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• How can I increase the size of an mp4 file to a specific value ?

  20 juin 2023, par zoomer-girl

  this is my first time here. I'm not a programmer. Question : For example, I have a video file size of 1500 mb, I need to increase the video size to 3500 mb, without changing the video quality or lenght. It is important that the final file size should have an accuracy of +- 10 mb. I thought it could be done by adding a second empty audio track using FFMPEG, but I didn't succeed :( If anyone knows how to do this, please help

  


  I tried to add an empty audio track lasting several hours and with a bitrate of 192 kbps using FFMPEG. However, the file size did not change much, although this audio track appeared in the VLC player, but for some reason it showed that the bitrate was 1 kbps

  


• Python : Extracting device and lens information from video metadata

  14 mai 2023, par cat_got_my_tongue

  I am interested in extracting device and lens information from videos. Specifically, make and model of the device and the focal length. I was able to do this successfully for still images using the exifread module and extract a whole bunch of very useful information :

  


  image type      : MPO
Image ImageDescription: Shot with DxO ONE
Image Make: DxO
Image Model: DxO ONE
Image Orientation: Horizontal (normal)
Image XResolution: 300
Image YResolution: 300
Image ResolutionUnit: Pixels/Inch
Image Software: V3.0.0 (2b448a1aee) APP:1.0
Image DateTime: 2022:04:05 14:53:45
Image YCbCrCoefficients: [299/1000, 587/1000, 57/500]
Image YCbCrPositioning: Centered
Image ExifOffset: 158
Thumbnail Compression: JPEG (old-style)
Thumbnail XResolution: 300
Thumbnail YResolution: 300
Thumbnail ResolutionUnit: Pixels/Inch
Thumbnail JPEGInterchangeFormat: 7156
Thumbnail JPEGInterchangeFormatLength: 24886
EXIF ExposureTime: 1/3
EXIF FNumber: 8
EXIF ExposureProgram: Aperture Priority
EXIF ISOSpeedRatings: 100
EXIF SensitivityType: ISO Speed
EXIF ISOSpeed: 100
EXIF ExifVersion: 0221
EXIF DateTimeOriginal: 2022:04:05 14:53:45
EXIF DateTimeDigitized: 2022:04:05 14:53:45
EXIF ComponentsConfiguration: CrCbY
EXIF CompressedBitsPerPixel: 3249571/608175
EXIF ExposureBiasValue: 0
EXIF MaxApertureValue: 212/125
EXIF SubjectDistance: 39/125
EXIF MeteringMode: MultiSpot
EXIF LightSource: Unknown
EXIF Flash: Flash did not fire
EXIF FocalLength: 1187/100
EXIF SubjectArea: [2703, 1802, 675, 450]
EXIF MakerNote: [68, 88, 79, 32, 79, 78, 69, 0, 12, 0, 0, 0, 21, 0, 3, 0, 5, 0, 2, 0, ... ]
EXIF SubSecTime: 046
EXIF SubSecTimeOriginal: 046
EXIF SubSecTimeDigitized: 046
EXIF FlashPixVersion: 0100
EXIF ColorSpace: sRGB
EXIF ExifImageWidth: 5406
EXIF ExifImageLength: 3604
Interoperability InteroperabilityIndex: R98
Interoperability InteroperabilityVersion: [48, 49, 48, 48]
EXIF InteroperabilityOffset: 596
EXIF FileSource: Digital Camera
EXIF ExposureMode: Auto Exposure
EXIF WhiteBalance: Auto
EXIF DigitalZoomRatio: 1
EXIF FocalLengthIn35mmFilm: 32
EXIF SceneCaptureType: Standard
EXIF ImageUniqueID: C01A1709306530020220405185345046
EXIF BodySerialNumber: C01A1709306530


  


  Unfortunately, I have been unable to extract this kind of info from videos so far.

  


  This is what I have tried so far, with the ffmpeg module :

  


  import ffmpeg
from pprint import pprint

test_video = "my_video.mp4"
pprint(ffmpeg.probe(test_video)["streams"])


  


  And the output I get contains a lot of info but nothing related to the device or lens, which is what I am looking for :

  


  [{'avg_frame_rate': '30/1',
  'bit_rate': '1736871',
  'bits_per_raw_sample': '8',
  'chroma_location': 'left',
  'codec_long_name': 'H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10',
  'codec_name': 'h264',
  'codec_tag': '0x31637661',
  'codec_tag_string': 'avc1',
  'codec_time_base': '1/60',
  'codec_type': 'video',
  'coded_height': 1088,
  'coded_width': 1920,
  'display_aspect_ratio': '16:9',
  'disposition': {'attached_pic': 0,
                  'clean_effects': 0,
                  'comment': 0,
                  'default': 1,
                  'dub': 0,
                  'forced': 0,
                  'hearing_impaired': 0,
                  'karaoke': 0,
                  'lyrics': 0,
                  'original': 0,
                  'timed_thumbnails': 0,
                  'visual_impaired': 0},
  'duration': '20.800000',
  'duration_ts': 624000,
  'has_b_frames': 0,
  'height': 1080,
  'index': 0,
  'is_avc': 'true',
  'level': 40,
  'nal_length_size': '4',
  'nb_frames': '624',
  'pix_fmt': 'yuv420p',
  'profile': 'Constrained Baseline',
  'r_frame_rate': '30/1',
  'refs': 1,
  'sample_aspect_ratio': '1:1',
  'start_pts': 0,
  'start_time': '0.000000',
  'tags': {'creation_time': '2021-05-08T13:23:20.000000Z',
           'encoder': 'AVC Coding',
           'handler_name': 'VideoHandler',
           'language': 'und'},
  'time_base': '1/30000',
  'width': 1920},
 {'avg_frame_rate': '0/0',
  'bit_rate': '79858',
  'bits_per_sample': 0,
  'channel_layout': 'stereo',
  'channels': 2,
  'codec_long_name': 'AAC (Advanced Audio Coding)',
  'codec_name': 'aac',
  'codec_tag': '0x6134706d',
  'codec_tag_string': 'mp4a',
  'codec_time_base': '1/48000',
  'codec_type': 'audio',
  'disposition': {'attached_pic': 0,
                  'clean_effects': 0,
                  'comment': 0,
                  'default': 1,
                  'dub': 0,
                  'forced': 0,
                  'hearing_impaired': 0,
                  'karaoke': 0,
                  'lyrics': 0,
                  'original': 0,
                  'timed_thumbnails': 0,
                  'visual_impaired': 0},
  'duration': '20.864000',
  'duration_ts': 1001472,
  'index': 1,
  'max_bit_rate': '128000',
  'nb_frames': '978',
  'profile': 'LC',
  'r_frame_rate': '0/0',
  'sample_fmt': 'fltp',
  'sample_rate': '48000',
  'start_pts': 0,
  'start_time': '0.000000',
  'tags': {'creation_time': '2021-05-08T13:23:20.000000Z',
           'handler_name': 'SoundHandler',
           'language': 'und'},
  'time_base': '1/48000'}]


  


  Are these pieces of info available for videos ? Should I be using a different package ?

  


  Thanks.

  


  Edit :

  


  pprint(ffmpeg.probe(test_video)["format"]) gives

  


  {'bit_rate': '1815244',
 'duration': '20.864000',
 'filename': 'my_video.mp4',
 'format_long_name': 'QuickTime / MOV',
 'format_name': 'mov,mp4,m4a,3gp,3g2,mj2',
 'nb_programs': 0,
 'nb_streams': 2,
 'probe_score': 100,
 'size': '4734158',
 'start_time': '0.000000',
 'tags': {'artist': 'Microsoft Game DVR',
          'compatible_brands': 'mp41isom',
          'creation_time': '2021-05-08T12:12:33.000000Z',
          'major_brand': 'mp42',
          'minor_version': '0',
          'title': 'Snipping Tool'}}


  


• Reading images from AXIS ip camera using OpenCV

  14 juin 2016, par batuman

  I am trying to access AXIS IP camera from my program using OpenCV.
  My OpenCV version is 3.1. I follow this tutorial link.

  I have all libraries installed.
  My following program can load mp4 video successfully. That means ffmpeg and necessary libraries are working fine.

  #include <iostream>
  
  #include <opencv2></opencv2>opencv.hpp>
  
  
  
  using namespace std;
  
  int main() {
  
      cv::VideoCapture vcap("test.mp4");
  
      cv::Mat image;
  
  //    const string address = "rtsp://root:pass@192.168.0.90/axis-media/media.amp?camera=1";
  
  //    if(!vcap.open(address)){
  
  //      std::cout &lt;&lt; "Error opening video stream or file " &lt;&lt; std::endl;
  
  //      return -1;
  
  //    }
  
      for(;;){
  
          if(!vcap.read(image)){
  
              std::cout &lt;&lt; "No frame" &lt;&lt; std::endl;
  
              cv::waitKey(0);
  
          }
  
          cv::imshow("Display", image);
  
          cv::waitKey(1);
  
      }
  
      return 0;
  
  }
  
  </iostream>

  When I tried to access the IP Camera as follow

  cv::VideoCapture vcap("rtsp://root:pass@192.168.0.90/axis-media/media.amp?camera=1");

  I have the following error

  GStreamer Plugin: Embedded video playback halted; module source reported: Could 
  
  not open resource for reading and writing.
  
  OpenCV Error: Unspecified error (GStreamer: unable to start pipeline
  
  ) in cvCaptureFromCAM_GStreamer, file /home/Softwares/opencv/opencv/modules
  
  /videoio/src/cap_gstreamer.cpp, line 818
  
  terminate called after throwing an instance of 'cv::Exception'
  
    what():  /home/Softwares/opencv/opencv/modules/videoio/src/cap_gstreamer.
  
  cpp:818: error: (-2) GStreamer: unable to start pipeline
  
   in function cvCaptureFromCAM_GStreamer

  User is root and password is pass and ip 192.168.0.90 are all defaults.

  My if config gave me

  ifconfig
  
  eth0      Link encap:Ethernet  HWaddr b8:2a:72:c6:b8:13  
  
            inet6 addr: fe80::ba2a:72ff:fec6:b813/64 Scope:Link
  
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
  
            RX packets:723959 errors:0 dropped:0 overruns:0 frame:0
  
            TX packets:116637 errors:0 dropped:0 overruns:0 carrier:0
  
            collisions:0 txqueuelen:1000 
  
            RX bytes:199422245 (199.4 MB)  TX bytes:13701699 (13.7 MB)
  
  
  
  lo        Link encap:Local Loopback  
  
            inet addr:127.0.0.1  Mask:255.0.0.0
  
            inet6 addr: ::1/128 Scope:Host
  
            UP LOOPBACK RUNNING  MTU:65536  Metric:1
  
            RX packets:24829 errors:0 dropped:0 overruns:0 frame:0
  
            TX packets:24829 errors:0 dropped:0 overruns:0 carrier:0
  
            collisions:0 txqueuelen:0 
  
            RX bytes:2502903 (2.5 MB)  TX bytes:2502903 (2.5 MB)
  
  
  
  wlan0     Link encap:Ethernet  HWaddr a0:a8:cd:99:92:60  
  
            UP BROADCAST MULTICAST  MTU:1500  Metric:1
  
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
  
            TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
  
            collisions:0 txqueuelen:1000 
  
            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

  What could be the problem for this access to the camera ?

  Thanks