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• Cannot play compressed video

  23 mai 2017, par Rares

  I am trying to compress a video from gallery.
  Steps :

  1)I open gallery.

  2)Pick a video and get it’s path

  3)Create new path for the output video

  4)Compress the video using FFmpeg( the video is saved automatically)

  Can you tell me why I can’t open the compressed video in my phone ? For example I run the code below and when I go in my phone to open the created file I get an error : Cannot play video. Unsupported file type. Here is an example : http://imgur.com/a/ePHzq

  I am compressing videos with size between 50-300MB.

           String filePath = getRealPathFromURI(getApplicationContext(), data.getData());
  
  
  
                      ///get the name of file without extension
  
                      StringBuilder stringBuilder = new StringBuilder(filePath);
  
                      int start = filePath.lastIndexOf('.');
  
                      stringBuilder.delete(start, filePath.length());
  
                      //--------------
  
                      //get file extension(e.g mp4)
  
                      File file = new File(filePath);
  
                      String contentType = getFileType(file.getAbsolutePath());
  
                      //--------------
  
                      //create compressed file path=initial file path+ _compressed+(random nr.)+ extension .mp4
  
                      Random random = new Random();
  
                      int fileNr = random.nextInt(999);
  
                      String compressedFilePath = stringBuilder.toString() + "_compressed" + fileNr +"."+ contentType;
  
  
  
                      //compress file from gallery and save it with the above name
  
                      String[] command = {"-y", "-i", filePath, "-s", "640x480", "-r", "25", "-vcodec",
  
                              "mpeg4", "-b:v", "150k", "-b:a", "48000", "-ac", "2", "-ar", "22050", compressedFilePath};
  
                      executeFFmpegBinary(command);

• Play H.264 camera streams using OpenCV

  26 octobre 2018, par peter bence

  How to play H.264 camera streams using OpenCV ? I was searching for a while but i didn’t find an answer. I think OpenCV can encode and decode h.264 videos since it uses ffmpeg and it is the documentation of the class VideoWriter ensures that as shown in this example :

  #include <iostream> // for standard I/O
  
  #include <string>   // for strings
  
  
  
  #include <opencv2></opencv2>core/core.hpp>        // Basic OpenCV structures (cv::Mat)
  
  #include <opencv2></opencv2>highgui/highgui.hpp>  // Video write
  
  
  
  using namespace std;
  
  using namespace cv;
  
  
  
  int main()
  
  {
  
      VideoWriter outputVideo; // For writing the video
  
  
  
      int width = ...; // Declare width here
  
      int height = ...; // Declare height here
  
      Size S = Size(width, height); // Declare Size structure
  
  
  
      // Open up the video for writing
  
      const string filename = ...; // Declare name of file here
  
  
  
      // Declare FourCC code
  
      int fourcc = CV_FOURCC('H','2','6','4');
  
  
  
      // Declare FPS here
  
      int fps = ...;
  
      outputVideo.open(filename, fourcc, fps, S);
  
  
  
      // Put your processing code here
  
      // ...
  
  
  
      // Logic to write frames here... see below for more details
  
      // ...
  
  
  
      return 0;
  
  }
  
  </string></iostream>

  So can OpenCV encode-decode h.264 stream as well ? if yes, please let me know how. thanks !!

• How can I encode a video to play on a DLink DSM-520 using FFMPEG ?

  4 octobre 2015, par tolsen64

  I have been searching, testing, and coming up with nothing for over a week. I want to use FFMPEG to convert mp4’s and mkv’s to AVI files that will play on my DLink DSM-520. Mencoder will do it. The files that FFMPEG generates cause the player to lock up less than a minute into the video. First, here’s what I use to encode the file using Mencoder (scraped from the test.bat file that PocketDIVXEncoder generates :

  mencoder.exe ftwd105.mp4 -af volnorm -srate 44100 -oac mp3lame -lameopts mode=0:cbr:br=128 -noodml -vf pp=ac,scale=720:404,crop=720:400,harddup -sws 9 -ovc lavc -lavcopts vcodec=mpeg4:mbd=1:last_pred=2:vstrict=1:threads=2:vmax_b_frames=0:vbitrate=1200 -ffourcc XVID -o ftwd105_HDTV.avi

  The output file plays perfectly on the DSM-520. Looking at the file using FFPROBE, I see this :

  Input #0, avi, from 'ftwd105_HDTV.avi':
  
    Metadata:
  
      encoder         : MEncoder Redxii-SVN-r37527-4.9.3 (x86_64)
  
    Duration: 00:44:32.96, start: 0.000000, bitrate: 1193 kb/s
  
      Stream #0:0: Video: mpeg4 (Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], 1053 kb/s, 23.98 fps, 23.98 tbr, 23.98 tbn, 24k tbc
  
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, stereo, s16p, 128 kb/s

  So now I try the same thing with FFMPEG.

  ffmpeg -i ftwd105.mp4 -vcodec mpeg4 -vtag XVID -b:v 1200k -s 720x400 -acodec libmp3lame -ab 128k -ar 44100 -ac 2 -f avi ftwd105_ffmpeg.avi

  This file does not play on the media player. It plays choppy with only clicking for sound for about 15-30 seconds, then it freezes. Looking at it with FFPROBE, it looks exactly the same as the one created by Mencoder.

  Input #0, avi, from 'ftwd105_ffmpeg.avi':
  
    Metadata:
  
      encoder         : Lavf57.0.100
  
    Duration: 00:44:33.14, start: 0.000000, bitrate: 1305 kb/s
  
      Stream #0:0: Video: mpeg4 (Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], 1165 kb/s, 23.98 fps, 23.98 tbr, 23.98 tbn, 24k tbc
  
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, stereo, s16p, 128 kb/s

  So now I encode the video using Xvid4PSP. It plays perfectly fine and FFPROBE shows this :

  Input #0, avi, from 'ftwd105_ps2.avi':
  
    Metadata:
  
      encoder         : VirtualDubMod 1.5.10.3 | www.virtualdub-fr.org || (build 2550/release)
  
    Duration: 00:44:33.09, start: 0.000000, bitrate: 861 kb/s
  
      Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], 723 kb/s, 23.98 fps, 23.98 tbr, 23.98 tbn, 23.98 tbc
  
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, s16p, 128 kb/s

  It’s using Advanced Simple Profile so I look this up and change my FFMPEG options :

  ffmpeg -i ftwd105.mp4 -vcodec mpeg4 -vtag XVID -b:v 1200k -s 720x400 -profile:v 15 -level 0 -acodec libmp3lame -ab 128k -ar 44100 -ac 2 -f avi ftwd105_ffmpeg.avi

  But though the output file looks the same using FFPROBE as the one made by Xvid4PSP, it still doesn’t play on the DSM-520.

  Input #0, avi, from 'ftwd105_ffmpeg_asp.avi':
  
    Metadata:
  
      encoder         : Lavf57.0.100
  
    Duration: 00:44:33.14, start: 0.000000, bitrate: 1305 kb/s
  
      Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], 1165 kb/s, 23.98 fps, 23.98 tbr, 23.98 tbn, 24k tbc
  
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, stereo, s16p, 128 kb/s

  So now i’m at a loss. Is FFMPEG incapable of generating a file that the DSM-520 can play ? The reason I want to use FFMPEG over Mencoder is that it’s much faster. What takes FFMPEG 15 minutes takes Mencoder 40.

  I should note that all the files created by FFMPEG play fine on the PC and on my Visio television. The DSM-520 is hooked up to a bedroom tv that isn’t a smart tv.

  Edit : I also tried libxvid in place of mpeg4 with the same results.