diff --git a/packager/media/formats/webvtt/text_readers.cc b/packager/media/formats/webvtt/text_readers.cc
index 02fa37dccc..0d6f0fd22f 100644
--- a/packager/media/formats/webvtt/text_readers.cc
+++ b/packager/media/formats/webvtt/text_readers.cc
@@ -6,117 +6,104 @@
 
 #include "packager/media/formats/webvtt/text_readers.h"
 
+#include <cstring>
+
 #include "packager/base/logging.h"
-#include "packager/file/file.h"
 
 namespace shaka {
 namespace media {
 
-Status FileReader::Open(const std::string& filename,
-                        std::unique_ptr<FileReader>* out) {
-  const char* kReadOnly = "r";
+LineReader::LineReader() : should_flush_(false) {}
 
-  std::unique_ptr<File, FileCloser> file(
-      File::Open(filename.c_str(), kReadOnly));
-
-  if (!file) {
-    return Status(error::INVALID_ARGUMENT,
-                  "Could not open input file " + filename);
-  }
-
-  *out = std::unique_ptr<FileReader>(new FileReader(std::move(file)));
-
-  return Status::OK;
+void LineReader::PushData(const uint8_t* data, size_t data_size) {
+  buffer_.Push(data, static_cast<int>(data_size));
+  should_flush_ = false;
 }
 
-bool FileReader::Next(char* out) {
-  // TODO(vaage): If file reading performance is poor, change this to buffer
-  //              data and read from the buffer.
-  return file_->Read(out, 1) == 1;
-}
-
-FileReader::FileReader(std::unique_ptr<File, FileCloser> file)
-    : file_(std::move(file)) {
-  DCHECK(file_);
-}
-
-PeekingReader::PeekingReader(std::unique_ptr<FileReader> source)
-    : source_(std::move(source)) {}
-
-bool PeekingReader::Next(char* out) {
-  DCHECK(out);
-  if (Peek(out)) {
-    has_cached_next_ = false;
-    return true;
-  }
-  return false;
-}
-
-bool PeekingReader::Peek(char* out) {
-  DCHECK(out);
-  if (!has_cached_next_ && source_->Next(&cached_next_)) {
-    has_cached_next_ = true;
-  }
-  if (has_cached_next_) {
-    *out = cached_next_;
-    return true;
-  }
-  return false;
-}
-
-LineReader::LineReader(std::unique_ptr<FileReader> source)
-    : source_(std::move(source)) {}
-
 // Split lines based on https://w3c.github.io/webvtt/#webvtt-line-terminator
 bool LineReader::Next(std::string* out) {
   DCHECK(out);
-  out->clear();
-  bool read_something = false;
-  char now;
-  while (source_.Next(&now)) {
-    read_something = true;
-    // handle \n
-    if (now == '\n') {
+
+  int i;
+  int skip = 0;
+  const uint8_t* data;
+  int data_size;
+  buffer_.Peek(&data, &data_size);
+  for (i = 0; i < data_size; i++) {
+    // Handle \n
+    if (data[i] == '\n') {
+      skip = 1;
       break;
     }
-    // handle \r and \r\n
-    if (now == '\r') {
-      char next;
-      if (source_.Peek(&next) && next == '\n') {
-        source_.Next(&next);  // Read in the '\n' that was just seen via |Peek|
+
+    // Handle \r and \r\n
+    if (data[i] == '\r') {
+      // Only read if we can see the next character; this ensures we don't get
+      // the '\n' in the next PushData.
+      if (i + 1 == data_size) {
+        if (!should_flush_)
+          return false;
+        skip = 1;
+      } else {
+        if (data[i + 1] == '\n')
+          skip = 2;
+        else
+          skip = 1;
       }
       break;
     }
-    out->push_back(now);
   }
-  return read_something;
+
+  if (i == data_size && (!should_flush_ || i == 0)) {
+    return false;
+  }
+
+  // TODO(modmaker): Handle character encodings?
+  out->assign(data, data + i);
+  buffer_.Pop(i + skip);
+  return true;
 }
 
-BlockReader::BlockReader(std::unique_ptr<FileReader> source)
-    : source_(std::move(source)) {}
+void LineReader::Flush() {
+  should_flush_ = true;
+}
+
+BlockReader::BlockReader() : should_flush_(false) {}
+
+void BlockReader::PushData(const uint8_t* data, size_t data_size) {
+  source_.PushData(data, data_size);
+  should_flush_ = false;
+}
 
 bool BlockReader::Next(std::vector<std::string>* out) {
   DCHECK(out);
 
-  out->clear();
-
-  bool in_block = false;
-
+  bool end_block = false;
   // Read through lines until a non-empty line is found. With a non-empty
   // line is found, start adding the lines to the output and once an empty
   // line if found again, stop adding lines and exit.
   std::string line;
   while (source_.Next(&line)) {
-    if (in_block && line.empty()) {
+    if (!temp_.empty() && line.empty()) {
+      end_block = true;
       break;
     }
-    if (in_block || !line.empty()) {
-      out->push_back(line);
-      in_block = true;
+    if (!line.empty()) {
+      temp_.emplace_back(std::move(line));
     }
   }
 
-  return in_block;
+  if (!end_block && (!should_flush_ || temp_.empty()))
+    return false;
+
+  *out = std::move(temp_);
+  return true;
 }
+
+void BlockReader::Flush() {
+  source_.Flush();
+  should_flush_ = true;
+}
+
 }  // namespace media
 }  // namespace shaka
diff --git a/packager/media/formats/webvtt/text_readers.h b/packager/media/formats/webvtt/text_readers.h
index 4fe0772148..1bafceabfa 100644
--- a/packager/media/formats/webvtt/text_readers.h
+++ b/packager/media/formats/webvtt/text_readers.h
@@ -11,7 +11,7 @@
 #include <string>
 #include <vector>
 
-#include "packager/file/file_closer.h"
+#include "packager/media/base/byte_queue.h"
 #include "packager/status.h"
 
 namespace shaka {
@@ -19,70 +19,47 @@ class File;
 
 namespace media {
 
-/// Class to read character-by-character from a file.
-class FileReader {
- public:
-  /// Create a new file reader by opening a file. If the file fails to open (in
-  /// readonly mode) a non-ok status will be returned. If the file successfully
-  /// opens, |out| will be set to a new FileReader and an ok status will be
-  /// returned.
-  static Status Open(const std::string& filename,
-                     std::unique_ptr<FileReader>* out);
-
-  /// Read the next character from the file. If there is a next character,
-  /// |out| will be set and true will be returned. If there is no next
-  /// character false will be returned.
-  bool Next(char* out);
-
- private:
-  explicit FileReader(std::unique_ptr<File, FileCloser> file);
-
-  FileReader(const FileReader& reader) = delete;
-  FileReader operator=(const FileReader& reader) = delete;
-
-  std::unique_ptr<File, FileCloser> file_;
-};
-
-class PeekingReader {
- public:
-  explicit PeekingReader(std::unique_ptr<FileReader> source);
-
-  bool Peek(char* out);
-  bool Next(char* out);
-
- private:
-  PeekingReader(const PeekingReader&) = delete;
-  PeekingReader operator=(const PeekingReader&) = delete;
-
-  std::unique_ptr<FileReader> source_;
-  char cached_next_ = 0;
-  bool has_cached_next_ = false;
-};
-
 class LineReader {
  public:
-  explicit LineReader(std::unique_ptr<FileReader> source);
+  LineReader();
 
+  /// Pushes data onto the end of the buffer.
+  void PushData(const uint8_t* data, size_t data_size);
+  /// Reads the next line from the buffer.
+  /// @return True if a line is read, false if there's no line in the buffer.
   bool Next(std::string* out);
+  /// Indicates that no more data is coming and that calls to Next should
+  /// return even possibly-incomplete data.
+  void Flush();
 
  private:
   LineReader(const LineReader&) = delete;
   LineReader operator=(const LineReader&) = delete;
 
-  PeekingReader source_;
+  ByteQueue buffer_;
+  bool should_flush_;
 };
 
 class BlockReader {
  public:
-  explicit BlockReader(std::unique_ptr<FileReader> source);
+  BlockReader();
 
+  /// Pushes data onto the end of the buffer.
+  void PushData(const uint8_t* data, size_t data_size);
+  /// Reads the next block from the buffer.
+  /// @return True if a block is read, false if there is no block in the buffer.
   bool Next(std::vector<std::string>* out);
+  /// Indicates that no more data is coming and that calls to Next should
+  /// return even possibly-incomplete data.
+  void Flush();
 
  private:
   BlockReader(const BlockReader&) = delete;
   BlockReader operator=(const BlockReader&) = delete;
 
   LineReader source_;
+  std::vector<std::string> temp_;
+  bool should_flush_;
 };
 
 }  // namespace media
diff --git a/packager/media/formats/webvtt/text_readers_unittest.cc b/packager/media/formats/webvtt/text_readers_unittest.cc
index 85dc1c5839..f60f5c6d7a 100644
--- a/packager/media/formats/webvtt/text_readers_unittest.cc
+++ b/packager/media/formats/webvtt/text_readers_unittest.cc
@@ -4,6 +4,7 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
+#include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
 #include "packager/file/file.h"
@@ -12,66 +13,15 @@
 
 namespace shaka {
 namespace media {
-namespace {
-const char* kFilename = "memory://test-file";
-}  // namespace
 
-TEST(TextReadersTest, ReadWholeStream) {
-  const char* text = "abcd";
-
-  ASSERT_TRUE(File::WriteStringToFile(kFilename, text));
-
-  std::unique_ptr<FileReader> source;
-  ASSERT_OK(FileReader::Open(kFilename, &source));
-
-  char c;
-  ASSERT_TRUE(source->Next(&c));
-  ASSERT_EQ(c, 'a');
-  ASSERT_TRUE(source->Next(&c));
-  ASSERT_EQ(c, 'b');
-  ASSERT_TRUE(source->Next(&c));
-  ASSERT_EQ(c, 'c');
-  ASSERT_TRUE(source->Next(&c));
-  ASSERT_EQ(c, 'd');
-  ASSERT_FALSE(source->Next(&c));
-}
-
-TEST(TextReadersTest, Peeking) {
-  const char* text = "abc";
-
-  ASSERT_TRUE(File::WriteStringToFile(kFilename, text));
-
-  std::unique_ptr<FileReader> source;
-  ASSERT_OK(FileReader::Open(kFilename, &source));
-
-  PeekingReader reader(std::move(source));
-
-  char c;
-  ASSERT_TRUE(reader.Peek(&c));
-  ASSERT_EQ(c, 'a');
-  ASSERT_TRUE(reader.Next(&c));
-  ASSERT_EQ(c, 'a');
-  ASSERT_TRUE(reader.Peek(&c));
-  ASSERT_EQ(c, 'b');
-  ASSERT_TRUE(reader.Next(&c));
-  ASSERT_EQ(c, 'b');
-  ASSERT_TRUE(reader.Peek(&c));
-  ASSERT_EQ(c, 'c');
-  ASSERT_TRUE(reader.Next(&c));
-  ASSERT_EQ(c, 'c');
-  ASSERT_FALSE(reader.Peek(&c));
-  ASSERT_FALSE(reader.Next(&c));
-}
+using testing::ElementsAre;
 
 TEST(TextReadersTest, ReadLinesWithNewLine) {
-  const char* text = "a\nb\nc";
+  const uint8_t text[] = "a\nb\nc";
 
-  ASSERT_TRUE(File::WriteStringToFile(kFilename, text));
-
-  std::unique_ptr<FileReader> source;
-  ASSERT_OK(FileReader::Open(kFilename, &source));
-
-  LineReader reader(std::move(source));
+  LineReader reader;
+  reader.PushData(text, sizeof(text) - 1);
+  reader.Flush();
 
   std::string s;
   ASSERT_TRUE(reader.Next(&s));
@@ -84,14 +34,11 @@ TEST(TextReadersTest, ReadLinesWithNewLine) {
 }
 
 TEST(TextReadersTest, ReadLinesWithReturnsAndNewLine) {
-  const char* text = "a\r\nb\r\nc";
+  const uint8_t text[] = "a\r\nb\r\nc";
 
-  ASSERT_TRUE(File::WriteStringToFile(kFilename, text));
-
-  std::unique_ptr<FileReader> source;
-  ASSERT_OK(FileReader::Open(kFilename, &source));
-
-  LineReader reader(std::move(source));
+  LineReader reader;
+  reader.PushData(text, sizeof(text) - 1);
+  reader.Flush();
 
   std::string s;
   ASSERT_TRUE(reader.Next(&s));
@@ -104,14 +51,11 @@ TEST(TextReadersTest, ReadLinesWithReturnsAndNewLine) {
 }
 
 TEST(TextReadersTest, ReadLinesWithNewLineAndReturns) {
-  const char* text = "a\n\rb\n\rc";
+  const uint8_t text[] = "a\n\rb\n\rc";
 
-  ASSERT_TRUE(File::WriteStringToFile(kFilename, text));
-
-  std::unique_ptr<FileReader> source;
-  ASSERT_OK(FileReader::Open(kFilename, &source));
-
-  LineReader reader(std::move(source));
+  LineReader reader;
+  reader.PushData(text, sizeof(text) - 1);
+  reader.Flush();
 
   std::string s;
   ASSERT_TRUE(reader.Next(&s));
@@ -128,14 +72,11 @@ TEST(TextReadersTest, ReadLinesWithNewLineAndReturns) {
 }
 
 TEST(TextReadersTest, ReadLinesWithReturnAtEnd) {
-  const char* text = "a\r\nb\r\nc\r";
+  const uint8_t text[] = "a\r\nb\r\nc\r";
 
-  ASSERT_TRUE(File::WriteStringToFile(kFilename, text));
-
-  std::unique_ptr<FileReader> source;
-  ASSERT_OK(FileReader::Open(kFilename, &source));
-
-  LineReader reader(std::move(source));
+  LineReader reader;
+  reader.PushData(text, sizeof(text) - 1);
+  reader.Flush();
 
   std::string s;
   ASSERT_TRUE(reader.Next(&s));
@@ -147,30 +88,44 @@ TEST(TextReadersTest, ReadLinesWithReturnAtEnd) {
   ASSERT_FALSE(reader.Next(&s));
 }
 
+TEST(TextReadersTest, ReadLinesWithMultiplePushes) {
+  const uint8_t text1[] = "a\nb";
+  const uint8_t text2[] = "c\nd";
+
+  LineReader reader;
+  reader.PushData(text1, sizeof(text1) - 1);
+
+  std::string s;
+  ASSERT_TRUE(reader.Next(&s));
+  ASSERT_EQ(s, "a");
+  ASSERT_FALSE(reader.Next(&s));
+
+  reader.PushData(text2, sizeof(text2) - 1);
+  reader.Flush();
+  ASSERT_TRUE(reader.Next(&s));
+  ASSERT_EQ(s, "bc");
+  ASSERT_TRUE(reader.Next(&s));
+  ASSERT_EQ(s, "d");
+  ASSERT_FALSE(reader.Next(&s));
+}
+
 TEST(TextReadersTest, ReadBlocksReadMultilineBlock) {
-  const char* text =
+  const uint8_t text[] =
       "block 1 - line 1\n"
       "block 1 - line 2";
 
-  ASSERT_TRUE(File::WriteStringToFile(kFilename, text));
-
-  std::unique_ptr<FileReader> source;
-  ASSERT_OK(FileReader::Open(kFilename, &source));
-
-  BlockReader reader(std::move(source));
+  BlockReader reader;
+  reader.PushData(text, sizeof(text) - 1);
+  reader.Flush();
 
   std::vector<std::string> block;
-
   ASSERT_TRUE(reader.Next(&block));
-  ASSERT_EQ(2u, block.size());
-  ASSERT_EQ("block 1 - line 1", block[0]);
-  ASSERT_EQ("block 1 - line 2", block[1]);
-
+  EXPECT_THAT(block, ElementsAre("block 1 - line 1", "block 1 - line 2"));
   ASSERT_FALSE(reader.Next(&block));
 }
 
 TEST(TextReadersTest, ReadBlocksSkipBlankLinesBeforeBlocks) {
-  const char* text =
+  const uint8_t text[] =
       "\n"
       "\n"
       "block 1\n"
@@ -178,38 +133,50 @@ TEST(TextReadersTest, ReadBlocksSkipBlankLinesBeforeBlocks) {
       "\n"
       "block 2\n";
 
-  ASSERT_TRUE(File::WriteStringToFile(kFilename, text));
-
-  std::unique_ptr<FileReader> source;
-  ASSERT_OK(FileReader::Open(kFilename, &source));
-
-  BlockReader reader(std::move(source));
+  BlockReader reader;
+  reader.PushData(text, sizeof(text) - 1);
+  reader.Flush();
 
   std::vector<std::string> block;
 
   ASSERT_TRUE(reader.Next(&block));
-  ASSERT_EQ(1u, block.size());
-  ASSERT_EQ("block 1", block[0]);
+  EXPECT_THAT(block, ElementsAre("block 1"));
 
   ASSERT_TRUE(reader.Next(&block));
-  ASSERT_EQ(1u, block.size());
-  ASSERT_EQ("block 2", block[0]);
-
+  EXPECT_THAT(block, ElementsAre("block 2"));
   ASSERT_FALSE(reader.Next(&block));
 }
 
 TEST(TextReadersTest, ReadBlocksWithOnlyBlankLines) {
-  const char* text = "\n\n\n\n";
+  const uint8_t text[] = "\n\n\n\n";
 
-  ASSERT_TRUE(File::WriteStringToFile(kFilename, text));
-
-  std::unique_ptr<FileReader> source;
-  ASSERT_OK(FileReader::Open(kFilename, &source));
-
-  BlockReader reader(std::move(source));
+  BlockReader reader;
+  reader.PushData(text, sizeof(text) - 1);
+  reader.Flush();
 
   std::vector<std::string> block;
   ASSERT_FALSE(reader.Next(&block));
 }
+
+TEST(TextReadersTest, ReadBlocksMultipleReads) {
+  const uint8_t text1[] = "block 1\n";
+  const uint8_t text2[] =
+      "block 2\n"
+      "\n"
+      "\n"
+      "end";
+
+  BlockReader reader;
+  reader.PushData(text1, sizeof(text1) - 1);
+
+  std::vector<std::string> block;
+  ASSERT_FALSE(reader.Next(&block));
+  reader.PushData(text2, sizeof(text2) - 1);
+  reader.Flush();
+
+  ASSERT_TRUE(reader.Next(&block));
+  EXPECT_THAT(block, ElementsAre("block 1", "block 2"));
+}
+
 }  // namespace media
 }  // namespace shaka
diff --git a/packager/media/formats/webvtt/webvtt_parser.cc b/packager/media/formats/webvtt/webvtt_parser.cc
index c3999527f7..311c5920df 100644
--- a/packager/media/formats/webvtt/webvtt_parser.cc
+++ b/packager/media/formats/webvtt/webvtt_parser.cc
@@ -12,6 +12,8 @@
 #include "packager/base/logging.h"
 #include "packager/base/strings/string_split.h"
 #include "packager/base/strings/string_util.h"
+#include "packager/file/file.h"
+#include "packager/file/file_closer.h"
 #include "packager/media/base/text_stream_info.h"
 #include "packager/media/formats/webvtt/webvtt_timestamp.h"
 #include "packager/status_macros.h"
@@ -19,7 +21,9 @@
 namespace shaka {
 namespace media {
 namespace {
+
 const uint64_t kStreamIndex = 0;
+const uint64_t kBufferSize = 64 * 1024 * 1024;
 
 std::string BlockToString(const std::string* block, size_t size) {
   std::string out = " --- BLOCK START ---\n";
@@ -99,9 +103,21 @@ bool WebVttParser::ValidateOutputStreamIndex(size_t stream_index) const {
 }
 
 Status WebVttParser::Run() {
-  std::unique_ptr<FileReader> reader;
-  RETURN_IF_ERROR(FileReader::Open(input_path_, &reader));
-  BlockReader block_reader(std::move(reader));
+  BlockReader block_reader;
+  std::unique_ptr<File, FileCloser> file(File::Open(input_path_.c_str(), "r"));
+  if (!file)
+    return Status(error::FILE_FAILURE, "Error reading from file");
+  while (true) {
+    std::vector<uint8_t> buffer(kBufferSize);
+    const auto size = file->Read(buffer.data(), buffer.size());
+    if (size < 0)
+      return Status(error::FILE_FAILURE, "Error reading from file");
+    if (size == 0)
+      break;
+
+    block_reader.PushData(buffer.data(), size);
+  }
+  block_reader.Flush();
 
   return Parse(&block_reader)
              ? FlushDownstream(kStreamIndex)