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• fftools/ffplay : constrain supported YUV color spaces

  5 février 2024, par Niklas Haas

  fftools/ffplay : constrain supported YUV color spaces
  SDL supports only these three matrices. Actually, it only supports these
  
  three combinations : BT.601+JPEG, BT.601+MPEG, BT.709+MPEG, but we have
  
  no way to restrict the specific *combination* of YUV range and YUV
  
  colorspace with the current filter design.
  See-Also : https://trac.ffmpeg.org/ticket/10839
  Instead of an incorrect conversion result, trying to play a YCgCo file
  
  with ffplay will simply error out with a "No conversion possible" error.
  

  • [DH] fftools/ffplay.c

• undefind reference to symbol 'avpriv_tak_parse_streaming@@LIBAVCODEC_FFMPEG_56'

  29 septembre 2019, par DJI_lover

  I recently compiled some ffmpeg code, but there were some compilation errors. I’ve solved some of them, but I don’t know how to solve the error below(Picture 1) . I’ve followed some online solutions to add option ’-lavcodec-ffmpeg’ after GCC but can’t solve this problem.I’ve been confused by it for several days.Could someone who konw the solution tell me how to fix this,I will be grateful.I use ubuntu 16.04 and I’ve installed n4.2dev version from ffmpeg git source and the standard libavcodec-ffmpeg56 as well as standard libav*-dev. My gcc version is 5.5.0 (Picture 2) .Thanks

  Picture1
  Picture2

  Update1:To prevent the picture 1 from not showing, I put out the error text here：

  /usr/bin/ld : /usr/local/lib/libavformat.a(takdec.o) : undefined reference to symbol ’avpriv_tak_parse_streaminfo@@LIBAVCODEC_FFMPEG_56’
  /usr/lib//libavcodec-ffmpeg.so.56 : error adding symbols : DSO missing from command line
  collect2 : error : ld returned 1 exit status
  CMakeFiles/simple_opencv_streaming.dir/build.make:145 : recipe for target ’simple_opencv_streaming’ failed
  make2 : * [simple_opencv_streaming] Error 1
  CMakeFiles/Makefile2:67 : recipe for target ’CMakeFiles/simple_opencv_streaming.dir/all’ failed
  make1 : * [CMakeFiles/simple_opencv_streaming.dir/all] Error 2
  Makefile:83 : recipe for target ’all’ failed
  make : *** [all] Error 2

  Update2 : My CMAKElist.txt :

  project(simple_opencv_streaming)

  cmake_minimum_required(VERSION 2.6.0 FATAL_ERROR)

  set(CMAKE_CXX_STANDARD 11)

  set(CMAKE_CXX_STANDARD_REQUIRED ON)

  set ( CMAKE_EXE_LINKER_FLAGS_RELEASE "$CMAKE_EXE_LINKER_FLAGS_RELEASE -pthread -lavcodec-ffmpeg")

  set(CMAKE_CXX_FLAGS_RELEASE "$CMAKE_CXX_FLAGS_RELEASE -O3 -std=c++11 -Wall")

  set ( CMAKE_EXE_LINKER_FLAGS_DEBUG "$CMAKE_EXE_LINKER_FLAGS_DEBUG -fsanitize=address -fsanitize=undefined")

  set(CMAKE_CXX_FLAGS_DEBUG "$CMAKE_CXX_FLAGS_DEBUG -std=c++11 -Wall -O0 -fno-omit-frame-pointer -fsanitize=address -fsanitize=undefined -D__FORTIFY_SOURCE=2 -rdynamic -DDEBUG")

  find_package(OpenCV REQUIRED)

  find_package(Qt5 REQUIRED COMPONENTS Core Gui Widgets Test Concurrent)

  get_target_property(QtCore_location Qt5::Core /usr/lib/x86_64-linux-gnu/)

  include(CMakeToolsHelpers OPTIONAL)

  include_directories($OpenCV_INCLUDE_DIRS)

  add_subdirectory(streamer)

  add_executable(simple_opencv_streaming main.cpp)

  find_library(AVCODEC_LIBRARY avcodec)

  find_library(AVFORMAT_LIBRARY avformat)

  find_library(AVUTIL_LIBRARY avutil)

  find_library(SWSCALE_LIBRARY swscale)

  MESSAGE($AVFORMAT_LIBRARY)

  target_link_libraries(simple_opencv_streaming streamer $OpenCV_LIBS $AVCODEC_LIBRARY $AVFORMAT_LIBRARY $AVUTIL_LIBRARY $SWSCALE_LIBRARY Qt5::Core)

• Getting metadata from a video using Paperclip-FFMPEG in Rails 3.2.6

  16 novembre 2012, par Graeme

  While still a Rails newbie, I've managed to get Paperclip-FFMPEG working. However, I'd like to extract some metadata from the uploaded video, in particular the length of the video. The README suggests this is possible, but I'm struggling to understand what I need to do :

  You may optionally add <attachment>_meta to your model and paperclip-ffmpeg will add information about the processed video.
  
  </attachment>

  Let's say the Paperclip attribute I have in my model is called "sourcefile". If I'm reading these instructions correctly, does this mean I need to add an extra attribute called sourcefile_meta ? Do I need to add generate a migration file to add this extra column to the model's table ? How would I get access to the length of the video in my view ? Should it be something like this :

  <p>Length: &lt;%= mymodel.sourcefile_meta.length %></p>

  Any pointers would be most useful, as I've hit a bit of a brick wall ! Thanks !