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• ffmpeg video to jpg frames poor quality

  23 décembre 2019, par Gert Gottschalk

  The quality of JPGs extracted by ffmpeg from an mp4 is much poorer than pause frame from video player (vlc). I am looking for ffmpeg cmd option to improve output quality.

  Using following cmd :

  /home/tools/bin/ffmpeg -i Merkurtransit_20191111_crf20_8fps_crop.mp4 Merkurtransit_20191111_crf20_8fps_crop_%04d.jpg -hide_banner

  The ffmpeg cmd is from instructions found here :
  https://www.bugcodemaster.com/article/extract-images-frame-frame-video-file-using-ffmpeg

  A comparing screen copy is here :
  http://skywatcher.space/download/vlc_player_vs_ffmpeg_bug.png

  A few items of note. I created the mp4 myself from high res png (actually originally from 16bit tiff) using ffmpeg :

  /home/tools/bin/ffmpeg -framerate 8.0 -i ./AS_P10_RS6_png_reg/Merkurtransit_20191111_%03d.png -vf "crop=760:560:20:40" -pix_fmt yuv420p -crf 20 -r 24 -y ./Video/Merkurtransit_20191111_crf20_8fps_crop.mp4

  The crf 20 is pretty high quality, close to 100% and the recovered frame should be close to original. The video player pause frame shows adequate quality. (though I can’t say if it is on a key frame or not)

  ffmpeg version info :

  home/tools/bin/ffmpeg -v
  
  ffmpeg version N-80251-g0c7fa15 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  
    configuration: --prefix=/home/tools/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/home/tools/ffmpeg_build/include --extra-ldflags=-L/home/tools/ffmpeg_build/lib --bindir=/home/tools/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree
  
    libavutil      55. 24.100 / 55. 24.100
  
    libavcodec     57. 45.100 / 57. 45.100
  
    libavformat    57. 37.101 / 57. 37.101
  
    libavdevice    57.  0.101 / 57.  0.101
  
    libavfilter     6. 46.101 /  6. 46.101
  
    libswscale      4.  1.100 /  4.  1.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100

• FFMPEG command faild

  11 octobre 2015, par Asad kamran

  I am experimenting FFMPEG command to convert any video format to mp4.

  Server admin execute the below command created by me and show me the errors :

  ffmpeg -ss 00:03:00  -i  /home/bbma7roo/public_html/site_data/video/1444107854.mov -c:v libx264 /home/bbma7roo/public_html/site_data/video/player/1444107854.mp4  -vframes 1 /home/bbma7roo/public_html/site_data/video/thumb/1444107854.jpg

  This is error :

  [aac @ 0x2b845a0] The encoder ’aac’ is experimental but experimental
  codecs are not enabled, add ’-strict -2’ if you want to use it.

  how can i avoid this error and also experimental codec, so can any one let me know what can be best codec if i explicitly specify it.

  my ffmpeg and server are as follow :

  ffmpeg version N-75903-g14573b9 Copyright (c) 2000-2015 the FFmpeg
  developers built with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-16)

• Can't build ffmpeg

  7 avril 2016, par Dev_Vlad

  I have some problems with building ffmpeg for servestream radio.

  Here’s the log :

  build-ffmpeg:
  
   [exec] arm-linux-androideabi-gcc is unable to create an executable file.
  
   [exec] C compiler test failed.
  
   [exec] 
  
   [exec] If you think configure made a mistake, make sure you are using the latest
  
   [exec] version from Git.  If the latest version fails, report the problem to the
  
   [exec] ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
  
   [exec] Include the log file "config.log" produced by configure as this will help
  
   [exec] solving the problem.
  
   [exec] Copying FFmpeg .so files from /home/vlad/WORK/Ubuntu/OnlineRadioSamples/servestream-master-minstrely/submodules/ffmpeg-0.11.1-android-2012-09-18/build/ffmpeg to /home/vlad/WORK/Ubuntu/OnlineRadioSamples/servestream-master-minstrely/jni/ffmpeg/ffmpeg/armeabi
  
   [exec] Copying FFmpeg .so files from /home/vlad/WORK/Ubuntu/OnlineRadioSamples/servestream-master-minstrely/submodules/ffmpeg-0.11.1-android-2012-09-18/build/ffmpeg to /home/vlad/WORK/Ubuntu/OnlineRadioSamples/servestream-master-minstrely/jni/ffmpeg/ffmpeg/armeabi-v7a
  
   [exec] Native build complete, exiting...
  
   [exec] cp: не could not execute stat for «/home/vlad/WORK/Ubuntu/OnlineRadioSamples/servestream-master-minstrely/submodules/ffmpeg-0.11.1-android-2012-09-18/build/ffmpeg/armeabi-v7a»: No such file or catalog
  
  
  
  native-clean:
  
   [exec] Android NDK: WARNING: APP_PLATFORM android-17 is larger than android:minSdkVersion 8 in ./AndroidManifest.xml    
  
   [exec] Android NDK: ERROR:jni/ffmpeg/Android.mk:avcodec: LOCAL_SRC_FILES points to a missing file    
  
   [exec] Android NDK: Check that jni/ffmpeg/ffmpeg/armeabi/lib/libavcodec.so exists  or that its path is correct   
  
   [exec] /home/vlad/android/ndk/build/core/prebuilt-library.mk:45: *** Android NDK: Aborting    .  Stop.

  In arm-build.sh file I edited some lines :

  export NDK=${HOME}/android-ndk

  to

  export NDK=/home/vlad/android/ndk

  next :

  TOOLCHAIN=`echo $NDK/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86*`

  to

  TOOLCHAIN=`echo $NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86*`

  What’s wrong ?