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• android ffmpeg halfninja av_open_input_file returns -2 (no such file or directory)

  20 janvier 2012, par cdavidyoung

  I have built ffmpeg for Android using the code and method described at

  https://github.com/halfninja/android-ffmpeg-x264

  using Ubuntu running in VirtualBox on windows. I then copied libvideokit.so into the Project\libs\armeabi folder of a Windows copy of the provided projects. From there I was able to run the ProjectTest from Eclipse on my Android device. I can see the ffmpeg code being executed but when it gets to the point of opening the input file it gives me the indicated error. I have noticed some discussion of this problem at

  FFMpeg on Android, undefined references to libavcodec functions, although it is listed on command line

  but the solutions have not helped since the file protocol is enabled in this build and I also tried putting "file:" in front of the filepath to no avail. For completeness I tried setting minimal_featureset=0 to enable all the defaults but this gives me the same error. Below is a snapshot of the logcat from Eclipse showing the output from Videokit with an extra call to LOGE to display the result from av_open_input_file. Any suggestions of things to try would be greatly appreciated.

  10-23 11:57:33.888: DEBUG/Videokit(4830): run() called
  10-23 11:57:33.888: DEBUG/Videokit(4830): run passing off to main()
  10-23 11:57:33.904: DEBUG/Videokit(4830): main(): registering all modules
  10-23 11:57:33.927: DEBUG/Videokit(4830): main(): registered everything
  10-23 11:57:33.927: DEBUG/Videokit(4830): main(): initting opts
  10-23 11:57:33.943: DEBUG/Videokit(4830): main(): initted opts.
  10-23 11:57:33.943: ERROR/Videokit(4830): ffmpeg version N-30996-gf925b24, Copyright (c) 2000-2011 the FFmpeg developers
  10-23 11:57:33.943: ERROR/Videokit(4830):   built on Oct 21 2011 13:54:03 with gcc 4.4.3
  10-23 11:57:33.943: ERROR/Videokit(4830):   configuration: --enable-cross-compile --arch=arm5te --enable-armv5te --target-os=linux --disable-stripping --prefix=../output --disable-neon --enable-version3 --disable-shared --enable-static --enable-gpl --enable-memalign-hack --cc=arm-linux-androideabi-gcc --ld=arm-linux-androideabi-ld --extra-cflags='-fPIC -DANDROID -D__thumb__ -mthumb -Wfatal-errors -Wno-deprecated' --disable-everything --enable-decoder=mjpeg --enable-demuxer=mjpeg --enable-parser=mjpeg --enable-demuxer=image2 --enable-muxer=mp4 --enable-encoder=libx264 --enable-libx264 --enable-decoder=rawvideo --enable-protocol=file --enable-hwaccels --disable-ffmpeg --disable-ffplay --disable-ffprobe --disable-ffserver --disable-network --enable-filter=buffer --enable-filter=buffersink --disable-demuxer=v4l --disable-demuxer=v4l2 --disable-indev=v4l --disable-indev=v4l2 --extra-cflags='-I../x264 -Ivideokit' --extra-ldflags=-L../x264
  10-23 11:57:33.943: DEBUG/Videokit(4830): main(): parsing options
  10-23 11:57:33.943: DEBUG/Videokit(4830): parse_options has 4 options to parse
  10-23 11:57:33.951: ERROR/Videokit(4830): opt_input_file av_open_input_file /mnt/sdcard/fun/snap0000.jpg -2 
  10-23 11:57:33.951: ERROR/Videokit(4830): /mnt/sdcard/fun/snap0000.jpg: No such file or directory
  10-23 11:57:33.951: ERROR/Videokit(4830): ffmpeg_exit(1) called!
  

• Securely using the PHP exec function

  19 janvier 2012, par siberiantiger

  I am writing a PHP script designed to run an executable file (ffmpeg.exe) via the exec() function. The problem is that I have read that using the exec() function can be a security risk and should be avoided if possible. I have been doing some research into how to run the exec() function securely, and the only thing that I keep coming across is to filter the command string with escapeshellcmd or escapeshellarg. What I want to know is if it is possible to further increase security when using the exec() function or if there is a secure alternative to exec(). Any help would be appreciated.

  Here is my code;

  define('FFMPEG_LIBRARY', 'c:\\ffmpeg7\\ffmpeg\\bin\\ffmpeg ');
  $transcode_string = FFMPEG_LIBRARY." -i " . $srcFile . " -acodec libmp3lame -ab 64k -ar 22050 -ac 1 -vcodec libx264 -b:v 250k -r 30 -f flv -y " . $destFile;
  $transcode_string = escapeshellcmd($transcode_string);
  exec($transcode_string);
  

  $srcFile is basically the video for transcoding while $destFile is the output file I wish to create.

• how to explicitly specify matroska format file to be VFR

  19 janvier 2012, par Ulterior

  I am moving my code performing AVI recording with ffmpeg library to matroska format due to native support of VFR stated by format. Changing guess_format to matroska not touching any other settings produced an mkv file which seems to be ok. But the MediaInfo reports it to be CFS (30).

  How do I explicitly state that its VFR?

  Format                           : Matroska
  File size                        : 5.27 MiB
  Duration                         : 8s 0ms
  Overall bit rate                 : 5 528 Kbps
  Writing application              : Lavf52.78.1
  Writing library                  : Lavf52.78.1
  
  Video
  ID                               : 1
  Format                           : MPEG-4 Visual
  Format profile                   : Simple@L1
  Format settings, BVOP            : Yes
  Format settings, QPel            : No
  Format settings, GMC             : No warppoints
  Format settings, Matrix          : Default (H.263)
  Codec ID                         : V_MPEG4/ISO/ASP
  Codec ID/Info                    : Advanced Simple Profile
  Duration                         : 8s 0ms
  Width                            : 1 280 pixels
  Height                           : 720 pixels
  Display aspect ratio             : 16:9
  Frame rate                       : 30.000 fps
  Color space                      : YUV
  Bit depth                        : 8 bits
  Scan type                        : Progressive
  Writing library                  : Intel(R) MPEG-4 encoder based on Intel(R) IPP 6.1 build 137.36[6.1.137.779]
  Language                         : English
  
  Audio
  ID                               : 2
  Format                           : MPEG Audio
  Codec ID                         : A_MPEG/L3
  Codec ID/Hint                    : MP3
  Duration                         : 8s 0ms
  Channel(s)                       : 2 channels
  Sampling rate                    : 44.1 KHz
  Language                         : English
  

• Grabbing rtsp/rtp stream with libavformat

  19 janvier 2012, par T0ha

  world. I'm trying to grab rtsp mjpeg stream from IP-camera (realtime) as described in http://www.inb.uni-luebeck.de/~boehme/using_libavcodec.html, but ported to newer version. It works well with mpeg file (loading it full as one AVPacket), but working with stream, avcodec_decode_video2 returns -1 (error). AVPacket in this case is a part of a frame.

  How can I fix this?

• How to map an audio clip to a video ?

  19 janvier 2012, par simpatico

  I have a video clip, and an audio clip extracted from it. How can I trim the the video clip to to the portion extracted in the audio clip?

  I imagine the solution will consist of:

  1. Automatically identify the pair of start position of the audio clip in the video clip, and the end position (e.g. <03:05,09:55>);
  2. Trim the video from the identified start to the identified end (that's easy).