From e54775cc93ceb27d9faabe1ddf9b1eacb269826b Mon Sep 17 00:00:00 2001
From: Lynne <dev@lynne.ee>
Date: Sat, 24 Sep 2022 01:05:19 +0200
Subject: [PATCH 3/6] ac3: convert encoder and decoder to lavu/tx

The fixed-point transforms are much better, faster, and more accurate.
---
 libavcodec/ac3dec.c          | 22 +++++++++++++---------
 libavcodec/ac3dec.h          |  6 +++---
 libavcodec/ac3dec_fixed.c    |  3 ++-
 libavcodec/ac3dec_float.c    |  1 +
 libavcodec/ac3enc.c          |  2 +-
 libavcodec/ac3enc.h          |  7 ++++---
 libavcodec/ac3enc_fixed.c    | 19 ++++---------------
 libavcodec/ac3enc_float.c    | 18 +++---------------
 libavcodec/ac3enc_template.c |  4 ++--
 9 files changed, 33 insertions(+), 49 deletions(-)

diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
index aba8e0fb7f..cd3320caa0 100644
--- a/libavcodec/ac3dec.c
+++ b/libavcodec/ac3dec.c
@@ -217,13 +217,17 @@ static av_cold int ac3_decode_init(AVCodecContext *avctx)
 {
     static AVOnce init_static_once = AV_ONCE_INIT;
     AC3DecodeContext *s = avctx->priv_data;
+    const float scale = 1.0f;
     int i, ret;
 
     s->avctx = avctx;
 
-    if ((ret = ff_mdct_init(&s->imdct_256, 8, 1, 1.0)) < 0 ||
-        (ret = ff_mdct_init(&s->imdct_512, 9, 1, 1.0)) < 0)
+    if ((ret = av_tx_init(&s->tx_128, &s->tx_fn_128, IMDCT_TYPE, 1, 128, &scale, 0)))
         return ret;
+
+    if ((ret = av_tx_init(&s->tx_256, &s->tx_fn_256, IMDCT_TYPE, 1, 256, &scale, 0)))
+        return ret;
+
     AC3_RENAME(ff_kbd_window_init)(s->window, 5.0, 256);
     ff_bswapdsp_init(&s->bdsp);
 
@@ -721,10 +725,10 @@ static inline void do_imdct(AC3DecodeContext *s, int channels, int offset)
     for (ch = 1; ch <= channels; ch++) {
         if (s->block_switch[ch]) {
             int i;
-            FFTSample *x = s->tmp_output + 128;
+            INTFLOAT *x = s->tmp_output + 128;
             for (i = 0; i < 128; i++)
                 x[i] = s->transform_coeffs[ch][2 * i];
-            s->imdct_256.imdct_half(&s->imdct_256, s->tmp_output, x);
+            s->tx_fn_128(s->tx_128, s->tmp_output, x, sizeof(INTFLOAT));
 #if USE_FIXED
             s->fdsp->vector_fmul_window_scaled(s->outptr[ch - 1], s->delay[ch - 1 + offset],
                                        s->tmp_output, s->window, 128, 8);
@@ -734,9 +738,9 @@ static inline void do_imdct(AC3DecodeContext *s, int channels, int offset)
 #endif
             for (i = 0; i < 128; i++)
                 x[i] = s->transform_coeffs[ch][2 * i + 1];
-            s->imdct_256.imdct_half(&s->imdct_256, s->delay[ch - 1 + offset], x);
+            s->tx_fn_256(s->tx_256, s->delay[ch - 1 + offset], x, sizeof(INTFLOAT));
         } else {
-            s->imdct_512.imdct_half(&s->imdct_512, s->tmp_output, s->transform_coeffs[ch]);
+            s->tx_fn_256(s->tx_256, s->tmp_output, s->transform_coeffs[ch], sizeof(INTFLOAT));
 #if USE_FIXED
             s->fdsp->vector_fmul_window_scaled(s->outptr[ch - 1], s->delay[ch - 1 + offset],
                                        s->tmp_output, s->window, 128, 8);
@@ -744,7 +748,7 @@ static inline void do_imdct(AC3DecodeContext *s, int channels, int offset)
             s->fdsp->vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1 + offset],
                                        s->tmp_output, s->window, 128);
 #endif
-            memcpy(s->delay[ch - 1 + offset], s->tmp_output + 128, 128 * sizeof(FFTSample));
+            memcpy(s->delay[ch - 1 + offset], s->tmp_output + 128, 128 * sizeof(INTFLOAT));
         }
     }
 }
@@ -1865,8 +1869,8 @@ skip:
 static av_cold int ac3_decode_end(AVCodecContext *avctx)
 {
     AC3DecodeContext *s = avctx->priv_data;
-    ff_mdct_end(&s->imdct_512);
-    ff_mdct_end(&s->imdct_256);
+    av_tx_uninit(&s->tx_256);
+    av_tx_uninit(&s->tx_128);
     av_freep(&s->fdsp);
     av_freep(&s->downmix_coeffs[0]);
 
diff --git a/libavcodec/ac3dec.h b/libavcodec/ac3dec.h
index 88651ae61f..138b462abb 100644
--- a/libavcodec/ac3dec.h
+++ b/libavcodec/ac3dec.h
@@ -50,6 +50,7 @@
 #ifndef AVCODEC_AC3DEC_H
 #define AVCODEC_AC3DEC_H
 
+#include "libavutil/tx.h"
 #include "libavutil/float_dsp.h"
 #include "libavutil/fixed_dsp.h"
 #include "libavutil/lfg.h"
@@ -60,7 +61,6 @@
 #include "avcodec.h"
 #include "bswapdsp.h"
 #include "get_bits.h"
-#include "fft.h"
 #include "fmtconvert.h"
 
 #define AC3_OUTPUT_LFEON  8
@@ -223,8 +223,8 @@ typedef struct AC3DecodeContext {
 
 ///@name IMDCT
     int block_switch[AC3_MAX_CHANNELS];     ///< block switch flags                     (blksw)
-    FFTContext imdct_512;                   ///< for 512 sample IMDCT
-    FFTContext imdct_256;                   ///< for 256 sample IMDCT
+    AVTXContext *tx_128, *tx_256;
+    av_tx_fn tx_fn_128, tx_fn_256;
 ///@}
 
 ///@name Optimization
diff --git a/libavcodec/ac3dec_fixed.c b/libavcodec/ac3dec_fixed.c
index 0a7ae6cfbf..c9e5cda69c 100644
--- a/libavcodec/ac3dec_fixed.c
+++ b/libavcodec/ac3dec_fixed.c
@@ -47,11 +47,12 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#define FFT_FLOAT 0
 #define USE_FIXED 1
 #include "ac3dec.h"
 #include "codec_internal.h"
+#define IMDCT_TYPE AV_TX_INT32_MDCT
 
+#include "ac3dec.h"
 
 static const int end_freq_inv_tab[8] =
 {
diff --git a/libavcodec/ac3dec_float.c b/libavcodec/ac3dec_float.c
index 8c1adb3e01..b8868d8ee1 100644
--- a/libavcodec/ac3dec_float.c
+++ b/libavcodec/ac3dec_float.c
@@ -29,6 +29,7 @@
  */
 
 #include "config_components.h"
+#define IMDCT_TYPE AV_TX_FLOAT_MDCT
 
 #include "ac3dec.h"
 #include "codec_internal.h"
diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index a090576823..fbedf40d20 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -2203,7 +2203,7 @@ av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
         av_freep(&block->cpl_coord_mant);
     }
 
-    s->mdct_end(s);
+    av_tx_uninit(&s->tx);
 
     return 0;
 }
diff --git a/libavcodec/ac3enc.h b/libavcodec/ac3enc.h
index f0dc006759..55e88d69e4 100644
--- a/libavcodec/ac3enc.h
+++ b/libavcodec/ac3enc.h
@@ -31,12 +31,13 @@
 #include <stdint.h>
 
 #include "libavutil/opt.h"
+#include "libavutil/tx.h"
+
 #include "ac3.h"
 #include "ac3defs.h"
 #include "ac3dsp.h"
 #include "avcodec.h"
 #include "codec_internal.h"
-#include "fft.h"
 #include "mathops.h"
 #include "me_cmp.h"
 #include "put_bits.h"
@@ -167,7 +168,8 @@ typedef struct AC3EncodeContext {
 #endif
     MECmpContext mecc;
     AC3DSPContext ac3dsp;                   ///< AC-3 optimized functions
-    FFTContext mdct;                        ///< FFT context for MDCT calculation
+    AVTXContext *tx;                        ///< FFT context for MDCT calculation
+    av_tx_fn tx_fn;
     const SampleType *mdct_window;          ///< MDCT window function array
 
     AC3Block blocks[AC3_MAX_BLOCKS];        ///< per-block info
@@ -257,7 +259,6 @@ typedef struct AC3EncodeContext {
     int warned_alternate_bitstream;
 
     /* fixed vs. float function pointers */
-    void (*mdct_end)(struct AC3EncodeContext *s);
     int  (*mdct_init)(struct AC3EncodeContext *s);
 
     /* fixed vs. float templated function pointers */
diff --git a/libavcodec/ac3enc_fixed.c b/libavcodec/ac3enc_fixed.c
index a22d3b4abf..76e5392733 100644
--- a/libavcodec/ac3enc_fixed.c
+++ b/libavcodec/ac3enc_fixed.c
@@ -27,7 +27,7 @@
  */
 
 #define AC3ENC_FLOAT 0
-#define FFT_FLOAT 0
+#include "internal.h"
 #include "audiodsp.h"
 #include "ac3enc.h"
 #include "codec_internal.h"
@@ -66,20 +66,8 @@ static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
     }
 }
 
-
 #include "ac3enc_template.c"
 
-
-/**
- * Finalize MDCT and free allocated memory.
- *
- * @param s  AC-3 encoder private context
- */
-static av_cold void ac3_fixed_mdct_end(AC3EncodeContext *s)
-{
-    ff_mdct_end(&s->mdct);
-}
-
 /**
  * Initialize MDCT tables.
  *
@@ -89,6 +77,7 @@ static av_cold void ac3_fixed_mdct_end(AC3EncodeContext *s)
 static av_cold int ac3_fixed_mdct_init(AC3EncodeContext *s)
 {
     float fwin[AC3_BLOCK_SIZE];
+    const float scale = -1.0f;
 
     int32_t *iwin = av_malloc_array(AC3_BLOCK_SIZE, sizeof(*iwin));
     if (!iwin)
@@ -104,7 +93,8 @@ static av_cold int ac3_fixed_mdct_init(AC3EncodeContext *s)
     if (!s->fdsp)
         return AVERROR(ENOMEM);
 
-    return ff_mdct_init(&s->mdct, 9, 0, -1.0);
+    return av_tx_init(&s->tx, &s->tx_fn, AV_TX_INT32_MDCT, 0,
+                      AC3_BLOCK_SIZE, &scale, 0);
 }
 
 
@@ -112,7 +102,6 @@ static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx)
 {
     AC3EncodeContext *s = avctx->priv_data;
     s->fixed_point = 1;
-    s->mdct_end                = ac3_fixed_mdct_end;
     s->mdct_init               = ac3_fixed_mdct_init;
     s->allocate_sample_buffers = allocate_sample_buffers;
     return ff_ac3_encode_init(avctx);
diff --git a/libavcodec/ac3enc_float.c b/libavcodec/ac3enc_float.c
index 6238980690..8a3f605b48 100644
--- a/libavcodec/ac3enc_float.c
+++ b/libavcodec/ac3enc_float.c
@@ -75,21 +75,8 @@ static void sum_square_butterfly(AC3EncodeContext *s, float sum[4],
     s->ac3dsp.sum_square_butterfly_float(sum, coef0, coef1, len);
 }
 
-
 #include "ac3enc_template.c"
 
-
-/**
- * Finalize MDCT and free allocated memory.
- *
- * @param s  AC-3 encoder private context
- */
-static av_cold void ac3_float_mdct_end(AC3EncodeContext *s)
-{
-    ff_mdct_end(&s->mdct);
-}
-
-
 /**
  * Initialize MDCT tables.
  *
@@ -98,6 +85,7 @@ static av_cold void ac3_float_mdct_end(AC3EncodeContext *s)
  */
 static av_cold int ac3_float_mdct_init(AC3EncodeContext *s)
 {
+    const float scale = -2.0 / AC3_WINDOW_SIZE;
     float *window = av_malloc_array(AC3_BLOCK_SIZE, sizeof(*window));
     if (!window) {
         av_log(s->avctx, AV_LOG_ERROR, "Cannot allocate memory.\n");
@@ -107,14 +95,14 @@ static av_cold int ac3_float_mdct_init(AC3EncodeContext *s)
     ff_kbd_window_init(window, 5.0, AC3_BLOCK_SIZE);
     s->mdct_window = window;
 
-    return ff_mdct_init(&s->mdct, 9, 0, -2.0 / AC3_WINDOW_SIZE);
+    return av_tx_init(&s->tx, &s->tx_fn, AV_TX_FLOAT_MDCT, 0,
+                      AC3_BLOCK_SIZE, &scale, 0);
 }
 
 
 av_cold int ff_ac3_float_encode_init(AVCodecContext *avctx)
 {
     AC3EncodeContext *s = avctx->priv_data;
-    s->mdct_end                = ac3_float_mdct_end;
     s->mdct_init               = ac3_float_mdct_init;
     s->allocate_sample_buffers = allocate_sample_buffers;
     s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
diff --git a/libavcodec/ac3enc_template.c b/libavcodec/ac3enc_template.c
index de66964d0d..be4ecebc9c 100644
--- a/libavcodec/ac3enc_template.c
+++ b/libavcodec/ac3enc_template.c
@@ -98,8 +98,8 @@ static void apply_mdct(AC3EncodeContext *s)
                                          &input_samples[AC3_BLOCK_SIZE],
                                          s->mdct_window, AC3_BLOCK_SIZE);
 
-            s->mdct.mdct_calc(&s->mdct, block->mdct_coef[ch+1],
-                              s->windowed_samples);
+            s->tx_fn(s->tx, block->mdct_coef[ch+1],
+                     s->windowed_samples, sizeof(float));
         }
     }
 }
-- 
2.37.2.609.g9ff673ca1a

