GS/HW: Prevent out of bounds copy in OI_BlitFMV()

pcsx2/GS/Renderers/Common/GSTexture.h

@@ -88,6 +88,7 @@ public:
 	int GetWidth() const { return m_size.x; }
 	int GetHeight() const { return m_size.y; }
 	GSVector2i GetSize() const { return m_size; }
+	GSVector4i GetRect() const { return GSVector4i(m_size).zwxy(); }
 	int GetMipmapLevels() const { return m_mipmap_levels; }
 	bool IsMipmap() const { return m_mipmap_levels > 1; }
 

pcsx2/GS/Renderers/HW/GSRendererHW.cpp

@@ -4560,7 +4560,7 @@ bool GSRendererHW::OI_BlitFMV(GSTextureCache::Target* _rt, GSTextureCache::Sourc
 
 		// Copy back the texture into the GS mem. I don't know why but it will be
 		// reuploaded again later
-		m_tc->Read(tex, r_texture);
+		m_tc->Read(tex, r_texture.rintersect(tex->m_texture->GetRect()));
 
 		m_tc->InvalidateVideoMemSubTarget(_rt);
 

pcsx2/GS/Renderers/HW/GSTextureCache.cpp

@@ -2830,6 +2830,9 @@ void GSTextureCache::Read(Target* t, const GSVector4i& r)
 
 void GSTextureCache::Read(Source* t, const GSVector4i& r)
 {
+	if (r.rempty())
+		return;
+
 	const GSVector4i drc(0, 0, r.width(), r.height());
 
 	if (!PrepareDownloadTexture(drc.z, drc.w, GSTexture::Format::Color, &m_color_download_texture))