Recherche avancée

Sur d’autres sites (6732)

• avcodec/utvideodec/enc : Fix edge case of creating Huffman table

  24 septembre 2020, par Andreas Rheinhardt

  avcodec/utvideodec/enc : Fix edge case of creating Huffman table
  The Ut Video format stores Huffman tables in its bitstream by coding
  
  the length of a given symbol ; it does not code the actual code directly,
  
  instead this is to be inferred by the rule that a symbol is to the left
  
  of every shorter symbol in the Huffman tree and that for symbols of the
  
  same length the symbol is descending from left to right. With one
  
  exception, this is also what our de- and encoder did.
  The exception only matters when there are codes of length 32, because
  
  in this case the first symbol of this length did not get the code 0,
  
  but 1 ; this is tantamount to pretending that there is a (nonexistent)
  
  leaf of length 32. This is simply false. The reference software agrees
  
  with this [1].
  [1] : https://github.com/umezawatakeshi/utvideo/blob/2700a471a78402e5c340150b38e8a793ef3676f1/utv_core/HuffmanCode.cpp#L280
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/utvideodec.c
  • [DH] libavcodec/utvideoenc.c

• lavu/riscv : CPU flag for the Zbb extension

  2 octobre 2022, par Rémi Denis-Courmont

  lavu/riscv : CPU flag for the Zbb extension
  Unfortunately, it is common, and will remain so, that the Bit
  
  manipulations are not enabled at compilation time. This is an official
  
  policy for Debian ports in general (though they do not support RISC-V
  
  officially as of yet) to stick to the minimal target baseline, which
  
  does not include the B extension or even its Zbb subset.
  For inline helpers (CPOP, REV8), compiler builtins (CTZ, CLZ) or
  
  even plain C code (MIN, MAX, MINU, MAXU), run-time detection seems
  
  impractical. But at least it can work for the byte-swap DSP functions.
  

  • [DH] libavutil/cpu.c
  • [DH] libavutil/cpu.h
  • [DH] libavutil/riscv/cpu.c
  • [DH] tests/checkasm/checkasm.c

• apply ffmpeg to many files

  30 juillet 2015, par puchu

  I have written simple script :

  #!/bin/bash
  
  find . -name "*.m4a" | while read filename;
  
  do
  
      new_filename=$(echo "$filename" | sed "s/^\(.*\)m4a$/\1flac/g");
  
      if [ ! -f "$new_filename" ]
  
      then
  
              #ffmpeg -i "$filename" -acodec flac "$new_filename" > /dev/null 2>&1;
  
              #wait $!;
  
              echo "$filename";
  
              echo "$new_filename";
  
      fi
  
  done

  it outputs correct result :

  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.m4a
  
  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.flac
  
  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.m4a
  
  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.flac

  if uncomment ffmpeg and wait :

  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.m4a
  
  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.flac
  
  uilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.m4a
  
  uilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.flac

  And no flacs has been done !

  PS

  #!/bin/bash
  
  find . -name "*.m4a" | while read filename;
  
  do
  
      new_filename=$(echo "$filename" | sed "s/^\(.*\)m4a$/\1flac/g");
  
      if [ ! -f "$new_filename" ]
  
      then
  
              ffmpeg -i "$filename" -acodec flac "$new_filename";
  
              echo "$filename";
  
              echo "$new_filename";
  
      fi
  
      sleep 5;
  
  done

  1) encode start but suddenly stop with no error messages

  2) encode couldn’t start because of "uilibrium" instead of "./Equilibrium"

  3) = 1)

  4) = 2)

  ...

  last) correctly