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qtblend: introduce a flag to avoid double PAR normalization and add a difensive fallback #1277

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Merged
ddennedy merged 2 commits into from
Aug 5, 2026
+19 −6
Merged

qtblend: introduce a flag to avoid double PAR normalization and add a difensive fallback #1277

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ec8e65d
qtblend: introduce a flag to avoid double PAR normalization and add a…
guiodic Aug 2, 2026
ab014fd
fix clang-format error, even though I hate it
guiodic Aug 2, 2026
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25 changes: 19 additions & 6 deletions src/modules/qt/transition_qtblend.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,9 @@ static int get_image(mlt_frame a_frame,
int b_height = mlt_properties_get_int(b_properties, "meta.media.height");
int normalized_width = profile->width;
int normalized_height = profile->height;
// Flag to avoid applying PAR normalization twice: set true whenever we
// intentionally set b_width/b_height to consumer/profile/requested values.
bool parAlreadyNormalized = false;

// reference rect
mlt_rect rect = {0, 0, (double) normalized_width, (double) normalized_height, 1.0};
Expand All @@ -87,6 +90,7 @@ static int get_image(mlt_frame a_frame,
if (b_height == 0) {
b_width = *width;
b_height = *height;
parAlreadyNormalized = true;
}
// Special case - aspect_ratio = 0
if (mlt_frame_get_aspect_ratio(b_frame) == 0) {
Expand All @@ -112,6 +116,7 @@ static int get_image(mlt_frame a_frame,
}
b_width = *width;
b_height = *height;
parAlreadyNormalized = true;
}

if (mlt_properties_get(transition_properties, "rect")) {
Expand All @@ -127,6 +132,7 @@ static int get_image(mlt_frame a_frame,
// Optimization, request profile sized image
b_width = normalized_width;
b_height = normalized_height;
parAlreadyNormalized = true;
}
int request_width = *width;
int request_height = *height;
Expand Down Expand Up @@ -159,16 +165,23 @@ static int get_image(mlt_frame a_frame,
// we will process operations on top frame, so also process b_frame
forceAlpha = true;
}

// Defensive default: if for some reason b_width/b_height were left unset or became
// non-positive earlier, fall back to requesting the profile-sized image.
if (b_width <= 0 || b_height <= 0) {
b_width = normalized_width;
b_height = normalized_height;
parAlreadyNormalized = true;
}

// Ensure we don't request an image with a 0 width or height
b_width = qMax(1, b_width);
b_height = qMax(1, b_height);
/*} else {
b_height = *height;
b_width = *width;
}*/

// Normalize source dimensions to consumer PAR to handle anamorphic sources
normalize_mlt_source_size(b_ar, consumer_ar, &b_width, b_height);
// If we didn't before, normalize source dimensions to consumer PAR to handle anamorphic sources
if (!parAlreadyNormalized) {
normalize_mlt_source_size(b_ar, consumer_ar, &b_width, b_height);
}

// Fix for bug #1228 and optimization.
// Adjust requested dimension so MLT (libswscale) does the preliminary downscaling.
Expand Down
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