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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
This commit is contained in:
Justin Ruggles 2009-10-05 21:27:36 +00:00
parent 1fe4abf397
commit d6eee9f3e9
1 changed files with 13 additions and 2 deletions
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15
libavcodec/alacenc.c
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@ -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;