[FFmpeg-devel] [PATCH 1/2] ac3enc: do not right-shift fixed-point coefficients in the final MDCT stage.

[Måns Rullgård]

Justin Ruggles <justin.ruggles at gmail.com> writes:

> This increases the accuracy of coefficients, leading to improved quality.
> Rescaling of the coefficients to full 25-bit accuracy is done rather than
> offsetting the exponent values. This requires coefficient scaling to be done
> before determining the rematrixing strategy. Also, the rematrixing strategy
> calculation must use 64-bit math to prevent overflow due to the higher
> precision coefficients.
> ---
>  libavcodec/ac3enc.c        |   25 ++++++++++-----------
>  libavcodec/ac3enc_fixed.c  |   49 ++++++++++++++++++++++++++++++++-----------
>  libavcodec/ac3enc_fixed.h  |    2 +
>  libavcodec/ac3enc_float.h  |    2 +
>  tests/ref/acodec/ac3_fixed |    2 +-
>  tests/ref/lavf/rm          |    2 +-
>  tests/ref/seek/ac3_rm      |   22 +++++++++---------
>  7 files changed, 65 insertions(+), 39 deletions(-)

Looks OK.

-- 
M?ns Rullg?rd
mans at mansr.com