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• Node_module needs executable

  26 avril 2016, par user2792129

  I do not understand this error I’m getting from fluent-ffmpeg : An error occurred : spawn ENOENT

  I can find the exact same error on its github repo - same exact issue - where they solved it by adding an executable in the required path, but where are they getting this executable and why do they need it ? Also how are they adding it to the FFMPEG_PATH variable ? My FFMPEG_PATH variable only contains the path to the ffmpeg node module. Is this path not supposed to point to the node module ?

• Create a demultiplexer for MPEG 2 TS in android

  17 novembre 2014, par anz

  I have a requirement where I need to extract ID3 tags from a MPEG2 TS(HLS STREAM). MPEG2 has a limited support in android in regards to playing the file. But my concern is to extract the ID3 tags(playing the file is not necessary). Hence I am not concerned with the codecs(encoding and decoding).

  I have explored the following options :

  libstagefright and OpenMax : A playback engine implemented by Google from Android 2.0.
  It has a MediaExtractor is responsible for retrieving track data and the corresponding meta data from the underlying file system or http stream. But according to this post Adding video codec to Android I need to build my own firmware or my own media player.I am hoping I don’t have to go down that path. More info on stagefright and openMax can be found here :

  An overview of Stagefright player

  Android’s Stagefright Media Player Architecture

  Custom Wrapper Codec Integration into Android

  How to integrate a decoder to multimedia framework

  Compiling and using FFMPEG : A complete, cross-platform solution to record, convert and stream audio and video. We can demultiplex ts files with this library as mentioned here :

  FFmpeg - Extracting video and audio from transport stream file (.ts).

  But I am not sure if I will be able to extract the ID3 tags from the HLS Stream. libavformat might be able to do this but I still need to come up with a mechanism for signaling the read metadata to my application.

  Compiling vlc for android : I have compiled vlc for android and made some modifications inside the transport module in demux component for extracting the tags, but it is not able to play all the streams that I am supplying to it.

  After looking through these options , I am still at a fix in how to achieve this. I don’t want to create a media player as I will not be playing the files nor do I want to build my own firmware. Using ffmpeg seems to be the most viable option, but I want to try this without using any third-party or open source library. My questions are :

  Is it even possible to create a demultiplexer from scratch that will work on android ?

  If possible then ,how to go about it ?

  Any options that I have missed ?

  I am new to this. Any help would be greatly appreciated..Thanks

• Opening file with unknown extension (Mjpeg ?) in OpenCV python

  14 novembre 2013, par bw4sz

  I am trying to open a third party video file into OpenCV with python.
  My camera (plotwatcher camera trap) shoots in a silly proprietary format. The extension is unique (.tlv) but i can play the file in VLC, and using ffmpeg i can see the following encoding :

  C:\Users\Ben>ffmpeg -i C:/Users/Ben/Documents/OpenCV_HummingbirdsMotion/PlotwatcherTest.tlv
  
  
  
  ffmpeg version N-58037-g355cea8 Copyright (c) 2000-2013 the FFmpeg developers
  
  built on Nov 11 2013 18:01:42 with gcc 4.8.2 (GCC)
  
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
  
  isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
  
  le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetyp
  
  e --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
  
  ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
  
  ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
  
  eex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aa
  
  cenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavp
  
  ack --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  
  libavutil      52. 52.100 / 52. 52.100
  
  libavcodec     55. 41.100 / 55. 41.100
  
  libavformat    55. 21.100 / 55. 21.100
  
  libavdevice    55.  5.100 / 55.  5.100
  
  libavfilter     3. 90.102 /  3. 90.102
  
  libswscale      2.  5.101 /  2.  5.101
  
  libswresample   0. 17.104 /  0. 17.104
  
  libpostproc    52.  3.100 / 52.  3.100
  
  Input #0, avi, from 'C:/Users/Ben/Documents/OpenCV_HummingbirdsMotion/Plotwatche
  
  rTest.tlv':
  
  Duration: 00:00:05.00, start: 0.000000, bitrate: 14608 kb/s
  
  Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj420p(pc), 1280x720, 10 tb
  
  r, 10 tbn, 10 tbc

  From this i can see file is encoded into mjpeg format.

  How can i open this file in open cv ?

  import cv2
  
  #import cv2.cv as cv
  
  import numpy as np
  
  cap = cv2.VideoCapture("C:/Users/Ben/Documents/OpenCV_HummingbirdsMotion/PlotwatcherTest.mjpg")
  
  ret, frame = cap.read()
  
  #show first image
  
  cv2.imshow('my window',frame)
  
  cv2.waitKey(0)
  
  cv2.destroyWindow('my window')

  I can see nothing has been loaded. When i try to view the first frame i get the error :

  File "C:\Users\Ben\Documents\OpenCV_HummingbirdsMotion\Test.py", line 21, in <module>
  
  cv2.imshow(&#39;my window&#39;,frame)
  
  error: ..\..\..\..\opencv\modules\highgui\src\window.cpp:261: error: (-215)
  
  size.width>0        &amp;&amp; size.height>0
  
  </module>

  I've tried leaving the native .tlv, mjpeg and mjpg, and .MJPG endings following the conceptual idea found here : MJPEG stream fails to open in OpenCV 2.4

  i appreciate all help !