openh264-bEnableFrameSkip = 0，无法控制比特率 [英] openh264 - bEnableFrameSkip=0, bitrate can't be controlled

问题描述

关于opencv + H.264，有很多问题要问，但是 他们都没有给出详细的解释.

我在Visual Studio中使用的是openh264(openh264-1.4.0-win32msvc.dll)和opencv 3.1(启用了ffmpeg的cmake的自定义版本)，我想将来自网络摄像头的视频保存为H.264压缩的mp4格式

there are a lot of questions asked regarding opencv + H.264 but none of them gave detailed explanation.

i am using openh264(openh264-1.4.0-win32msvc.dll) along with opencv 3.1(custom build with cmake having ffmpeg enabled) in visual studio, i wanted to save video coming from webcam in mp4 format with H.264 compression

VideoWriter写入= VideoWriter("D:/movie.mp4"，CV_FOURCC('H'，'2'， '6'，'4')，10.0，cv :: Size(192，144)，true);

VideoWriter write = VideoWriter("D:/movie.mp4", CV_FOURCC('H', '2', '6', '4'), 10.0, cv::Size(192, 144), true);

在使用openh264之前，在控制台窗口中我看到一条警告消息 无法加载openh264库:openh264-1.4.0-win32msvc.dll 请检查您的环境和/或从此处下载: https://github.com/cisco/openh264/releases (视频也未保存)

before using openh264, in console window i was seeing an warning message "Failed to load openh264 library : openh264-1.4.0-win32msvc.dll please check your environment and/or download from here: https://github.com/cisco/openh264/releases" (also video was not been saved)

所以我下载了dll&与我的程序文件(exe)放在一个文件夹中 现在，当我运行程序时，我看到了不同的错误 "[OpenH264]此= 0x0DE312C0，警告:bEnabledFrameSkip = 0，如果不启用跳过帧就无法控制RC_QUALITY_MODE和RC_TIMESTAMP_MODE的比特率" (现在已保存视频，但是大小非常高！比特率约为1200 Kbps)

so i downloaded the dll & kept in a folder with my program file(exe) now when i run the program, i'm seeing different error "[OpenH264] this = 0x0DE312C0, warning: bEnabledFrameSkip=0, bitrate can't be controlled for RC_QUALITY_MODE and RC_TIMESTAMP_MODE without enabling skip frame" (now video is saved, but size is very high! bit rate is around 1200 Kbps)

对我来说，使用h264的唯一目的是减小文件大小..我想我可能不得不自己进行一些更改来构建openh264才能消除此错误，任何人都可以指导我如何做?还是告诉我是否有一种方法可以通过代码降低比特率?

for me, the sole purpose of using h264 is to reduce the file size.. i think i may have to build openh264 myself with some changes to remove this error, can anyone guide me how? or tell me if there is a way to reduce bit rate somehow through code?

P.S:我尝试提供-1而不是CV_FOURCC()，但系统中显示了已安装的编解码器"窗口，即使我安装了各种编解码器包，我也找不到h264或x264或h264vfw.来自此处

P.S: I tried giving -1 instead of CV_FOURCC(), 'installed codecs' window in my system showed up, i couldn't find h264 or x264 or h264vfw even though i have installed variety of codec packs & h264 from here

感谢&问候

推荐答案

如果要控制比特率，则必须同时使用

If you want to control bitrate, You have to use both

encoderParemeters.iRCMode = RC_OFF_MODE;
encoderParemeters.bEnableFrameSkip = true; 

在这里，我以示例显示所有Openh264编码参数:

Here I am showing all the Openh264 Encoding parameters as an Example:

long nReturnedValueFromEncoder = WelsCreateSVCEncoder(&m_pSVCVideoEncoder);


    m_nVideoWidth = 352;
    m_nVideoHeight = 288;

    SEncParamExt encoderParemeters;

    memset(&encoderParemeters, 0, sizeof(SEncParamExt));

    m_pSVCVideoEncoder->GetDefaultParams(&encoderParemeters);

    encoderParemeters.iUsageType = CAMERA_VIDEO_REAL_TIME;
    encoderParemeters.iTemporalLayerNum = 0;
    encoderParemeters.uiIntraPeriod = 15;
    encoderParemeters.eSpsPpsIdStrategy = INCREASING_ID;
    encoderParemeters.bEnableSSEI = false;
    encoderParemeters.bEnableFrameCroppingFlag = true;
    encoderParemeters.iLoopFilterDisableIdc = 0;
    encoderParemeters.iLoopFilterAlphaC0Offset = 0;
    encoderParemeters.iLoopFilterBetaOffset = 0;
    encoderParemeters.iMultipleThreadIdc = 0;

    encoderParemeters.iRCMode = RC_BITRATE_MODE;
    encoderParemeters.iMinQp = 0;
    encoderParemeters.iMaxQp = 52;



    encoderParemeters.bEnableDenoise = false;
    encoderParemeters.bEnableSceneChangeDetect = false;
    encoderParemeters.bEnableBackgroundDetection = true;
    encoderParemeters.bEnableAdaptiveQuant = false;
    encoderParemeters.bEnableFrameSkip = true;
    encoderParemeters.bEnableLongTermReference = true;
    encoderParemeters.iLtrMarkPeriod = 20;
    encoderParemeters.bPrefixNalAddingCtrl = false;
    encoderParemeters.iSpatialLayerNum = 1;


    SSpatialLayerConfig *spartialLayerConfiguration = &encoderParemeters.sSpatialLayers[0];

    spartialLayerConfiguration->uiProfileIdc = PRO_BASELINE;//;

    encoderParemeters.iPicWidth = spartialLayerConfiguration->iVideoWidth = m_nVideoWidth;
    encoderParemeters.iPicHeight = spartialLayerConfiguration->iVideoHeight = m_nVideoHeight;
    encoderParemeters.fMaxFrameRate = spartialLayerConfiguration->fFrameRate = (float)30;

    encoderParemeters.iTargetBitrate = spartialLayerConfiguration->iSpatialBitrate = 500000;
    encoderParemeters.iTargetBitrate = spartialLayerConfiguration->iMaxSpatialBitrate = 500000;


    spartialLayerConfiguration->iDLayerQp = 24;
    //spartialLayerConfiguration->sSliceCfg.uiSliceMode = SM_SINGLE_SLICE;
    spartialLayerConfiguration->sSliceArgument.uiSliceMode = SM_SINGLE_SLICE;


    nReturnedValueFromEncoder = m_pSVCVideoEncoder->InitializeExt(&encoderParemeters);

希望它会对您有所帮助.

Hope it will help you.

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