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• Capture still image from remote ip cam using avconv

  12 août 2015, par Stevanicus

  I’m attempting to capture a single still from an ip camera with avconv in ubuntu (server).

  Can only tell me what’s wrong with the following command :

  avconv -i rtsp://[USER]:[PASS]@[IPADDRESS]:554/11 -s 1920x1080 -f image2 foo.jpg

  The error message I’m getting at the moment is :

  [rtsp @ 0xb938e0] Could not find codec parameters (Video: h264, 1920x1080)
  
  [rtsp @ 0xb938e0] Estimating duration from bitrate, this may be inaccurate
  
  Guessed Channel Layout for  Input Stream #0.1 : mono
  
  Input #0, rtsp, from 'rtsp://xxx:xxx@xxx.xxx.xxx.xxx:554/11':
  
    Metadata:
  
      title           : rtsp session
  
    Duration: N/A, bitrate: N/A
  
      Stream #0.0: Video: h264, 1920x1080, 90k tbn
  
      Stream #0.1: Audio: pcm_alaw, 8000 Hz, mono, s16, 64 kb/s
  
  [buffer @ 0xb98520] Invalid pixel format string '-1'
  
  Error opening filters!

  In case it’s of any value, I’m using a 2.0 MB IP Camera from Sinocam. I am able to view a live stream from the camera remoting using iSpy - however, I just can’t create an image still from it.

  Thank you.

• FFmpeg libswresample linker error

  11 juillet 2016, par Davide Caresia

  I’m trying to set-up a function, using the ffmpeg c api, to re-sample a stream (AVStream format) to fixed (1channel - u8 sample) format.

  I’m using ffmpeg libswresample library, but when I try to compile, I get a linker error that is strictly connected to swresample functions.

  Let me post the code :

  double *resample8(AVFrame *frame, int size, AVCodec* codec){
  
  
  
      /* initialization of the output array */
  
      double *out = new double[size];
  
  
  
      /* create resampling context */
  
      struct SwrContext *resampleContext;
  
      resampleContext = swr_alloc();
  
      if (!resampleContext) {
  
      fprintf(stderr, "Could not allocate resampler context\n");
  
      return NULL;
  
      }
  
  
  
      /* set options */
  
      av_opt_set_int(resampleContext, "in_channel_layout", *(codec->channel_layouts), 0);
  
      av_opt_set_sample_fmt(resampleContext, "in_sample_fmt", *(codec->sample_fmts), 0);
  
  
  
      av_opt_set_int(resampleContext, "out_channel_layout", AV_CH_LAYOUT_MONO, 0);
  
      av_opt_set_sample_fmt(resampleContext, "out_sample_fmt", AV_SAMPLE_FMT_U8, 0);
  
  
  
      /* initialize the resampling context */
  
      if (swr_init(resampleContext) < 0) {
  
      fprintf(stderr, "Failed to initialize the resampling context\n");
  
      return NULL;
  
      }
  
  
  
      return NULL;
  
  
  
  }

  Here is the inclusion :

  #ifdef __cplusplus
  
  extern "C"
  
  {
  
  #endif // __cplusplus
  
      #include <libavcodec></libavcodec>avcodec.h>
  
      #include <libavformat></libavformat>avformat.h>
  
      #include <libavutil></libavutil>avutil.h>
  
      #include <libavutil></libavutil>opt.h>
  
      #include <libavutil></libavutil>channel_layout.h>
  
      #include <libavutil></libavutil>samplefmt.h>
  
      #include <libswresample></libswresample>swresample.h>
  
  #ifdef __cplusplus
  
  } // end extern "C".
  
  #endif // __cplusplus

  And here is the error I get, compiling with netbeans, g++
  (additional g++ commands : -lavcodec -lavformat -lavutil -lswresample -lfftw3 -lm)

  "/usr/bin/make" -f nbproject/Makefile-Debug.mk QMAKE= SUBPROJECTS= .build-conf
  
  make[1]: ingresso nella directory "/home/davide/Documenti/Tesi/audiosync-fin/audiosync"
  
  "/usr/bin/make"  -f nbproject/Makefile-Debug.mk dist/Debug/GNU-Linux-x86/audiosync
  
  make[2]: ingresso nella directory "/home/davide/Documenti/Tesi/audiosync-fin/audiosync"
  
  mkdir -p build/Debug/GNU-Linux-x86
  
  rm -f "build/Debug/GNU-Linux-x86/main.o.d"
  
  g++    -c -g -MMD -MP -MF "build/Debug/GNU-Linux-x86/main.o.d" -o build/Debug/GNU-Linux-x86/main.o main.cpp
  
  mkdir -p dist/Debug/GNU-Linux-x86
  
  g++ -o dist/Debug/GNU-Linux-x86/audiosync build/Debug/GNU-Linux-x86/dataReader.o build/Debug/GNU-Linux-x86/main.o build/Debug/GNU-Linux-x86/tansforms.o build/Debug/GNU-Linux-x86/tognuplot.o  -lavcodec -lavformat -lavutil -lswresample -lfftw3 -lm
  
  build/Debug/GNU-Linux-x86/dataReader.o: nella funzione "resample8(AVFrame*, int, AVCodec*)":
  
  /home/davide/Documenti/Tesi/audiosync-fin/audiosync/dataReader.cpp:285: riferimento non definito a "av_opt_set_sample_fmt"
  
  /home/davide/Documenti/Tesi/audiosync-fin/audiosync/dataReader.cpp:288: riferimento non definito a "av_opt_set_sample_fmt"
  
  /usr/local/lib/libswresample.so: riferimento non definito a "av_calloc@LIBAVUTIL_54"
  
  collect2: error: ld returned 1 exit status
  
  nbproject/Makefile-Debug.mk:65: set di istruzioni per l'obiettivo "dist/Debug/GNU-Linux-x86/audiosync" non riuscito
  
  make[2]: *** [dist/Debug/GNU-Linux-x86/audiosync] Errore 1
  
  make[2]: uscita dalla directory "/home/davide/Documenti/Tesi/audiosync-fin/audiosync"
  
  nbproject/Makefile-Debug.mk:62: set di istruzioni per l'obiettivo ".build-conf" non riuscito
  
  make[1]: *** [.build-conf] Errore 2
  
  make[1]: uscita dalla directory "/home/davide/Documenti/Tesi/audiosync-fin/audiosync"
  
  nbproject/Makefile-impl.mk:39: set di istruzioni per l'obiettivo ".build-impl" non riuscito
  
  make: *** [.build-impl] Errore 2
  
  
  
  BUILD FAILED (exit value 2, total time: 5s)

  here is the linker configuration linker config

  I searched for any clue about the linker error, and I found that it could be caused by multiple versions of ffmpeg installed. I removed ubuntu (I’m using 15.04) base installation of ffmpeg and installed ffmpeg 2.7.2 from the tar downloaded by ffmpeg.org

  I can’t seem to find a solution at the moment, can anyone help ?

• Redirect video stream from an Ip

  23 juin 2017, par Psykomusic

  I’m developping an embded device with Yocto (krogoth) OS. The device belong to a network with IpCamera. I’m looking for a light solution to redirect the stream received from a port and forward it to an other IP.
  I don’t know if it clear enought but for the moment I use GStreamer and this command :
  gst-launch-0.10 udpsrc port=myport ! udpsink host=xxx.xxx.xxx.xxx port=otherport.

  I hope there is an other solution because this command requires GStreamer and it’s quit heavy on my device.

  I have already ffmpeg on it maybe ffmpeg offers a solution for this.
  How can I do this redirection without Gstreamer ?

  Thank you,
  Antoine