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avcodec/vc2enc_dwt: avoid signed overflow in the 5/3 and Haar DWT

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Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer
2026-06-06 19:07:39 +00:00
committed by michaelni
parent 5f91556215
commit 7c7ca349bc
1 changed files with 17 additions and 17 deletions
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libavcodec/vc2enc_dwt.c
+17 -17
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@@ -141,7 +141,7 @@ static void vc2_subband_dwt_53(VC2TransformContext *t, dwtcoef *data,
ptrdiff_t stride, int width, int height)
{
int x, y;
dwtcoef *synth = t->buffer, *synthl = synth, *datal = data;
uint32_t *synth = (uint32_t *)t->buffer, *synthl = synth, *datal = (uint32_t *)data;
const ptrdiff_t synth_width = width << 1;
const ptrdiff_t synth_height = height << 1;
@@ -161,16 +161,16 @@ static void vc2_subband_dwt_53(VC2TransformContext *t, dwtcoef *data,
for (y = 0; y < synth_height; y++) {
/* Lifting stage 2. */
for (x = 0; x < width - 1; x++)
synthl[2 * x + 1] -= (synthl[2 * x] + synthl[2 * x + 2] + 1) >> 1;
synthl[2 * x + 1] -= (dwtcoef)(synthl[2 * x] + synthl[2 * x + 2] + 1) >> 1;
synthl[synth_width - 1] -= (2*synthl[synth_width - 2] + 1) >> 1;
synthl[synth_width - 1] -= (dwtcoef)(2*synthl[synth_width - 2] + 1) >> 1;
/* Lifting stage 1. */
synthl[0] += (2*synthl[1] + 2) >> 2;
synthl[0] += (dwtcoef)(2*synthl[1] + 2) >> 2;
for (x = 1; x < width - 1; x++)
synthl[2 * x] += (synthl[2 * x - 1] + synthl[2 * x + 1] + 2) >> 2;
synthl[2 * x] += (dwtcoef)(synthl[2 * x - 1] + synthl[2 * x + 1] + 2) >> 2;
synthl[synth_width - 2] += (synthl[synth_width - 3] + synthl[synth_width - 1] + 2) >> 2;
synthl[synth_width - 2] += (dwtcoef)(synthl[synth_width - 3] + synthl[synth_width - 1] + 2) >> 2;
synthl += synth_width;
}
@@ -178,37 +178,37 @@ static void vc2_subband_dwt_53(VC2TransformContext *t, dwtcoef *data,
/* Vertical synthesis: Lifting stage 2. */
synthl = synth + synth_width;
for (x = 0; x < synth_width; x++)
synthl[x] -= (synthl[x - synth_width] + synthl[x + synth_width] + 1) >> 1;
synthl[x] -= (dwtcoef)(synthl[x - synth_width] + synthl[x + synth_width] + 1) >> 1;
synthl = synth + (synth_width << 1);
for (y = 1; y < height - 1; y++) {
for (x = 0; x < synth_width; x++)
synthl[x + synth_width] -= (synthl[x] + synthl[x + synth_width * 2] + 1) >> 1;
synthl[x + synth_width] -= (dwtcoef)(synthl[x] + synthl[x + synth_width * 2] + 1) >> 1;
synthl += (synth_width << 1);
}
synthl = synth + (synth_height - 1) * synth_width;
for (x = 0; x < synth_width; x++)
synthl[x] -= (2*synthl[x - synth_width] + 1) >> 1;
synthl[x] -= (dwtcoef)(2*synthl[x - synth_width] + 1) >> 1;
/* Vertical synthesis: Lifting stage 1. */
synthl = synth;
for (x = 0; x < synth_width; x++)
synthl[x] += (2*synthl[synth_width + x] + 2) >> 2;
synthl[x] += (dwtcoef)(2*synthl[synth_width + x] + 2) >> 2;
synthl = synth + (synth_width << 1);
for (y = 1; y < height - 1; y++) {
for (x = 0; x < synth_width; x++)
synthl[x] += (synthl[x + synth_width] + synthl[x - synth_width] + 2) >> 2;
synthl[x] += (dwtcoef)(synthl[x + synth_width] + synthl[x - synth_width] + 2) >> 2;
synthl += (synth_width << 1);
}
synthl = synth + (synth_height - 2)*synth_width;
for (x = 0; x < synth_width; x++)
synthl[x] += (synthl[x - synth_width] + synthl[x + synth_width] + 2) >> 2;
synthl[x] += (dwtcoef)(synthl[x - synth_width] + synthl[x + synth_width] + 2) >> 2;
deinterleave(data, stride, width, height, synth);
deinterleave(data, stride, width, height, (dwtcoef *)synth);
}
static av_always_inline void dwt_haar(VC2TransformContext *t, dwtcoef *data,
@@ -216,7 +216,7 @@ static av_always_inline void dwt_haar(VC2TransformContext *t, dwtcoef *data,
const int s)
{
int x, y;
dwtcoef *synth = t->buffer, *synthl = synth, *datal = data;
uint32_t *synth = (uint32_t *)t->buffer, *synthl = synth, *datal = (uint32_t *)data;
const ptrdiff_t synth_width = width << 1;
const ptrdiff_t synth_height = height << 1;
@@ -225,7 +225,7 @@ static av_always_inline void dwt_haar(VC2TransformContext *t, dwtcoef *data,
for (x = 0; x < synth_width; x += 2) {
synthl[y*synth_width + x + 1] = (datal[y*stride + x + 1] - datal[y*stride + x]) * (1 << s);
synthl[y*synth_width + x] = datal[y*stride + x + 0] * (1 << s) +
((synthl[y*synth_width + x + 1] + 1) >> 1);
((dwtcoef)(synthl[y*synth_width + x + 1] + 1) >> 1);
}
}
@@ -235,11 +235,11 @@ static av_always_inline void dwt_haar(VC2TransformContext *t, dwtcoef *data,
synthl[(y + 1)*synth_width + x] = synthl[(y + 1)*synth_width + x] -
synthl[y*synth_width + x];
synthl[y*synth_width + x] = synthl[y*synth_width + x] +
((synthl[(y + 1)*synth_width + x] + 1) >> 1);
((dwtcoef)(synthl[(y + 1)*synth_width + x] + 1) >> 1);
}
}
deinterleave(data, stride, width, height, synth);
deinterleave(data, stride, width, height, (dwtcoef *)synth);
}
static void vc2_subband_dwt_haar(VC2TransformContext *t, dwtcoef *data,