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• avcodec/bink : Fix off by 1 error in ref end

  11 janvier 2023, par Michael Niedermayer

  avcodec/bink : Fix off by 1 error in ref end
  Fixes : out of array access
  
  Fixes : 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_BINK_fuzzer-6657932926517248
  Alterantivly to this it is possibly to allocate a bigger array
  Note : oss-fuzz assigned this issue to a unrelated theora bug so the bug number matches that
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/bink.c

• How to stich images into a video with resolution larger then 4K using FFMPEG ?

  14 janvier 2023, par Aviram Fireberger

  I have a folder with images that I've extracted from one video.
The resolution for each image is 5760 X 2880.
All images are in the following format :
out-1.jpg, out-2.jpg , out-3.jpg ..... out-1000.jpg

  


  I tried couple of different ways to stich them :

  


  Using CPU - libx264

  


  ffmpeg -r 30 -f image2 -s 5760X2880 -start_number 1 -i "AllFrames/out-%d.jpg" -vframes 119 -vcodec libx264 -crf 25  -pix_fmt yuv420p "/AllVideoChunks/Chunk_1.mp4"


  


  Worked well but the speed is about X0.05 only.

  


  Using GPU - h264_nvenc

  


  ffmpeg -r 30 -f image2 -s 4000X2000 -start_number 1 -i "AllFrames/out-%d.jpg" -vframes 119 -vcodec h264_nvenc -gpu  0 -preset slow -b:v 75M  -pix_fmt yuv420p"/AllVideoChunks/Chunk_1.mp4"


  


  Working very fast and high quality, but the problem is that I can't use it for images and output bigger then width 4096

  


  Using GPU - hevc_nvenc

  


  ffmpeg -r 30 -f image2 -s 5760X2880 -start_number 1 -i "AllFrames/out-%d.jpg" -vframes 119 -vcodec hevc_nvenc -gpu  0 -preset slow -b:v 75M  -pix_fmt yuv420p"/AllVideoChunks/Chunk_1.mp4"


  


  Working X10 more then the CPU at the speed of X0.5, good quality, but the problem is that I can't use it in normal players (can't play it in Unity)

  


  Is there another video codec that can work on GPU that support more then 4K resolution ?
Can I transform the 'hevc_nvenc ' output to 'h264' on GPU in higher resolution ? should I do this transformation on CPU ?

  


• Static ffmpeg library windows

  29 novembre 2022, par peter

  Im trying to use the ffmpeg libraries (libavutil, libswscale, ...) in a bigger project by statically linking them, im not interested in the binaries. Now the issue comes down to getting them statically built. I tried searching for pre-compiled builds but without success.

  


  Following the docs, i compiled them on wsl2 for win64 with

  


  ./configure --arch=x86_64 --target-os=mingw32 --cross-prefix=i686-w64-mingw32- --disable-shared --enable-static
make


  


  After that i copied the libavformat/libavformat.a as libavformat.lib (which should be fine since they are cross-compiled ar archives ?) into my project and linked them with CMake.

  


  When compiling smth like

  


  AVFormatContext* pFormatContext = avformat_alloc_context();


  


  i get a linker error saying

  


  lld-link : error : undefined symbol: avformat_alloc_context


  


  When looking at the libs with dumpbin -linkermember libavformat.lib, i can see

  


  >dumpbin -linkermember libavformat.lib
...
  135CD92 _avformat_alloc_context
...


  


  notice the underscore.

  


  Can i not link the cross-compiled *.a files directly into a windows executable ?

  


  Honestly at this point any ideas are welcome.

  


  Thanks