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• Revision 343c092e2e : High bit-depth support for wedge partition expt Change-Id : Idbd27e66d4f4a7953f8

  11 avril 2015, par Debargha Mukherjee

  Changed Paths :
   Modify /vp9/common/vp9_reconinter.c

  
   Modify /vp9/common/vp9_rtcd_defs.pl

  
   Modify /vp9/encoder/vp9_encoder.c

  
   Modify /vp9/encoder/vp9_sad.c

  
   Modify /vp9/encoder/vp9_variance.c

  
  
  High bit-depth support for wedge partition expt

  Change-Id : Idbd27e66d4f4a7953f888137d5752856215a6760

• ffmpeg open remote video with high latency while gstreamer not

  30 octobre 2014, par madcc

  I use MJPEG-Streamer to send my remote camera video via wifi. I use such command to see video :

  gstreamer :

  gst-launch -v souphttpsrc location= "http://192.168.1.1:8080/?action=stream&type=.mjpg" do-timestamp=true is_live=true ! multipartdemux ! jpegdec ! autovideosink

  ffmpeg :

   ffplay "http://192.168.1.1:8080/?action=stream&type=.mjpg"

  or :

   ffplay "http://192.168.1.1:8080/?action=stream&type=.mjpg" -fflags nobuffer

  however the ffplay has a high latency up to 3 10 seconds in my test, while the gstreamer
  show almost no latency.

  when using localhost MJPEG-Streamer, both two methods show low latency. so what’s the reason ? and how to decrease the latency ?

  more detail :

  I want to use opencv to capture a remote camera,my opencv compile with ffmpeg support but without gstreamer support ( I tried but failed,the cmake seemed to not find my gstreamer,I don’t know which gstreamer library to install in opensuse 13.1), I can get the video in opencv but with high latency,so I compared ffmpeg with gstreamer,the result is as above.so how to decrease the latency ? I read this link,but still no solution.

  thank you.

• Decoding a h264 (High) stream with OpenCV's ffmpeg on Ubuntu

  9 janvier 2017, par arvids

  I am working with a video stream (no audio) from an ip camera on Ubuntu 14.04. Also i am a beginner with Ubuntu and everything on it. Everything was going great with a camera that has these parameters (from FFMPEG) :

  Input #0, rtsp, from 'rtsp://*private*:8900/live.sdp': 0B f=0/0   
  
    Metadata:
  
      title           : RTSP server
  
      Stream #0:0: Video: h264 (Main), yuv420p(progressive), 352x192, 29.97 tbr, 90k tbn, 180k tbc

  But then i changed to a newer camera, which has these parameters :

  Input #0, rtsp, from 'rtsp://*private*/media/video2':0B f=0/0   
  
    Metadata:
  
      title           : VCP IPC Realtime stream
  
      Stream #0:0: Video: h264 (High), yuvj420p(pc, bt709, progressive), 1280x720, 25 fps, 25 tbr, 90k tbn, 50 tbc

  My C++ program uses OpenCV3 to process the stream. By default OpenCV uses ffmpeg to decode and display the stream with function VideoCapture.

  VideoCapture vc;
  
  vc.open(input_stream);
  
  while ((vc >> frame), !frame.empty()) {
  
     *do work*
  
  }

  With the new camera stream i get errors like these (from ffmpeg) :

  [h264 @ 0x7c6980] cabac decode of qscale diff failed at 41 38
  
  [h264 @ 0x7c6980] error while decoding MB 41 38, bytestream (3572)
  
  [h264 @ 0x7c6980] left block unavailable for requested intra mode at 0 44
  
  [h264 @ 0x7c6980] error while decoding MB 0 44, bytestream (4933)
  
  [h264 @ 0x7bc2c0] SEI type 25 truncated at 208
  
  [h264 @ 0x7bfaa0] SEI type 25 truncated at 206
  
  [h264 @ 0x7c6980] left block unavailable for requested intra mode at 0 18
  
  [h264 @ 0x7c6980] error while decoding MB 0 18, bytestream (14717)

  The image sometimes is glitched, sometimes completely frozen. After a few seconds to a few minutes the stream freezes completely without an error. However on vlc it plays perfectly. I installed the newest version (3.2.2) of ffmpeg player with

  ./configure --enable-gpl --enable-libx264

  Now playing directly with ffplay (instead of launching from source code with OpenCV function VideoCapture), the stream plays better, doesn’t freeze, but sometimes still displays warnings :

  [NULL @ 0x7f834c008c00] SEI type 25 size 896 truncated at 320=1/1   
  
  [h264 @ 0x7f834c0d5d20] SEI type 25 size 896 truncated at 319=1/1   
  
  [rtsp @ 0x7f834c0008c0] max delay reached. need to consume packet   
  
  [rtsp @ 0x7f834c0008c0] RTP: missed 1 packets
  
  [h264 @ 0x7f834c094740] concealing 675 DC, 675 AC, 675 MV errors in P frame
  
  [NULL @ 0x7f834c008c00] SEI type 25 size 896 truncated at 320=1/1  

  Changing the camera hardware is not an option. The camera can be set to encode to h265 or mjpeg. When encoding to mjpeg it can output 5 fps, which is not enough. Decoding to a static video is not an option either, because i need to display real time results about the stream. Here is a list of API backends that can be used in function VideoCapture. Maybe i should swithc to some other decoder and player ?
  From my research i conclude that i have these options :

  • Somehow get OpenCV to use the ffmpeg player from another directory, where it is compiled with libx264

  • Somehow get OpenCV to use libVlc instead of ffmpeg

  One example of switching to vlc is here, but i don’t understand it well enough to say if that is what i need. Or maybe i should be parsing the stream in code ? I don’t rule out that this could be some basic problem due to a lack of dependencies, because, as i said, i’m a beginner with Ubuntu.

  • Use vlc to preprocess the stream, as suggested here.

  This is probably slow, which again is bad for real time results.
  Any suggestions and coments will be appreciated.