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• RTP Streaming with ffmpeg : server streaming, client failing

  27 novembre 2013, par Christoph Kuhr

  I compiled ffmpeg and x264 myself.

  x264 version:

   #define X264_REV 2377
   #define X264_REV_DIFF 0
   #define X264_VERSION " r2377 1ca7bb9"
   #define X264_POINTVER "0.140.2377 1ca7bb9"
  

  ffmpeg version: 0.11.4
  ffmpeg configuration:

   --enable-x11grab --enable-pthreads --enable-libfaac --enable-libxvid --enable-libx264 --enable-libv4l2 --enable-libmp3lame --enable-libpulse --enable-gpl --enable-nonfree --disable-yasm
  

  streaming server call:

  ffmpeg -f x11grab -s 1600x900 -framerate 50 -i :0.0 -vcodec libx264 -threads 4 -preset ultrafast -crf 0 -q:v 1 -b:v 8M -an -f rtp rtp://192.168.188.30:8710
  
  ...
  
   Output #0, rtp, to 'rtp://192.168.188.30:8710':
    Metadata:
      encoder         : Lavf54.6.100
      Stream #0:0: Video: h264, yuv420p, 1600x900, q=-1--1, 8000 kb/s, 90k tbn, 50 tbc
  Stream mapping:
    Stream #0:0 -> #0:0 (rawvideo -> libx264)
  SDP:
  v=0
  o=- 0 0 IN IP4 127.0.0.1
  s=No Name
  c=IN IP4 192.168.188.30
  t=0 0
  a=tool:libavformat 54.6.100
  m=video 8710 RTP/AVP 96
  b=AS:8000
  a=rtpmap:96 H264/90000
  a=fmtp:96 packetization-mode=1
  

  Everything looks good so far...

  Now the problem. I create foo.sdp from the SDP output of the server and try to playback the stream with ffmpeg ffplay foo.sdp. ffplay fails with the following error:

   [sdp @ 0x7f5e0c0008c0] decoding for stream 0 failed
   [sdp @ 0x7f5e0c0008c0] Could not find codec parameters (Video: h264)
   [sdp @ 0x7f5e0c0008c0] Estimating duration from bitrate, this may be inaccurate
   gameserver.sdp: could not find codec parameters
  

  If I try the same with VLC, it also fails, but with the different error:

    [0x7f3278c045b8] live555 demux error: no data received in 10s, aborting
  

  Look like different reasons. But I could not solve either. Does anyone have a clue?

• How can I get a thumbnail from a video that a user has uploaded to my server ?

  27 novembre 2013, par user3041398

  
  I'm working on a video sharing website where people can upload their own videos and I want the most recent uploads to be shown on the index page, but not as videos but thumbnails, so that when you click on the thumbnail you get to the video page. You guys all know how youtube's index looks/works -- that's what I'm trying to simulate.
  
  I read about ffmpeg but it seems to me it would only work if you have ffmpeg installed on your computer. I want this to be an automated process though without the user having to first install something on their pc.
  Is there a way I can code this? Or do i have to use some kind of framework or CMS? Could this problem be solved by simply getting ffmpeg hosting (example)?
  If there is no manual way to do this in php, is there way using python?
  
  Fyi, my website is written in php and i use jwplayer to stream the videos.
  Please note that I want to get a thumbnail from a video that's been uploaded on my server and not a youtube or vimeo thumbnail.

• How to programatically generate video of a number or countdown

  27 novembre 2013, par xorsyst

  I've got some python that drives ffmpeg to convert some videos and do other processing. I'd like to prepend the videos with a couple of seconds of a number, and append a short countdown timer video.

  Each video could have different values for the numbers and length of countdown. Is there an easy programatic way to generate this sort of video? I was thinking of perhaps coding some wxpython to generate the required stuff, but how to save that out as a video file or stream it to ffmpeg?

  Ideas welcome - doesn't have to involve Python, external programs (Windows) are ok.

• include/c++/4.6.3/bits/stl_algobase.h:329 : undefined reference to

  27 novembre 2013, par user3041105

  My program is fails to compile with this error when I use my own account but when use the root account it compiles successfully. I have installed boost, ffmpeg and opencv.

  The errors are as follows:

  === linking: release/DenseTrack ===
   g++ -L/opt/lib -L/home/huangng/software/boost/lib -L/home/huangng/software/opencv/lib -L/home/huangng/software/ffmpeg/lib -pipe -Wall -O3 -ggdb -o release/DenseTrack .build_release/DenseTrack.o -lboost_program_options -lboost_regex -lboost_system -lboost_filesystem -lopencv_core -lopencv_highgui -lopencv_video -lopencv_imgproc -lavformat -lavdevice -lavutil -lavcodec -lswscale
   .build_release/DenseTrack.o: In function `main':
   /home/huangng/lab/dense_trajectory_release_v1.1/DenseTrack.cpp:103: undefined reference to `IplImagePyramid::rebuild(IplImageWrapper)'
   /home/huangng/lab/dense_trajectory_release_v1.1/DenseTrack.cpp:307: undefined reference to `IplImagePyramid::rebuild(IplImageWrapper)'
   /home/huangng/lab/dense_trajectory_release_v1.1/DenseTrack.cpp:56: undefined reference to `IplImageWrapper::operator=(IplImageWrapper const&)'
   /home/huangng/lab/dense_trajectory_release_v1.1/DenseTrack.cpp:58: undefined reference to `IplImageWrapper::operator=(IplImageWrapper const&)'
   /home/huangng/lab/dense_trajectory_release_v1.1/DenseTrack.cpp:60: undefined reference to `IplImageWrapper::operator=(IplImageWrapper const&)'
   /home/huangng/lab/dense_trajectory_release_v1.1/DenseTrack.cpp:62: undefined reference to `IplImageWrapper::operator=(IplImageWrapper const&)'
   /home/huangng/lab/dense_trajectory_release_v1.1/DenseTrack.cpp:68: undefined reference to `IplImagePyramid::rebuild(IplImageWrapper)'
   .build_release/DenseTrack.o: In function `IplImagePyramid':
   /home/huangng/lab/dense_trajectory_release_v1.1/./opencv/IplImagePyramid.hpp:34: undefined reference to `IplImagePyramid::init(CvSize, int, int, double)'
   .build_release/DenseTrack.o: In function `__copy_m':
   /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/stl_algobase.h:343: undefined reference to `IplImageWrapper::operator=(IplImageWrapper const&)'
   .build_release/DenseTrack.o: In function `__copy_m':
   /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/stl_algobase.h:343: undefined reference to `IplImageWrapper::operator=(IplImageWrapper const&)'
   collect2: ld returned 1 exit status
   make: *** [release/DenseTrack] Error 1
  

• How to downlaod 5 min video from 1 hour you tube video

  27 novembre 2013, par psanjib

  I have tried and also success to download you tube video for that i use ffmpeg. But there is a problem if the video duration is long (1 hour) the that will take more time to download.

  Is there any way to download 5 min video from 1 hour you tube video

  Thanks in advance