[n] = NULL;// (uint8_t*)aryData[n];
        m_pFrame->linesize[n] = 0;// = aryStride[n];
    }


    int nRet = 0;
    int nStride = m_mtInput.GetStride();
    nRet = m_spAVCodecDlls->av_image_fill_arrays(m_pFrame->data, m_pFrame->linesize, pData, ePixFmt, m_pFrame->width, m_pFrame->height, 32);
    if (nRet < 0)
    {
        return false;
    }

    m_pFrame->pts = (int64_t) rtStart;
    m_pFrame->duration = rtEnd - rtStart;
    nRet = m_spAVCodecDlls->avcodec_send_frame(m_pCodecCtx, m_pFrame);
    if (nRet == AVERROR(EAGAIN))
    {
        ReceivePacket();
        nRet = m_spAVCodecDlls->avcodec_send_frame(m_pCodecCtx, m_pFrame);
    }

    if (nRet < 0)
    {
        return false;
    }

    // Receive the encoded packets
    ReceivePacket();

    return true;
}

bool VideoEncoder::ReceivePacket()
{
    bool bRet = true;
    AVPacket* pkt = m_spAVCodecDlls->av_packet_alloc();
    while (m_spAVCodecDlls->avcodec_receive_packet(m_pCodecCtx, pkt) == 0)
    {
        // Write pkt->data to output file or stream
        m_pCallback->VideoEncoderWriteEncodedSample(pkt);
        if (m_OutFile.IsOpen())
            m_OutFile.Write(pkt->data, pkt->size);
        m_spAVCodecDlls->av_packet_unref(pkt);
    }
    m_spAVCodecDlls->av_packet_free(&pkt);

    return bRet;
}


  


  I must have done something wrong. The result is not correct. For example, rather than a video with a person's face showing in the middle of the screen, I get a mostly green screen with parts of the face showing up at the lower left and lower right corners.

  


  Can someone help me ?

  


• dxva2_vc1 : fix signaling of intensity compensation values

  12 décembre 2013, par Hendrik Leppkes

  dxva2_vc1 : fix signaling of intensity compensation values
  lumscale/lumshift don’t get reset back to their default values if
  
  intensity compensation is not active, and a wrong signaling here can
  
  cause playback issues.
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/dxva2_vc1.c

• Getting List of default argument values if not used in FFMPEG command execution

  12 juillet 2020, par Pradeep Prabhu

  When I use FFMPEG to capture a live IPTV stream on my MAC, I generally end up with an interrupted video. When I send these four arguments, the capture is successful.

  


  -reconnect 1 -reconnect_at_eof 1 -reconnect_streamed 1 -reconnect_delay_max 2

  


  I don't want to specify these arguments everytime, So I decided to update the default values in the source code. Unsure if I have done it right - I updated http.c which contains these arguments. I re-compiled FFMPEG successfully.

  


  I want to know if my changes are applied. Is there a way I can list out all the default values of the arguments. I can use this compiled version of FFMPEG for a week, and determine if the fix is applied or not, I was wondering, if there is a quicker and easier way to do it.

  


  If this is successful, I can use this version of FFMPEG for Emby & TellyTV.