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• avutil/mips : refactor msa load and store macros.

  17 juillet 2019, par Shiyou Yin

  avutil/mips : refactor msa load and store macros.
  Replace STnxm_UB and LDnxm_SH with new macros ST_H/W/D1/2/4/8.
  
  The old macros are difficult to use because they don't follow the same parameter passing rules.
  
  Changing details as following :
  
  1. remove LD4x4_SH.
  
  2. replace ST2x4_UB with ST_H4.
  
  3. replace ST4x2_UB with ST_W2.
  
  4. replace ST4x4_UB with ST_W4.
  
  5. replace ST4x8_UB with ST_W8.
  
  6. replace ST6x4_UB with ST_W2 and ST_H2.
  
  7. replace ST8x1_UB with ST_D1.
  
  8. replace ST8x2_UB with ST_D2.
  
  9. replace ST8x4_UB with ST_D4.
  
  10. replace ST8x8_UB with ST_D8.
  
  11. replace ST12x4_UB with ST_D4 and ST_W4.
  Examples of new macro : ST_H4(in, idx0, idx1, idx2, idx3, pdst, stride)
  
  ST_H4 store four half-word elements in vector 'in' to pdst with stride.
  
  About the macro name :
  
  1) 'ST' means store operation.
  
  2) 'H/W/D' means type of vector element is 'half-word/word/double-word'.
  
  3) Number '1/2/4/8' means how many elements will be stored.
  
  About the macro parameter :
  
  1) 'in0, in1...' 128-bits vector.
  
  2) 'idx0, idx1...' elements index.
  
  3) 'pdst' destination pointer to store to
  
  4) 'stride' stride of each store operation.
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/mips/h263dsp_msa.c
  • [DH] libavcodec/mips/h264chroma_msa.c
  • [DH] libavcodec/mips/h264dsp_msa.c
  • [DH] libavcodec/mips/h264idct_msa.c
  • [DH] libavcodec/mips/h264qpel_msa.c
  • [DH] libavcodec/mips/hevc_idct_msa.c
  • [DH] libavcodec/mips/hevc_lpf_sao_msa.c
  • [DH] libavcodec/mips/hevc_mc_bi_msa.c
  • [DH] libavcodec/mips/hevc_mc_biw_msa.c
  • [DH] libavcodec/mips/hevc_mc_uni_msa.c
  • [DH] libavcodec/mips/hevc_mc_uniw_msa.c
  • [DH] libavcodec/mips/hevcdsp_msa.c
  • [DH] libavcodec/mips/hevcpred_msa.c
  • [DH] libavcodec/mips/hpeldsp_msa.c
  • [DH] libavcodec/mips/qpeldsp_msa.c
  • [DH] libavcodec/mips/vp3dsp_idct_msa.c
  • [DH] libavcodec/mips/vp8_idct_msa.c
  • [DH] libavcodec/mips/vp8_lpf_msa.c
  • [DH] libavcodec/mips/vp8_mc_msa.c
  • [DH] libavcodec/mips/vp9_idct_msa.c
  • [DH] libavcodec/mips/vp9_intra_msa.c
  • [DH] libavcodec/mips/vp9_lpf_msa.c
  • [DH] libavcodec/mips/vp9_mc_msa.c
  • [DH] libavutil/mips/generic_macros_msa.h

• Linking ffmpeg's libswresample from MacOS X 10.9 with C++

  8 janvier 2014, par user2530102

  I am trying to link to ffmpeg's libswresample from a C++ application. I have installed ffmpeg through Homebrew on Mac OS X 10.9. A simple test application links if it's compiled as C, but not if it's compiled as C++. Here is the sample code :

  #include 
  
  #include <libswresample></libswresample>swresample.h>
  
  
  
  int main()
  
  {
  
    swr_alloc();
  
    printf("Hello world\n");
  
    return 0;
  
  }

  When compiled as C with clang -I/usr/local/include -L/usr/local/lib -lswresample -o hello hello.c this creates the application as expected. When compiled with C++ using clang++ -I/usr/local/include -L/usr/local/lib -lswresample -o hello hello.cc it results in an error like the following :

  Undefined symbols for architecture x86_64:
  
    "swr_alloc()", referenced from:
  
        _main in hello-9jqOY4.o
  
  ld: symbol(s) not found for architecture x86_64
  
  clang: error: linker command failed with exit code 1 (use -v to see invocation)

  But running nm -a /usr/local/lib/libswresample.dylib includes 000000000000d8a9 T _swr_alloc and file /usr/local/lib/libswresample.dylib shows /usr/local/lib/libswresample.dylib: Mach-O 64-bit dynamically linked shared library x86_64 which I assume is expected. I have the same issue compiling the example with gcc/g++, and I also have the same issue when compiling ffmpeg with either clang or gcc, which leads me to think that there is just something I don't know about linking that should be obvious, but I haven't found any references suggesting that it should be different linking a library in C++ vs. C, and linking other libraries (sox, for example) presents no difficulties with an identical setup.

  I have seen posts related to linking issues in Mac OS X 10.9 because of the change from libstdc++ to libc++, but adding -stdlib=libstdc++ or -stdlib=libc++ seems to make no difference. It also makes no difference to add -mmacosx-version-min=10.6 or 10.9.

  Any help is greatly appreciated.

• Using FFMPEG : How to do a Scene Change Detection ? with timecode ?

  24 novembre 2016, par Mozart

  Based on this article it seems that it is possible to use FFMPEG to detect scene change in videos :
  http://www.luckydinosaur.com/u/ffmpeg-scene-change-detector

  Now I have a video that displays a book text and when the text (word or sentence) is spoken it gets highlighted.
  Something like this audio book : https://youtu.be/lA7L6ZNVKjc

  I need to know the timestamp when the text gets highlighted (hence scene change), this will allow me to add timestamp tags on my youtube video, so it becomes easier for listeners to navigate through the audiobook.

  What is the magic command line that would do this ?

  Thank you very much !