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• Upload part of a video files to server

  10 septembre 2014, par Peter Lur

  I want to make a webpage where you can upload a video to the server (let say using a File Input HTML TAG). I would like to know if it’s possible in ANY languages to upload only small parts of the video files without uploading the whole file first and then splitting the file.

  Let me give you an example of what I am trying to achieve. I am trying to create a service where one upload a long & big video file and I give them 10 samples segment of the video file as a result.

  Let say I have a 1 hours long & /1 Gig size video (avi) file.

  I would like to get a sample of 10 segments of 1 minutes spread across the entire file uploaded to the server.

  I know that I could upload the whole file and then split it but uploading a 1G file would be way long for the user.

  I want to know if upfront there is a way to choose what part of the file need to be uploaded so I could upload only specific segments and then re-construct the files to make them readable.

  I know this is more of a subjective question and it may not be well fitted for Stack Overflow but I really need to figure out how to do that.

• Android ndk link failed on libgnustl_shared.so

  15 juin 2016, par nmxprime

  i have compiled ffmpeg with libstagefright

  In the last, while linking i got undefined references using below

  $PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -soname libffsft1.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffsft1.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog -lstdc++ -lx264 -lmedia -lutils  -lstagefright -lbinder --warn-once  --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-linux-androideabi/4.4.3/$CPU/libgcc.a

  Refering this i modified as below

  $PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -soname libffsft1.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffsft1.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog -lstdc++ -lx264 -lmedia -lutils  -lstagefright -lbinder --warn-once  --dynamic-linker=/system/bin/linker $NDK/sources/cxx-stl/gnu-libstdc++/libs/armeY-›v7a/libgnustl_shared.so $PREBUILT/lib/gcc/arm-linux-androideabi/4.4.3/$CPU/libgcc.a

  where

  CPU=armv7-a
  
  PREFIX=./android/$CPU
  
  NDK=~/Android/android-ndk-r7c
  
  PLATFORM=$NDK/platforms/android-9/arch-arm/
  
  PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86

  Now i got the .so file, but when using it in Android, i got

  03-11 03:26:35.760: E/AndroidRuntime(24036):    at dalvik.system.NativeStart.main(Native Method)
  
  03-11 03:26:35.760: E/AndroidRuntime(24036): Caused by: java.lang.UnsatisfiedLinkError: Cannot load library: link_image[1892]:  1908 could not load needed library 'libgnustl_shared.so' for 'libffsft1.so' (load_library[1094]: Library 'libgnustl_shared.so' not found)
  
  03-11 03:26:35.760: E/AndroidRuntime(24036):    at java.lang.Runtime.loadLibrary(Runtime.java:370)
  
  03-11 03:26:35.760: E/AndroidRuntime(24036):    at java.lang.System.loadLibrary(System.java:535)

  So should i copy the required library and use a System.loadlibrary to load it ? or do am i doing it in wrong way ?

  ---

  For your reference, i add the undefied references i got while not linking with $NDK/sources/cxx-stl/gnu-libstdc++/libs/armeY-›v7a/libgnustl_shared.so

  libavcodec/libavcodec.a(libstagefright.o):In function `std::_Rb_tree_const_iterator >::operator--()':/home/Android/android-ndk-r7c/sources/cxx-stl/gnu-libstdc++/include/bits/stl_tree.h:274: undefined reference to `std::_Rb_tree_decrement(std::_Rb_tree_node_base const*)'
  
  libavcodec/libavcodec.a(libstagefright.o): In function `std::_Rb_tree<long long="long" timestamp="timestamp">, std::_Select1st >, std::less<long long="long">, std::allocator > >::_M_insert_(std::_Rb_tree_node_base const*, std::_Rb_tree_node_base const*, std::pair<long long="long" timestamp="timestamp"> const&amp;)':/home/Android/android-ndk-r7c/sources/cxx-stl/gnu-libstdc++/include/bits/stl_tree.h:923: undefined reference to `std::_Rb_tree_insert_and_rebalance(bool, std::_Rb_tree_node_base*, std::_Rb_tree_node_base*, std::_Rb_tree_node_base&amp;)'
  
  libavcodec/libavcodec.a(libstagefright.o): In function `std::_Rb_tree_const_iterator >::operator++()':/home/Android/android-ndk-r7c/sources/cxx-stl/gnu-libstdc++/include/bits/stl_tree.h:259: undefined reference to `std::_Rb_tree_increment(std::_Rb_tree_node_base const*)'
  
  libavcodec/libavcodec.a(libstagefright.o): In function `std::_Rb_tree_iterator >::operator++(int)':/home/Android/android-ndk-r7c/sources/cxx-stl/gnu-libstdc++/include/bits/stl_tree.h:192: undefined reference to `std::_Rb_tree_increment(std::_Rb_tree_node_base*)'
  
  libavcodec/libavcodec.a(libstagefright.o): In function `std::_Rb_tree<long long="long" timestamp="timestamp">, std::_Select1st >, std::less<long long="long">, std::allocator > >::erase(std::_Rb_tree_iterator >)':/home/Android/android-ndk-r7c/sources/cxx-stl/gnu-libstdc++/include/bits/stl_tree.h:1387: undefined reference to `std::_Rb_tree_rebalance_for_erase(std::_Rb_tree_node_base*, std::_Rb_tree_node_base&amp;)'
  
  libavcodec/libavcodec.a(libstagefright.o): In function `std::_Rb_tree_iterator >::operator--()':/home/Android/android-ndk-r7c/sources/cxx-stl/gnu-libstdc++/include/bits/stl_tree.h:199: undefined reference to `std::_Rb_tree_decrement(std::_Rb_tree_node_base*)'
  
  </long></long></long></long></long>

• pausing a video and audio

  12 mars 2024, par AAB

  I have a video which is 40 seconds long, I want to make it 55 seconds long, I wanted that the video's first frame along with it's audio freezes (frame freezes) for the first 15 seconds and after the countdown of 15 seconds it starts running so that I can get the video 55 seconds long, is it possible ?
I tried a trick but it didn't work, I will share it with you. I took a screen shot of the first frame of the video, saved it in 1.jpg, then I ran the following command.

  


  ffmpeg -loop 1 -t 15 -i 1.jpg  -c:v libx264 -vf 'scale=-2:min(1080\,trunc(ih/2)*2)' -r 30 1.mp4

  


  Afterwards I tried this video combine with the original video so that this 1.mp4 will run for 15 seconds with the first frame and then after 15 seconds the original video will start running, it works but in the process the seconds/original video louses its sound, the command which I used it following.

  


  ffmpeg -f concat -safe 0 -i list.txt -c copy out.mp4

  


  list.txt has the names of the videos.

  


  Can someone help me in achieving this ?