[Bf-blender-cvs] [d8578925532] blender-v2.92-release: VSE: Fix proxy images have incorrect size

[Richard Antalik]

Commit: d85789255320fe4e1aca8049a252241f3b8ef540
Author: Richard Antalik
Date:   Mon Feb 1 10:53:27 2021 +0100
Branches: blender-v2.92-release
https://developer.blender.org/rBd85789255320fe4e1aca8049a252241f3b8ef540

VSE: Fix proxy images have incorrect size

This bug happens when media size doesn't match scene size and proxies
are enabled. This is because some strips are rendered in preview size
already -  effects, mask or strips using proxies.
If strip input is prescaled it needs to be known when transforming
images, which does also scaling to preview size as one operation.

whether image needs prescaling is defined in function
`seq_need_scale_to_render_size()`

Problem was introduced in 571362642201. Previously all images were
scaled to fit into preview, and this was considered as baseline for
further image transformation.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D10183

===================================================================

M	source/blender/sequencer/intern/render.c

===================================================================

diff --git a/source/blender/sequencer/intern/render.c b/source/blender/sequencer/intern/render.c
index cd993ae45c1..0ab2a67e560 100644
--- a/source/blender/sequencer/intern/render.c
+++ b/source/blender/sequencer/intern/render.c
@@ -490,6 +490,7 @@ typedef struct ImageTransformThreadInitData {
   StripTransform *transform;
   float scale_to_fit;
   float image_scale_factor;
+  float preview_scale_factor;
   bool for_render;
 } ImageTransformThreadInitData;
 
@@ -498,7 +499,10 @@ typedef struct ImageTransformThreadData {
   ImBuf *ibuf_out;
   StripTransform *transform;
   float scale_to_fit;
+  /* image_scale_factor is used to scale proxies to correct preview size. */
   float image_scale_factor;
+  /* Preview scale factor is needed to correct translation to match preview size. */
+  float preview_scale_factor;
   bool for_render;
   int start_line;
   int tot_line;
@@ -516,6 +520,7 @@ static void sequencer_image_transform_init(void *handle_v,
   handle->ibuf_out = init_data->ibuf_out;
   handle->transform = init_data->transform;
   handle->image_scale_factor = init_data->image_scale_factor;
+  handle->preview_scale_factor = init_data->preview_scale_factor;
   handle->for_render = init_data->for_render;
 
   handle->start_line = start_line;
@@ -528,13 +533,11 @@ static void *sequencer_image_transform_do_thread(void *data_v)
   const StripTransform *transform = data->transform;
   const float scale_x = transform->scale_x * data->image_scale_factor;
   const float scale_y = transform->scale_y * data->image_scale_factor;
-  const float scale_to_fit_offs_x = (data->ibuf_out->x - data->ibuf_source->x) / 2;
-  const float scale_to_fit_offs_y = (data->ibuf_out->y - data->ibuf_source->y) / 2;
-  const float translate_x = transform->xofs * data->image_scale_factor + scale_to_fit_offs_x;
-  const float translate_y = transform->yofs * data->image_scale_factor + scale_to_fit_offs_y;
-  const int width = data->ibuf_out->x;
-  const int height = data->ibuf_out->y;
-  const float pivot[2] = {width / 2 - scale_to_fit_offs_x, height / 2 - scale_to_fit_offs_y};
+  const float image_center_offs_x = (data->ibuf_out->x - data->ibuf_source->x) / 2;
+  const float image_center_offs_y = (data->ibuf_out->y - data->ibuf_source->y) / 2;
+  const float translate_x = transform->xofs * data->preview_scale_factor + image_center_offs_x;
+  const float translate_y = transform->yofs * data->preview_scale_factor + image_center_offs_y;
+  const float pivot[2] = {data->ibuf_source->x / 2, data->ibuf_source->y / 2};
   float transform_matrix[3][3];
   loc_rot_size_to_mat3(transform_matrix,
                        (const float[]){translate_x, translate_y},
@@ -543,6 +546,7 @@ static void *sequencer_image_transform_do_thread(void *data_v)
   invert_m3(transform_matrix);
   transform_pivot_set_m3(transform_matrix, pivot);
 
+  const int width = data->ibuf_out->x;
   for (int yi = data->start_line; yi < data->start_line + data->tot_line; yi++) {
     for (int xi = 0; xi < width; xi++) {
       float uv[2] = {xi, yi};
@@ -595,10 +599,27 @@ static void multibuf(ImBuf *ibuf, const float fmul)
   }
 }
 
+/* Effect, mask and scene in strip input strips are rendered in preview resolution. They are
+ * already downscaled. input_preprocess() does not expect this to happen. Other strip types are
+ * rendered with original media resolution, unless proxies are enabled for them. With proxies
+ * is_proxy_image will be set correctly to true.*/
+static bool seq_need_scale_to_render_size(const Sequence *seq, bool is_proxy_image)
+{
+  if (is_proxy_image) {
+    return true;
+  }
+  if ((seq->type & SEQ_TYPE_EFFECT) != 0 || seq->type == SEQ_TYPE_MASK ||
+      (seq->type == SEQ_TYPE_SCENE && ((seq->flag & SEQ_SCENE_STRIPS) != 0))) {
+    return true;
+  }
+  return false;
+}
+
 static ImBuf *input_preprocess(const SeqRenderData *context,
                                Sequence *seq,
                                float timeline_frame,
-                               ImBuf *ibuf)
+                               ImBuf *ibuf,
+                               const bool is_proxy_image)
 {
   Scene *scene = context->scene;
   ImBuf *preprocessed_ibuf = NULL;
@@ -630,10 +651,15 @@ static ImBuf *input_preprocess(const SeqRenderData *context,
     const int height = ibuf->y;
     const StripCrop *c = seq->strip->crop;
 
-    const int left = c->left;
-    const int right = c->right;
-    const int top = c->top;
-    const int bottom = c->bottom;
+    /* Proxy image is smaller, so crop values must be corrected by proxy scale factor.
+     * Proxy scale factor always matches preview_scale_factor. */
+    const float crop_scale_factor = seq_need_scale_to_render_size(seq, is_proxy_image) ?
+                                        preview_scale_factor :
+                                        1.0f;
+    const int left = c->left * crop_scale_factor;
+    const int right = c->right * crop_scale_factor;
+    const int top = c->top * crop_scale_factor;
+    const int bottom = c->bottom * crop_scale_factor;
     const float col[4] = {0.0f, 0.0f, 0.0f, 0.0f};
 
     /* Left. */
@@ -655,7 +681,13 @@ static ImBuf *input_preprocess(const SeqRenderData *context,
     init_data.ibuf_source = ibuf;
     init_data.ibuf_out = preprocessed_ibuf;
     init_data.transform = seq->strip->transform;
-    init_data.image_scale_factor = preview_scale_factor;
+    if (seq_need_scale_to_render_size(seq, is_proxy_image)) {
+      init_data.image_scale_factor = 1.0f;
+    }
+    else {
+      init_data.image_scale_factor = preview_scale_factor;
+    }
+    init_data.preview_scale_factor = preview_scale_factor;
     init_data.for_render = context->for_render;
     IMB_processor_apply_threaded(context->recty,
                                  sizeof(ImageTransformThreadData),
@@ -734,7 +766,7 @@ static ImBuf *seq_render_preprocess_ibuf(const SeqRenderData *context,
   }
 
   if (use_preprocess) {
-    ibuf = input_preprocess(context, seq, timeline_frame, ibuf);
+    ibuf = input_preprocess(context, seq, timeline_frame, ibuf, is_proxy_image);
   }
 
   seq_cache_put(context, seq, timeline_frame, SEQ_CACHE_STORE_PREPROCESSED, ibuf, false);