diff --git a/core/fpdfapi/parser/cpdf_cross_ref_table.cpp b/core/fpdfapi/parser/cpdf_cross_ref_table.cpp
index bae1962..6400208 100644
--- a/core/fpdfapi/parser/cpdf_cross_ref_table.cpp
+++ b/core/fpdfapi/parser/cpdf_cross_ref_table.cpp
@@ -33,7 +33,8 @@
 CPDF_CrossRefTable::~CPDF_CrossRefTable() = default;
 
 void CPDF_CrossRefTable::AddCompressed(uint32_t obj_num,
-                                       uint32_t archive_obj_num) {
+                                       uint32_t archive_obj_num,
+                                       uint32_t archive_obj_index) {
   if (obj_num >= CPDF_Parser::kMaxObjectNumber ||
       archive_obj_num >= CPDF_Parser::kMaxObjectNumber) {
     NOTREACHED();
@@ -48,7 +49,8 @@
     return;
 
   info.type = ObjectType::kCompressed;
-  info.archive_obj_num = archive_obj_num;
+  info.archive.obj_num = archive_obj_num;
+  info.archive.obj_index = archive_obj_index;
   info.gennum = 0;
 
   objects_info_[archive_obj_num].type = ObjectType::kObjStream;
diff --git a/core/fpdfapi/parser/cpdf_cross_ref_table.h b/core/fpdfapi/parser/cpdf_cross_ref_table.h
index c5f004d..304f5d7 100644
--- a/core/fpdfapi/parser/cpdf_cross_ref_table.h
+++ b/core/fpdfapi/parser/cpdf_cross_ref_table.h
@@ -28,12 +28,15 @@
 
   struct ObjectInfo {
     ObjectInfo() : pos(0), type(ObjectType::kFree), gennum(0) {}
-    // if type is ObjectType::kCompressed the archive_obj_num should be used.
-    // if type is ObjectType::kNotCompressed the pos should be used.
-    // In other cases its are unused.
+    // If `type` is `ObjectType::kCompressed`, `archive` should be used.
+    // If `type` is `ObjectType::kNotCompressed`, `pos` should be used.
+    // In other cases, it is unused.
     union {
       FX_FILESIZE pos;
-      uint32_t archive_obj_num;
+      struct {
+        uint32_t obj_num;
+        uint32_t obj_index;
+      } archive;
     };
     ObjectType type;
     uint16_t gennum;
@@ -48,7 +51,9 @@
   explicit CPDF_CrossRefTable(RetainPtr<CPDF_Dictionary> trailer);
   ~CPDF_CrossRefTable();
 
-  void AddCompressed(uint32_t obj_num, uint32_t archive_obj_num);
+  void AddCompressed(uint32_t obj_num,
+                     uint32_t archive_obj_num,
+                     uint32_t archive_obj_index);
   void AddNormal(uint32_t obj_num, uint16_t gen_num, FX_FILESIZE pos);
   void SetFree(uint32_t obj_num);
 
diff --git a/core/fpdfapi/parser/cpdf_object_stream.cpp b/core/fpdfapi/parser/cpdf_object_stream.cpp
index 320c48c..18c02be 100644
--- a/core/fpdfapi/parser/cpdf_object_stream.cpp
+++ b/core/fpdfapi/parser/cpdf_object_stream.cpp
@@ -16,7 +16,6 @@
 #include "core/fxcrt/cfx_readonlymemorystream.h"
 #include "core/fxcrt/fx_safe_types.h"
 #include "third_party/base/check.h"
-#include "third_party/base/containers/adapters.h"
 #include "third_party/base/ptr_util.h"
 
 namespace {
@@ -74,18 +73,20 @@
 
 RetainPtr<CPDF_Object> CPDF_ObjectStream::ParseObject(
     CPDF_IndirectObjectHolder* pObjList,
-    uint32_t obj_number) const {
-  for (const ObjectInfo& info : pdfium::base::Reversed(object_info_)) {
-    if (info.obj_num != obj_number)
-      continue;
+    uint32_t obj_number,
+    uint32_t archive_obj_index) const {
+  if (archive_obj_index >= object_info_.size())
+    return nullptr;
 
-    RetainPtr<CPDF_Object> result =
-        ParseObjectAtOffset(pObjList, info.obj_offset);
-    if (result)
-      result->SetObjNum(obj_number);
-    return result;
-  }
-  return nullptr;
+  const auto& info = object_info_[archive_obj_index];
+  if (info.obj_num != obj_number)
+    return nullptr;
+
+  RetainPtr<CPDF_Object> result =
+      ParseObjectAtOffset(pObjList, info.obj_offset);
+  if (result)
+    result->SetObjNum(obj_number);
+  return result;
 }
 
 void CPDF_ObjectStream::Init(const CPDF_Stream* stream) {
diff --git a/core/fpdfapi/parser/cpdf_object_stream.h b/core/fpdfapi/parser/cpdf_object_stream.h
index 5b3195e..bc09db3 100644
--- a/core/fpdfapi/parser/cpdf_object_stream.h
+++ b/core/fpdfapi/parser/cpdf_object_stream.h
@@ -36,7 +36,8 @@
   ~CPDF_ObjectStream();
 
   RetainPtr<CPDF_Object> ParseObject(CPDF_IndirectObjectHolder* pObjList,
-                                     uint32_t obj_number) const;
+                                     uint32_t obj_number,
+                                     uint32_t archive_obj_index) const;
   const std::vector<ObjectInfo>& object_info() const { return object_info_; }
 
  private:
diff --git a/core/fpdfapi/parser/cpdf_object_stream_unittest.cpp b/core/fpdfapi/parser/cpdf_object_stream_unittest.cpp
index ffabeea..835eb60 100644
--- a/core/fpdfapi/parser/cpdf_object_stream_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_object_stream_unittest.cpp
@@ -44,24 +44,36 @@
                           CPDF_ObjectStream::ObjectInfo(11, 14),
                           CPDF_ObjectStream::ObjectInfo(12, 21)));
 
+  // Check expected indices.
   CPDF_IndirectObjectHolder holder;
-  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10);
+  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10, 0);
   ASSERT_TRUE(obj10);
   EXPECT_EQ(10u, obj10->GetObjNum());
   EXPECT_EQ(0u, obj10->GetGenNum());
   EXPECT_TRUE(obj10->IsDictionary());
 
-  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11);
+  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11, 1);
   ASSERT_TRUE(obj11);
   EXPECT_EQ(11u, obj11->GetObjNum());
   EXPECT_EQ(0u, obj11->GetGenNum());
   EXPECT_TRUE(obj11->IsArray());
 
-  RetainPtr<CPDF_Object> obj12 = obj_stream->ParseObject(&holder, 12);
+  RetainPtr<CPDF_Object> obj12 = obj_stream->ParseObject(&holder, 12, 2);
   ASSERT_TRUE(obj12);
   EXPECT_EQ(12u, obj12->GetObjNum());
   EXPECT_EQ(0u, obj12->GetGenNum());
   EXPECT_TRUE(obj12->IsNumber());
+
+  // Check bad indices.
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 10, 1));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 10, 2));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 10, 3));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 11, 0));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 11, 2));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 11, 3));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 12, 0));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 12, 1));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 12, 3));
 }
 
 TEST(CPDF_ObjectStreamTest, StreamNoDict) {
@@ -195,9 +207,9 @@
                           CPDF_ObjectStream::ObjectInfo(12, 21)));
 
   CPDF_IndirectObjectHolder holder;
-  EXPECT_FALSE(obj_stream->ParseObject(&holder, 10));
-  EXPECT_FALSE(obj_stream->ParseObject(&holder, 11));
-  EXPECT_FALSE(obj_stream->ParseObject(&holder, 12));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 10, 0));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 11, 1));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 12, 2));
 }
 
 TEST(CPDF_ObjectStreamTest, StreamDictTooFewCount) {
@@ -216,19 +228,19 @@
                           CPDF_ObjectStream::ObjectInfo(11, 14)));
 
   CPDF_IndirectObjectHolder holder;
-  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10);
+  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10, 0);
   ASSERT_TRUE(obj10);
   EXPECT_EQ(10u, obj10->GetObjNum());
   EXPECT_EQ(0u, obj10->GetGenNum());
   EXPECT_TRUE(obj10->IsDictionary());
 
-  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11);
+  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11, 1);
   ASSERT_TRUE(obj11);
   EXPECT_EQ(11u, obj11->GetObjNum());
   EXPECT_EQ(0u, obj11->GetGenNum());
   EXPECT_TRUE(obj11->IsArray());
 
-  EXPECT_FALSE(obj_stream->ParseObject(&holder, 12));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 12, 2));
 }
 
 TEST(CPDF_ObjectStreamTest, StreamDictTooManyObject) {
@@ -250,7 +262,11 @@
                           CPDF_ObjectStream::ObjectInfo(2, 3)));
 
   CPDF_IndirectObjectHolder holder;
-  EXPECT_FALSE(obj_stream->ParseObject(&holder, 2));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 2, 0));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 2, 1));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 2, 2));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 2, 3));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 2, 4));
 }
 
 TEST(CPDF_ObjectStreamTest, StreamDictGarbageObjNum) {
@@ -289,13 +305,13 @@
                           CPDF_ObjectStream::ObjectInfo(12, 21)));
 
   CPDF_IndirectObjectHolder holder;
-  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10);
+  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10, 0);
   ASSERT_TRUE(obj10);
   EXPECT_EQ(10u, obj10->GetObjNum());
   EXPECT_EQ(0u, obj10->GetGenNum());
   EXPECT_TRUE(obj10->IsDictionary());
 
-  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11);
+  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11, 1);
   ASSERT_TRUE(obj11);
   EXPECT_EQ(11u, obj11->GetObjNum());
   EXPECT_EQ(0u, obj11->GetGenNum());
@@ -321,7 +337,7 @@
                           CPDF_ObjectStream::ObjectInfo(12, 21)));
 
   CPDF_IndirectObjectHolder holder;
-  EXPECT_FALSE(obj_stream->ParseObject(&holder, 11));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 11, 1));
 }
 
 TEST(CPDF_ObjectStreamTest, StreamDictObjectOffsetTooBig) {
@@ -343,7 +359,7 @@
                           CPDF_ObjectStream::ObjectInfo(12, 21)));
 
   CPDF_IndirectObjectHolder holder;
-  EXPECT_FALSE(obj_stream->ParseObject(&holder, 11));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 11, 1));
 }
 
 TEST(CPDF_ObjectStreamTest, StreamDictDuplicateObjNum) {
@@ -358,20 +374,28 @@
   auto obj_stream = CPDF_ObjectStream::Create(stream.Get());
   ASSERT_TRUE(obj_stream);
 
-  // TODO(thestig): Should object 10 be at offset 0 instead?
   EXPECT_THAT(obj_stream->object_info(),
               ElementsAre(CPDF_ObjectStream::ObjectInfo(10, 0),
                           CPDF_ObjectStream::ObjectInfo(10, 14),
                           CPDF_ObjectStream::ObjectInfo(12, 21)));
 
   CPDF_IndirectObjectHolder holder;
-  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10);
+  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10, 0);
+  ASSERT_TRUE(obj10);
+  EXPECT_EQ(10u, obj10->GetObjNum());
+  EXPECT_EQ(0u, obj10->GetGenNum());
+  EXPECT_TRUE(obj10->IsDictionary());
+
+  obj10 = obj_stream->ParseObject(&holder, 10, 1);
   ASSERT_TRUE(obj10);
   EXPECT_EQ(10u, obj10->GetObjNum());
   EXPECT_EQ(0u, obj10->GetGenNum());
   EXPECT_TRUE(obj10->IsArray());
 
-  RetainPtr<CPDF_Object> obj12 = obj_stream->ParseObject(&holder, 12);
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 10, 2));
+  EXPECT_FALSE(obj_stream->ParseObject(&holder, 10, 3));
+
+  RetainPtr<CPDF_Object> obj12 = obj_stream->ParseObject(&holder, 12, 2);
   ASSERT_TRUE(obj12);
   EXPECT_EQ(12u, obj12->GetObjNum());
   EXPECT_EQ(0u, obj12->GetGenNum());
@@ -398,19 +422,19 @@
                           CPDF_ObjectStream::ObjectInfo(10, 21)));
 
   CPDF_IndirectObjectHolder holder;
-  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10);
+  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10, 2);
   ASSERT_TRUE(obj10);
   EXPECT_EQ(10u, obj10->GetObjNum());
   EXPECT_EQ(0u, obj10->GetGenNum());
   EXPECT_TRUE(obj10->IsNumber());
 
-  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11);
+  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11, 0);
   ASSERT_TRUE(obj11);
   EXPECT_EQ(11u, obj11->GetObjNum());
   EXPECT_EQ(0u, obj11->GetGenNum());
   EXPECT_TRUE(obj11->IsDictionary());
 
-  RetainPtr<CPDF_Object> obj12 = obj_stream->ParseObject(&holder, 12);
+  RetainPtr<CPDF_Object> obj12 = obj_stream->ParseObject(&holder, 12, 1);
   ASSERT_TRUE(obj12);
   EXPECT_EQ(12u, obj12->GetObjNum());
   EXPECT_EQ(0u, obj12->GetGenNum());
@@ -439,19 +463,19 @@
                           CPDF_ObjectStream::ObjectInfo(12, 14)));
 
   CPDF_IndirectObjectHolder holder;
-  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10);
+  RetainPtr<CPDF_Object> obj10 = obj_stream->ParseObject(&holder, 10, 0);
   ASSERT_TRUE(obj10);
   EXPECT_EQ(10u, obj10->GetObjNum());
   EXPECT_EQ(0u, obj10->GetGenNum());
   EXPECT_TRUE(obj10->IsNumber());
 
-  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11);
+  RetainPtr<CPDF_Object> obj11 = obj_stream->ParseObject(&holder, 11, 1);
   ASSERT_TRUE(obj11);
   EXPECT_EQ(11u, obj11->GetObjNum());
   EXPECT_EQ(0u, obj11->GetGenNum());
   EXPECT_TRUE(obj11->IsDictionary());
 
-  RetainPtr<CPDF_Object> obj12 = obj_stream->ParseObject(&holder, 12);
+  RetainPtr<CPDF_Object> obj12 = obj_stream->ParseObject(&holder, 12, 2);
   ASSERT_TRUE(obj12);
   EXPECT_EQ(12u, obj12->GetObjNum());
   EXPECT_EQ(0u, obj12->GetGenNum());
diff --git a/core/fpdfapi/parser/cpdf_parser.cpp b/core/fpdfapi/parser/cpdf_parser.cpp
index bed2a14..07b8d5b 100644
--- a/core/fpdfapi/parser/cpdf_parser.cpp
+++ b/core/fpdfapi/parser/cpdf_parser.cpp
@@ -621,7 +621,8 @@
         m_CrossRefTable->AddNormal(obj.obj_num, obj.info.gennum, obj.info.pos);
         break;
       case ObjectType::kCompressed:
-        m_CrossRefTable->AddCompressed(obj.obj_num, obj.info.archive_obj_num);
+        m_CrossRefTable->AddCompressed(obj.obj_num, obj.info.archive.obj_num,
+                                       obj.info.archive.obj_index);
         break;
       default:
         NOTREACHED();
@@ -699,11 +700,13 @@
 
       if (obj_num < kMaxObjectNumber) {
         cross_ref_table->AddNormal(obj_num, gen_num, obj_pos);
-        if (const auto object_stream =
-                CPDF_ObjectStream::Create(pStream.Get())) {
-          for (const auto& info : object_stream->object_info()) {
+        const auto object_stream = CPDF_ObjectStream::Create(pStream.Get());
+        if (object_stream) {
+          const auto& object_info = object_stream->object_info();
+          for (size_t i = 0; i < object_info.size(); ++i) {
+            const auto& info = object_info[i];
             if (info.obj_num < kMaxObjectNumber)
-              cross_ref_table->AddCompressed(info.obj_num, obj_num);
+              cross_ref_table->AddCompressed(info.obj_num, obj_num, i);
           }
         }
       }
@@ -842,7 +845,9 @@
   if (!IsValidObjectNumber(archive_obj_num))
     return;
 
-  m_CrossRefTable->AddCompressed(obj_num, archive_obj_num);
+  const uint32_t archive_obj_index = GetVarInt(
+      entry_span.subspan(field_widths[0] + field_widths[1], field_widths[2]));
+  m_CrossRefTable->AddCompressed(obj_num, archive_obj_num, archive_obj_index);
 }
 
 const CPDF_Array* CPDF_Parser::GetIDArray() const {
@@ -925,12 +930,13 @@
   if (GetObjectType(objnum) != ObjectType::kCompressed)
     return nullptr;
 
-  const CPDF_ObjectStream* pObjStream =
-      GetObjectStream(m_CrossRefTable->GetObjectInfo(objnum)->archive_obj_num);
+  const ObjectInfo& info = *m_CrossRefTable->GetObjectInfo(objnum);
+  const CPDF_ObjectStream* pObjStream = GetObjectStream(info.archive.obj_num);
   if (!pObjStream)
     return nullptr;
 
-  return pObjStream->ParseObject(m_pObjectsHolder.Get(), objnum);
+  return pObjStream->ParseObject(m_pObjectsHolder.Get(), objnum,
+                                 info.archive.obj_index);
 }
 
 const CPDF_ObjectStream* CPDF_Parser::GetObjectStream(uint32_t object_number) {
diff --git a/testing/SUPPRESSIONS b/testing/SUPPRESSIONS
index 3d687da..1ed29ab 100644
--- a/testing/SUPPRESSIONS
+++ b/testing/SUPPRESSIONS
@@ -344,9 +344,6 @@
 # TODO(pdfium:1571): Remove after associated bug is fixed
 bug_1571.in * * * *
 
-# TODO(pdfium:1733): Remove after associated bug is fixed
-bug_1733.in * * * *
-
 # TODO(chromium:237527): Remove after associated bug is fixed
 bug_237527_1.in * * * *