From c97e057ee57d552a3ccad2d12e29b5969d04be97 Mon Sep 17 00:00:00 2001 From: Martijn van Beurden Date: Wed, 3 Dec 2014 14:59:19 +0100 Subject: [PATCH] Improve LPC order guess The recent compression preset retuning improved upon most material but it the few tracks that show regression are usually classical music. This patch improves compression by improving the LPC order guess, of which classical music benefits most. Improvement is 0.007% on average but up to 0.1%. I haven't seen regressions for any of my test samples. Signed-off-by: Erik de Castro Lopo --- src/libFLAC/lpc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/libFLAC/lpc.c b/src/libFLAC/lpc.c index ca98c5cf..f7c643a8 100644 --- a/src/libFLAC/lpc.c +++ b/src/libFLAC/lpc.c @@ -1308,7 +1308,7 @@ FLAC__double FLAC__lpc_compute_expected_bits_per_residual_sample(FLAC__double lp FLAC__ASSERT(total_samples > 0); - error_scale = 0.5 * M_LN2 * M_LN2 / (FLAC__double)total_samples; + error_scale = 0.5 / (FLAC__double)total_samples; return FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(lpc_error, error_scale); } @@ -1338,7 +1338,7 @@ unsigned FLAC__lpc_compute_best_order(const FLAC__double lpc_error[], unsigned m FLAC__ASSERT(max_order > 0); FLAC__ASSERT(total_samples > 0); - error_scale = 0.5 * M_LN2 * M_LN2 / (FLAC__double)total_samples; + error_scale = 0.5 / (FLAC__double)total_samples; best_index = 0; best_bits = (unsigned)(-1);