diff --git a/indra/llimage/llimagej2c.cpp b/indra/llimage/llimagej2c.cpp
index 8c6fe3386..08d1358e7 100644
--- a/indra/llimage/llimagej2c.cpp
+++ b/indra/llimage/llimagej2c.cpp
@@ -363,8 +363,7 @@ S32 LLImageJ2C::calcHeaderSizeJ2C()
 	return FIRST_PACKET_SIZE; // Hack. just needs to be >= actual header size...
 }
 
-//static
-S32 LLImageJ2C::calcDataSizeJ2C(S32 w, S32 h, S32 comp, S32 discard_level, F32 rate)
+static S32 cald_data_size_help(S32 w, S32 h, S32 comp, S32 discard_level, F32 rate)
 {
 	if (rate <= 0.f) rate = .125f;
 	while (discard_level > 0)
@@ -376,10 +375,25 @@ S32 LLImageJ2C::calcDataSizeJ2C(S32 w, S32 h, S32 comp, S32 discard_level, F32 r
 		discard_level--;
 	}
 	S32 bytes = (S32)((F32)(w*h*comp)*rate);
-	//bytes = llmax(bytes, calcHeaderSizeJ2C());
 	return bytes;
 }
 
+
+//static
+S32 LLImageJ2C::calcDataSizeJ2C(S32 w, S32 h, S32 comp, S32 discard_level, F32 rate)
+{
+		static const LLCachedControl<F32> exponent("SianaJ2CSizeExponent", 1.0f);
+		static const LLCachedControl<S32> offset("SianaJ2CSizeOffset", 0);
+		S32 size = cald_data_size_help(w, h, comp, discard_level, rate);
+		S32 size_d0 = cald_data_size_help(w, h, comp, 0, rate);
+
+		llassert_always(size_d0);
+		S32 bytes = pow(size/size_d0, exponent)*size_d0 + offset;
+		bytes = llmax (0, bytes - 600);
+		bytes = ((bytes + (1000 - 1))/1000)*1000 + 600;
+		return bytes;
+}
+
 S32 LLImageJ2C::calcHeaderSize()
 {
 	return calcHeaderSizeJ2C();
@@ -392,15 +406,7 @@ S32 LLImageJ2C::calcDataSize(S32 discard_level)
 	static const LLCachedControl<bool> legacy_size("SianaLegacyJ2CSize", false);
 	
 	if (legacy_size) {
-		static const LLCachedControl<F32> exponent("SianaJ2CSizeExponent", 1.0f);
-		static const LLCachedControl<S32> offset("SianaJ2CSizeOffset", 0);
-		
-		S32 size = calcDataSizeJ2C(getWidth(), getHeight(), getComponents(), discard_level, mRate);
-		S32 size_d0 = calcDataSizeJ2C(getWidth(), getHeight(), getComponents(), 0, mRate);
-		llassert_always(size_d0);
-		S32 bytes = pow(size/size_d0, exponent)*size_d0 + offset;
-		bytes = llmax(bytes, calcHeaderSizeJ2C());
-		return bytes;
+		return calcDataSizeJ2C(getWidth(), getHeight(), getComponents(), discard_level, mRate);
 	}
 
 	discard_level = llclamp(discard_level, 0, MAX_DISCARD_LEVEL);
diff --git a/indra/llimagej2coj/llimagej2coj.cpp b/indra/llimagej2coj/llimagej2coj.cpp
index afcd914f4..d55a3e738 100644
--- a/indra/llimagej2coj/llimagej2coj.cpp
+++ b/indra/llimagej2coj/llimagej2coj.cpp
@@ -149,7 +149,14 @@ BOOL LLImageJ2COJ::decodeImpl(LLImageJ2C &base, LLImageRaw &raw_image, F32 decod
 	opj_setup_decoder(dinfo, &parameters);
 
 	/* open a byte stream */
+#if 0
+	std::vector<U8> data(base.getData(), base.getData()+base.getDataSize());
+	data.push_back((U8)0xFF);
+	data.push_back((U8)0xD9);
+	cio = opj_cio_open((opj_common_ptr)dinfo, &data[0], data.size());
+#else
 	cio = opj_cio_open((opj_common_ptr)dinfo, base.getData(), base.getDataSize());
+#endif
 
 	/* decode the stream and fill the image structure */
 	image = opj_decode(dinfo, cio);
diff --git a/indra/newview/app_settings/settings.xml b/indra/newview/app_settings/settings.xml
index 2ecbfbb56..f14115db6 100644
--- a/indra/newview/app_settings/settings.xml
+++ b/indra/newview/app_settings/settings.xml
@@ -287,7 +287,7 @@
 		<key>Type</key>
 		<string>F32</string>
 		<key>Value</key>
-		<real>0.5</real>
+		<real>1.0</real>
 	</map>
 	<key>SianaJ2CSizeOffset</key>
 	<map>