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• Read H264 streaming from Elp H264 with OpenCV + Pyhton

  15 janvier 2017, par Francesco Paissan

  I’m trying to read an udp streaming of a H264 encoded image. The software structure is like follows :

  On a BeagleBoneBlack (Ubuntu 16.04) I’ve an Elp H264 cam (see here : https://www.amazon.com/ELP-Support-Android-Windows-Surveillance/dp/B00VDSBH9G ). I stream frames with ffmpeg on a Unicast UDP Stream.

  I want to read this images from python and opencv to be able to process them.

  I tried with this simple code to see if the cap is opened or not :

  import cv2

  try:
  
       cap = cv2.VideoCapture("udp://localhost:1234/")
  
      cap.set(CV_CAP_PROP_FOURCC, CV_FOURCC('H', '2', '6', '4'));
  
  except Exception, e:
  
      print str(e)

  But when I run this script python says :

  DtsGetHWFeatures : Create File Failed DtsGetHWFeatures : Create File
  Failed Running DIL (3.22.0) Version DtsDeviceOpen : Opening HW in mode
  0 DtsDeviceOpen : Create File Failed libva info : VA-API version 0.38.1
  libva info : va_getDriverName() returns -1 libva error :
  va_getDriverName() failed with unknown libva error,driver_name=(null)
  libva info : VA-API version 0.38.1 libva info : va_getDriverName()
  returns -1 libva error : va_getDriverName() failed with unknown libva
  error,driver_name=(null) libva info : VA-API version 0.38.1 libva info :
  va_getDriverName() returns -1 libva error : va_getDriverName() failed
  with unknown libva error,driver_name=(null) libva info : VA-API version
  0.38.1 libva info : va_getDriverName() returns -1 libva error : va_getDriverName() failed with unknown libva error,driver_name=(null)
  GStreamer Plugin : Embedded video playback halted ; module vaapidecode
  reported : Could not initialize supporting library. OpenCV
  Error : Unspecified error (GStreamer : unable to start pipeline ) in
  cvCaptureFromCAM_GStreamer, file /builddir/build/BUILD/opencv-
  2.4.12.3/modules/highgui/src/cap_gstreamer.cpp, line 816 /builddir/build/BUILD/opencv-2.4.12.3/modules/highgui/src/cap_gstreamer.cpp:816 :
  error : (-2) GStreamer : unable to start pipeline in function
  cvCaptureFromCAM_GStreamer

  Can anybody help me ?

  Thanks,

  Francesco.

• lavf : deprecate av_stream_get_end_pts()

  17 août 2022, par Anton Khirnov

  lavf : deprecate av_stream_get_end_pts()
  According to its documentation it returns "pts of the last muxed packet
  
  + its duration", but the value it actually returns right now is
  
  (possibly guessed) dts after muxer-internal bitstream filtering (if
  
  any).
  This function was added for ffmpeg.c, but it is not used there anymore.
  
  Since the value it returns is ill-defined and so inappropriate for any
  
  serious use, deprecate it.
  

  • [DH] doc/APIchanges
  • [DH] libavformat/avformat.h
  • [DH] libavformat/mux_utils.c
  • [DH] libavformat/version_major.h

• Using ffmpeg to merge video segments created by the MediaRecorder API

  10 avril 2023, par Dario Cimmino

  I am recording a live video from a webcam using mediarecorder API un chunks of 3 seconds :

  


  startButton.addEventListener('click', () => {
navigator.mediaDevices.getUserMedia({
    video: {
        width: 1280,
        height: 720,
        frameRate: { ideal: 30, max: 30 }
    }
})
    .then(stream => {
        video.srcObject = stream;
        mediaRecorder = new MediaRecorder(stream, { mimeType: 'video/webm' });
        mediaRecorder.ondataavailable = async (event) => {
            const blob = new Blob([event.data], { type: 'video/mp4' });
            const formData = new FormData();
            formData.append('segment', blob, `segment${segmentNumber}.mp4`);

            // When a new video segment is ready
            fetch('http://localhost:3000/upload', {
                method: 'POST',
                body: formData
            })
                .then((response) => response.text())
                .then((result) => {
                    console.log('Upload result:', result);
                })
                .catch((error) => {
                    console.error('Error uploading video segment:', error);
                });
            //Upload data to mysql
            fetch('upload.php', {
                method: 'POST',
                body: formData
            })
                .then(response => response.text())
                .then(result => {
                    console.log('Upload result to MYSQL:', result);
                })
                .catch(error => {
                    console.error('Error uploading video segment to MYSQL:', error);
                });
            segmentNumber++;
        };

        mediaRecorder.start(3000);
    })
    .catch(error => {
        console.error('Error accessing camera:', error);
    });


  


  }) ;

  


  I am left with only the first segment playable, as is expected.

  


  How ever when the recording stops, i'd like to merge all those segments recorded using ffmpeg (or any other) with the help of my nodeJs server.

  


  I am having difficulty understand the parsing of mp4 files.

  


  if I try the command :

  


  ffmpeg -i segment1.mp4 -i segment2.mp4 -i segment3.mp4  out.mp4


  


  I get the following error :

  


      ffmpeg version N-110223-gb18a9c2971-20230410 Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (crosstool-NG 1.25.0.152_89671bf)
  configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --disable-libpulse --enable-libvmaf --disable-libxcb --disable-xlib --enable-amf --enable-libaom --enable-libaribb24 --enable-avisynth --enable-chromaprint --enable-libdav1d --enable-libdavs2 --disable-libfdk-aac --enable-ffnvcodec --enable-cuda-llvm --enable-frei0r --enable-libgme --enable-libkvazaar --enable-libass --enable-libbluray --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librist --enable-libssh --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --disable-libmfx --enable-libvpl --enable-openal --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopenmpt --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --disable-libdrm --disable-vaapi --enable-libvidstab --enable-vulkan --enable-libshaderc --enable-libplacebo --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --enable-libzvbi --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-ldexeflags= --extra-libs=-lgomp --extra-version=20230410
  libavutil      58.  6.100 / 58.  6.100
  libavcodec     60.  9.100 / 60.  9.100
  libavformat    60.  4.101 / 60.  4.101
  libavdevice    60.  2.100 / 60.  2.100
  libavfilter     9.  5.100 /  9.  5.100
  libswscale      7.  2.100 /  7.  2.100
  libswresample   4. 11.100 /  4. 11.100
  libpostproc    57.  2.100 / 57.  2.100
Input #0, matroska,webm, from 'segment1.mp4':
  Metadata:
    encoder         : Chrome
  Duration: N/A, start: 0.000000, bitrate: N/A
  Stream #0:0(eng): Video: h264 (Constrained Baseline), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], 30.30 fps, 30 tbr, 1k tbn (default)
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001d93cf25fc0] Format mov,mp4,m4a,3gp,3g2,mj2 detected only with low score of 1, misdetection possible!
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001d93cf25fc0] moov atom not found
segment2.mp4: Invalid data found when processing input


  


  any help or inputs are appreciated. THanks !