diff --git a/media/libstagefright/id3/ID3.cpp b/media/libstagefright/id3/ID3.cpp
index 425468f..e97f6eb 100644
--- a/media/libstagefright/id3/ID3.cpp
+++ b/media/libstagefright/id3/ID3.cpp
@@ -107,20 +107,6 @@
     }
 }
 
-ID3::ID3(DataSourceBase *source, bool ignoreV1, off64_t offset)
-    : mIsValid(false),
-      mData(NULL),
-      mSize(0),
-      mFirstFrameOffset(0),
-      mVersion(ID3_UNKNOWN),
-      mRawSize(0) {
-    mIsValid = parseV2(source, offset);
-
-    if (!mIsValid && !ignoreV1) {
-        mIsValid = parseV1(source);
-    }
-}
-
 ID3::ID3(const uint8_t *data, size_t size, bool ignoreV1)
     : mIsValid(false),
       mData(NULL),
@@ -247,44 +233,14 @@
         return false;
     }
 
-    if (header.version_major == 4) {
-        void *copy = malloc(size);
-        if (copy == NULL) {
-            free(mData);
-            mData = NULL;
-            ALOGE("b/24623447, no more memory");
-            return false;
-        }
-
-        memcpy(copy, mData, size);
-
-        bool success = removeUnsynchronizationV2_4(false /* iTunesHack */);
-        if (!success) {
-            memcpy(mData, copy, size);
-            mSize = size;
-
-            success = removeUnsynchronizationV2_4(true /* iTunesHack */);
-
-            if (success) {
-                ALOGV("Had to apply the iTunes hack to parse this ID3 tag");
-            }
-        }
-
-        free(copy);
-        copy = NULL;
-
-        if (!success) {
-            free(mData);
-            mData = NULL;
-
-            return false;
-        }
-    } else if (header.flags & 0x80) {
+    // first handle global unsynchronization
+    if (header.flags & 0x80) {
         ALOGV("removing unsynchronization");
 
         removeUnsynchronization();
     }
 
+    // handle extended header, if present
     mFirstFrameOffset = 0;
     if (header.version_major == 3 && (header.flags & 0x40)) {
         // Version 2.3 has an optional extended header.
@@ -296,6 +252,7 @@
             return false;
         }
 
+        // v2.3 does not have syncsafe integers
         size_t extendedHeaderSize = U32_AT(&mData[0]);
         if (extendedHeaderSize > SIZE_MAX - 4) {
             free(mData);
@@ -367,6 +324,48 @@
         mFirstFrameOffset = ext_size;
     }
 
+    // Handle any v2.4 per-frame unsynchronization
+    // The id3 spec isn't clear about what should happen if the global
+    // unsynchronization flag is combined with per-frame unsynchronization,
+    // or whether that's even allowed, so this code assumes id3 writing
+    // tools do the right thing and not apply double-unsynchronization,
+    // but will honor the flags if they are set.
+    if (header.version_major == 4) {
+        void *copy = malloc(size);
+        if (copy == NULL) {
+            free(mData);
+            mData = NULL;
+            ALOGE("b/24623447, no more memory");
+            return false;
+        }
+
+        memcpy(copy, mData, size);
+
+        bool success = removeUnsynchronizationV2_4(false /* iTunesHack */);
+        if (!success) {
+            memcpy(mData, copy, size);
+            mSize = size;
+
+            success = removeUnsynchronizationV2_4(true /* iTunesHack */);
+
+            if (success) {
+                ALOGV("Had to apply the iTunes hack to parse this ID3 tag");
+            }
+        }
+
+        free(copy);
+        copy = NULL;
+
+        if (!success) {
+            free(mData);
+            mData = NULL;
+
+            return false;
+        }
+    }
+
+
+
     if (header.version_major == 2) {
         mVersion = ID3_V2_2;
     } else if (header.version_major == 3) {
@@ -411,7 +410,7 @@
 bool ID3::removeUnsynchronizationV2_4(bool iTunesHack) {
     size_t oldSize = mSize;
 
-    size_t offset = 0;
+    size_t offset = mFirstFrameOffset;
     while (mSize >= 10 && offset <= mSize - 10) {
         if (!memcmp(&mData[offset], "\0\0\0\0", 4)) {
             break;
@@ -445,7 +444,7 @@
         }
 
         if ((flags & 2) && (dataSize >= 2)) {
-            // This file has "unsynchronization", so we have to replace occurrences
+            // This frame has "unsynchronization", so we have to replace occurrences
             // of 0xff 0x00 with just 0xff in order to get the real data.
 
             size_t readOffset = offset + 11;
diff --git a/media/libstagefright/id3/test/ID3Test.cpp b/media/libstagefright/id3/test/ID3Test.cpp
index a8f1470..cd5cd9e 100644
--- a/media/libstagefright/id3/test/ID3Test.cpp
+++ b/media/libstagefright/id3/test/ID3Test.cpp
@@ -24,6 +24,7 @@
 #include <datasource/FileSource.h>
 
 #include <media/stagefright/foundation/hexdump.h>
+#include <media/MediaExtractorPluginHelper.h>
 #include <ID3.h>
 
 #include "ID3TestEnvironment.h"
@@ -42,7 +43,8 @@
     string path = gEnv->getRes() + GetParam();
     sp<FileSource> file = new FileSource(path.c_str());
     ASSERT_EQ(file->initCheck(), (status_t)OK) << "File initialization failed! \n";
-    ID3 tag(file.get());
+    DataSourceHelper helper(file->wrap());
+    ID3 tag(&helper);
     ASSERT_TRUE(tag.isValid()) << "No valid ID3 tag found for " << path.c_str() << "\n";
 
     ID3::Iterator it(tag, nullptr);
@@ -61,7 +63,8 @@
     sp<android::FileSource> file = new FileSource(path.c_str());
     ASSERT_EQ(file->initCheck(), (status_t)OK) << "File initialization failed! \n";
 
-    ID3 tag(file.get());
+    DataSourceHelper helper(file->wrap());
+    ID3 tag(&helper);
     ASSERT_TRUE(tag.isValid()) << "No valid ID3 tag found for " << path.c_str() << "\n";
     ASSERT_TRUE(tag.version() >= versionNumber)
             << "Expected version: " << tag.version() << " Found version: " << versionNumber;
@@ -73,7 +76,8 @@
     sp<android::FileSource> file = new FileSource(path.c_str());
     ASSERT_EQ(file->initCheck(), (status_t)OK) << "File initialization failed! \n";
 
-    ID3 tag(file.get());
+    DataSourceHelper helper(file->wrap());
+    ID3 tag(&helper);
     ASSERT_TRUE(tag.isValid()) << "No valid ID3 tag found for " << path.c_str() << "\n";
     int countTextFrames = 0;
     ID3::Iterator it(tag, nullptr);
@@ -99,7 +103,8 @@
     sp<android::FileSource> file = new FileSource(path.c_str());
     ASSERT_EQ(file->initCheck(), (status_t)OK) << "File initialization failed! \n";
 
-    ID3 tag(file.get());
+    DataSourceHelper helper(file->wrap());
+    ID3 tag(&helper);
     ASSERT_TRUE(tag.isValid()) << "No valid ID3 tag found for " << path.c_str() << "\n";
     size_t dataSize;
     String8 mime;
@@ -124,7 +129,8 @@
     sp<android::FileSource> file = new FileSource(path.c_str());
     ASSERT_EQ(file->initCheck(), (status_t)OK) << "File initialization failed! \n";
 
-    ID3 tag(file.get());
+    DataSourceHelper helper(file->wrap());
+    ID3 tag(&helper);
     ASSERT_TRUE(tag.isValid()) << "No valid ID3 tag found for " << path.c_str() << "\n";
     int count = 0;
     ID3::Iterator it(tag, nullptr);
diff --git a/media/libstagefright/id3/testid3.cpp b/media/libstagefright/id3/testid3.cpp
index 9984d85..5cd51cf 100644
--- a/media/libstagefright/id3/testid3.cpp
+++ b/media/libstagefright/id3/testid3.cpp
@@ -24,6 +24,7 @@
 #include <binder/ProcessState.h>
 #include <datasource/FileSource.h>
 #include <media/stagefright/foundation/ADebug.h>
+#include <media/MediaExtractorPluginHelper.h>
 
 #define MAXPATHLEN 256
 
@@ -72,7 +73,8 @@
     sp<FileSource> file = new FileSource(path);
     CHECK_EQ(file->initCheck(), (status_t)OK);
 
-    ID3 tag(file.get());
+    DataSourceHelper helper(file->wrap());
+    ID3 tag(&helper);
     if (!tag.isValid()) {
         printf("FAIL %s\n", path);
     } else {
diff --git a/media/libstagefright/include/ID3.h b/media/libstagefright/include/ID3.h
index 2843a7a..0be5896 100644
--- a/media/libstagefright/include/ID3.h
+++ b/media/libstagefright/include/ID3.h
@@ -37,7 +37,6 @@
     };
 
     explicit ID3(DataSourceHelper *source, bool ignoreV1 = false, off64_t offset = 0);
-    explicit ID3(DataSourceBase *source, bool ignoreV1 = false, off64_t offset = 0);
     ID3(const uint8_t *data, size_t size, bool ignoreV1 = false);
     ~ID3();