[FFmpeg-devel] [PATCH v7 0/3] 32bps FLAC patches

[Martijn van Beurden]

Op vr 28 okt. 2022 om 22:13 schreef Martijn van Beurden <mvanb1 at gmail.com>:
>
> Op di 11 okt. 2022 om 19:24 schreef Martijn van Beurden <mvanb1 at gmail.com>:
> >
> > Recently libFLAC gained the ability (first released in FLAC 1.4.0)
> > to create FLAC files containing 32-bit int PCM samples. To
> > keep complexity reasonable, the choice was made to limit residuals
> > to 32-bit integers, which the encoder must make sure of. In case
> > the encoder cannot find any predictor of which the residuals fit
> > this limit, it must default to using a verbatim subframe. Tests have
> > shown that this does not happen often (<0.1% of subframes on a
> > music corpus of various styles). See also discussion here:
> > https://github.com/ietf-wg-cellar/flac-specification/pull/148
> >
> > These two patches implement decoding and encoding following this
> > format.
> >
> > Changes since v1:
> > fix copy-paste error in encoder, several invocations of
> > lpc_encode_choose_datapath used wrong parameters, making FATE fail as
> > compression was less than it should be
> >
> > Changes since v2:
> > Rebased decoder part as it didn't apply anymore
> >
> > Changes since v3:
> > Moved put_golomb part to flacenc.c (as it is now quite specific to FLAC)
> > and renamed put_sbits64 to put_sbits63 (and changed assert accordingly)
> >
> > Changes since v4:
> > Fix check of decoded_buffer_33bps malloc. Fix reading of wasted bits
> > for 33bps subframe. Add fate test
> >
> > Changes since v5:
> > Slimmed down 32 bps fate flac test from 2 to 1 input file. Replaced
> > -strict -2 with -strict experimental in fate and encoder warning.
> >
> > Changes since v6:
> > Deduplicated function bodies with preprocessor macros in both
> > encoder and decoder, declared variables in loop body where possible
> > and changed ff_ctz to ff_ctzll where necessary
> >
> > Martijn van Beurden (3):
> >   libavcodec/flacdec: Implement decoding of 32 bit-per-sample PCM
> >   libavcodec/flacenc: Implement encoding of 32 bit-per-sample PCM
> >   fate/flac: Add test of 32 bps encoding/decoding
> >
> >  libavcodec/flac.c       |   4 +-
> >  libavcodec/flacdec.c    | 218 ++++++++++++++++--
> >  libavcodec/flacenc.c    | 480 +++++++++++++++++++++++++++++++---------
> >  libavcodec/get_bits.h   |  12 +
> >  libavcodec/mathops.h    |   9 +
> >  libavcodec/put_bits.h   |   7 +
> >  libavcodec/put_golomb.h |  14 --
> >  tests/fate/flac.mak     |   4 +
> >  8 files changed, 602 insertions(+), 146 deletions(-)
> >
>
> Hi all,
>
> With this email, I would like to renew the attention of the mailing
> list for these patches.
>
> Kind regards, Martijn van Beurden

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