From 205172946bdab65de6b07b181bcd2aa3701e2ce9 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Tue, 27 Oct 2026 01:37:23 +0100
Subject: [PATCH] avfilter/wavelet97: expose the per line analysis and
 synthesis

Lets a filter run the row and column passes over ranges of lines, as
slice threading needs.

Assisted-by: Claude
---
 libavfilter/wavelet97.c | 30 +++++++++++++++---------------
 libavfilter/wavelet97.h | 23 ++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/libavfilter/wavelet97.c b/libavfilter/wavelet97.c
index 3a2a52e417..c639b8d596 100644
--- a/libavfilter/wavelet97.c
+++ b/libavfilter/wavelet97.c
@@ -90,13 +90,13 @@ static inline void compose(float *dst, const float *src_l, const float *src_h,
     }
 }
 
-static inline void decompose2D(float *dst_l, float *dst_h, const float *src,
-                               const double coeff[2][5],
-                               int xlinesize, int ylinesize,
-                               int step, int w, int h)
+void ff_wavelet97_decompose_lines(float *dst_l, float *dst_h, const float *src,
+                                  const double coeff[2][5],
+                                  int xlinesize, int ylinesize,
+                                  int step, int w, int line0, int line1)
 {
     int y, x;
-    for (y = 0; y < h; y++)
+    for (y = line0; y < line1; y++)
         for (x = 0; x < step; x++)
             decompose(dst_l + ylinesize*y + xlinesize*x,
                       dst_h + ylinesize*y + xlinesize*x,
@@ -104,12 +104,12 @@ static inline void decompose2D(float *dst_l, float *dst_h, const float *src,
                       coeff, step * xlinesize, (w - x + step - 1) / step);
 }
 
-static inline void compose2D(float *dst, const float *src_l, const float *src_h,
-                             int xlinesize, int ylinesize,
-                             int step, int w, int h)
+void ff_wavelet97_compose_lines(float *dst, const float *src_l, const float *src_h,
+                                int xlinesize, int ylinesize,
+                                int step, int w, int line0, int line1)
 {
     int y, x;
-    for (y = 0; y < h; y++)
+    for (y = line0; y < line1; y++)
         for (x = 0; x < step; x++)
             compose(dst   + ylinesize*y + xlinesize*x,
                     src_l + ylinesize*y + xlinesize*x,
@@ -121,15 +121,15 @@ void ff_wavelet97_decompose(float *dst[4], const float *src, float *temp[2],
                             const double coeff[2][5],
                             int linesize, int step, int w, int h)
 {
-    decompose2D(temp[0], temp[1], src,     coeff, 1, linesize, step, w, h);
-    decompose2D( dst[0],  dst[1], temp[0], coeff, linesize, 1, step, h, w);
-    decompose2D( dst[2],  dst[3], temp[1], coeff, linesize, 1, step, h, w);
+    ff_wavelet97_decompose_lines(temp[0], temp[1], src,     coeff, 1, linesize, step, w, 0, h);
+    ff_wavelet97_decompose_lines( dst[0],  dst[1], temp[0], coeff, linesize, 1, step, h, 0, w);
+    ff_wavelet97_decompose_lines( dst[2],  dst[3], temp[1], coeff, linesize, 1, step, h, 0, w);
 }
 
 void ff_wavelet97_compose(float *dst, float *const src[4], float *temp[2],
                           int linesize, int step, int w, int h)
 {
-    compose2D(temp[0],  src[0],  src[1], linesize, 1, step, h, w);
-    compose2D(temp[1],  src[2],  src[3], linesize, 1, step, h, w);
-    compose2D(dst,     temp[0], temp[1], 1, linesize, step, w, h);
+    ff_wavelet97_compose_lines(temp[0],  src[0],  src[1], linesize, 1, step, h, 0, w);
+    ff_wavelet97_compose_lines(temp[1],  src[2],  src[3], linesize, 1, step, h, 0, w);
+    ff_wavelet97_compose_lines(dst,     temp[0], temp[1], 1, linesize, step, w, 0, h);
 }
diff --git a/libavfilter/wavelet97.h b/libavfilter/wavelet97.h
index 956d841fa5..a8ed9f2034 100644
--- a/libavfilter/wavelet97.h
+++ b/libavfilter/wavelet97.h
@@ -32,7 +32,28 @@
 extern const double ff_wavelet97_coeff[2][5];
 
 /**
- * One level of 2D analysis, filters are mirrored at the plane borders.
+ * Undecimated analysis of lines line0..line1-1 along one direction.
+ * Line y, sample x is at src[y * ylinesize + x * xlinesize], x < w, w >= 2.
+ *
+ * @param dst_l    lowpass output, same layout as src
+ * @param dst_h    highpass output, same layout as src
+ * @param coeff    lowpass and highpass filters, normally ff_wavelet97_coeff
+ * @param step     dilation of the filters, 1 << level
+ */
+void ff_wavelet97_decompose_lines(float *dst_l, float *dst_h, const float *src,
+                                  const double coeff[2][5],
+                                  int xlinesize, int ylinesize,
+                                  int step, int w, int line0, int line1);
+
+/**
+ * Inverse of ff_wavelet97_decompose_lines() with ff_wavelet97_coeff.
+ */
+void ff_wavelet97_compose_lines(float *dst, const float *src_l, const float *src_h,
+                                int xlinesize, int ylinesize,
+                                int step, int w, int line0, int line1);
+
+/**
+ * One level of undecimated 2D analysis, filters are mirrored at the plane borders.
  *
  * @param dst      output bands LL, LH, HL, HH (horizontal/vertical filter)
  * @param src      input plane