Recherche avancée

Sur d’autres sites (13848)

• vf_scale : Detecting changes of incoming frame properties and dinamically evaluate...

  18 janvier 2016, par Bela Bodecs

  vf_scale : Detecting changes of incoming frame properties and dinamically evaluate width and height expressions
  Currently scale filter accepts expressions in its width and height
  
  parameters but evaluates them only once at init and replaces them with
  
  their actual values. Later on, if any parameter of incoming frames
  
  changes - ie those were used in the original size expressions -  then
  
  they new values will not have any affect for width and heigth values.
  
  They remain the same. This patch makes possible that width and height
  
  expressions be evaluated frame-by-frame basis if width/height/sar/format
  
  properties of incoming frame would change. To retain the current
  
  behaviour and not to break any earlier app, a new config parameter has
  
  been introduced. Its name is "eval" and it has two distinct values :
  
  "init" and "frame". The default value is "init".
  
  This feature is very usefull in case of DVBT mpeg-ts streams where SAR
  
  may change time-by-time from 4/3 to 16/9 and vica-versa and the size
  
  remains the same and you want to create a variable sized output with 1/1
  
  SAR.
  Signed-off-by : Bela Bodecs <bodecsb@vivanet.hu>
  
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavfilter/vf_scale.c

• Which command line and version do I need to reproduce those properties ?

  26 décembre 2015, par Zurechtweiser

  I have a file for which ffmpeg gave those properties :

  ...
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'TEST.MOV':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2015-12-26 07:45:26
  
    Duration: 00:00:02.75, start: 0.000000, bitrate: 4935 kb/s
  
      Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuvj420p(pc), 1280x720 [SAR 1:1 DAR 16:9], 4775 kb/s, 59.94 fps, 59.94 tbr, 180k tbn, 119.88 tbc (default)
  
      Metadata:
  
        creation_time   : 2015-12-26 07:45:26
  
        handler_name    : Ambarella AVC
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 64 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-12-26 07:45:26
  
        handler_name    : Ambarella AAC

  Which command line and version do I need to reproduce those properties ?

  I tried

  ffmpeg -i "test.mp4" -s 1280x720 -vcodec libx264 -c:a libvo_aacenc -q:a 3 -r 59.94 -b:v 4935k -b:a 64k -ac 1 -ar 48000 TEST2.MOV

  But it’s not the same.

  Goal is simple : my actioncam has a hdmi-output. I want to watch movies next to my own footage using my actioncam when I am abroad. Goal is to make the actioncam think, it was it’s own footage to play it back. Currently I only get ’invalid’.

• OpenCV in Python on Windows does not report correct video properties from VideoReader

  24 décembre 2015, par Mircea Davidescu

  I am running into a problem with using VideoReader in OpenCV with Python. Many of the properties that I should be able to get from the video reader are either somehow invalid (returning 0), or return the wrong number. For instance.

  vidFile = cv2.VideoCapture('movie.avi')
  
  vidFile.get(cv2.CAP_PROP_FRAME_COUNT)
  
  vidFile.get(cv2.CAP_PROP_FPS)

  The first get command returns a wrong value, while the second get command returns 0. The output of the ffprobe command is given below :

  built with gcc 5.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls 
  
  --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm 
  
  --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus 
  
  --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab 
  
  --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 
  
  --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib
  
    libavutil      55.  5.100 / 55.  5.100
  
    libavcodec     57. 12.100 / 57. 12.100
  
    libavformat    57. 11.100 / 57. 11.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 14.101 /  6. 14.101
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.100 /  2.  0.100
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, avi, from 'movie.avi':
  
    Metadata:
  
      encoder         : Lavf55.0.100
  
    Duration: 00:31:59.97, start: 0.000000, bitrate: 24321 kb/s
  
      Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj420p(pc, bt470bg/unknown/unknown), 1392x1040 [SAR 1:1 DAR 87:65], 24316 kb/s, 30 fps, 30 tbr, 30 tbn, 
  
  30 tbc

  I am running a Windows 10 machine with Python 2.7.11 (Anaconda 2.4.1 64-bit). I have installed OpenCV 3.0.0 according the instructions provided here. Because I am using the VideoReader feature I also added C :\opencv\sources\3rdparty\ffmpeg to the system PATH and renamed both opencv_ffmpeg300.dll and opencv_ffmpeg_x64.dll to opencv_ffmpeg300.dll and opencv_ffmpeg300_64.dll respectively, as specified here.

  Thank you for your help with this problem !