Newest 'ffmpeg' Questions - Stack Overflow

Les articles publiés sur le site

• JavaCV capture a frame using FFmpeg

  4 décembre 2013, par Ioanna

  I create a class that capture frame from a video. When it capture a frame, it's saved as a picture. When the video is .avi, application works ok. When format is .avi.

  public static void main(String[] args) {
  
       FFmpegFrameGrabber grabber = new FFmpegFrameGrabber("C:/Users/Ioanna/Desktop/video1.avi");
  
       try {
           IplImage img; 
  
           //Start grabber to capture video
           grabber.start(); 
  
           //grab video frame to IplImage
           img = grabber.grab();
  
           if (img != null) {         
               //save video frame as a picture
               cvSaveImage("capture.jpg", img);
           }
  
       }catch (Exception e) {      
       }
  }
  

  The error is

  Exception in thread "main" java.lang.ExceptionInInitializerError
      at com.googlecode.javacv.FFmpegFrameGrabber.(FFmpegFrameGrabber.java:106)
      at Video.main(Video.java:75)
  Caused by: java.lang.IllegalStateException: Can't overwrite cause with java.lang.UnsatisfiedLinkError: no avcodec in java.library.path
      at java.lang.Throwable.initCause(Throwable.java:457)
      at com.googlecode.javacpp.Loader.load(Loader.java:581)
      at com.googlecode.javacpp.Loader.load(Loader.java:532)
      at com.googlecode.javacv.cpp.avcodec.(avcodec.java:39)
      ... 2 more
  Caused by: java.lang.UnsatisfiedLinkError: no jniavcodec in java.library.path
      at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1837)
  

  Do anyone know what is the problem?

  Thanks in advance

• Live streaming from iphone To wowza server

  4 décembre 2013, par user2959377

  I need to develop an iphone app that streams live video to wowza server. For encoding the captured video in H.264 and to compress it i need to use FFmpeg. I am unable to proceed because of limited content on internet explaining compilation of FFmpeg. I used https://github.com/lajos/iFrameExtractor to start with compiling of FFmpeg, but i dont understand how to use the generated files in my application. I am using AVFoundation and can successfully generate the video but dont know how to compile the captured video through FFmpeg. Any link that could help in starting with compiling and using ffmpeg in iphone would be of great help.

• Android : Live Stream RMTP video from Wowza server

  4 décembre 2013, par Tamanna

  I am developing an android application in which i want to publish as well as stream a video..

  What I want is :

  1. My app record a video and that video is sent to server

  2. The recorded vieo will ve streamed live to another android device at the same time..

  I have completed the first task using javac and ffmpeg

  I am stuck in second task.. i have searched a lot to stream the video from server but didn't succeed..

  I dont want to use WebView and play the video in It. I want RMTP player ..

  This task has been completed in iOS.. I want dame for Android..
  Can anyone suggest me some link to fulfill my task ???

  P.S. :

  I am using wowza server and RMTP stream.. I would like to stream RMTP video(.flv).. If no solution avaliable. i can swicth to RSTP

• FFMPEG : Working of parser of a video decoder

  4 décembre 2013, par Zax

  I'm going through the working of H.263 video decoders parser in FFMPEG multimedia framework.

  What i know:

  Every video decoder needs a parser to fetch frames from a given input stream and once data related to a frame is obtained, it is sent to the decoder for decoding process.

  Every codec's parser needs to define a structure of type AVCodecParser. This structure has a function pointers:

  .parser_parse -> Points to the function which deals with the parsing functionality

  .parser_close -> points to a function that performs buffer deallocation.
  

  Taking the example of a video decoder H.264, it has a parser function as shown below:

  static int h263_parse(AVCodecParserContext *s,
                             AVCodecContext *avctx,
                             const uint8_t **poutbuf, int *poutbuf_size,
                             const uint8_t *buf, int buf_size)
  {
      ParseContext *pc = s->priv_data;
      int next;
  
      if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
          next = buf_size;
      } else {
          next= ff_h263_find_frame_end(pc, buf, buf_size);
  
          if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
              *poutbuf = NULL;
              *poutbuf_size = 0;
              return buf_size;
          }
      }
  
      *poutbuf = buf;
      *poutbuf_size = buf_size;
      return next;
  }
  

  Could anyone please explain, the parameters of the above function.

  According to me:

  poutbuf-> is a pointer that points to parsed frame data.
  
  poutbuf_size-> contains the size of the data.
  

  Are my above assumptions right? Which parameter holds the input buffer data? And what is the above parse function returning? Also a brief explanation for the above code will be anyone who is referring to the post. Any information regarding the same will be really helpful.

  Thanks in advance.

  -Regards

• using streams with php

  3 décembre 2013, par Abdul Ali

  I am completely new to streams and cannot (till now) find anything helpful.

  Purpose is to open a stream in PHP , assign a unique id to it for accessing and send data to that stream from a web service (images encoded in base64).

  Those image(s) needs to be sent to ffmpeg at realtime for it to join them into a video for live streaming.

  Any help will be appreciated.

  a.ali