add more debug info, clip bps computation to 0.0

diff --git a/src/libFLAC/lpc.c b/src/libFLAC/lpc.c
index 87b5f6490d248d6549d76de5534ceae8eab828e6..10bdf11e68630827f1ac7de30c56cc811b59917d 100644 (file)
--- a/src/libFLAC/lpc.c
+++ b/src/libFLAC/lpc.c
@@ -149,19 +149,19 @@ void FLAC__lpc_compute_residual_from_qlp_coefficients(const int32 data[], unsign
                        sum += qlp_coeff[j] * (*(--history));
 #ifdef FLAC_OVERFLOW_DETECT
                        sumo += (int64)qlp_coeff[j] * (int64)(*history);
-                       if(sumo > 2147483647ll || sumo < -2147483648ll)
-                               fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients: OVERFLOW, sumo=%lld\n",sumo);
+                       if(sumo > 2147483647ll || sumo < -2147483648ll) {
+                               fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients: OVERFLOW, i=%u, j=%u, c=%d, d=%d, sumo=%lld\n",i,j,qlp_coeff[j],*history,sumo);
+                       }
 #endif
                }
                *(residual++) = *(data++) - (sum >> lp_quantization);
        }
 
-       /* Here's a slightly slower but clearer version:
+       /* Here's a slower but clearer version:
        for(i = 0; i < data_len; i++) {
                sum = 0;
-               history = &(data[i]);
                for(j = 0; j < order; j++)
-                       sum += qlp_coeff[j] * (*(--history));
+                       sum += qlp_coeff[j] * data[i-j-1];
                residual[i] = data[i] - (sum >> lp_quantization);
        }
        */
@@ -173,7 +173,8 @@ void FLAC__lpc_restore_signal(const int32 residual[], unsigned data_len, const i
        int64 sumo;
 #endif
        unsigned i, j;
-       int32 sum, *history;
+       int32 sum;
+       const int32 *history;
 
 #ifdef FLAC_OVERFLOW_DETECT_VERBOSE
        fprintf(stderr,"FLAC__lpc_restore_signal: data_len=%d, order=%u, lpq=%d",data_len,order,lp_quantization);
@@ -188,17 +189,27 @@ void FLAC__lpc_restore_signal(const int32 residual[], unsigned data_len, const i
                sumo = 0;
 #endif
                sum = 0;
-               history = data+i;
+               history = data;
                for(j = 0; j < order; j++) {
                        sum += qlp_coeff[j] * (*(--history));
 #ifdef FLAC_OVERFLOW_DETECT
                        sumo += (int64)qlp_coeff[j] * (int64)(*history);
-                       if(sumo > 2147483647ll || sumo < -2147483648ll)
-                               fprintf(stderr,"FLAC__lpc_restore_signal: OVERFLOW, sumo=%lld\n",sumo);
+                       if(sumo > 2147483647ll || sumo < -2147483648ll) {
+                               fprintf(stderr,"FLAC__lpc_restore_signal: OVERFLOW, i=%u, j=%u, c=%d, d=%d, sumo=%lld\n",i,j,qlp_coeff[j],*history,sumo);
+                       }
 #endif
                }
+               *(data++) = *(residual++) + (sum >> lp_quantization);
+       }
+
+       /* Here's a slower but clearer version:
+       for(i = 0; i < data_len; i++) {
+               sum = 0;
+               for(j = 0; j < order; j++)
+                       sum += qlp_coeff[j] * data[i-j-1];
                data[i] = residual[i] + (sum >> lp_quantization);
        }
+       */
 }
 
 real FLAC__lpc_compute_expected_bits_per_residual_sample(real lpc_error, unsigned total_samples)
@@ -210,10 +221,16 @@ real FLAC__lpc_compute_expected_bits_per_residual_sample(real lpc_error, unsigne
 
        escale = 0.5 * M_LN2 * M_LN2 / (real)total_samples;
 
-       if(lpc_error > 0.0)
-               return 0.5 * log(escale * lpc_error) / M_LN2;
-       else
+       if(lpc_error > 0.0) {
+               real bps = 0.5 * log(escale * lpc_error) / M_LN2;
+               if(bps >= 0.0)
+                       return bps;
+               else
+                       return 0.0;
+       }
+       else {
                return 0.0;
+       }
 }
 
 unsigned FLAC__lpc_compute_best_order(const real lpc_error[], unsigned max_order, unsigned total_samples, unsigned bits_per_signal_sample)