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• ffmpeg and VLC input rtp

  19 juillet 2014, par ILoveSelfStudiyn

  I want to stream screen desktop through ffmpeg library in RTP and take this stream in VLC player.

  So, I have done next steps :

  1. Load static ffmpeg and run RTP strem of my desktop throught next command :

  ffmpeg -f gdigrab -framerate 30 -i desktop -q 0 -an -f rtp
  rtp ://127.0.0.1:2304 > 1.sdp

  stream successfully works.
  https://dl.dropboxusercontent.com/u/8262546/HjbKq%5B1%5D.jpg

  When I connect to this stream throught ffplay 1.sdp - everything is ok.

  2.When I connect to this stream(rtp ://127.0.0.1:2304) through VLC player, I receive next error :

  SDP required : A description in SDP format is required to receive the
  RTP stream. Note that rtp :// URIs cannot work with dynamic RTP payload
  format (96).

  According with error I open 1.sdp file which generated by ffmpeg, but this don’t resolve problem.

  1.sdp :

  v=0

  o=- 0 0 IN IP4 127.0.0.1

  s=No Name

  c=IN IP4 127.0.0.1

  t=0 0

  a=tool:libavformat 55.48.101

  m=video 2304 RTP/AVP 96

  b=AS:200

  a=rtpmap:96 MP4V-ES/90000

  a=fmtp:96 profile-level-id=1

  Dear friends, how can I open RTP stream which generates ffmpeg through VLC player ?
  It can be rtsp stream too, I tried it, but this don’t resolve problem.
  Thanks a lot !

• Issue while opening a .mp4 file - CPU shoots up 100%

  16 juillet 2014, par AnilJ

  I am using IMediaWriter, to write out about 20 video frames into an independent .mp4 file and creating a new writer to write a new file. This is a logic (not so efficient one), I’ve used to chunk the web-cam feed into chunks. I am able to successfully able to create multiple .mp4 video files and when opened then in a VLC player, they can be played back.

  However, when I try to open one of the chunked file into a new IContainer object (see below code snippet), my program :

  • Gets stuck at the container.open() call ( see * below), and the CPU
    utilization shoots above 100%.
  • Sometimes it throws an error "moov atom not found", and hence can not open the file.

  In both the cases, my program does not work.

  <code snippet="snippet">
  
          String file = BASE_PATH + File.separator + "output" + File.separator + "output.mp4";  // This is one of the chunk.
  
          IContainer container = IContainer.make();
  
          FileChannel channel = null;
  
  
  
          try {
  
              @SuppressWarnings("resource")
  
              RandomAccessFile inFile = new RandomAccessFile(chunkFile, "r");
  
              channel = inFile.getChannel();
  
          } catch (FileNotFoundException e) {
  
              e.printStackTrace();
  
          }
  
  
  
          // Open up the container
  
  ***        int retval = container.open(channel, IContainer.Type.READ, null);
  
          if (retval &lt; 0) {
  
              // This little trick converts the non friendly integer return value into 
  
              // a slightly more friendly object to get a human-readable error name
  
              IError error = IError.make(retval);
  
              throw new IllegalArgumentException("could not open file: " + mInputFileChannel + "; Error: " + error.getDescription());
  
          }
  
  <code snippet="snippet">
  
  

  Subsequently, I ran the AtomicParsley tool to dump the file content, and it prints following. I am not aware of video file internals and seeking help to know the issue here and potential solution.

  Atom ftyp @ 0 of size: 28, ends @ 28
  
  Atom free @ 28 of size: 8, ends @ 36
  
  Atom mdat @ 36 of size: 45175, ends @ 45211
  
  Atom moov @ 45211 of size: 1052, ends @ 46263
  
       Atom mvhd @ 45219 of size: 108, ends @ 45327
  
       Atom trak @ 45327 of size: 839, ends @ 46166
  
           Atom tkhd @ 45335 of size: 92, ends @ 45427
  
           Atom edts @ 45427 of size: 36, ends @ 45463
  
               Atom elst @ 45435 of size: 28, ends @ 45463
  
           Atom mdia @ 45463 of size: 703, ends @ 46166
  
               Atom mdhd @ 45471 of size: 32, ends @ 45503
  
               Atom hdlr @ 45503 of size: 45, ends @ 45548
  
               Atom minf @ 45548 of size: 618, ends @ 46166
  
                   Atom vmhd @ 45556 of size: 20, ends @ 45576
  
                   Atom dinf @ 45576 of size: 36, ends @ 45612
  
                       Atom dref @ 45584 of size: 28, ends @ 45612
  
                           Atom url  @ 45600 of size: 12, ends @ 45612
  
                   Atom stbl @ 45612 of size: 554, ends @ 46166
  
                       Atom stsd @ 45620 of size: 198, ends @ 45818
  
                           Atom mp4v @ 45636 of size: 182, ends @ 45818
  
                               Atom esds @ 45722 of size: 96, ends @ 45818
  
                       Atom stts @ 45818 of size: 176, ends @ 45994
  
                       Atom stss @ 45994 of size: 24, ends @ 46018
  
                       Atom stsc @ 46018 of size: 28, ends @ 46046
  
                       Atom stsz @ 46046 of size: 100, ends @ 46146
  
                       Atom stco @ 46146 of size: 20, ends @ 46166
  
       Atom udta @ 46166 of size: 97, ends @ 46263
  
           Atom meta @ 46174 of size: 89, ends @ 46263
  
               Atom hdlr @ 46186 of size: 33, ends @ 46219
  
               Atom ilst @ 46219 of size: 44, ends @ 46263
  
                   Atom ©too @ 46227 of size: 36, ends @ 46263
  
                       Atom data @ 46235 of size: 28, ends @ 46263
  
  ------------------------------------------------------
  
  Total size: 46263 bytes; 31 atoms total. AtomicParsley from svn built on Jul 15 2014 (utf8)
  
  Media data: 45175 bytes; 1088 bytes all other atoms (2.352% atom overhead).
  
  Total free atom space: 8 bytes; 0.017% waste.
  
  ------------------------------------------------------

  I am not sure if there is anything wrong with the file itself. Can you please help me understand this ?

• Video Quality Assessment (No-reference)

  17 décembre 2020, par Gufran Pathan

  I am looking to analyze the quality of videos using some no-reference methods. ie. I don't have a reference video to compare my videos with.

  



  I want to identify frame-freezes, jitter, jerkiness etc. Basically, temporal artifacts.

  



  There's a lot of academic literature available for this (eg. here), but I'm trying to figure out if there is an open source library / tool that I could use. Would this be possible using tools like FFMPEG ?