ac3enc: correct the flipped sign in the ac3_fixed encoder
ac3enc: select bandwidth based on bit rate, sample rate, and number offull-bandwidth channels.
This reduces high-frequency artifacts and improves the quality of the lowerfrequency audio at low bit rates.
ac3enc: use generic fixed-point mdct
This makes the AC3 encoder use the shared fixed-point MDCT ratherthan its own implementation. The checksum changes are due todifferent rounding in the MDCT.
Signed-off-by: Mans Rullgard <firstname.lastname@example.org>
Add apply_window_int16() to DSPContext with x86-optimized versions and use itin the ac3_fixed encoder.
ac3enc: do not right-shift fixed-point coefficients in the final MDCT stage.
This increases the accuracy of coefficients, leading to improved quality.Rescaling of the coefficients to full 25-bit accuracy is done rather thanoffsetting the exponent values. This requires coefficient scaling to be done...
ac3enc: fix bug in stereo rematrixing decision.
The rematrixing strategy reuse flags are not reset between frames, so theyneed to be initialized for all blocks, not just block 0.
ac3enc: change default floor code to 7.
This is to match the value in every (E-)AC-3 file from commercial sources.It has a negligible effect on audio quality.
ac3enc: Change EXP_DIFF_THRESHOLD to 500.
This patch changes the exponent difference threshold in the exponentstrategy decision function of the AC-3 encoder. I tested lowering inincrements of 100. From 1000 down to 500 generally increased in qualitywith each step, but 400 was generally much worse....
Add stereo rematrixing support to the AC-3 encoders.This improves the audio quality significantly for stereo source with both thefixed-point and floating-point AC-3 encoders.Update acodec-ac3_fixed and seek-ac3_rm test references.
Originally committed as revision 26271 to svn://svn.ffmpeg.org/ffmpeg/trunk
Change the AC-3 encoder to use floating-point.Fixed-point AC-3 encoder renamed to ac3_fixed.Regression test acodec-ac3 renamed to acodec-ac3_fixed.Regression test lavf-rm changed to use ac3_fixed encoder.
Originally committed as revision 26209 to svn://svn.ffmpeg.org/ffmpeg/trunk