Recherche avancée

Sur d’autres sites (12774)

• Adjust video capture input port using C++ / python

  19 juillet 2017, par Tarek

  I am having a video capture device (VCD) that acquires frames from a TV which have various output ports (VGA, HDMI, DVI). I read these frames using C++/OpenCV, process them and then show the output on a C++/Qt QLabel.

  My problems show up when I change the input port (DVI to HDMI or HDMI to VGA,...), at then I need to manually open the crossbar dialog window for the VCD and switch the input port.

  Shows command window with ffmpeg command line + crossbar window for the video capture device

  

  Moreover, for each input port, I need to adjust some parameters relating to color range, scaling size and wire’s length.

  I need to automate this process of selecting the right input port with the corresponding right parameters using a C++ or python code.

  I was searching for a way to read all the input pins of the crossbar dialog box for the video capture device and this set/unset the required pins.

  Thanks in advance.

• HTML 5 how to record filtered canvas

  16 mars 2015, par sercanD

  I am gonna use my webcam as a source and show my view on webpage , than I will manipulate my view like (blacknwhite , fiseye, etc.) and show that manipulated video in my canvas.
  An example ( http://photobooth.orange-coding.net/ )

  Ok everything is cool for now . I can capture that manipulated canvas as a image.

  Is there any way to record that manipulated canvas as video ?

  I also found an example (https://www.webrtc-experiment.com/ffmpeg/audio-plus-canvas-recording.html)

  But when I tried that code on my webcam recording project , it’s just recording my source view(not blacknwhite) . It is not implementing my effect to record.

  Any idea or is it possible ?
  Thank you.

• libswresample/swresamplec : Err num(negative-size) was used as a function parameter

  8 décembre 2021, par Yu Yang

  libswresample/swresamplec : Err num(negative-size) was used as a function parameter
  If memory allocation fails, ERROR(ENOMEM) '-12' will be returned.
  
  When resample() is done first, the negative size param would cause buffer-overflow and SEGV in swri_rematrix().
  
  When swri_rematrix() is run first, resample() would not cause an error but Err num as a wrong parameter passing.
  
  Err num should be returned immediately. And remove an unneeded term from an assert.
  coredump info :
  
      #0 0x499517 in posix_memalign (/home/r1/ffmpeg/ffmpeg_4.4.1+0x499517)
  
      #1 0x6c1f0b4 in av_malloc /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/mem.c:86:9
  
      #2 0x6c208fe in av_mallocz /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/mem.c:239:17
  
      #3 0x6c207ad in av_mallocz_array /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/mem.c:195:12
  
      #4 0x654b2e5 in swri_realloc_audio /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libswresample/swresample.c:418:14
  
      #5 0x654f9a1 in swr_convert_internal /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libswresample/swresample.c:601:17
  
      #6 0x654d2c0 in swr_convert /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libswresample/swresample.c:766:19
  
      #7 0x186cf56 in flush_frame /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/af_aresample.c:251:13
  
      #8 0x186a454 in request_frame /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/af_aresample.c:288:20
  
      #9 0x787d9c in ff_request_frame_to_filter /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:459:15
  
      #10 0x7877f1 in forward_status_change /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:1257:19
  
      #11 0x77ed7e in ff_filter_activate_default /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:1288:20
  
      #12 0x77e4e1 in ff_filter_activate /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:1441:11
  
      #13 0x793b3f in ff_filter_graph_run_once /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfiltergraph.c:1403:12
  
      #14 0x7a7bee in get_frame_internal /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/buffersink.c:131:19
  
      #15 0x7a7287 in av_buffersink_get_frame_flags /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/buffersink.c:142:12
  
      #16 0x792888 in avfilter_graph_request_oldest /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfiltergraph.c:1356:17
  
      #17 0x5d07df in transcode_from_filter /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4639:11
  
      #18 0x59e557 in transcode_step /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4729:20
  
      #19 0x593970 in transcode /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4805:15
  
      #20 0x58f7a4 in main /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:5010:9
  
      #21 0x7f6fd2dee0b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
  SUMMARY : AddressSanitizer : negative-size-param (/home/r1/ffmpeg/ffmpeg_4.4.1+0x497e67) in __asan_memcpy
  Reported-by : TOTE Robot <oslab@tsinghua.edu.cn>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libswresample/swresample.c