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• (Cross-platform) FFMPEG based GUI direct stream copy linear video editor [on hold]

  14 octobre 2014, par Fluorescent Hallucinogen

  FFMPEG official site has list of FFMPEG based projects (https://trac.ffmpeg.org/wiki/Projects).

  I use VirtualDub for linear video montage using direct stream copy mode (without recompression). It is GNU GPL licensed, but is designed only for Microsoft Windows and operates only AVI files.

  FFMPEG is excellent cross-platform utility that supports many formats (codecs and containers). It can be used for split and merge video files (not only AVI) using direct stream copy mode, but FFMPEG is console UI application.

  Is there GUI video editor (based on FFMPEG) (cross-platform or maybe only for Linux or maybe only for Windows) that can split and merge video files (not only AVI) using direct stream copy mode and have preview window ?

  Now I use video player, watch the input video file, remember the time for split video to fragments and write console line script for merge these fragments. All work is OK, but it is very inconvenient.

  At the worst, are there players or editors that can generate project file (that contains time markers for split and merge) that can be used with FFMPEG ?

• avconv / ffmpeg webcam capture while using minimum CPU processing

  10 septembre 2015, par user3585723

  I have a question about avconv (or ffmpeg) usage.

  My goal is to capture video from a webcam and saving it to a file.
  Also, I don’t want to use too much CPU processing. (I don’t want avconv to scale or re-encode the stream)

  So, I was thinking to use the compressed mjpeg video stream from the webcam and directly saving it to a file.

  My webcam is a Microsoft LifeCam HD 3000 and its capabilities are :

  ffmpeg -f v4l2 -list_formats all -i /dev/video0
  
  
  
  Raw: yuyv422 : YUV 4:2:2 (YUYV) : 640x480 1280x720 960x544 800x448 640x360 424x240 352x288 320x240 800x600 176x144 160x120 1280x800
  
  
  
  Compressed: mjpeg : MJPEG : 640x480 1280x720 960x544 800x448 640x360 800x600 416x240 352x288 176x144 320x240 160x120

  What would be the avconv command to save the Compressed stream directly without having avconv doing scaling or re-encoding.

  For now, I am using this command :

  avconv -f video4linux2 -r 30 -s 320x240 -i /dev/video0 test.avi

  I’m not sure that this command is CPU efficient since I don’t tell anywhere to use the mjpeg Compressed capability of the webcam.

  Is avconv taking care of the configuration of the webcam setting before starting to record the file ? Is it always working of raw stream and doing scaling and enconding on the raw stream ?

  Thanks for your answer

• Can I use avcodec_free_context() on an opened context ?

  23 mars 2017, par Ashe the human

  The latest documentation says here that opening a context that’s closed again is not supported any more. I see why. Some codecs don’t work properly when they’re reopened. So after finding this bug, I decided to not use avcodec_close() and call avcodec_free_context() on the contexts right away instead.

  But I’m not sure if it’s safe to do so with 2.8.4, the version that I linked to my program. The documentation from that time doesn’t clarify. Does anyone know ? At least empirically ?

  ffmpeg version 2.8.4 Copyright (c) 2000-2015 the FFmpeg developers
  
  built with Microsoft (R) C/C++ 최적화 컴파일러 버전 18.00.31101(x64)
  
  configuration: --toolchain=msvc --enable-gpl --enable-nonfree --enable-nvenc --enable-libvorbis --enable-libmp3lame --enable-libtheora --enable-libx264 --enable-libx265 --enable-libxvid --enable-libopus --enable-libvpx --enable-static --disable-shared --disable-debug --extra-cflags=-MT --extra-cxxflags=-MT --extra-ldflags='/nodefaultlib:msvcrt.lib' --extra-libs='zlib.lib libogg_static.lib libvorbis_static.lib libmpghip-static.lib libmp3lame-static.lib libtheora_static.lib libx264.lib x265-static.lib libxvidcore.lib silk_fixed.lib silk_common.lib silk_float.lib celt.lib opus.lib vpxmt.lib'
  
  libavutil      54. 31.100 / 54. 31.100
  
  libavcodec     56. 60.100 / 56. 60.100
  
  libavformat    56. 40.101 / 56. 40.101
  
  libavdevice    56.  4.100 / 56.  4.100
  
  libavfilter     5. 40.101 /  5. 40.101
  
  libswscale      3.  1.101 /  3.  1.101
  
  libswresample   1.  2.101 /  1.  2.101
  
  libpostproc    53.  3.100 / 53.  3.100

  I know there’s a bunch of forums I could post on but I’d felt like to ask it here first.