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• OpenCV 2.4.7 with FFMpeg support build with VS 2010 (x86)

  24 novembre 2013, par GregPhil

  I'm fighting with new version of OpenCV 2.4.7 for almost one week (prev. used 2.4.2). My motivation for the new setup is the fact that I run into problems using the Videowriter for uncompressed grayscale videos (http://answers.opencv.org/question/3603/videowriter-videocapture-and-uncompressed-avi/). In https://github.com/Itseez/opencv/pull/1516 "akarsakov" is recommending to build OpenCV without vfw support and open uncompressed video through ffmpeg. That's what I tried to do. I followed basically the instructions mentioned in this video : http://docs.opencv.org/trunk/doc/tutorials/introduction/windows_install/windows_install.html

  I had successfully build opencv with Qt 5.1.1 (http://answers.opencv.org/question/24184/how-to-compile-opencv-247-with-qt-and-ffmpeg/). But I'm not able to get the VideoWriter & VideoCapture work for me. So what I did :

  1. I downloaded the newest ffmpeg build from http://ffmpeg.zeranoe.com/builds/

  2. I generated the vs2010 project disabling VfW and enabling ffmpeg instead :

     Video I/O:
     
     
     
     Video for Windows:           NO
     
     DC1394 1.x:                  NO
     
     DC1394 2.x:                  NO
     
     FFMPEG:                      YES (prebuilt binaries)
     
       codec:                     YES (ver 55.18.102)
     
       format:                    YES (ver 55.12.100)
     
       util:                      YES (ver 52.38.100)
     
       swscale:                   YES (ver 2.3.100)
     
       gentoo-style:              YES
     
       OpenNI:                    NO
     
     OpenNI PrimeSensor Modules:  NO
     
     PvAPI:                       NO
     
     GigEVisionSDK:               NO
     
     DirectShow:                  YES
     
     Media Foundation:            NO
     
     XIMEA:                       NO

  3. I added the include directories and libs for ffmpeg to the highgui module.

  I was not able to compile OpenCV without any errors but the behaviour what I see is not what I expect :

  1. Build OpenCV 2.4.7 without VfW -> VideoWriter.open () returns always false !
  2. Build OpenCV 2.4.7 with VfW -> VideoWriter.open () returns true for the time, calling a release() and an open() on the same object returns always a false.
  3. With or without ffmpeg -> An VideoCapture.open () gives a error message asking for libiconv-2dll !

  Does some had the same problems and is able to point me to my mistake ?

  Thank you in advance.
  cheers

• How do I avoid batch video transcoding error when encountering whitespaces in filename using ffmpeg [duplicate]

  20 février 2019, par russell newton

  This question already has an answer here :

  • Looping through find output in Bash where file name contains white spaces
    
    2 answers
    

  I am running a bash script to batch transcode videos on a LAMP server using find and ffmpeg

  dir="/srv/videos"
  
  for OUTPUT in "$(find $dir -iname *.AVI -o -iname *.MOV)"
  
  do
  
      ffmpeg -i "$OUTPUT" "${OUTPUT%%.*}.mp4"  -hide_banner
  
  done

  ffmpeg returns an error if file has whitespaces

   /srv/videos/file with white spaces.MOV: No such file or directory

  For files without white spaces it works fine.
  If I print the filenames inside quotes it looks as though it should be working

  for OUTPUT in "$(find $dir -iname *.MOV)"; do echo "$OUTPUT";done

  returns

  /srv/videos/file with white spaces.MOV

  What do I need to alter to avoid the error please ?

  EDIT
  added "" to $OUTPUT%%.*.mp4, I get the same error and corrected extension capitalisation (mov to MOV)

• av_interleaved_write_frame return 0 but no data written

  11 août 2015, par Jerikc XIONG

  I use the ffmpeg to stream the encoded aac data , i use the

  av_interleaved_write_frame()

  to write frame.

  The return value is 0,and it means success as the description.

  Write a packet to an output media file ensuring correct interleaving.

  The packet must contain one audio or video frame. If the packets are already correctly interleaved, the application should call av_write_frame() instead as it is slightly faster. It is also important to keep in mind that completely non-interleaved input will need huge amounts of memory to interleave with this, so it is preferable to interleave at the demuxer level.

  Parameters

  s media file handle

  pkt The packet containing the data to be written. pkt->buf must be set to a valid AVBufferRef describing the packet data. Libavformat takes ownership of this reference and will unref it when it sees fit. The caller must not access the data through this reference after this function returns. This can be NULL (at any time, not just at the end), to flush the interleaving queues. Packet’s stream_index field must be set to the index of the corresponding stream in s.streams. It is very strongly recommended that timing information (pts, dts duration) is set to correct values.

  Returns

  0 on success, a negative AVERROR on error.

  However, I found no data written.

  What did i miss ? How to solve it ?