ref: 4cd3dd31eebaf30c50fe908dcdd44a1ba78f6590
parent: 79afa9c605fa740d0180d34c5ed526deabccfa15
author: Jean-Marc Valin <[email protected]>
date: Thu Jan 27 10:47:15 EST 2011
Comparison tool for decoder compliance
--- /dev/null
+++ b/tools/opus_compare.m
@@ -1,0 +1,79 @@
+%% Tests bit-stream compliance for the Opus codec
+%% x: Signal from the Opus reference implementation (float or fixed)
+%% y: Signal from the decoder under test
+%% stereo: 0 for mono, 1 for stereo
+function [err, NMR] = opus_compare(x, y, stereo)
+
+% Bands on which we compute the pseudo-NMR (Bark-derived CELT bands)
+b = 2*[0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 20, 24, 28, 34, 40, 48, 60, 78, 100];
+d = diff(b);
+
+% Per-band SNR threshold
+T = 50-.7*[1:21];
+
+% Noise floor
+N = 10 .^ ((10-0.6*[1:21])/10);
+
+% Error signal
+e=x-y;
+
+%Add a +/- 1 dead zone on the error
+e = e - min(1, max(-1, e));
+
+% Compute spectrum of original and error
+if (stereo)
+ X=(abs(specgram(x(1:2:end),480))+abs(specgram(x(2:2:end),480)))/2;
+ E=(abs(specgram(e(1:2:end),480))+abs(specgram(e(2:2:end),480)))/2;
+else
+ X=abs(specgram(x,480));
+ E=abs(specgram(e,480));
+endif
+
+% Group energy per band
+for k=1:21
+ Xb(k,:) = sum(X(b(k)+1:b(k+1),:).^2)/d(k)+1;
+ Eb(k,:) = sum(E(b(k)+1:b(k+1),:).^2)/d(k)+1;
+end
+
+% Frequency masking (low to high) with 10 dB/Bark slope
+Xb = filter(1, [1, -.1], Xb);
+% Frequency masking (high to low) with 15 dB/Bark slope
+Xb(end:-1:1,:) = filter(1, [1, -.03], Xb(end:-1:1,:));
+
+% Temporal masking with 5 dB/5 ms slope
+Xb = filter(1, [1, -.3], Xb')';
+
+% NMR threshold
+T0 = ones(length(Eb), 1)*(10.^((T)/10));
+
+% Time-frequency SNR
+NMR = (Xb./Eb)';
+
+%Picking only errors in the 90th percentile
+tmp = Eb(:);
+thresh = sort(tmp)(round(.90*length(tmp)));
+weight = Eb'>thresh;
+
+printf("Average pseudo-NMR: %3.2f dB\n", mean(mean(10*log10(NMR))));+
+if (sum(sum(weight))<1)
+ printf("Mismatch level: below noise floor\n");+ err = -100*ones(size(NMR));
+else
+ M = (T0./NMR) .* weight;
+
+ err = 10*log10(sum(sum(M)) / sum(sum(weight)));
+
+ printf("Weighted mismatch: %3.2f dB\n", err);+endif
+
+printf("\n");+
+if (err < 0)
+ printf("**Decoder PASSES test (mismatch < 0 dB)\n");+else
+ printf("**Decoder FAILS test (mismatch >= 0 dB)\n");+endif
+
+
+