[FFmpeg-devel] [PATCH v2 0/2] 32bps FLAC patches

Martijn van Beurden mvanb1 at gmail.com
Mon Aug 15 23:39:38 EEST 2022


Op ma 1 aug. 2022 om 14:03 schreef Martijn van Beurden <mvanb1 at 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. The decoding patch has been send in for review earlier,
> but didn't get any feedback yet, so I'm sending it in again,
> unchanged, this time with a patch for encoding too.
>
> 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
>
> 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    | 499 ++++++++++++++++++++++++++++++++--------
>  libavcodec/get_bits.h   |  12 +
>  libavcodec/mathops.h    |   9 +
>  libavcodec/put_bits.h   |   7 +
>  libavcodec/put_golomb.h |  19 +-
>  7 files changed, 668 insertions(+), 130 deletions(-)
>

I'd like to bring these patches to the attention of the mailing list again.


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