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• Build Opencv3.1 with ffmpeg

  10 mai 2018, par batuman

  I tried to build Opencv3.1 at Ubuntu16.04 with ffmpeg. I follow the instructions how to install ffmpeg at here.

  According to this discussion ,I checked.

  >> mediainfo ~/Desktop/grb_2.mp4 
  General
  Complete name                            : /home/nyan/Desktop/grb_2.mp4
  Format                                   : MPEG-4
  Format profile                           : Base Media
  Codec ID                                 : isom (isom/iso2/avc1/mp41)
  File size                                : 445 KiB
  Duration                                 : 27s 862ms
  Overall bit rate                         : 131 Kbps
  Encoded date                             : UTC 1904-01-01 00:00:00
  Tagged date                              : UTC 1904-01-01 00:00:00
  Writing application                      : Lavf57.66.105
  
  Video
  ID                                       : 1
  Format                                   : AVC
  Format/Info                              : Advanced Video Codec
  Format profile                           : High@L3
  Format settings, CABAC                   : Yes
  Format settings, ReFrames                : 4 frames
  Codec ID                                 : avc1
  Codec ID/Info                            : Advanced Video Coding
  Duration                                 : 27s 862ms
  Bit rate                                 : 128 Kbps
  Width                                    : 720 pixels
  Height                                   : 480 pixels
  Display aspect ratio                     : 4:3
  Original display aspect ratio            : 4:3
  Frame rate mode                          : Constant
  Frame rate                               : 29.970 (30000/1001) fps
  Standard                                 : NTSC
  Color space                              : YUV
  Chroma subsampling                       : 4:2:0
  Bit depth                                : 8 bits
  Scan type                                : Progressive
  Bits/(Pixel*Frame)                       : 0.012
  Stream size                              : 435 KiB (98%)
  Writing library                          : x264 core 148
  Encoding settings                        : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=23.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
  Encoded date                             : UTC 1904-01-01 00:00:00
  Tagged date                              : UTC 1904-01-01 00:00:00 
  
  
  
  
  
  ffmpeg -codecs | grep -i avc
  ffmpeg version N-90982-gb995ec0 Copyright (c) 2000-2018 the FFmpeg developers
    built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.9) 20160609
    configuration: --prefix=/home/nyan/ffmpeg_build --enable-shared --extra-cflags=-I/home/nyan/ffmpeg_build/include --extra-ldflags=-L/home/nyan/ffmpeg_build/lib --extra-libs='-lpthread -lm' --bindir=/home/nyan/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree
    libavutil      56. 18.100 / 56. 18.100
    libavcodec     58. 19.100 / 58. 19.100
    libavformat    58. 13.101 / 58. 13.101
    libavdevice    58.  4.100 / 58.  4.100
    libavfilter     7. 21.100 /  7. 21.100
    libswscale      5.  2.100 /  5.  2.100
    libswresample   3.  2.100 /  3.  2.100
    libpostproc    55.  2.100 / 55.  2.100
   DEV.LS h264                 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders: h264 h264_v4l2m2m ) (encoders: libx264 libx264rgb h264_v4l2m2m h264_vaapi )
   D.A.L. avc                  On2 Audio for Video Codec (decoders: on2avc )
  

  So my ffmpeg installation is ok.

  When I cmake to my Opencv, I have set up to ffmpeg as

  

  But when I make to compile, I have error as

  make[2]: *** No rule to make target '/home/nyan/ffmpeg_build/lib/libavresample.a', needed by 'lib/libopencv_videoio.so.3.1.0'.  Stop.
  CMakeFiles/Makefile2:8709: recipe for target 'modules/videoio/CMakeFiles/opencv_videoio.dir/all' failed
  make[1]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/all] Error 2
  Makefile:160: recipe for target 'all' failed
  make: *** [all] Error 2
  

  How can I fix the problem?

  I install libavresample manually and

  sudo apt-get install libavresample-dev
  [sudo] password for nyan: 
  Reading package lists... Done
  Building dependency tree       
  Reading state information... Done
  libavresample-dev is already the newest version (7:2.8.14-0ubuntu0.16.04.1).
  

  It is newest version.

  EDIT:
  

  Actually libavresample at ffmpeg is deprecated already. So I tried to install Opencv3.4.1 higher version. Compile, build and installation are fine. But VideoCapture cap(0); does not read from the device. So I checked ffmpeg at Opencv3.4.1 installation as

  python -c "import cv2; print(cv2.getBuildInformation())" | grep -i ffmpeg
  

  FFMMPEG IS NO. So build with ffmpeg is not successful even though there was no error at build for Opencv3.4.1.

• Installing FFMPEG from Conda = not found

  10 mai 2018, par dartdog

  Have installed FFMPEG via conda using conda install -c conda-forge ffmpeg and am getting RuntimeError: Requested MovieWriter (ffmpeg) not available any ideas? a direct Import ffmpeg yields not found as well conda list shows ffmpeg 4.0 installed using Ubuntu 16.04 current conda in an env..

• Playing javacv-ffmpeg decoded audio in Android with Audiotrack

  10 mai 2018, par Ichigo Kurosaki

  i am developing android application in which i need to play AAC live audio stream coming from Red5 server.
  I have successfully decoded the audio stream by using javacv-ffmpeg.
  But my problem is how to play the audio from decoded samples.
  I have tried by following way

  int len = avcodec.avcodec_decode_audio4( audio_c,  samples_frame,  got_frame,  pkt2);
  if (len <= 0){
      this.pkt2.size(0);
  } else {
      if (this.got_frame[0] != 0) {
              long pts = avutil.av_frame_get_best_effort_timestamp(samples_frame);
              int sample_format = samples_frame.format();
                     int planes = avutil.av_sample_fmt_is_planar(sample_format) != 0 ? samples_frame.channels() : 1;
                     int data_size = avutil.av_samples_get_buffer_size((IntPointer)null, audio_c.channels(), samples_frame.nb_samples(), audio_c.sample_fmt(), 1) / planes;
  
                     if ((samples_buf == null) || (samples_buf.length != planes)) {
  
                         samples_ptr = new BytePointer[planes];
                         samples_buf = new Buffer[planes];
                     }
                             BytePointer ptemp = samples_frame.data(0);
                 BytePointer[] temp_ptr = new BytePointer[1];
                 temp_ptr[0] = ptemp.capacity(sample_size);
                 ByteBuffer btemp = ptemp.asBuffer();
                 byte[] buftemp = new byte[sample_size];
                 btemp.get(buftemp, 0, buftemp.length);
  
                             play the buftemp[] with audiotrack.....
          }
  

  But only noise is heard from speakers, is there any processing is need to be done on AVFrame we get from decode_audio4(...) .
  The Incoming audio stream is correctly encoded with AAC codec.
  Any help, suggestion appreciated.
  Thanks in advance.

• getting error while converting wav to amr using ffmpeg

  10 mai 2018, par sohilv

  I am using ffmpeg to convert amr to wav and wav to amr.Its successfully converting amr to wav but not viceversa. As ffmpeg is supporting amr encoder decoder, its giving error.

  ffmpeg -i testwav.wav audio.amr

  Error while opening encoder for output stream #0.0 - maybe incorrect parameters such as bit_rate, rate, width or height

• Generate thumbnail for inmemory uploaded video file

  10 mai 2018, par Adarsh

  The client app uploaded a video file and i need to generate a thumbnail and dump it to AWS s3 and return the client the link to the thumbnail. I searched around and found ffmpeg fit for the purpose. The following was the code i could come up with:

  from ffmpy import FFmpeg
  import tempfile
  
  def generate_thumbnails(file_name):
      output_file = tempfile.NamedTemporaryFile(suffix='.jpg', delete=False, prefix=file_name)
      output_file_path = output_file.name
      try:
          # generate the thumbnail using the first frame of the video
          ff = FFmpeg(inputs={file_name: None}, outputs={output_file_path: ['-ss', '00:00:1', '-vframes', '1']})
          ff.run()
  
          # upload generated thumbnail to s3 logic
          # return uploaded s3 path 
      except:
          error = traceback.format_exc()
          write_error_log(error)
      finally:
          os.remove(output_file_path)
      return ''
  

  I was using django and was greeted with permission error for the above. I found out later than ffmpeg requires the file to be on the disk and doesn't just take into account the InMemory uploaded file (I may be wrong as i assumed this).

  Is there a way to read in memory video file likes normal ones using ffmpeg or should i use StringIO and dump it onto a temp. file? I prefer not to do the above as it is an overhead.

  Any alternative solution with a better benchmark also would be appreciated.

  Thanks.

  Update: To save the inmemory uploaded file to disk: How to copy InMemoryUploadedFile object to disk