Sur d’autres sites (9861)

• ffmpeg status & quality / cuda (CPU/GPU)

  18 juin 2024, par cocco

  ffmpeg am I doing it right ?

  


  So much time has passed since I use ffmpeg to convert clips on my home web server, now that mp4 (h264 & aac) is the current overall standard (works on every console, smartphone, smartTV, pc) I decided to convert my old clips from various digital cameras to to this new container/codecs.

  


  

  1. less space & the same quality.

  


  2. compatibility

  


  3. support for tags (subler for mac)

  


  


  after some research I opted for ffmpeg because of various reasons

  


  

  1. commandline (I made my simple web interface with default settings which I execute with php's exec)

  


  2. the quality/size amount

  


  


  I read that many expensive video conversion software programs are not able to handle low bitrate videos properly. I also tested some of them and personally I could not find the proper export settings or I was not impressed by the results... some had fixed default export settings, most had a lower video quality at the same filesize. ffmpeg allows me to set the -crf (18-24 usually) and -preset (veryslow, fast..) which allows me to reduce the filesize drastically maintaining the same visible quality.

  


  Said that I'm using the preset at very slow (there is also placebo but the final video file is only 1% smaller in size).

  


  And here is the command I use

  


  ffmpeg
-y //overwrite the file if it exists

-i INPUTFILE // replace with the input file

-metadata title=THETITLE // set a nice title, visible on modern devices
-metadata date=THEDATE // set a nice title, visible on modern devices

-c:v libx264 // use the h264 codec
 -crf 21 // try different numbers between 18-26
 -preset veryslow // placebo,slow,fast,ultrafast==big file 
 -tune film // tune it a little
 -pix_fmt yuv420p // preferred on most modern devices
 -profile:v main // preferred on most modern devices
 -level 3.1 // preferred on most modern devices 
 -refs 4 // preferred on most modern devices

-c:a libfdk_aac // use aac
 -metadata:s:a language=eng // set a language, visible on modern devices 
 -b:a 128k // audio bitrate 128k is like mp3 192k
 -ar 48000 // 44100 ... whatever
 -ac 2 // audiochannels
 -movflags +faststart //move the metadata in the front of the video so it loads faster

OUTPUTFILE


  


  Some camcorder clips with m2ts already have the avc/h264 compatible codec so I just copy the stream.
  
some have the ac3/Dolby surround audio. I convert the audio but keep the ac3 as second audio track mapping the ffmpeg streams. this allows me to watch the mp4 on browsers and mobile devices but I'm able to keep the surround sound to playback on some tv's, advanced media players or devices like apple tv.

  


  Not that I'm not happy with the speed (using quad core's) but I recently read again about cuda opencl and there is also the simple fact that I'm not using other converters than ffmpeg since a lot of time.

  


  Is ffmpeg (with the setting I use) a good converter to keep the same video quality than the source reducing the space occupied by and average of 30-40% ?

  


  Is GPU conversion really that bad (cuda .. testing a gtx970) ?
it would be nice to add some more speed to the conversions by using both the gpu and the cpu..but for my understanding they cannot work together ??? and using only GPU is a drastically quality loss...cpu is more precise, GPU is faster in calculation are too imprecise from what I read.. so expensive software programs use cuda only for preview purpose... right ?

  


  Is ffmpeg or another software compatible with CPU+GPU encoding ?
I really don't remember where, but I read that the ffmpeg is not a good videoconverter.

  


  I'm really happy with the size/quality, I gained an average of 30% in space with no visible quality loss. With some extra parameters i can adjust some really old analog videos that are deinterlaced in a really bad way.

  


  


  maybe I could gain more size/quality with another software ???

  


  


  note : I like ffmpeg.it's free and it has commandline so I can create my own interface with php html & js and use it on various machines without the need to install it in every device I use. I upload the idevice clips directly to the ffmpeg server.

  


  EDIT :

  


  @talonmies ...cuda tag removed :

  


  http://www.nvidia.com/object/cuda_home_new.html

  


  


  CUDA® is a parallel computing platform and programming model invented
by NVIDIA. It enables dramatic increases in computing performance by
harnessing the power of the graphics processing unit (GPU). With
millions of CUDA-enabled GPUs sold to date, software developers,
scientists and researchers are finding broad-ranging uses for GPU
computing with CUDA. Here are a few examples : - See more at :
http://www.nvidia.com/object/cuda_home_new.html#sthash.dEYaqae7.dpuf

  


  


  isn't cuda the programming model that a theoretical ffmpeg library should support to handle GPU encoding on nvidia cards like the gtx 970 ?? like the badaboom software http://www.geforce.com/games-applications/pc-applications/badaboom-media-converter.

  


• ffmpeg status & quality / cuda (CPU/GPU)

  18 avril 2015, par cocco

  ffmpeg am i doing it right ?

  So much time has passed since i use ffmpeg to convert clips on my home web server, now that mp4 (h264 & aac) is the current overall standard (works on every console, smartphone, smartTV, pc) i decided to convert my old clips from various digital cameras to to this new container/codecs.

  1. less space & the same quality.
  2. compatibility
  3. support for tags (subler for mac)

  after some research i opted for ffmpeg because of various reasons

  1. commandline (i made my simple web interface with default settings wich i execute with php’s exec)
  2. the quality/size amount

  I read that many expensive video conversion softwares are not able to handle low bitrate videos properly. I also tested some of them and personally i could not find the proper export settings or i was not impressed by the results... some had fixed default export setings, most had a lower video quality at the same filesize. ffmpeg allows me to set the -crf (18-24 usually) and -preset (veryslow, fast..) witch allows me to reduce the filesize drastically mantaining the same
  visible quality.

  Said that i’m using the preset at veryslow.(there is also placebo but the final video file is only 1% smaller in size).

  And here is the command i use

  ffmpeg
  
  -y //overwrite the file if it exists
  
  
  
  -i INPUTFILE // replace with the input file
  
  
  
  -metadata title=THETITLE // set a nice title, visible on modern devices
  
  -metadata date=THEDATE // set a nice title, visible on modern devices
  
  
  
  -c:v libx264 // use the h264 codec
  
   -crf 21 // try different numbers between 18-26
  
   -preset veryslow // placebo,slow,fast,ultrafast==big file 
  
   -tune film // tune it a little
  
   -pix_fmt yuv420p // preferred on most modern devices
  
   -profile:v main // preferred on most modern devices
  
   -level 3.1 // preferred on most modern devices 
  
   -refs 4 // preferred on most modern devices
  
  
  
  -c:a libfdk_aac // use aac
  
   -metadata:s:a language=eng // set a language, visible on modern devices 
  
   -b:a 128k // audio bitrate 128k is like mp3 192k
  
   -ar 48000 // 44100 ... whatever
  
   -ac 2 // audiochannels
  
   -movflags +faststart //move the metadata in the front of the video so it loads faster
  
  
  
  OUTPUTFILE

  some camcorder clips with m2ts already have the avc/h264 compatible codec so i just copy the stream.
  some have the ac3/dolby sorround audio. I convert the audio but keep the ac3 as second audio track mapping the ffmpeg streams.this allows me to watch the mp4 on browsers and mobile devices but i’m able to keep the surround sound to playback on some tv’s, advanced media players or devices like apple tv.

  not that i’m not happy with the speed (using quad core’s) but i recently read again about cuda opencl and there is also the simple fact that i’m not using other converters than ffmpeg since alot of time.

  Is ffmpeg (with the setting i use) a good converter to keep the same video quality than the source reducing the space occupied by and average of 30-40% ?

  Is GPU conversion really that bad (cuda .. testing a gtx970) ?
  it would be nice to add some more speed to the conversions by using both the gpu and the cpu..but for my understanding they cannot work together ??? and using only gpu is a drastical quality loss...cpu si more precise, gpu is faster in calculation are too imprecise from what i read.. so expensive softwares use cuda only for preview purpose... right ?

  Is ffmpeg or another software compatible with CPU+GPU encoding ?
  i really don’t remember where, but i read that the ffmpeg is not a good videoconverter.

  i’m really happy with the size/quality, i gained an average of 30% in space with no visible quality loss. With some extra parameters i can adjust some really old analog videos that are deinterlaced in a really bad way.

  maybe i could gain more size/quality with another software ???

  note : i like ffmpeg.it’s free and it has commandline so i can create my own interface with php html & js and use it on various machines without the need to install it in every device i use. i uplad the idevice clips directly to the ffmpeg server.

  btw. : explain the downvotes...

  EDIT :

  @talonmies ...cuda tag removed :

  http://www.nvidia.com/object/cuda_home_new.html

  CUDA® is a parallel computing platform and programming model invented
  by NVIDIA. It enables dramatic increases in computing performance by
  harnessing the power of the graphics processing unit (GPU). With
  millions of CUDA-enabled GPUs sold to date, software developers,
  scientists and researchers are finding broad-ranging uses for GPU
  computing with CUDA. Here are a few examples : - See more at :
  http://www.nvidia.com/object/cuda_home_new.html#sthash.dEYaqae7.dpuf

  isn’t cuda the programming model that a theoretical ffmpeg library should support to handle GPU encoding on nvidia cards like the gtx 970 ?? like the badaboom software http://www.geforce.com/games-applications/pc-applications/badaboom-media-converter.

• Compile Shotdetect on CentOS 7

  14 septembre 2015, par BitLegacy01

  I’m migrating a service from a Debian server to a CentOS 7 one.

  The service needs the Shotdetect command (github , official site).

  I could not make it work on CentOS though I followed all steps :

  1. Compile ffmpeg compilation guide

     # ffmpeg
     
     ffmpeg version git-2015-08-21-7a806c6 Copyright (c) 2000-2015 the FFmpeg developers
     
       built with gcc 4.8.3 (GCC) 20140911 (Red Hat 4.8.3-9)
     
       configuration: --prefix=/root/ffmpeg_build --extra-cflags=-I/root/ffmpeg_build/include --extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin --pkg-config-flags=--static --enable-gpl --enable-nonfree --enable-libfdk-aac --enable-libfreetype --disable-libmp3lame --disable-libopus --disable-libvorbis --disable-libvpx --enable-libx264 --disable-libx265 --disable-lzma
     
       libavutil      54. 31.100 / 54. 31.100
     
       libavcodec     56. 58.100 / 56. 58.100
     
       libavformat    56. 40.101 / 56. 40.101
     
       libavdevice    56.  4.100 / 56.  4.100
     
       libavfilter     5. 36.100 /  5. 36.100
     
       libswscale      3.  1.101 /  3.  1.101
     
       libswresample   1.  2.101 /  1.  2.101
     
       libpostproc    53.  3.100 / 53.  3.100
     
     Hyper fast Audio and Video encoder
     
     usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...

     2. Install needed packages

        # yum install gd-devel libxml2-devel libxslt-devel clang libvpx libvorbis

     3. Add pthread in the CMakeList file, in TARGET_LINK_LIBRARIES, because it throws an lpthread missing in linker error

     4. Compile Shotdetect

        # FFMPEG_DIR="/root/ffmpeg_build"  ./compile.sh cmd

  5.Lost in contemplation

  -- avformat library found: /root/ffmpeg_build/lib/libavformat.a
  
  -- avcodec library found: /root/ffmpeg_build/lib/libavcodec.a
  
  -- avutil library found: /root/ffmpeg_build/lib/libavutil.a
  
  -- swscale library found: /root/ffmpeg_build/lib/libswscale.a
  
  Found all FFmpeg libraries in /root/ffmpeg_build/lib/libavformat.a;/root/ffmpeg_build/lib/libavdevice.a;/root/ffmpeg_build/lib/libavcodec.a;/root/ffmpeg_build/lib/libavutil.a;/root/ffmpeg_build/lib/libswscale.a.
  
  -- Found GD: /usr/lib64/libgd.so
  
  Found libgd: /usr/lib64/libgd.so;/usr/lib64/libpng.so;/usr/lib64/libz.so;/usr/lib64/libjpeg.so in /usr/include
  
  Found libxml2: /usr/lib64/libxml2.so in /usr/include/libxml2
  
  Found libxslt: /usr/lib64/libxslt.so in /usr/include
  
  -- Configuring done
  
  -- Generating done
  
  -- Build files have been written to: /root/Shotdetect-master/build
  
  [ 71%] Built target shotdetect
  
  Linking CXX executable shotdetect-cmd
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacdec.o): in the function « fdk_aac_decode_frame »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:323: undefined reference to « aacDecoder_Fill »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:329: undefined reference to « aacDecoder_DecodeFrame »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacdec.o): in the function « get_stream_info »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:88: undefined reference to « aacDecoder_GetStreamInfo »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacdec.o): in the function « fdk_aac_decode_close »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:201: undefined reference to « aacDecoder_Close »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacdec.o): in the function « fdk_aac_decode_init »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:214: undefined reference to « aacDecoder_Open »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:221: undefined reference to « aacDecoder_ConfigRaw »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:228: undefined reference to « aacDecoder_SetParam »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:252: undefined reference to « aacDecoder_SetParam »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:270: undefined reference to « aacDecoder_SetParam »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:277: undefined reference to « aacDecoder_SetParam »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:284: undefined reference to « aacDecoder_SetParam »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacdec.o):/root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:291: encore plus de références indéfinies suivent vers « aacDecoder_SetParam »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacdec.o): in the function « fdk_aac_decode_init »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:261: undefined reference to « aacDecoder_AncDataInit »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacdec.o): in the function « fdk_aac_decode_flush »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacdec.c:367: undefined reference to « aacDecoder_SetParam »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacenc.o): in the function « aac_encode_close »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:97: undefined reference to « aacEncClose »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacenc.o): in the function « aac_encode_frame »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:357: undefined reference to « aacEncEncode »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacenc.o): in the function « aac_encode_init »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:114: undefined reference to « aacEncOpen »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:123: undefined reference to « aacEncoder_SetParam »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:130: undefined reference to « aacEncoder_SetParam »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:138: undefined reference to « aacEncoder_SetParam »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:172: undefined reference to « aacEncoder_SetParam »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:179: undefined reference to « aacEncoder_SetParam »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacenc.o):/root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:197: encore plus de références indéfinies suivent vers « aacEncoder_SetParam »
  
  /root/ffmpeg_build/lib/libavcodec.a(libfdk-aacenc.o): in the function « aac_encode_init »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:276: undefined reference to « aacEncEncode »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libfdk-aacenc.c:282: undefined reference to « aacEncInfo »
  
  /root/ffmpeg_build/lib/libavcodec.a(libx264.o): in the function « X264_frame »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:260: undefined reference to « x264_picture_init »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:262: undefined reference to « x264_bit_depth »
  
  /root/ffmpeg_build/lib/libavcodec.a(libx264.o): in the function « reconfig_encoder »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:246: undefined reference to « x264_encoder_reconfig »
  
  /root/ffmpeg_build/lib/libavcodec.a(libx264.o): in the function « X264_frame »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:283: undefined reference to « x264_encoder_encode »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:289: undefined reference to « x264_encoder_delayed_frames »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:283: undefined reference to « x264_encoder_encode »
  
  /root/ffmpeg_build/lib/libavcodec.a(libx264.o): in the function « reconfig_encoder »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:173: undefined reference to « x264_encoder_reconfig »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:178: undefined reference to « x264_encoder_reconfig »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:185: undefined reference to « x264_encoder_reconfig »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:205: undefined reference to « x264_encoder_reconfig »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:211: undefined reference to « x264_encoder_reconfig »
  
  /root/ffmpeg_build/lib/libavcodec.a(libx264.o):/root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:191: encore plus de références indéfinies suivent vers « x264_encoder_reconfig »
  
  /root/ffmpeg_build/lib/libavcodec.a(libx264.o): in the function « X264_init_static »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:806: undefined reference to « x264_bit_depth »
  
  /root/ffmpeg_build/lib/libavcodec.a(libx264.o): in the function « X264_close »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:339: undefined reference to « x264_encoder_close »
  
  /root/ffmpeg_build/lib/libavcodec.a(libx264.o): in the function « X264_init »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:413: undefined reference to « x264_param_default »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:418: undefined reference to « x264_param_default_preset »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:440: undefined reference to « x264_param_parse »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:470: undefined reference to « x264_param_parse »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:514: undefined reference to « x264_levels »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:516: undefined reference to « x264_levels »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:540: undefined reference to « x264_param_parse »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:541: undefined reference to « x264_param_parse »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:542: undefined reference to « x264_param_parse »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:543: undefined reference to « x264_param_parse »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:601: undefined reference to « x264_param_apply_fastfirstpass »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:651: undefined reference to « x264_param_apply_profile »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:703: undefined reference to « x264_param_parse »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:705: undefined reference to « x264_param_parse »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:717: undefined reference to « x264_param_parse »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:735: undefined reference to « x264_encoder_open_148 »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/libx264.c:744: undefined reference to « x264_encoder_headers »
  
  /root/ffmpeg_build/lib/libavcodec.a(opusdec.o): in the function « opus_decode_subpacket »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:379: undefined reference to « swr_is_initialized »
  
  /root/ffmpeg_build/lib/libavcodec.a(opusdec.o): in the function « opus_decode_frame »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:220: undefined reference to « swr_is_initialized »
  
  /root/ffmpeg_build/lib/libavcodec.a(opusdec.o): in the function « opus_init_resample »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:161: undefined reference to « swr_init »
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:167: undefined reference to « swr_convert »
  
  /root/ffmpeg_build/lib/libavcodec.a(opusdec.o): in the function « opus_decode_frame »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:234: undefined reference to « swr_convert »
  
  /root/ffmpeg_build/lib/libavcodec.a(opusdec.o): in the function « opus_flush_resample »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:115: undefined reference to « swr_convert »
  
  /root/ffmpeg_build/lib/libavcodec.a(opusdec.o): in the function « opus_decode_subpacket »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:411: undefined reference to « swr_close »
  
  /root/ffmpeg_build/lib/libavcodec.a(opusdec.o): in the function « opus_decode_flush »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:614: undefined reference to « swr_close »
  
  /root/ffmpeg_build/lib/libavcodec.a(opusdec.o): in the function « opus_decode_close »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:638: undefined reference to « swr_free »
  
  /root/ffmpeg_build/lib/libavcodec.a(opusdec.o): in the function « opus_decode_init »:
  
  /root/ffmpeg_sources/ffmpeg/libavcodec/opusdec.c:705: undefined reference to « swr_alloc »
  
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  
  make[2]: *** [shotdetect-cmd] Error 1
  
  make[1]: *** [CMakeFiles/shotdetect-cmd.dir/all] Error 2
  
  make: *** [all] Error 2

  I’ve done a lot of research about the above errors but I didn’t find any clue.

  How to compile successfully Shotdetect on CentOS7 ?

  Thanks to tryp here is a working CMakelist file :

  # CMake integration by Christian Frisson
  
  cmake_minimum_required(VERSION 2.8)
  
  PROJECT(shotdetect)
  
  
  
  SET(CMAKE_C_COMPILER "/usr/bin/clang")
  
  SET(CMAKE_CXX_COMPILER "/usr/bin/clang++")
  
  SET(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
  
  
  
  
  
  # Get git version information for automatic embedding in version string:
  
  
  
  include(GetGitRevisionDescription)
  
  get_git_head_revision(GIT_REFSPEC GIT_SHA1)
  
  # Take the first 12 characters of the SHA1 as short identifier:
  
  STRING(SUBSTRING ${GIT_SHA1} 0 11 GIT_SHA1_SHORT)
  
  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/src/version.cc.in" "${CMAKE_CURRENT_BINARY_DIR}/version.cc" @ONLY)
  
  list(APPEND SOURCES "${CMAKE_CURRENT_BINARY_DIR}/version.cc" src/version.h)
  
  
  
  # Miscellaneous compilation options:
  
  
  
  OPTION(USE_WXWIDGETS "Compile GUI app with wxWidgets, otherwise commandline app" ON)
  
  OPTION(USE_POSTGRESQL "Compile with PostgreSQL support" OFF)
  
  
  
  # Dependency: pkg-config (required if cross-compiling with MXE)
  
  
  
  IF ( MINGW AND CMAKE_TOOLCHAIN_FILE)
  
      FIND_PACKAGE (PkgConfig)
  
      IF(NOT PKG_CONFIG_FOUND)
  
          MESSAGE(FATAL_ERROR "pkgconfig required for cross-compiling with MXE for windows")
  
      ENDIF()
  
      SET(PKG_CONFIG_EXECUTABLE ${PKG_CONFIG_EXECUTABLE} CACHE STRING "pkg-config")
  
  ENDIF()
  
  
  
  # Dependency: FFmpeg (required)
  
  
  
  FIND_PACKAGE( FFmpeg )
  
  IF ( MINGW AND CMAKE_TOOLCHAIN_FILE)
  
      PKG_CHECK_MODULES (FFMPEG_PKG REQUIRED libavcodec libavfilter libavutil libavdevice libavformat libavformat libswscale)
  
      IF (FFMPEG_PKG_FOUND)
  
          MESSAGE( "FFmpeg cflags found through pkg-config: ${FFMPEG_PKG_CFLAGS}" )
  
          MESSAGE( "FFmpeg ldflags found through pkg-config: ${FFMPEG_PKG_LDFLAGS}" )
  
          STRING(REGEX REPLACE ";" " " FFMPEG_PKG_CFLAGS "${FFMPEG_PKG_CFLAGS}")
  
          SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${FFMPEG_PKG_CFLAGS}")
  
          SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${FFMPEG_PKG_CFLAGS}")
  
          SET(FFMPEG_LIBRARIES ${FFMPEG_LIBRARY} ${FFMPEG_PKG_LDFLAGS})
  
          MESSAGE("FFMPEG_LIBRARIES ${FFMPEG_LIBRARIES}")
  
      ELSE (FFMPEG_PKG_FOUND)
  
          MESSAGE( FATAL_ERROR "FFmpeg cflags/ldflags not found through pkg-config." )
  
      ENDIF (FFMPEG_PKG_FOUND)
  
  ENDIF()
  
  IF(FFMPEG_LIBAVFORMAT_FOUND)
  
      MESSAGE(STATUS "avformat library found: ${FFMPEG_LIBAVFORMAT_LIBRARIES}")
  
  ELSE()
  
      MESSAGE(STATUS "avformat library not found.")
  
  ENDIF()
  
  IF(FFMPEG_LIBAVCODEC_FOUND)
  
      MESSAGE(STATUS "avcodec library found: ${FFMPEG_LIBAVCODEC_LIBRARIES}")
  
  ELSE()
  
      MESSAGE(STATUS "avcodec library not found.")
  
  ENDIF()
  
  IF(FFMPEG_LIBAVUTIL_FOUND)
  
      MESSAGE(STATUS "avutil library found: ${FFMPEG_LIBAVUTIL_LIBRARIES}")
  
  ELSE()
  
      MESSAGE(STATUS "avutil library not found.")
  
  ENDIF()
  
  IF(FFMPEG_LIBSWSCALE_FOUND)
  
      MESSAGE(STATUS "swscale library found: ${FFMPEG_LIBSWSCALE_LIBRARIES}")
  
  ELSE()
  
      MESSAGE(STATUS "swscale library not found.")
  
  ENDIF()
  
  IF(FFMPEG_FOUND)
  
      INCLUDE_DIRECTORIES(${FFMPEG_INCLUDE_DIR} ${FFMPEG_INCLUDE_DIRS})
  
      SET(FFMPEG_LIBRARIES "${FFMPEG_LIBRARIES};/root/ffmpeg_build/lib/libswresample.a;/root/ffmpeg_build/lib/libx264.a;/lib64/libdl.so.2;/root/ffmpeg_build/lib/libfdk-aac.a;/root/ffmpeg_build/lib/libswresample.a")
  
      MESSAGE("Found all FFmpeg libraries in ${FFMPEG_LIBRARIES}.")
  
  ELSE()
  
      MESSAGE(FATAL_ERROR "Some FFmpeg libraries are missing.")
  
  ENDIF()
  
  
  
  # Dependency: GD (required)
  
  
  
  FIND_PACKAGE(GD REQUIRED)
  
  IF ( MINGW AND CMAKE_TOOLCHAIN_FILE)
  
      EXEC_PROGRAM(${CMAKE_FIND_ROOT_PATH}/bin/gdlib-config ARGS "--cflags" OUTPUT_VARIABLE GD_PKG_CFLAGS) 
  
      EXEC_PROGRAM(${CMAKE_FIND_ROOT_PATH}/bin/gdlib-config ARGS "--libs" OUTPUT_VARIABLE GD_PKG_LDFLAGS)
  
      MESSAGE( "gd cflags found through gdlib-config: ${GD_PKG_CFLAGS}" )
  
      MESSAGE( "gd ldflags found through gdlib-config: ${GD_PKG_LDFLAGS}" )
  
      SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${GD_PKG_CFLAGS}")
  
      SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${GD_PKG_CFLAGS}")
  
      SET(GD_LIBRARIES ${GD_LIBRARY} ${GD_PKG_LDFLAGS})
  
      MESSAGE("GD_LIBRARIES ${GD_LIBRARIES}")
  
  ENDIF()
  
  IF(GD_FOUND)
  
      INCLUDE_DIRECTORIES(${GD_INCLUDE_DIR})
  
      MESSAGE("Found libgd: ${GD_LIBRARIES} in ${GD_INCLUDE_DIR}")
  
  ELSE()
  
      MESSAGE(FATAL_ERROR "Couldn't find libgd")
  
  ENDIF()
  
  
  
  # Dependency: libxml2 (required)
  
  
  
  FIND_PACKAGE(LibXml2 2.7 REQUIRED)
  
  IF ( MINGW AND CMAKE_TOOLCHAIN_FILE)
  
      PKG_CHECK_MODULES (LIBXML2_PKG REQUIRED libxml-2.0)
  
      IF (LIBXML2_PKG_FOUND)
  
          MESSAGE( "LibXml2 cflags found through pkg-config: ${LIBXML2_PKG_CFLAGS}" )
  
          MESSAGE( "LibXml2 ldflags found through pkg-config: ${LIBXML2_PKG_LDFLAGS}" )
  
          STRING(REGEX REPLACE ";" " " LIBXML2_PKG_CFLAGS "${LIBXML2_PKG_CFLAGS}")
  
          SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${LIBXML2_PKG_CFLAGS}")
  
          SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${LIBXML2_PKG_CFLAGS}")
  
          SET(LIBXML2_LIBRARIES ${LIBXML2_LIBRARY} ${LIBXML2_PKG_LDFLAGS})
  
          MESSAGE("LIBXML2_LIBRARIES ${LIBXML2_LIBRARIES}")
  
      ELSE (LIBXML2_PKG_FOUND)
  
          MESSAGE( FATAL_ERROR "LibXml2 cflags/ldflags not found through pkg-config." )
  
      ENDIF (LIBXML2_PKG_FOUND)
  
  ENDIF()
  
  IF(LIBXML2_FOUND)
  
      MESSAGE("Found libxml2: ${LIBXML2_LIBRARIES} in ${LIBXML2_INCLUDE_DIR}")
  
      INCLUDE_DIRECTORIES(${LIBXML2_INCLUDE_DIR})
  
  ELSE()
  
      MESSAGE(FATAL_ERROR "Couldn't find libxml2")
  
  ENDIF()
  
  
  
  # Dependency: libxslt (required)
  
  
  
  FIND_PACKAGE(LibXslt REQUIRED)
  
  IF(LIBXSLT_FOUND)
  
      MESSAGE("Found libxslt: ${LIBXSLT_LIBRARIES} in ${LIBXSLT_INCLUDE_DIR}")
  
      INCLUDE_DIRECTORIES(${LIBXSLT_INCLUDE_DIR})
  
  ELSE()
  
      MESSAGE(FATAL_ERROR "Couldn't find libxslt")
  
  ENDIF()
  
  
  
  # Dependency: wxWidgets (optional)
  
  IF(USE_WXWIDGETS)
  
      FIND_PACKAGE(wxWidgets)# COMPONENTS core base)
  
      IF(wxWidgets_FOUND)
  
          MESSAGE("Found wxWidgets: ${wxWidgets_LIBRARIES} in ${wxWidgets_INCLUDE_DIRS}")
  
          INCLUDE_DIRECTORIES(${wxWidgets_INCLUDE_DIRS})
  
          ADD_DEFINITIONS(-DWXWIDGETS)
  
          INCLUDE("${wxWidgets_USE_FILE}")
  
      ELSE()
  
          MESSAGE(FATAL_ERROR "Couldn't find wxWidgets. Set USE_WXWIDGETS to OFF or install wxWidgets.")
  
      ENDIF()
  
  ENDIF()
  
  
  
  # Dependency: PostgreSQL (optional)
  
  IF(USE_POSTGRESQL)
  
      FIND_PACKAGE(PostgreSQL)
  
      IF(PostgreSQL_FOUND)
  
          MESSAGE("Found PostgreSQL: ${PostgreSQL_LIBRARIES} in ${PostgreSQL_INCLUDE_DIR}")
  
          INCLUDE_DIRECTORIES(${PostgreSQL_INCLUDE_DIR})
  
      ELSE()
  
          MESSAGE(FATAL_ERROR "Couldn't find PostgreSQL. Set USE_POSTGRESQL to OFF or install PostgreSQL.")
  
      ENDIF()
  
  ENDIF()
  
  
  
  # shotdetect
  
  
  
  SET(TARGET_NAME "shotdetect")
  
  INCLUDE_DIRECTORIES(.)
  
  
  
  # shotdetect library
  
  
  
  SET(${TARGET_NAME}_LIBRARY_SRCS src/film.cc src/graph.cc src/image.cc src/shot.cc src/xml.cc)
  
  SET(${TARGET_NAME}_LIBRARY_HDRS  src/film.h src/graph.h src/image.h src/shot.h src/xml.h)
  
  IF(USE_POSTGRESQL)
  
      SET(${TARGET_NAME}_LIBRARY_SRCS ${${TARGET_NAME}_LIBRARY_SRCS} src/bdd.cc)
  
      SET(${TARGET_NAME}_LIBRARY_HDRS ${${TARGET_NAME}_LIBRARY_HDRS} src/bdd.h)
  
  ENDIF()
  
  ADD_LIBRARY(${TARGET_NAME} ${${TARGET_NAME}_LIBRARY_SRCS} ${${TARGET_NAME}_LIBRARY_HDRS})
  
  TARGET_LINK_LIBRARIES(${TARGET_NAME} ${FFMPEG_LIBRARIES} ${LIBXML2_LIBRARIES} ${LIBXSLT_LIBRARIES} ${GD_LIBRARIES} "pthread" "m" "z")
  
  IF(USE_WXWIDGETS AND wxWidgets_FOUND)
  
      TARGET_LINK_LIBRARIES(${TARGET_NAME} ${wxWidgets_LIBRARIES})
  
  ENDIF()
  
  IF(USE_POSTGRESQL AND PostgreSQL_FOUND)
  
      TARGET_LINK_LIBRARIES(${TARGET_NAME} ${PostgreSQL_LIBRARY})
  
  ENDIF()
  
  
  
  # shotdetect application: gui or commandline
  
  
  
  IF(APPLE)
  
      SET(APP_TYPE "MACOSX_BUNDLE")
  
  ELSEIF(WIN32)
  
      SET(APP_TYPE "WIN32")
  
  ENDIF()
  
  
  
  IF(USE_WXWIDGETS AND wxWidgets_FOUND)
  
      LIST(APPEND ${TARGET_NAME}_GUI_SRCS src/main.cc src/ui/dialog_help.cc src/ui/dialog_shotdetect.cc src/ui/process_video_thread.cc)
  
      LIST(APPEND ${TARGET_NAME}_GUI_HDRS src/ui/dialog_help.h src/ui/dialog_shotdetect.h src/ui/process_video_thread.h)
  
      ADD_EXECUTABLE(${TARGET_NAME}-gui ${APP_TYPE} ${SOURCES} ${${TARGET_NAME}_GUI_SRCS} ${${TARGET_NAME}_GUI_HDRS})
  
      TARGET_LINK_LIBRARIES(${TARGET_NAME}-gui ${TARGET_NAME})
  
      # Make this target optional to install:
  
      SET(TARGETS_TO_INSTALL ${TARGET_NAME}-gui)
  
  ELSE()
  
      LIST(APPEND ${TARGET_NAME}_COMMANDLINE_SRCS src/commandline.cc)
  
      ADD_EXECUTABLE(${TARGET_NAME}-cmd ${SOURCES} ${${TARGET_NAME}_COMMANDLINE_SRCS})
  
      TARGET_LINK_LIBRARIES(${TARGET_NAME}-cmd ${TARGET_NAME})
  
      # Make this target optional to install:
  
      SET(TARGETS_TO_INSTALL ${TARGET_NAME}-cmd)
  
  ENDIF()
  
  
  
  
  
  # Routines for installing shotdetect.
  
  # Taken from official documentation (http://www.cmake.org/cmake/help/cmake2.6docs.html#command:install)
  
  install( 
  
      TARGETS ${TARGETS_TO_INSTALL}
  
      RUNTIME DESTINATION bin
  
      LIBRARY DESTINATION lib
  
      ARCHIVE DESTINATION lib/static
  
  )

  the built binary will be in the built directory, you can move there and execute

  make install

  to make the binary system wide.