Recherche avancée

Sur d’autres sites (12993)

• video is always wrong when using cv::videowriter

  24 novembre 2017, par 周远远

  I have written a test code using cv::videowriter, the video is always wrong(undesired color and shape). But the frames were correct when I saved them via cv::imwrite. The system is centos 7, opencv 2.4.5, ffmpeg 2.6.8
  thank a lot ![sorry, I cannot publish the test result, the output aaaaa.jpg is a gray image, but the video capture is a color image with green and pink]

  #include 
  
  
  
  #include 
  
  #include "/usr/include/opencv/cv.h"
  
  #include "/usr/include/opencv/highgui.h"
  
  
  
  int main(int, char**)
  
  {
  
      cv::VideoWriter outputVideo;
  
      outputVideo.open("out.avi", CV_FOURCC('M','J','P','G'), 30,         cv::Size(400,400), true);
  
      if (!outputVideo.isOpened()){
  
          printf("aaa\n");
  
      }
  
      cv::Mat frame, f1,f2, f3;
  
      char *Frame_buff = (char *)(malloc(400 * 400 * 3));
  
      for(int iii = 0; iii < 400; iii++) {
  
          for(int jjj = 0; jjj < 400; jjj++) {
  
              Frame_buff[jjj * 400 * 3 + iii * 3 + 0] = iii;
  
              Frame_buff[jjj * 400 * 3 + iii * 3 + 1] = iii;
  
              Frame_buff[jjj * 400 * 3 + iii * 3 + 2] = iii;  
  
          }
  
      }
  
  
  
      frame = cv::Mat(400, 400, CV_8UC3, Frame_buff);
  
      f1 = cv::Mat(400, 400, CV_8UC3, Frame_buff);
  
      cv::imwrite("aaaaa.jpg", f1);
  
  
  
      for(int iii = 0; iii < 400; iii++) {
  
          for(int jjj = 0; jjj < 400; jjj++) {
  
              Frame_buff[jjj * 400 * 3 + iii * 3 + 0] = jjj;
  
              Frame_buff[jjj * 400 * 3 + iii * 3 + 1] = jjj;
  
              Frame_buff[jjj * 400 * 3 + iii * 3 + 2] = jjj;  
  
         }
  
      }
  
      f2 = cv::Mat(400, 400, CV_8UC3, cv::Scalar(0, 0, 255));
  
      cv::imwrite("bbbb.jpg", f2);
  
      f3 = cv::Mat(400, 400, CV_8UC3, Frame_buff);
  
      cv::imwrite("cccc.jpg", f3);
  
  
  
      for(int i = 0; i < 240; i++){
  
          if(i < 80){
  
              printf("ccc");
  
              outputVideo.write(f1);
  
          }
  
          else if(i<160){
  
              printf("bbb");
  
              outputVideo.write(frame);
  
          }
  
          else{
  
              printf("aaa");
  
              outputVideo.write(f2);
  
          }       
  
      }
  
      printf("\n");
  
      getchar();
  
      outputVideo.release();
  
  
  
      return 0;
  
  }

• ffmpeg add an audio to a video using apad, but duration not exactly same [closed]

  27 avril 2023, par Richard

  I am using ffmpeg to add an audio to a silent video, and the audio is shorter than the video, so I want to add silence to the end of the audio and make sure they have same duration. I use below command

  


  ffmpeg -i video.mp4 -i audio.mp3 -filter_complex "[1:0]apad" -c:v copy -shortest output.mp4


  


  but the output durations are not exactly the same

  


  

  1. Am I making any mistake here ?

  


  2. Is there a way to make them exactly same ?

  


  


  ffprobe -v error -show_entries stream=codec_type,duration,start_pts,start_time -sexagesimal output.mp4
[STREAM]
codec_type=audio
start_pts=0
start_time=0:00:00.000000
duration=0:00:03.621995
[/STREAM]
[STREAM]
codec_type=video
start_pts=0
start_time=0:00:00.000000
duration=0:00:03.640000
[/STREAM]


  


  input file info

  


  ▶ ffmpeg -i video.mp4                                                                                   
ffmpeg version 4.4-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 8 (Debian 8.3.0-6)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.76.100
  Duration: 00:00:03.64, start: 0.000000, bitrate: 394 kb/s
  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1080x1920, 390 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]


▶ ffmpeg  -i audio.mp3                                                                                     
ffmpeg version 4.4-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 8 (Debian 8.3.0-6)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
Input #0, mp3, from 'audio.mp3':
  Metadata:
    TCM             : A
    TT1             : xxx
    title           : yyy
    encoded_by      : ProTranscoderTool (Apple MP3 v1
  Duration: 00:00:02.77, start: 0.000000, bitrate: 271 kb/s
  Stream #0:0: Audio: mp3, 44100 Hz, stereo, fltp, 265 kb/s




  


• avcodec/encode : Fix check for allowed LJPEG pixel formats

  6 avril 2021, par Andreas Rheinhardt

  avcodec/encode : Fix check for allowed LJPEG pixel formats
  The pix_fmts of the LJPEG encoder already contain all supported pixel
  
  formats (including the ones only supported when strictness is unofficial
  
  or less) ; yet the check in ff_encode_preinit() ignored this list in case
  
  strictness is unofficial or less. But the encoder presumed that it is
  
  always applied and blacklists some of the entries in pix_fmts when
  
  strictness is > unofficial. The result is that if one uses an entry not
  
  on that list and sets strictness to unofficial, said entry passes both
  
  checks and this can lead to segfaults lateron (e.g. when using gray).
  Fix this by removing the exception for LJPEG in ff_encode_preinit().
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/encode.c