Recherche avancée

Sur d’autres sites (9354)

• Suppress black margins on the sides of an animation

  26 avril 2018, par Clinton Winant

  I need to make an animation out of a collection of jpeg images. The image size, as given by display, is 1200x900. I can control the size of the jpg images with convert, but not sure what a good size would be. I use the following ffmpeg call :

  ffmpeg -f image2 -i img%04d.jpg -r 24  sound.avi

  In spite of a long string of warnings like

  Past duration 0.879997 too large

  sound.avi is produced, however the animation includes black right and left margins (see attached screen shot of the first frame)

  

  that I need to suppress. I am under the impression that the 4x3 format of the jpg images is standard ? I view the animation with

  mplayer sound.avi

  The OS is Debian buster

  Further experiments suggest that the black margins disappear if the jpg files have an aspect ratio 16:9. Is that the only AR possible ?

  The output of

  ffmpeg -f image2 -i img%04d.jpg -vf cropdetect -vframes 5 -f null

  requested by @Gyan is

  ffmpeg version 3.4.2-2 Copyright (c) 2000-2018 the FFmpeg developers
  
    built with gcc 7 (Debian 7.3.0-15)
  
    configuration: --prefix=/usr --extra-version=2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  
    libavutil      55. 78.100 / 55. 78.100
  
    libavcodec     57.107.100 / 57.107.100
  
    libavformat    57. 83.100 / 57. 83.100
  
    libavdevice    57. 10.100 / 57. 10.100
  
    libavfilter     6.107.100 /  6.107.100
  
    libavresample   3.  7.  0 /  3.  7.  0
  
    libswscale      4.  8.100 /  4.  8.100
  
    libswresample   2.  9.100 /  2.  9.100
  
    libpostproc    54.  7.100 / 54.  7.100
  
  Trailing options were found on the commandline.
  
  Input #0, image2, from 'img%04d.jpg':
  
    Duration: 00:00:00.40, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1200x900 [SAR 150:150 DAR 4:3], 25 fps, 25 tbr, 25 tbn, 25 tbc

• Black video when using ffplay of received data over upd [closed]

  4 février 2023, par Alexandru-Marian Buza

  I'm encoding frames from a id3d11texture2d, and the receive packet size is around 70-80.
When i'm sending over udp, and use ffplay to show the video, i get a black screen.
Resolution and fps are well determined by ffplay.

  


  AcquiredBuffer.Attach(Buffer.MetaData.pSurface);

            ID3D11Texture2D* texture;
            ID3D11Texture2D* stagingTexture;
            AcquiredBuffer->QueryInterface(IID_PPV_ARGS(&texture));
            
            texture->GetDesc(&desc);
            desc.Usage = D3D11_USAGE_STAGING;
            desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
            desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
            desc.BindFlags = 0;
            desc.MiscFlags = 0;
            hr = m_Device->Device->CreateTexture2D(&desc, NULL, &stagingTexture);
            if (stagingTexture != 0) {
                m_Device->DeviceContext->CopyResource(stagingTexture, texture);
                D3D11_MAPPED_SUBRESOURCE mappedData;
                m_Device->DeviceContext->Map(stagingTexture, 0, D3D11_MAP_READ, 0, &mappedData);
                
                memcpy(frame->data[0], mappedData.pData, mappedData.DepthPitch);
                auto ret = avcodec_send_frame(codec, frame);
                if (ret < 0) {
                    writeText("Send frame failed");
                }
                else {
                    while (ret >= 0) {
                        ret = avcodec_receive_packet(codec, packet);
                        for (int i = 0; i < packet->size; i++) {
                            if (packet->data[i] != 0) {
                            }
                        }
                        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
                            break;
                        }
                        else if (ret < 0) {
                            writeText("Error durring encoding");
                        }
                        if (sendto(s, (char*)packet->data, packet->size * sizeof(uint8_t), 0, (sockaddr*)&dest, sizeof(dest)) == SOCKET_ERROR) {
                            writeText("Failed to send frame");
                        }
                        av_packet_unref(packet);
                    }
                }
                
                m_Device->DeviceContext->Unmap(stagingTexture, 0);
                stagingTexture->Release();


  


• opencv3.1 python VideoCapture black screen

  3 mai 2017, par alex

  i’m trying to use opencv3.1 with python3.5
  following this official)tutorial
  http://docs.opencv.org/3.0-beta/doc/py_tutorials/py_gui/py_video_display/py_video_display.html#display-video

  the camera led is "on" but the window doesn’t show any image (black)

  my current enviroment :
   windows 10
   python 3.5.2 (32bit)
   numpy 1.12.0b1 (32bit) binaries downloaded from : http://www.lfd.uci.edu/ gohlke/pythonlibs/
   opencv 3.1.0 (32bit) binaries downloaded from : http://www.lfd.uci.edu/ gohlke/pythonlibs/

  they seem installed correctly !

  as the tutorial says :

  Note Make sure proper versions of ffmpeg or gstreamer is installed. Sometimes, it is a headache to work with Video Capture mostly due to wrong installation of ffmpeg/gstreamer.

  i’ve no ffmpeg installed !!! so i suppose this is the cause of my problem
  so the questions are :
  1) which version of ffmpeg is needed ?
  2) how install ffmpeg on windows ? it seems a setup doesn’t exist(there is a binary section with a zip file ? how to use it after unzipped ?)
  3) is possible to see(in some way) if the opencv binaries(that i’ve downloaded) were compiled with ffmpeg support(flag ?)

  PS : i’ve tried to add the ffmpeg folder path the the PATH enviroment variable but nothing change