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TAV fix 13/7 wavelet not decoding correctly

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minjaesong
2025-12-18 20:09:06 +09:00
parent 629ed5fb12
commit c71920b95d
3 changed files with 180 additions and 57 deletions
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23
video_encoder/lib/libtavdec/tav_video_decoder.c
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@@ -800,6 +800,8 @@ static void dwt_53_inverse_1d(float *data, int length) {
static void dwt_cdf137_inverse_1d(float *data, int length) {
if (length < 2) return;
const float K = 1.230174105f; // Same scaling factor as encoder
float *temp = malloc(sizeof(float) * length);
int half = (length + 1) / 2;
@@ -817,15 +819,26 @@ static void dwt_cdf137_inverse_1d(float *data, int length) {
odd[i] = data[half + i];
}
// Inverse update
// Undo scaling (reverse of encoder: low-pass /= K, high-pass *= K)
for (int i = 0; i < nE; i++) {
float d = (i < nO) ? odd[i] : 0.0f;
even[i] = even[i] - 0.25f * d;
even[i] /= K;
}
for (int i = 0; i < nO; i++) {
odd[i] *= K;
}
// Inverse predict
// Inverse update: undo even[i] += 0.25 * (odd[i-1] + odd[i])
for (int i = 0; i < nE; i++) {
float oddPrev = (i > 0) ? odd[i - 1] : 0.0f;
float oddCurr = (i < nE - 1 && i < nO) ? odd[i] : 0.0f;
even[i] -= 0.25f * (oddPrev + oddCurr);
}
// Inverse predict: undo odd[i] = data[odd] - 0.5 * (even[i] + even[i+1])
for (int i = 0; i < nO; i++) {
odd[i] = odd[i] + 0.5f * even[i];
float evenLeft = even[i];
float evenRight = (i + 1 < nE) ? even[i + 1] : even[i];
odd[i] += 0.5f * (evenLeft + evenRight);
}
// Interleave