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• select a screen section ffmpeg c++ on macos

  21 avril 2022, par C1ngh10

  I am trying to record the screen on macos, with ffmpeg. I would like to be able to select a section of the screen instead of the whole desktop. I tried to set several options such as vf, with values like "crop=150:150:0:0", or video_size with value "150x150". The result was that the output video had the correct dimensions (150x150) but whole screen has been recorded instead of the specified section. Does anybody know another way to do that ?

  


  int ScreenRecorder::openVideoDevice() {
    value = 0;
    videoOptions = nullptr;
    pAVFormatContext = nullptr;

    pAVFormatContext = avformat_alloc_context();


    string dimension = to_string(width) + "x" + to_string(height);
    av_dict_set(&videoOptions, "video_size", dimension.c_str(), 0);   //option to set the dimension of the screen section to record
    value = av_dict_set(&videoOptions, "framerate", "25", 0);
    if (value < 0) {
        cerr << "Error in setting dictionary value (setting framerate)" << endl;
        exit(-1);
    }

    value = av_dict_set(&videoOptions, "preset", "ultrafast", 0);
    if (value < 0) {
        cerr << "Error in setting dictionary value (setting preset value)" << endl;
        exit(-1);
    }

    //The distance from the left edge of the screen or desktop
    value = av_dict_set(&videoOptions, "vf", ("crop=" + to_string(width) + ":" + to_string(height) + ":" + to_string(x_offset) + ":" +
        to_string(y_offset)).c_str(), 0);

    if (value < 0) {
        cerr << "Error in setting crop" << endl;
        exit(-1);
    }

    value = av_dict_set(&videoOptions, "pixel_format", "yuv420p", 0);
    if (value < 0) {
        cerr << "Error in setting pixel format" << endl;
        exit(-1);
    }
    
    pAVInputFormat = av_find_input_format("avfoundation");

    if (avformat_open_input(&pAVFormatContext, "1:none", pAVInputFormat, &videoOptions) != 0) {
        cerr << "Error in opening input device" << endl;
        exit(-1);
    }
    //get video stream infos from context
    value = avformat_find_stream_info(pAVFormatContext, nullptr);
    if (value < 0) {
        cerr << "Error in retrieving the stream info" << endl;
        exit(-1);
    }

    VideoStreamIndx = -1;
    for (int i = 0; i < pAVFormatContext->nb_streams; i++) {
        if (pAVFormatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
            VideoStreamIndx = i;
            break;
        }
    }
    if (VideoStreamIndx == -1) {
        cerr << "Error: unable to find video stream index" << endl;
        exit(-2);
    }

    pAVCodecContext = pAVFormatContext->streams[VideoStreamIndx]->codec;
    pAVCodec = avcodec_find_decoder(pAVCodecContext->codec_id/*params->codec_id*/);
    if (pAVCodec == nullptr) {
        cerr << "Error: unable to find decoder video" << endl;
        exit(-1);
    }

    return 0;
}


  


• Live555 Multicast RTSP Server - Display in FFMPEG

  31 mai 2021, par BanB

  I made a multicast RTSP server using the Live555 library.
  
It is displayed by VLC but not from VMS (NX Witness) or FFMPEG.
  
If I use the Unicast, I can display it, but I do not know how to change the file that is streaming in the Unicast.
  
Is there a way to change the streaming file in Unicast or make it viewable in FFMPEG with Multicast ?

  


  This is my code.

  


  


  Header

  


  


  #include <iostream>&#xA;#include <string>&#xA;#include <filesystem>&#xA;#include <fstream>&#xA;#include <ctime>&#xA;#include &#xA;#include &#xA;#include  &#xA;#include <opencv2></opencv2>videoio.hpp>&#xA;#include <opencv2></opencv2>imgcodecs.hpp>&#xA;&#xA;void Start(const char* streamPath, int port);&#xA;void AddDataL(BYTE* data, int length);&#xA;AddDataHW(BYTE* data, int height, int width);&#xA;&#xA;void Play();&#xA;void AfterPlaying(void*);&#xA;&#xA;void EncodeToH264(cv::Mat image);&#xA;long long GetTimeMs();&#xA;int GetFileCount();&#xA;const char* GetFirstFilePath();&#xA;&#xA;const int fourcc = cv::VideoWriter::fourcc(&#x27;x&#x27;, &#x27;2&#x27;, &#x27;6&#x27;, &#x27;4&#x27;);&#xA;&#xA;UsageEnvironment* env;&#xA;H264ServerMediaSubsession* h264;&#xA;H264VideoStreamFramer* videoSource;&#xA;RTPSink* videoSink;&#xA;&#xA;const char* dataPath = "data/";&#xA;const char* extension = ".h264";&#xA;</ctime></fstream></filesystem></string></iostream>

  


  


  CPP

  


  


  void Start()
{
    askScheduler *scheduler = BasicTaskScheduler::createNew();
    env = BasicUsageEnvironment::createNew(*scheduler);

    RTSPServer *rtspServer = RTSPServer::createNew(*env, 8554);

    if (rtspServer == NULL)
        throw;

    struct sockaddr_storage destinationAddress;
    destinationAddress.ss_family = AF_INET;
    ((struct sockaddr_in &)destinationAddress).sin_addr.s_addr = chooseRandomIPv4SSMAddress(*env);

    const unsigned short rtpPortNum = 18888;
    const unsigned short rtcpPortNum = rtpPortNum + 1;
    const unsigned char ttl = 255;

    const Port rtpPort(rtpPortNum);
    const Port rtcpPort(rtcpPortNum);

    Groupsock rtpGroupsock(*env, destinationAddress, rtpPort, ttl);
    rtpGroupsock.multicastSendOnly();
    Groupsock rtcpGroupsock(*env, destinationAddress, rtcpPort, ttl);
    rtcpGroupsock.multicastSendOnly();

    OutPacketBuffer::maxSize = 300000;
    videoSink = H264VideoRTPSink::createNew(*env, &rtpGroupsock, 96);

    const unsigned estimatedSessionBandwidth = 5000;
    const unsigned maxCNAMElen = 100;
    unsigned char CNAME[maxCNAMElen + 1];
    gethostname((char *)CNAME, maxCNAMElen);
    CNAME[maxCNAMElen] = '\0';

    RTCPInstance *rtcp = RTCPInstance::createNew(*env, &rtcpGroupsock, estimatedSessionBandwidth, CNAME, videoSink, NULL, True);

    ServerMediaSession *sms = ServerMediaSession::createNew(*env, "live", "live", "Session streamed by \"Test Server\"", True);
    sms->addSubsession(PassiveServerMediaSubsession::createNew(*videoSink, rtcp));
    rtspServer->addServerMediaSession(sms);

    *env << "Start > " << rtspServer->rtspURL(sms) << "\n";

    Play();

    env->taskScheduler().doEventLoop();
}

void AddData(BYTE* data, int length)
{
    EncodeToH264(cv::imdecode(cv::Mat(1, length, CV_8UC3, data), 1));
}

void EncodeToH264(cv::Mat image)
{
    std::string fileName = dataPath + std::to_string(GetTimeMs()) + extension;
    cv::VideoWriter writer(fileName.c_str(), fourcc, 1, image.size());
    writer.write(image);
    writer.write(image);
    writer.release();
}

void Play()
{
    while (GetFileCount() == 0);

    const char* fileName = GetFirstFilePath();

    ByteStreamFileSource* fileSource;
    while ((fileSource = ByteStreamFileSource::createNew(*env, fileName)) == NULL);

    FramedSource* videoES = fileSource;

    videoSource = H264VideoStreamFramer::createNew(*env, videoES);

    videoSink->startPlaying(*videoSource, AfterPlaying, videoSink);
}

void AfterPlaying(void*)
{
    videoSink->stopPlaying();
    Medium::close(videoSource);

    if (GetFileCount() > 1)
        std::filesystem::remove(GetFirstFilePath());

    Play();
}

long long GetTimeMs()
{
    return std::chrono::duration_cast(std::chrono::system_clock::now().time_since_epoch()).count();
}

int GetFileCount() 
{
    return std::distance(std::filesystem::directory_iterator(dataPath), std::filesystem::directory_iterator());
}

const char* GetFirstFilePath()
{
    for (const auto& entry : std::filesystem::directory_iterator(dataPath))
        return entry.path().string().c_str();
}


  


• ffmpeg motions not working properly while using multiple urls

  22 avril 2021, par al pacino

  I am trying to apply ffmpeg transitions but sometimes video gets concatenated without any transition. In the command below I have used input 1 which in present on derectory and second input is online video url. the output video got concatenated without distance transition -

  


  one example of distance transition command is below-

  


  ffmpeg -i video1.webm -i 'url2' -filter_complex '[0]scale=1280:720,settb=AVTB[v0];[1]scale=1280:720,settb=AVTB[v1];[v0][v1]xfade=transition=distance:duration=1:offset=9,format=yuv420p’ output_video.webm


  


  and log is below-

  


   ffmpeg version n4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --prefix= --prefix=/usr --disable-debug --disable-doc --disable-static --enable-cuda --enable-cuda-sdk --enable-cuvid --enable-libdrm --enable-ffplay --enable-gnutls --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfontconfig --enable-libfreetype --enable-libmp3lame --enable-libnpp --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopus --enable-libpulse --enable-sdl2 --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libv4l2 --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxvid --enable-nonfree --enable-nvenc --enable-omx --enable-openal --enable-opencl --enable-runtime-cpudetect --enable-shared --enable-vaapi --enable-vdpau --enable-version3 --enable-xlib
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0, matroska,webm, from '/home/abc/xyz/887c28b7-8819-42d3-bb4f-95c44a72bce9.webm':
  Metadata:
    MINOR_VERSION   : 0
    COMPATIBLE_BRANDS: mp42mp41isomavc1
    MAJOR_BRAND     : mp42
    ENCODER         : Lavf58.45.100
  Duration: 00:00:21.03, start: -0.006000, bitrate: 346 kb/s
    Stream #0:0: Video: vp9 (Profile 0), yuv420p(tv), 480x360, SAR 1:1 DAR 4:3, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
    Metadata:
      ENCODER         : Lavc58.91.100 libvpx-vp9
      DURATION        : 00:00:21.033000000
    Stream #0:1: Audio: opus, 48000 Hz, stereo, fltp (default)
    Metadata:
      HANDLER_NAME    : L-SMASH Audio Handler
      ENCODER         : Lavc58.91.100 libopus
      DURATION        : 00:00:10.013000000
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'https://player.vimeo.com/external/521230771.sd.mp4?s=9ee7ac91c97713d955848e34deac37d6d03d76a8&profile_id=164':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: mp42mp41isomavc1
    creation_time   : 2021-03-09T03:42:34.000000Z
  Duration: 00:00:10.01, start: 0.000000, bitrate: 619 kb/s
    Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, smpte170m), 640x360, 488 kb/s, 30 fps, 30 tbr, 30 tbn, 60 tbc (default)
    Metadata:
      creation_time   : 2021-03-09T03:42:34.000000Z
      handler_name    : L-SMASH Video Handler
      encoder         : AVC Coding
    Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 125 kb/s (default)
    Metadata:
      creation_time   : 2021-03-09T03:42:34.000000Z
      handler_name    : L-SMASH Audio Handler
Stream mapping:
  Stream #0:0 (vp9) -> scale (graph 0)
  Stream #1:0 (h264) -> scale (graph 0)
  format (graph 0) -> Stream #0:0 (libvpx-vp9)
  Stream #0:1 -> #0:1 (opus (native) -> opus (libopus))
Press [q] to stop, [?] for help
[libopus @ 0x5597e87c5bc0] No bit rate set. Defaulting to 96000 bps.
[libvpx-vp9 @ 0x5597e87c46c0] v1.7.0
[libvpx-vp9 @ 0x5597e87c46c0] Neither bitrate nor constrained quality specified, using default CRF of 32
Output #0, webm, to '/home/abc/afcb26e1-9c7a-4065-be6e-d1a2940ee0d9.webm':
  Metadata:
    MINOR_VERSION   : 0
    COMPATIBLE_BRANDS: mp42mp41isomavc1
    MAJOR_BRAND     : mp42
    encoder         : Lavf58.45.100
    Stream #0:0: Video: vp9 (libvpx-vp9), yuv420p, 480x360 [SAR 1:1 DAR 4:3], q=-1--1, 30 fps, 1k tbn, 30 tbc (default)
    Metadata:
      encoder         : Lavc58.91.100 libvpx-vp9
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
    Stream #0:1: Audio: opus (libopus), 48000 Hz, stereo, flt, 96 kb/s (default)
    Metadata:
      HANDLER_NAME    : L-SMASH Audio Handler
      DURATION        : 00:00:10.013000000
      encoder         : Lavc58.91.100 libopus
frame=  858 fps= 44 q=0.0 Lsize=    1141kB time=00:00:29.00 bitrate= 322.2kbits/s speed=1.48x    
video:1130kB audio:1kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.861019%