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• avutil/parseutils : accept everything in av_parse_time that ff_iso8601_to_unix_time...

  4 février 2016, par Marton Balint

  avutil/parseutils : accept everything in av_parse_time that ff_iso8601_to_unix_time accepts
  Also parse timezone information previously ignored in ff_iso8601_to_unix_time.
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] libavutil/parseutils.c
  • [DH] tests/ref/fate/parseutils

• avconv : use the new buffersrc parameters API

  12 février 2016, par Anton Khirnov

  avconv : use the new buffersrc parameters API
  The timebase change in the zmbv-8bit test is due to the fact that
  
  previously the timebase string was evaluated as floating point, then
  
  converted to a rational. After this commit, the timebase is passed
  
  directly as is.
  

  • [DBH] avconv_filter.c
  • [DBH] tests/ref/fate/zmbv-8bit

• avcodec : add a native SMPTE VC-2 HQ encoder

  10 février 2016, par Rostislav Pehlivanov

  avcodec : add a native SMPTE VC-2 HQ encoder
  This commit adds a new encoder capable of creating BBC/SMPTE Dirac/VC-2 HQ
  
  profile files.
  Dirac is a wavelet based codec created by the BBC a little more than 10
  
  years ago. Since then, wavelets have mostly gone out of style as they
  
  did not provide adequate encoding gains at lower bitrates. Dirac was a
  
  fully featured video codec equipped with perceptual masking, support for
  
  most popular pixel formats, interlacing, overlapped-block motion
  
  compensation, and other features. It found new life after being stripped
  
  of various features and standardized as the VC-2 codec by the SMPTE with
  
  an extra profile, the HQ profile that this encoder supports, added.
  The HQ profile was based off of the Low-Delay profile previously
  
  existing in Dirac. The profile forbids DC prediction and arithmetic
  
  coding to focus on high performance and low delay at higher bitrates.
  
  The standard bitrates for this profile vary but generally 1:4
  
  compression is expected ( 525 Mbps vs the 2200 Mbps for uncompressed
  
  1080p50). The codec only supports I-frames, hence the high bitrates.
  The structure of this encoder is simple : do a DWT transform on the
  
  entire image, split it into multiple slices (specified by the user) and
  
  encode them in parallel. All of the slices are of the same size, making
  
  rate control and threading very trivial. Although only in C, this encoder
  
  is capable of 30 frames per second on an 4 core 8 threads Ivy Bridge.
  
  A lookup table is used to encode most of the coefficients.
  No code was used from the GSoC encoder from 2007 except for the 2
  
  transform functions in diracenc_transforms.c. All other code was written
  
  from scratch.
  This encoder outperforms any other encoders in quality, usability and in
  
  features. Other existing implementations do not support 4 level
  
  transforms or 64x64 blocks (slices), which greatly increase compression.
  As previously said, the codec is meant for broadcasting, hence support
  
  for non-broadcasting image widths, heights, bit depths, aspect ratios,
  
  etc. are limited by the "level". Although this codec supports a few
  
  chroma subsamplings (420, 422, 444), signalling those is generally
  
  outside the specifications of the level used (3) and the reference
  
  decoder will outright refuse to read any image with such a flag
  
  signalled (it only supports 1920x1080 yuv422p10). However, most
  
  implementations will happily read files with alternate dimensions,
  
  framerates and formats signalled.
  Therefore, in order to encode files other than 1080p50 yuv422p10le, you
  
  need to provide an "-strict -2" argument to the command line. The FFmpeg
  
  decoder will happily read any files made with non-standard parameters,
  
  dimensions and subsamplings, and so will other implementations. IMO this
  
  should be "-strict -1", but I’ll leave that up for discussion.
  There are still plenty of stuff to implement, for instance 5 more
  
  wavelet transforms are still in the specs and supported by the decoder.
  The encoder can be lossless, given a high enough bitrate.
  Signed-off-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  

  • [DH] libavcodec/Makefile
  • [DH] libavcodec/allcodecs.c
  • [DH] libavcodec/vc2enc.c
  • [DH] libavcodec/vc2enc_dwt.c
  • [DH] libavcodec/vc2enc_dwt.h
  • [DH] libavcodec/version.h