[refactor] reorganize platform and wire sources

apps/desktop/src/common/nv12_scaler.h

@@ -0,0 +1,23 @@
+#ifndef CROSSDESK_COMMON_NV12_SCALER_H_
+#define CROSSDESK_COMMON_NV12_SCALER_H_
+
+#include <cstdint>
+#include <vector>
+
+#include "libyuv/scale.h"
+
+namespace crossdesk {
+
+// Scales NV12 by separating the interleaved chroma plane before filtering.
+// This avoids the downward chroma rounding bias in libyuv::NV12Scale while
+// preserving the requested filtering quality.
+int ScaleNv12ViaI420(const uint8_t* src_y, int src_stride_y,
+                     const uint8_t* src_uv, int src_stride_uv, int src_width,
+                     int src_height, uint8_t* dst_y, int dst_stride_y,
+                     uint8_t* dst_uv, int dst_stride_uv, int dst_width,
+                     int dst_height, libyuv::FilterMode filtering,
+                     std::vector<uint8_t>* scratch_buffer);
+
+}  // namespace crossdesk
+
+#endif  // CROSSDESK_COMMON_NV12_SCALER_H_