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• avcodec/dvdsubenc : Add dvdsub workaround for some players

  9 juillet 2014, par Oliver Fromme

  avcodec/dvdsubenc : Add dvdsub workaround for some players
  The issue affects dvdsub subtitles (a.k.a. VOBSUB).
  Some players — in particular hardware players — cut off
  
  the lowest row of pixels if the number of rows in the subtitle
  
  is odd.
  The patch below implements a work-around for that.  If the
  
  number of rows is odd, it is simply rounded up to an even
  
  number, adding an invisible (i.e. fully transparent) row.
  
  The work-around can be enabled or disabled with a new
  
  option -even_rows_fix.  The default is disabled, so there
  
  is no change of behaviour for users who don’t care about it.
  The overhead for the fix is low, and in many cases even zero :
  
  For subtitles with an odd number of rows (i.e. in 50% of
  
  cases on average), the size increases by two bytes because
  
  a fully transparent row is encoded as 0x00 0x00.  However,
  
  in the VOBSUB standard, all data packets are padded to 2KB
  
  anyway, so in most cases the additional bytes just use some
  
  part of the padding, so there is no overhead.  Only in the
  
  rare case that the 2KB boundary is hit (0.1% chance), a full
  
  2KB block is added.
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/dvdsubenc.c

• stream_encoder : Improve selection of residual accumulator width

  19 juin 2014, par Miroslav Lichvar

  stream_encoder : Improve selection of residual accumulator width
  In the precompute_partition_info_sums_ function, instead of selecting
  
  64-bit accumulator when the signal bps is larger than 16, revert to the
  
  original approach based on partition size, but make room for few extra
  
  bits to not overflow with unusual signals where the average residual
  
  magnitude may be larger than bps.
  It slightly improves the performance with standard encoding levels and
  
  16-bit files as the 17-bit side channel can still be processed with the
  
  32-bit accumulator and correctly selects the 64-bit accumulator with
  
  very large 16-bit partitions.
  This is related to commits 6f7ec60c and 187e596e.
  Signed-off-by : Erik de Castro Lopo <erikd@mega-nerd.com>
  

  • [DH] src/libFLAC/include/private/stream_encoder.h
  • [DH] src/libFLAC/stream_encoder.c
  • [DH] src/libFLAC/stream_encoder_intrin_sse2.c
  • [DH] src/libFLAC/stream_encoder_intrin_ssse3.c

• Revision 9ac2f66320 : Re-design quantization process This commit re-designs the quantization process

  2 juillet 2014, par Jingning Han

  Changed Paths :
   Modify /vp9/common/vp9_rtcd_defs.pl

  
   Modify /vp9/encoder/vp9_block.h

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_encodemb.c

  
   Modify /vp9/encoder/vp9_encodemb.h

  
   Modify /vp9/encoder/vp9_quantize.c

  
   Modify /vp9/encoder/vp9_quantize.h

  
   Modify /vp9/encoder/vp9_speed_features.c

  
   Modify /vp9/encoder/vp9_speed_features.h

  
   Modify /vp9/encoder/x86/vp9_quantize_ssse3_x86_64.asm

  
  
  Re-design quantization process

  This commit re-designs the quantization process for transform
  coefficient blocks of size 4x4 to 16x16. It improves compression
  performance for speed 7 by 3.85%. The SSSE3 version for the
  new quantization process is included.

  The average runtime of the 8x8 block quantization is reduced
  from 285 cycles -> 255 cycles, i.e., over 10% faster.

  Change-Id : I61278aa02efc70599b962d3314671db5b0446a50