Re: [FFmpeg-devel] [PATCH v4 0/2] 32bps FLAC patches

[Martijn van Beurden <mvanb1@gmail.com>]

Op za 3 sep. 2022 om 11:21 schreef Martijn van Beurden <mvanb1@gmail.com>:

> Recently libFLAC gained the ability (not in any released version yet
> though) 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)
>
> Martijn van Beurden (2):
>   libavcodec/flacdec: Implement decoding of 32 bit-per-sample PCM
>   libavcodec/flacenc: Implement encoding of 32 bit-per-sample PCM
>
>  libavcodec/flac.c       |   4 +-
>  libavcodec/flacdec.c    | 248 +++++++++++++++++--
>  libavcodec/flacenc.c    | 519 ++++++++++++++++++++++++++++++++--------
>  libavcodec/get_bits.h   |  12 +
>  libavcodec/mathops.h    |   9 +
>  libavcodec/put_bits.h   |   7 +
>  libavcodec/put_golomb.h |  14 --
>  7 files changed, 674 insertions(+), 139 deletions(-)
>
> --
> 2.30.2
>
>
Perhaps a little early for a reminder, sorry about that. I'd just like to
add to the above email that the FLAC reference implementation, libFLAC, has
had a release yesterday including the functionality of these patches
(encoding/decoder of 32 bps audio).
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