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• Adding FFmpeg library as dependency in Visual studio project to get rid of LNK2019 error

  13 mars 2019, par MSD Paul

  While compiling a project on Microsoft visual studio (to generate dll), I am getting the following linking errors (LNK2019)

  Severity Code Description Project File Line Suppression State
  Error LNK2019 unresolved external symbol av_strerror referenced in function "private : void __cdecl DecoderFFmpeg::printErrorMsg(int)" (?printErrorMsg@DecoderFFmpeg@@AEAAXH@Z)
  Severity Code Description Project File Line Suppression State
  Error LNK2019 unresolved external symbol av_get_channel_layout_nb_channels referenced in function "private : int __cdecl DecoderFFmpeg::initSwrContext(void)"

  several other functions like av_dict_set, av_dict_free, avcodec_decode2 which is related to the ffmpeg libraries. Can anyone please tell me how to properly add "ffmpeg" as dependenciesto this project and link it properly ?

• ffmpeg static link in Visual Studio [duplicate]

  24 avril 2019, par iz25

  This question already has an answer here :

  • What is an undefined reference/unresolved external symbol error and how do I fix it ?
    
    33 answers
    

  I have build ffmpeg static library on Windows. It seems that everything completed with success. The result of build are following files :

  libavcodec.a
  
  libavdevice.a
  
  libavfilter.a
  
  libavformat.a
  
  libavutil.a
  
  libswscale.a

  I tried to specify above files in Linker->Input in my C++ libray project, but linking fails. Following is build output :

  1>libavutil.a(samplefmt.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavutil.a(error.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavutil.a(log.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavutil.a(utils.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavutil.a(avstring.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavutil.a(bprint.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavformat.a(id3v2.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavutil.a(opt.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavutil.a(dict.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavutil.a(pixdesc.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavcodec.a(ratecontrol.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavcodec.a(qsv.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavformat.a(utils.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavformat.a(aviobuf.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavcodec.a(utils.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavcodec.a(ffv1enc.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavcodec.a(exif.o) : error LNK2001: unresolved external symbol ___stdio_common_vsprintf
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_img_wrap
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_version_str
  
  1>libavcodec.a(libvpxdec.o) : error LNK2001: unresolved external symbol _vpx_codec_version_str
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_build_config
  
  1>libavcodec.a(libvpxdec.o) : error LNK2001: unresolved external symbol _vpx_codec_build_config
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_err_to_string
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_error
  
  1>libavcodec.a(libvpxdec.o) : error LNK2001: unresolved external symbol _vpx_codec_error
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_error_detail
  
  1>libavcodec.a(libvpxdec.o) : error LNK2001: unresolved external symbol _vpx_codec_error_detail
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_destroy
  
  1>libavcodec.a(libvpxdec.o) : error LNK2001: unresolved external symbol _vpx_codec_destroy
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_control_
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_enc_init_ver
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_enc_config_default
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_encode
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_get_cx_data
  
  1>libavcodec.a(libvpxenc.o) : error LNK2001: unresolved external symbol _vpx_codec_vp8_cx
  
  1>libavcodec.a(libvpxdec.o) : error LNK2001: unresolved external symbol _vpx_codec_dec_init_ver
  
  1>libavcodec.a(libvpxdec.o) : error LNK2001: unresolved external symbol _vpx_codec_decode
  
  1>libavcodec.a(libvpxdec.o) : error LNK2001: unresolved external symbol _vpx_codec_get_frame
  
  1>libavcodec.a(libvpxdec.o) : error LNK2001: unresolved external symbol _vpx_codec_vp8_dx_algo
  
  1>libavutil.a(opt.o) : error LNK2001: unresolved external symbol ___stdio_common_vsscanf
  
  1>libavutil.a(parseutils.o) : error LNK2001: unresolved external symbol ___stdio_common_vsscanf
  
  1>libavcodec.a(h264_sei.o) : error LNK2001: unresolved external symbol ___stdio_common_vsscanf
  
  1>libavcodec.a(ratecontrol.o) : error LNK2001: unresolved external symbol ___stdio_common_vsscanf
  
  1>libavcodec.a(qsv.o) : error LNK2001: unresolved external symbol ___stdio_common_vsscanf
  
  1>libavformat.a(id3v2.o) : error LNK2001: unresolved external symbol ___stdio_common_vsscanf
  
  1>libavutil.a(log.o) : error LNK2001: unresolved external symbol ___acrt_iob_func
  
  1>libavutil.a(log.o) : error LNK2001: unresolved external symbol ___stdio_common_vfprintf

  What could be missing here ?

• ffmpeg to calculate audio/visual difference between compressed and non-compressed video

  14 juin 2019, par Asymetr

  I’m trying to calculate the audio + visual difference between a harshly compressed video file and one that hasn’t been.
  I’m using pipes because ultimately I wish this to take src from a camera stream.

  I’ve managed to get the video results that I’m looking for, but I’m struggling with the audio.
  I’ve added a line to invert the phase of the compressed audio, so that when they add up in the blend they should almost cancel each other out, but that doesn’t happen.

  ffmpeg -i input.avi -f avi -c:v libxvid -qscale:v 30 -c:a wmav1 - | \
  
  ffmpeg -i - -f avi -af "aeval='-val(0)':c=same" - | \
  
  ffmpeg -i input.avi -i - -filter_complex "blend=all_mode=difference" -c:v libx264 -crf 18 -f avi - | \
  
  ffplay -

  I can still hear all the audio, when what I should be hearing are solely compression artifacts. thx