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lavu/tx: add DCT-I and DST-I transforms

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These are true, actual DCT-I and DST-I transforms, unlike the
libavcodec versions, which are plainly not.
This commit is contained in:
Lynne 2023-08-03 18:23:02 +02:00
parent 11e22730e1
commit ef8fd7bc3c
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2 changed files with 127 additions and 0 deletions
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24
libavutil/tx.h
View File

@ -105,6 +105,30 @@ enum AVTXType {
AV_TX_DOUBLE_DCT = 10,
AV_TX_INT32_DCT = 11,
/**
* Discrete Cosine Transform I
*
* The forward transform is a DCT-I.
* The inverse transform is a DCT-I multiplied by 2/(N + 1).
*
* The input array is always overwritten.
*/
AV_TX_FLOAT_DCT_I = 12,
AV_TX_DOUBLE_DCT_I = 13,
AV_TX_INT32_DCT_I = 14,
/**
* Discrete Sine Transform I
*
* The forward transform is a DST-I.
* The inverse transform is a DST-I multiplied by 2/(N + 1).
*
* The input array is always overwritten.
*/
AV_TX_FLOAT_DST_I = 15,
AV_TX_DOUBLE_DST_I = 16,
AV_TX_INT32_DST_I = 17,
/* Not part of the API, do not use */
AV_TX_NB,
};

103
libavutil/tx_template.c
View File

@ -2004,6 +2004,107 @@ static const FFTXCodelet TX_NAME(ff_tx_dctIII_def) = {
.prio = FF_TX_PRIO_BASE,
};
static av_cold int TX_NAME(ff_tx_dcstI_init)(AVTXContext *s,
const FFTXCodelet *cd,
uint64_t flags,
FFTXCodeletOptions *opts,
int len, int inv,
const void *scale)
{
int ret;
SCALE_TYPE rsc = *((SCALE_TYPE *)scale);
if (inv) {
len *= 2;
s->len *= 2;
rsc *= 0.5;
}
/* We want a half-complex RDFT */
flags |= cd->type == TX_TYPE(DCT_I) ? AV_TX_REAL_TO_REAL :
AV_TX_REAL_TO_IMAGINARY;
if ((ret = ff_tx_init_subtx(s, TX_TYPE(RDFT), flags, NULL,
(len - 1 + 2*(cd->type == TX_TYPE(DST_I)))*2,
0, &rsc)))
return ret;
s->tmp = av_mallocz((len + 1)*2*sizeof(TXSample));
if (!s->tmp)
return AVERROR(ENOMEM);
return 0;
}
static void TX_NAME(ff_tx_dctI)(AVTXContext *s, void *_dst,
void *_src, ptrdiff_t stride)
{
TXSample *dst = _dst;
TXSample *src = _src;
const int len = s->len - 1;
TXSample *tmp = (TXSample *)s->tmp;
stride /= sizeof(TXSample);
for (int i = 0; i < len; i++)
tmp[i] = tmp[2*len - i] = src[i * stride];
tmp[len] = src[len * stride]; /* Middle */
s->fn[0](&s->sub[0], dst, tmp, sizeof(TXSample));
}
static void TX_NAME(ff_tx_dstI)(AVTXContext *s, void *_dst,
void *_src, ptrdiff_t stride)
{
TXSample *dst = _dst;
TXSample *src = _src;
const int len = s->len + 1;
TXSample *tmp = (void *)s->tmp;
stride /= sizeof(TXSample);
tmp[0] = 0;
for (int i = 1; i < len; i++) {
TXSample a = src[(i - 1) * stride];
tmp[i] = -a;
tmp[2*len - i] = a;
}
tmp[len] = 0; /* i == n, Nyquist */
s->fn[0](&s->sub[0], dst, tmp, sizeof(float));
}
static const FFTXCodelet TX_NAME(ff_tx_dctI_def) = {
.name = TX_NAME_STR("dctI"),
.function = TX_NAME(ff_tx_dctI),
.type = TX_TYPE(DCT_I),
.flags = AV_TX_UNALIGNED | AV_TX_INPLACE | FF_TX_OUT_OF_PLACE,
.factors = { 2, TX_FACTOR_ANY },
.nb_factors = 2,
.min_len = 2,
.max_len = TX_LEN_UNLIMITED,
.init = TX_NAME(ff_tx_dcstI_init),
.cpu_flags = FF_TX_CPU_FLAGS_ALL,
.prio = FF_TX_PRIO_BASE,
};
static const FFTXCodelet TX_NAME(ff_tx_dstI_def) = {
.name = TX_NAME_STR("dstI"),
.function = TX_NAME(ff_tx_dstI),
.type = TX_TYPE(DST_I),
.flags = AV_TX_UNALIGNED | AV_TX_INPLACE | FF_TX_OUT_OF_PLACE,
.factors = { 2, TX_FACTOR_ANY },
.nb_factors = 2,
.min_len = 2,
.max_len = TX_LEN_UNLIMITED,
.init = TX_NAME(ff_tx_dcstI_init),
.cpu_flags = FF_TX_CPU_FLAGS_ALL,
.prio = FF_TX_PRIO_BASE,
};
int TX_TAB(ff_tx_mdct_gen_exp)(AVTXContext *s, int *pre_tab)
{
int off = 0;
@ -2101,6 +2202,8 @@ const FFTXCodelet * const TX_NAME(ff_tx_codelet_list)[] = {
&TX_NAME(ff_tx_rdft_c2r_def),
&TX_NAME(ff_tx_dctII_def),
&TX_NAME(ff_tx_dctIII_def),
&TX_NAME(ff_tx_dctI_def),
&TX_NAME(ff_tx_dstI_def),
NULL,
};