From 0bbe264a0c597a5a871ffc2bfea06e717bc9e0a1 Mon Sep 17 00:00:00 2001
From: Lynne <dev@lynne.ee>
Date: Thu, 3 Aug 2023 18:23:02 +0200
Subject: [PATCH 2/2] lavu/tx: add DCT-I and DST-I transforms
These are true, actual DCT-I and DST-I transforms, unlike the
libavcodec versions, which are plainly not.
---
libavutil/tx.h | 24 ++++++++++
libavutil/tx_template.c | 103 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 127 insertions(+)
@@ -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,
};
@@ -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 (0 && 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,
};
--
2.40.1