flacenc, lpc: Move LPC code from flacenc.c to new lpc.[ch] files.

Originally committed as revision 14790 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 2 insertions, 189 deletions

diff --git a/libavcodec/flacenc.c b/libavcodec/flacenc.c
index 27502096c2..4876895c67 100644
--- a/libavcodec/flacenc.c
+++ b/libavcodec/flacenc.c
@@ -25,6 +25,7 @@
 #include "bitstream.h"
 #include "dsputil.h"
 #include "golomb.h"
+#include "lpc.h"
 
 #define FLAC_MAX_CH  8
 #define FLAC_MIN_BLOCKSIZE  16
@@ -41,17 +42,8 @@
 #define FLAC_CHMODE_RIGHT_SIDE      9
 #define FLAC_CHMODE_MID_SIDE       10
 
-#define ORDER_METHOD_EST     0
-#define ORDER_METHOD_2LEVEL  1
-#define ORDER_METHOD_4LEVEL  2
-#define ORDER_METHOD_8LEVEL  3
-#define ORDER_METHOD_SEARCH  4
-#define ORDER_METHOD_LOG     5
-
 #define FLAC_STREAMINFO_SIZE  34
 
-#define MIN_LPC_ORDER       1
-#define MAX_LPC_ORDER      32
 #define MAX_FIXED_ORDER     4
 #define MAX_PARTITION_ORDER 8
 #define MAX_PARTITIONS     (1 << MAX_PARTITION_ORDER)
@@ -635,185 +627,6 @@ void ff_flac_compute_autocorr(const int32_t *data, int len, int lag,
     }
 }
 
-/**
- * Levinson-Durbin recursion.
- * Produces LPC coefficients from autocorrelation data.
- */
-static void compute_lpc_coefs(const double *autoc, int max_order,
-                              double lpc[][MAX_LPC_ORDER], double *ref)
-{
-   int i, j, i2;
-   double r, err, tmp;
-   double lpc_tmp[MAX_LPC_ORDER];
-
-   for(i=0; i<max_order; i++) lpc_tmp[i] = 0;
-   err = autoc[0];
-
-   for(i=0; i<max_order; i++) {
-      r = -autoc[i+1];
-      for(j=0; j<i; j++) {
-          r -= lpc_tmp[j] * autoc[i-j];
-      }
-      r /= err;
-      ref[i] = fabs(r);
-
-      err *= 1.0 - (r * r);
-
-      i2 = (i >> 1);
-      lpc_tmp[i] = r;
-      for(j=0; j<i2; j++) {
-         tmp = lpc_tmp[j];
-         lpc_tmp[j] += r * lpc_tmp[i-1-j];
-         lpc_tmp[i-1-j] += r * tmp;
-      }
-      if(i & 1) {
-          lpc_tmp[j] += lpc_tmp[j] * r;
-      }
-
-      for(j=0; j<=i; j++) {
-          lpc[i][j] = -lpc_tmp[j];
-      }
-   }
-}
-
-/**
- * Quantize LPC coefficients
- */
-static void quantize_lpc_coefs(double *lpc_in, int order, int precision,
-                               int32_t *lpc_out, int *shift, int max_shift, int zero_shift)
-{
-    int i;
-    double cmax, error;
-    int32_t qmax;
-    int sh;
-
-    /* define maximum levels */
-    qmax = (1 << (precision - 1)) - 1;
-
-    /* find maximum coefficient value */
-    cmax = 0.0;
-    for(i=0; i<order; i++) {
-        cmax= FFMAX(cmax, fabs(lpc_in[i]));
-    }
-
-    /* if maximum value quantizes to zero, return all zeros */
-    if(cmax * (1 << max_shift) < 1.0) {
-        *shift = zero_shift;
-        memset(lpc_out, 0, sizeof(int32_t) * order);
-        return;
-    }
-
-    /* calculate level shift which scales max coeff to available bits */
-    sh = max_shift;
-    while((cmax * (1 << sh) > qmax) && (sh > 0)) {
-        sh--;
-    }
-
-    /* since negative shift values are unsupported in decoder, scale down
-       coefficients instead */
-    if(sh == 0 && cmax > qmax) {
-        double scale = ((double)qmax) / cmax;
-        for(i=0; i<order; i++) {
-            lpc_in[i] *= scale;
-        }
-    }
-
-    /* output quantized coefficients and level shift */
-    error=0;
-    for(i=0; i<order; i++) {
-        error += lpc_in[i] * (1 << sh);
-        lpc_out[i] = av_clip(lrintf(error), -qmax, qmax);
-        error -= lpc_out[i];
-    }
-    *shift = sh;
-}
-
-static int estimate_best_order(double *ref, int max_order)
-{
-    int i, est;
-
-    est = 1;
-    for(i=max_order-1; i>=0; i--) {
-        if(ref[i] > 0.10) {
-            est = i+1;
-            break;
-        }
-    }
-    return est;
-}
-
-/**
- * Calculate LPC coefficients for multiple orders
- */
-static int lpc_calc_coefs(DSPContext *s,
-                          const int32_t *samples, int blocksize, int max_order,
-                          int precision, int32_t coefs[][MAX_LPC_ORDER],
-                          int *shift, int use_lpc, int omethod, int max_shift, int zero_shift)
-{
-    double autoc[MAX_LPC_ORDER+1];
-    double ref[MAX_LPC_ORDER];
-    double lpc[MAX_LPC_ORDER][MAX_LPC_ORDER];
-    int i, j, pass;
-    int opt_order;
-
-    assert(max_order >= MIN_LPC_ORDER && max_order <= MAX_LPC_ORDER);
-
-    if(use_lpc == 1){
-        s->flac_compute_autocorr(samples, blocksize, max_order, autoc);
-
-        compute_lpc_coefs(autoc, max_order, lpc, ref);
-    }else{
-        LLSModel m[2];
-        double var[MAX_LPC_ORDER+1], weight;
-
-        for(pass=0; pass<use_lpc-1; pass++){
-            av_init_lls(&m[pass&1], max_order);
-
-            weight=0;
-            for(i=max_order; i<blocksize; i++){
-                for(j=0; j<=max_order; j++)
-                    var[j]= samples[i-j];
-
-                if(pass){
-                    double eval, inv, rinv;
-                    eval= av_evaluate_lls(&m[(pass-1)&1], var+1, max_order-1);
-                    eval= (512>>pass) + fabs(eval - var[0]);
-                    inv = 1/eval;
-                    rinv = sqrt(inv);
-                    for(j=0; j<=max_order; j++)
-                        var[j] *= rinv;
-                    weight += inv;
-                }else
-                    weight++;
-
-                av_update_lls(&m[pass&1], var, 1.0);
-            }
-            av_solve_lls(&m[pass&1], 0.001, 0);
-        }
-
-        for(i=0; i<max_order; i++){
-            for(j=0; j<max_order; j++)
-                lpc[i][j]= m[(pass-1)&1].coeff[i][j];
-            ref[i]= sqrt(m[(pass-1)&1].variance[i] / weight) * (blocksize - max_order) / 4000;
-        }
-        for(i=max_order-1; i>0; i--)
-            ref[i] = ref[i-1] - ref[i];
-    }
-    opt_order = max_order;
-
-    if(omethod == ORDER_METHOD_EST) {
-        opt_order = estimate_best_order(ref, max_order);
-        i = opt_order-1;
-        quantize_lpc_coefs(lpc[i], i+1, precision, coefs[i], &shift[i], max_shift, zero_shift);
-    } else {
-        for(i=0; i<max_order; i++) {
-            quantize_lpc_coefs(lpc[i], i+1, precision, coefs[i], &shift[i], max_shift, zero_shift);
-        }
-    }
-
-    return opt_order;
-}
-
 
 static void encode_residual_verbatim(int32_t *res, int32_t *smp, int n)
 {
@@ -1042,7 +855,7 @@ static int encode_residual(FlacEncodeContext *ctx, int ch)
     }
 
     /* LPC */
-    opt_order = lpc_calc_coefs(&ctx->dsp, smp, n, max_order, precision, coefs,
+    opt_order = ff_lpc_calc_coefs(&ctx->dsp, smp, n, max_order, precision, coefs,
                                shift, ctx->options.use_lpc, omethod, MAX_LPC_SHIFT, 0);
 
     if(omethod == ORDER_METHOD_2LEVEL ||