From d6eee9f3e9bb5a5b8833d28d68612a25758438f7 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 5 Oct 2009 21:27:36 +0000
Subject: [PATCH] alacenc: add a fixed LPC coefficient mode as compression
level 1. old compression level 1 is now compression level 2 and is still the
default.
Originally committed as revision 20173 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
libavcodec/alacenc.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/libavcodec/alacenc.c b/libavcodec/alacenc.c
index 691e6df41e3..4f869ee230b 100644
--- a/libavcodec/alacenc.c
+++ b/libavcodec/alacenc.c
@@ -132,12 +132,23 @@ static void calc_predictor_params(AlacEncodeContext *s, int ch)
int shift[MAX_LPC_ORDER];
int opt_order;
+ if (s->avctx->compression_level > 1) {
opt_order = ff_lpc_calc_coefs(&s->dspctx, s->sample_buf[ch], s->avctx->frame_size, s->min_prediction_order, s->max_prediction_order,
ALAC_MAX_LPC_PRECISION, coefs, shift, 1, ORDER_METHOD_EST, ALAC_MAX_LPC_SHIFT, 1);
s->lpc[ch].lpc_order = opt_order;
s->lpc[ch].lpc_quant = shift[opt_order-1];
memcpy(s->lpc[ch].lpc_coeff, coefs[opt_order-1], opt_order*sizeof(int));
+ } else {
+ s->lpc[ch].lpc_order = 6;
+ s->lpc[ch].lpc_quant = 6;
+ s->lpc[ch].lpc_coeff[0] = 160;
+ s->lpc[ch].lpc_coeff[1] = -190;
+ s->lpc[ch].lpc_coeff[2] = 170;
+ s->lpc[ch].lpc_coeff[3] = -130;
+ s->lpc[ch].lpc_coeff[4] = 80;
+ s->lpc[ch].lpc_coeff[5] = -25;
+ }
}
static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n)
@@ -375,9 +386,9 @@ static av_cold int alac_encode_init(AVCodecContext *avctx)
// Set default compression level
if(avctx->compression_level == FF_COMPRESSION_DEFAULT)
- s->compression_level = 1;
+ s->compression_level = 2;
else
- s->compression_level = av_clip(avctx->compression_level, 0, 1);
+ s->compression_level = av_clip(avctx->compression_level, 0, 2);
// Initialize default Rice parameters
s->rc.history_mult = 40;
--
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