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

[Justin Ruggles]

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(-)

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