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• Crop video into a 4x4 grid/tiles/matrix efficiently via command-line ffmpeg ?

  22 avril 2017, par Dylan

  Hello Stackoverflow community !

  I dread having to ask questions, but there seems to be no efficient way to take a single input video and apply a matrix transformation/split the video into equal sized pieces, preferably 4x4=16 segments per input.

  I tried using all the libraries such as ffmpeg and mencoder, but having 16 outputs can be as slow as 0.15x. The goal of my project is the split the video into 16 segments, rearrange those segments and combine back into a final video ; later reversing the process in HTML5 canvas. Here is a picture to help you understand what I am talking about :
  the source but also the final destination after reorganizing the pieces

  after the segments are exported, I will recombine the pieces in a puzzle manner (they are also inverted and rotated but unrelated)

  I do not believe you can do this all in one command, so my goal is to crop into 16 mapped outputs quickly, then reassemble them in a different order. But I can do the other parts myself. Ideally there would be a way to move pixel blocks eg 100x100 and just move them around. My math is not strong enough..
  I really appreciate the work you guys do !

  admin@dr.com

• Are there people interested in converting ffmpeg source to Go ?

  30 septembre 2018, par No One

  After seeing that Go compiler have been converted from C to Go I thought same for ffmpeg ? Don’t want to go deep into reasons as I think they are obvious. It was very hard to be so close to the have rich library as ffmpeg in other language. It was even hard to make bindings for that scale of library. I’m not enough advanced to start something like this myself, so is there anybody else interested in this ? If yes then where this question worth to be addressed, so people interested in this may have discussion ?

  (Seems not enough obvious so adding some details.)

  For applications which use large amount of commands with different complexity it is hard to read the code as it’s not actually a code. Instead, it’s commands which you will need to understand by reading docs from ffmpeg’s docs page. I had used ffmpeg before in Nodejs and there was lots of logic of manipulating command string. Also sometimes in windows it was ending with cmd limitations error. When you are working with some language it is nice to see whole logic in that language. So you know go ? than you know everything that is happening with this code without even going off from code and reading docs of another application.

  There may be some benefits from executing stuff in goroutines so you can handle concurrency in the way you want not in the way it is implemented in ffmpeg.

  Build faster with Go.

  Less code.

  Possibility to split code into smaller packages.

  Also if you are familiar why community converted compiler from C to Go than I think some reasons will fit too.

• Trouble building ffmpeg with cuda for windows 32 with visual studio 2022

  27 juillet 2022, par manou

  Here is my building process

  


  I open mingw32 from the x64 Native Tools Command Prompt for VS 2022

  


  then in the mingw32 shell :

  


  # cd /
# ./c/Program\ Files/Microsoft\ Visual\ Studio/2022/Community/VC/Auxiliary/Build/vcvars32.bat
# cd ~
# pacman -Sy diffutils git make gcc yasm pkg-config --noconfirm
# git clone --depth 1 https://git.ffmpeg.org/ffmpeg.git ffmpeg 
# git clone https://git.videolan.org/git/ffmpeg/nv-codec-headers.git nv-codec-headers 
# cd nv-codec-headers/
# make PREFIX=/usr/local
# make install PREFIX=/usr/local
# cd ..
# mkdir nv_sdk
# cp -r /c/Program\ Files/NVIDIA\ GPU\ Computing\ Toolkit/CUDA/v11.7/lib/Win32/* nv_sdk
# cp -r /c/Program\ Files/NVIDIA\ GPU\ Computing\ Toolkit/CUDA/v11.7/include/* nv_sdk
# export PATH="/c/Program Files/Microsoft Visual Studio/2022/Community/VC/Tools/MSVC/14.32.31326/bin/Hostx86/x86/":$PATH
# export PATH="/c/Program Files/NVIDIA GPU Computing Toolkit/CUDA/v11.7/bin/":$PATH
# ./configure --disable-everything --enable-decoder=h264 --enable-decoder=hevc --enable-cross-compile --disable-avdevice --disable-swresample --disable-postproc --disable-avfilter --target-os=mingw32 --enable-cuda-nvcc --enable-nonfree --toolchain=msvc --extra-cflags=-I../nv_sdk --extra-ldflags=" -m32 -L../nv_sdk" --enable-shared --shlibdir=SHARED_LIBS --arch=x86_32 --enable-runtime-cpudetect --enable-w32threads
# make -j8
# make install


  


  first I have a bunch of warnings during the making looking like that :
libavutil/opt.c(1075): warning C4133: 'fonction' : types incompatibles - de 'AVPixelFormat *' à 'int *'

  


  And finally the make install returns :

  


  EXTERN_PREFIX="_" AR="lib.exe" NM="dumpbin.exe -symbols" ./compat/windows/makedef libavutil/libavutil.ver libavutil/adler32.o libavutil/aes.o libavutil/aes_ctr.o libavutil/audio_fifo.o libavutil/avsscanf.o libavutil/avstring.o libavutil/base64.o libavutil/blowfish.o libavutil/bprint.o libavutil/buffer.o libavutil/camellia.o libavutil/cast5.o libavutil/channel_layout.o libavutil/color_utils.o libavutil/cpu.o libavutil/crc.o libavutil/des.o libavutil/detection_bbox.o libavutil/dict.o libavutil/display.o libavutil/dovi_meta.o libavutil/downmix_info.o libavutil/encryption_info.o libavutil/error.o libavutil/eval.o libavutil/fifo.o libavutil/file.o libavutil/file_open.o libavutil/film_grain_params.o libavutil/fixed_dsp.o libavutil/float_dsp.o libavutil/frame.o libavutil/hash.o libavutil/hdr_dynamic_metadata.o libavutil/hdr_dynamic_vivid_metadata.o libavutil/hmac.o libavutil/hwcontext.o libavutil/hwcontext_d3d11va.o libavutil/hwcontext_dxva2.o libavutil/imgutils.o libavutil/integer.o libavutil/intmath.o libavutil/lfg.o libavutil/lls.o libavutil/log.o libavutil/log2_tab.o libavutil/lzo.o libavutil/mastering_display_metadata.o libavutil/mathematics.o libavutil/md5.o libavutil/mem.o libavutil/murmur3.o libavutil/opt.o libavutil/parseutils.o libavutil/pixdesc.o libavutil/pixelutils.o libavutil/random_seed.o libavutil/rational.o libavutil/rc4.o libavutil/reverse.o libavutil/ripemd.o libavutil/samplefmt.o libavutil/sha.o libavutil/sha512.o libavutil/slicethread.o libavutil/spherical.o libavutil/stereo3d.o libavutil/tea.o libavutil/threadmessage.o libavutil/time.o libavutil/timecode.o libavutil/tree.o libavutil/twofish.o libavutil/tx.o libavutil/tx_double.o libavutil/tx_float.o libavutil/tx_int32.o libavutil/utils.o libavutil/version.o libavutil/video_enc_params.o libavutil/x86/cpu.o libavutil/x86/cpuid.o libavutil/x86/fixed_dsp.o libavutil/x86/fixed_dsp_init.o libavutil/x86/float_dsp.o libavutil/x86/float_dsp_init.o libavutil/x86/imgutils.o libavutil/x86/imgutils_init.o libavutil/x86/lls.o libavutil/x86/lls_init.o libavutil/x86/tx_float.o libavutil/x86/tx_float_init.o libavutil/xga_font_data.o libavutil/xtea.o > libavutil/avutil-57.def
Could not create temporary library.
make: *** [ffbuild/library.mak:118: libavutil/avutil-57.dll] Error 1


  


  What am I doing wrong ?
shall I install others packets from pacman ?