Recherche avancée

Sur d’autres sites (12155)

• rtp mpg stream using jrtplib occurred error "illegal timestamp unit"

  13 avril 2013, par socket

  I wanna code rtp video stream sender and use VLC to play it in the LAN. I just have a mpeg4 file "a.mpg". And in my opinion, jrtplib can pack the packed well, so I think I can use sendPacket() function directly to send the mpg file. code below :

  #include 
  
  #include 
  
  #include 
  
  #include 
  
  #include 
  
  #include 
  
  #include 
  
  #include <iostream>
  
  #include
  
  
  
  using namespace jrtplib;
  
  using namespace std;
  
  int main()
  
  {
  
  RTPSession s;
  
  RTPSessionParams sparam;
  
  s.SetTimestampUnit(160.0/104857.0);//~
  
  RTPUDPv4TransmissionParams tparam;
  
  tparam.SetPortbase(9000);
  
  int status=s.Create(sparam,&amp;tparam);
  
  if(status&lt;0)
  
  {
  
      cerr&lt;&lt;"error 1"&lt;/~
  
  s.SetDefaultMark(false);
  
  s.SetDefaultTimestampIncrement(160);//~~
  
  
  
  unsigned char buf[160];
  
  FILE*f=fopen("a.mpg","rb");
  
  while(!feof(f))
  
  {
  
      fread(buf,1,160,f);
  
      RTPTime delay(0.02);//~
  
      bool ret=false;
  
      status=s.SendPacket(buf,160);
  
      if(status&lt;0)
  
      {
  
          cerr&lt;&lt;"error 3"&lt;code></iostream>

  Then, I compile it :

   g++ jrtpsend.cpp -ljrtp -I /usr/local/include/jrtplib3

  After that, I run the program but error occurred :

  kl@kl-ubuntu:~/code/RTP$ ./a.out 
  
  error 1
  
  Speficied an illegal timestamp unit for the the RTCP packet builder

  Actually, I didn't know timestamp exactly. When I use ffplay to play a.mpg showing that :

  Input #0, mpeg, from 'a.mpg':q=    0KB vq=    0KB sq=    0B f=0/0   
  
  Duration: 00:01:00.69, start: 0.529089, bitrate: 556 kb/s
  
  Stream #0:0[0x1e0]: Video: mpeg1video, yuv420p, 640x480 [SAR 239:182 DAR 478:273],   104857 kb/s, 25 fps, 25 tbr, 90k tbn, 25 tbc
  
  Stream #0:1[0x1c0]: Audio: mp2, 44100 Hz, stereo, s16p, 128 kb/s

  2.46 A-V : -0.003 fd= 7 aq= 2KB vq= 33KB sq= 0B f=0/0

  So, I use the data 104857kb/s in the code (setTimestampUnit()), but I have no idea whether I use it correctly.
  All in all, please give me some suggestion how to run the program well or ...
  Best regards :-)

• FFMPEG : extracting jpegs at 1 fps rate with "-r 1" or "vf fps=fps=1" causes first three frames to be wrong [closed]

  11 avril 2013, par Stefan

  I need to use ffmpeg to extract video stills from a video, one picture per second, starting with second 0. I created a 4min test video with a running timecode (25fps, starting with 00:00:00 running to 03:59:24) If I use either

  ffmpeg -i input.mp4 -f image2 -r 1 still-%d.jpeg

  or

  ffmpeg -i input.mp4 -f image2 -vf fps="fps=1" still-%d.jpeg

  I fail because the first three images do not display expected time codes 00:00:00, 00:01:00, 00:02:00, but 00:00:00, 00:00:01, 00:00:13, and all subsequent images show having frame 13 in their timecode (and not :00). This causes my video preview to be off by 1-2 seconds.

  I had to resort to invoke ffmpeg for each frame, using -ss 0..240 and -vframes 1 to extract exactly one frame at the exact time. This works perfectly, all output files show the timecode of the first frame of that second.

  This method is considerably slower, however, and I'd rather not use it.

  Is there something I missed with the -r option or fps filter ? I tried specifying fps=fps=1:round=zero, but I got an error saying that the key "round" was not found.

  Thank you in advance !

• Revision ec2599cc91 : Merge "Move diff to MACROBLOCKD per-plane data." into experimental

  19 avril 2013, par John Koleszar

  Merge "Move diff to MACROBLOCKD per-plane data." into experimental