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avfft: avoid overreads with RDFT API users 

The new API requires an extra array member at the very end,
which old API users did not do.

This disables in-place RDFT transforms and instead
does the transform out of place by copying once, there shouldn't
be a significant loss of speed as our in-place FFT requires a reorder
which is likely more expensive in the majority of cases to do.
This commit is contained in:
Lynne 2024-02-09 18:17:54 +01:00
parent ce7c90ff82
commit 90adef99ca
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GPG Key ID: A2FEA5F03F034464
1 changed files with 25 additions and 6 deletions
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31
libavcodec/avfft.c
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@ -152,7 +152,7 @@ RDFTContext *av_rdft_init(int nbits, enum RDFTransformType trans)
return NULL;
ret = av_tx_init(&s->ctx, &s->fn, AV_TX_FLOAT_RDFT, trans == IDFT_C2R,
1 << nbits, &scale, AV_TX_INPLACE);
1 << nbits, &scale, 0x0);
if (ret < 0) {
av_free(s);
return NULL;
@ -162,17 +162,35 @@ RDFTContext *av_rdft_init(int nbits, enum RDFTransformType trans)
s->len = 1 << nbits;
s->inv = trans == IDFT_C2R;
s->tmp = av_malloc((s->len + 2)*sizeof(float));
if (!s->tmp) {
av_tx_uninit(&s->ctx);
av_free(s);
return NULL;
}
return (RDFTContext *)s;
}
void av_rdft_calc(RDFTContext *s, FFTSample *data)
{
AVTXWrapper *w = (AVTXWrapper *)s;
if (w->inv)
FFSWAP(float, data[1], data[w->len]);
w->fn(w->ctx, data, (void *)data, w->stride);
if (!w->inv)
FFSWAP(float, data[1], data[w->len]);
float *src = w->inv ? w->tmp : (float *)data;
float *dst = w->inv ? (float *)data : w->tmp;
if (w->inv) {
memcpy(src, data, w->len*sizeof(float));
src[w->len] = src[1];
src[1] = 0.0f;
}
w->fn(w->ctx, dst, (void *)src, w->stride);
if (!w->inv) {
dst[1] = dst[w->len];
memcpy(data, dst, w->len*sizeof(float));
}
}
av_cold void av_rdft_end(RDFTContext *s)
@ -180,6 +198,7 @@ av_cold void av_rdft_end(RDFTContext *s)
if (s) {
AVTXWrapper *w = (AVTXWrapper *)s;
av_tx_uninit(&w->ctx);
av_free(w->tmp);
av_free(w);
}
}