[CodeHealth] Spanify AudioFifo

This CL remove AudioFifo's use of "float* AudioBus::channel()" and
memcopy, in favor of the safer base::span alternatives.

This CL also adds a missing UT, per an ancient TODO.

Bug: 373960632
Change-Id: I99113b34bbefe1e4bd441b581bf184f7eacbf93d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6154858
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Auto-Submit: Thomas Guilbert <tguilbert@chromium.org>
Commit-Queue: Guido Urdaneta <guidou@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1407289}

media/audio/flac_audio_handler.cc

@@ -84,7 +84,7 @@ bool FlacAudioHandler::CopyTo(AudioBus* bus, size_t* frames_written) {
   DCHECK(is_initialized());
 
   if (AtEnd()) {
-    DCHECK_EQ(fifo_->frames(), 0);
+    DCHECK_EQ(fifo_->frames(), 0u);
     bus->Zero();
     return true;
   }
@@ -93,7 +93,8 @@ bool FlacAudioHandler::CopyTo(AudioBus* bus, size_t* frames_written) {
   DCHECK_EQ(bus->channels(), num_channels_);
 
   // Records the number of frames copied into `bus`.
-  int frames_copied = 0;
+  size_t frames_copied = 0;
+  size_t bus_size = static_cast<size_t>(bus->frames());
 
   do {
     if (fifo_->frames() == 0 && !AtEnd()) {
@@ -103,13 +104,12 @@ bool FlacAudioHandler::CopyTo(AudioBus* bus, size_t* frames_written) {
       }
     }
 
-    if (fifo_->frames() > 0) {
+    if (fifo_->frames() > 0u) {
-      const int frames =
+      const size_t frames = std::min(bus_size - frames_copied, fifo_->frames());
-          std::min(bus->frames() - frames_copied, fifo_->frames());
       fifo_->Consume(bus, frames_copied, frames);
       frames_copied += frames;
     }
-  } while (!AtEnd() && frames_copied < bus->frames());
+  } while (!AtEnd() && frames_copied < bus_size);
 
   *frames_written = frames_copied;
   return true;

media/base/audio_fifo.cc

@@ -2,17 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifdef UNSAFE_BUFFERS_BUILD
-// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
-#pragma allow_unsafe_buffers
-#endif
-
 #include "media/base/audio_fifo.h"
 
 #include <cstring>
 
 #include "base/check_op.h"
+#include "base/numerics/safe_math.h"
 #include "base/trace_event/trace_event.h"
+#include "base/types/zip.h"
 
 namespace media {
 
@@ -25,32 +22,33 @@ namespace media {
 // where we have not yet reached the "edge" of the FIFO. If |pos| + |in_size|
 // exceeds the total size of the FIFO, we must wrap around and start reusing
 // a part the allocated memory. The size of this part is given by |wrap_size|.
-static void GetSizes(
+static void GetSizes(size_t pos,
-    int pos, int max_size, int in_size, int* size, int* wrap_size) {
+                     size_t max_size,
-  if (pos + in_size > max_size) {
+                     size_t in_size,
+                     size_t* size,
+                     size_t* wrap_size) {
+  const size_t frames_before_end = base::CheckSub(max_size, pos).ValueOrDie();
+  if (in_size > frames_before_end) {
     // Wrapping is required => derive size of each segment.
     *size = max_size - pos;
     *wrap_size = in_size - *size;
   } else {
     // Wrapping is not required.
     *size = in_size;
-    *wrap_size = 0;
+    *wrap_size = 0u;
   }
 }
 
 // Updates the read/write position with |step| modulo the maximum number of
 // elements in the FIFO to ensure that the position counters wraps around at
 // the endpoint.
-static int UpdatePos(int pos, int step, int max_size) {
+static size_t UpdatePos(size_t pos, size_t step, int max_size) {
   return ((pos + step) % max_size);
 }
 
 AudioFifo::AudioFifo(int channels, int frames)
     : audio_bus_(AudioBus::Create(channels, frames)),
-      max_frames_(frames),
+      max_frames_(base::checked_cast<size_t>(frames)) {}
-      frames_(0),
-      read_pos_(0),
-      write_pos_(0) {}
 
 AudioFifo::~AudioFifo() = default;
 
@@ -64,35 +62,40 @@ void AudioFifo::Push(const AudioBus* source, int source_size) {
   DCHECK_LE(source_size, source->frames());
 
   // Ensure that there is space for the new data in the FIFO.
-  CHECK_LE(source_size + frames_, max_frames_);
+  const size_t source_frames = base::checked_cast<size_t>(source_size);
+  const size_t remaining_frames =
+      base::CheckSub(max_frames_, frames_).ValueOrDie();
+  CHECK_LE(source_frames, remaining_frames);
 
   TRACE_EVENT_BEGIN2(TRACE_DISABLED_BY_DEFAULT("audio"), "AudioFifo::Push",
                      "this", static_cast<void*>(this), "fifo frames", frames_);
 
   // Figure out if wrapping is needed and if so what segment sizes we need
   // when adding the new audio bus content to the FIFO.
-  int append_size = 0;
+  size_t append_size = 0u;
-  int wrap_size = 0;
+  size_t wrap_size = 0u;
-  GetSizes(write_pos_, max_frames_, source_size, &append_size, &wrap_size);
+  GetSizes(write_pos_, max_frames_, source_frames, &append_size, &wrap_size);
 
   // Copy all channels from the source to the FIFO. Wrap around if needed.
-  for (int ch = 0; ch < source->channels(); ++ch) {
+  for (auto [data_src, fifo_dest] :
-    float* dest = audio_bus_->channel(ch);
+       base::zip(source->AllChannels(), audio_bus_->AllChannels())) {
-    const float* src = source->channel(ch);
+    auto [append_data, wrap_data] = data_src.split_at(append_size);
 
     // Append part of (or the complete) source to the FIFO.
-    memcpy(&dest[write_pos_], &src[0], append_size * sizeof(src[0]));
+    fifo_dest.subspan(write_pos_, append_size)
+        .copy_from_nonoverlapping(append_data);
+
     if (wrap_size > 0) {
       // Wrapping is needed: copy remaining part from the source to the FIFO.
-      memcpy(&dest[0], &src[append_size], wrap_size * sizeof(src[0]));
+      fifo_dest.first(wrap_size).copy_from_nonoverlapping(wrap_data);
     }
   }
 
-  frames_ += source_size;
+  frames_ += source_frames;
   DCHECK_LE(frames_, max_frames_);
-  write_pos_ = UpdatePos(write_pos_, source_size, max_frames_);
+  write_pos_ = UpdatePos(write_pos_, source_frames, max_frames_);
   TRACE_EVENT_END1(TRACE_DISABLED_BY_DEFAULT("audio"), "AudioFifo::Push",
-                   "frames", source_size);
+                   "frames", source_frames);
 }
 
 void AudioFifo::Consume(AudioBus* destination,
@@ -101,48 +104,53 @@ void AudioFifo::Consume(AudioBus* destination,
   DCHECK(destination);
   DCHECK_EQ(destination->channels(), audio_bus_->channels());
 
+  const size_t dest_offset = base::checked_cast<size_t>(start_frame);
+  const size_t frame_count = base::checked_cast<size_t>(frames_to_consume);
+
   // It is not possible to ask for more data than what is available in the FIFO.
-  CHECK_LE(frames_to_consume, frames_);
+  CHECK_LE(frame_count, frames_);
 
   // A copy from the FIFO to |destination| will only be performed if the
   // allocated memory in |destination| is sufficient.
-  CHECK_LE(frames_to_consume + start_frame, destination->frames());
+  const size_t free_frames_in_dest =
+      base::CheckSub(destination->frames(), dest_offset).ValueOrDie();
+  CHECK_LE(frame_count, free_frames_in_dest);
 
   TRACE_EVENT_BEGIN2(TRACE_DISABLED_BY_DEFAULT("audio"), "AudioFifo::Consume",
                      "this", static_cast<void*>(this), "fifo frames", frames_);
 
   // Figure out if wrapping is needed and if so what segment sizes we need
   // when removing audio bus content from the FIFO.
-  int consume_size = 0;
+  size_t consume_size = 0u;
-  int wrap_size = 0;
+  size_t wrap_size = 0u;
-  GetSizes(read_pos_, max_frames_, frames_to_consume, &consume_size,
+  GetSizes(read_pos_, max_frames_, frame_count, &consume_size, &wrap_size);
-           &wrap_size);
 
   // For all channels, remove the requested amount of data from the FIFO
   // and copy the content to the destination. Wrap around if needed.
-  for (int ch = 0; ch < destination->channels(); ++ch) {
+  for (auto [data_dest, fifo_src] :
-    float* dest = destination->channel(ch);
+       base::zip(destination->AllChannels(), audio_bus_->AllChannels())) {
-    const float* src = audio_bus_->channel(ch);
+    auto [consume_data, wrap_data] =
+        data_dest.subspan(dest_offset, frame_count).split_at(consume_size);
 
     // Copy a selected part of the FIFO to the destination.
-    memcpy(&dest[start_frame], &src[read_pos_], consume_size * sizeof(src[0]));
+    consume_data.copy_from_nonoverlapping(
+        fifo_src.subspan(read_pos_, consume_size));
     if (wrap_size > 0) {
       // Wrapping is needed: copy remaining part to the destination.
-      memcpy(&dest[consume_size + start_frame], &src[0],
+      wrap_data.copy_from_nonoverlapping(fifo_src.first(wrap_size));
-             wrap_size * sizeof(src[0]));
     }
   }
 
-  frames_ -= frames_to_consume;
+  frames_ -= frame_count;
-  read_pos_ = UpdatePos(read_pos_, frames_to_consume, max_frames_);
+  read_pos_ = UpdatePos(read_pos_, frame_count, max_frames_);
   TRACE_EVENT_END1(TRACE_DISABLED_BY_DEFAULT("audio"), "AudioFifo::Consume",
-                   "frames", frames_to_consume);
+                   "frames", frame_count);
 }
 
 void AudioFifo::Clear() {
-  frames_ = 0;
+  frames_ = 0u;
-  read_pos_ = 0;
+  read_pos_ = 0u;
-  write_pos_ = 0;
+  write_pos_ = 0u;
 }
 
 }  // namespace media

media/base/audio_fifo.h

@@ -46,9 +46,9 @@ class MEDIA_EXPORT AudioFifo {
   void Clear();
 
   // Number of actual audio frames in the FIFO.
-  int frames() const { return frames_; }
+  size_t frames() const { return frames_; }
 
-  int max_frames() const { return max_frames_; }
+  size_t max_frames() const { return max_frames_; }
 
  private:
   // The actual FIFO is an audio bus implemented as a ring buffer.
@@ -56,16 +56,16 @@ class MEDIA_EXPORT AudioFifo {
 
   // Maximum number of elements the FIFO can contain.
   // This value is set by |frames| in the constructor.
-  const int max_frames_;
+  const size_t max_frames_;
 
   // Number of actual elements in the FIFO.
-  int frames_;
+  size_t frames_ = 0u;
 
   // Current read position.
-  int read_pos_;
+  size_t read_pos_ = 0u;
 
   // Current write position.
-  int write_pos_;
+  size_t write_pos_ = 0u;
 };
 
 }  // namespace media

media/base/audio_fifo_unittest.cc

@@ -2,16 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifdef UNSAFE_BUFFERS_BUILD
+#include "media/base/audio_fifo.h"
-// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
-#pragma allow_unsafe_buffers
-#endif
-
-// TODO(henrika): add test which included |start_frame| in Consume() call.
 
+#include <algorithm>
 #include <memory>
 
-#include "media/base/audio_fifo.h"
+#include "base/containers/span.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media {
@@ -25,42 +21,42 @@ class AudioFifoTest : public testing::Test {
 
   ~AudioFifoTest() override = default;
 
-  void VerifyValue(const float data[], int size, float value) {
+  void VerifyValue(base::span<float> data, float value) {
-    for (int i = 0; i < size; ++i)
+    for (size_t i = 0; i < data.size(); ++i) {
       ASSERT_FLOAT_EQ(value, data[i]) << "i=" << i;
+    }
   }
-
- protected:
 };
 
 // Verify that construction works as intended.
 TEST_F(AudioFifoTest, Construct) {
-  static const int kChannels = 6;
+  static constexpr int kChannels = 6;
-  static const int kMaxFrameCount = 128;
+  static constexpr size_t kMaxFrameCount = 128;
   AudioFifo fifo(kChannels, kMaxFrameCount);
-  EXPECT_EQ(fifo.frames(), 0);
+  EXPECT_EQ(fifo.frames(), 0u);
 }
 
 // Pushes audio bus objects to a FIFO and fill it up to different degrees.
 TEST_F(AudioFifoTest, Push) {
-  static const int kChannels = 2;
+  static constexpr int kChannels = 2;
-  static const int kMaxFrameCount = 128;
+  static constexpr size_t kMaxFrameCount = 128;
   AudioFifo fifo(kChannels, kMaxFrameCount);
   {
     SCOPED_TRACE("Push 50%");
+    static constexpr size_t kHalfFrameCount = kMaxFrameCount / 2;
     std::unique_ptr<AudioBus> bus =
-        AudioBus::Create(kChannels, kMaxFrameCount / 2);
+        AudioBus::Create(kChannels, kHalfFrameCount);
-    EXPECT_EQ(fifo.frames(), 0);
+    EXPECT_EQ(fifo.frames(), 0u);
     fifo.Push(bus.get());
-    EXPECT_EQ(fifo.frames(), bus->frames());
+    EXPECT_EQ(fifo.frames(), kHalfFrameCount);
     fifo.Clear();
   }
   {
     SCOPED_TRACE("Push 100%");
     std::unique_ptr<AudioBus> bus = AudioBus::Create(kChannels, kMaxFrameCount);
-    EXPECT_EQ(fifo.frames(), 0);
+    EXPECT_EQ(fifo.frames(), 0u);
     fifo.Push(bus.get());
-    EXPECT_EQ(fifo.frames(), bus->frames());
+    EXPECT_EQ(fifo.frames(), static_cast<size_t>(bus->frames()));
     fifo.Clear();
   }
 }
@@ -68,7 +64,7 @@ TEST_F(AudioFifoTest, Push) {
 // Consumes audio bus objects from a FIFO and empty it to different degrees.
 TEST_F(AudioFifoTest, Consume) {
   static const int kChannels = 2;
-  static const int kMaxFrameCount = 128;
+  static const size_t kMaxFrameCount = 128;
   AudioFifo fifo(kChannels, kMaxFrameCount);
   {
     std::unique_ptr<AudioBus> bus = AudioBus::Create(kChannels, kMaxFrameCount);
@@ -77,10 +73,11 @@ TEST_F(AudioFifoTest, Consume) {
   }
   {
     SCOPED_TRACE("Consume 50%");
+    static constexpr size_t kHalfFrameCount = kMaxFrameCount / 2;
     std::unique_ptr<AudioBus> bus =
-        AudioBus::Create(kChannels, kMaxFrameCount / 2);
+        AudioBus::Create(kChannels, kHalfFrameCount);
     fifo.Consume(bus.get(), 0, bus->frames());
-    EXPECT_TRUE(fifo.frames() == bus->frames());
+    EXPECT_EQ(fifo.frames(), kHalfFrameCount);
     fifo.Push(bus.get());
     EXPECT_EQ(fifo.frames(), kMaxFrameCount);
   }
@@ -88,23 +85,51 @@ TEST_F(AudioFifoTest, Consume) {
     SCOPED_TRACE("Consume 100%");
     std::unique_ptr<AudioBus> bus = AudioBus::Create(kChannels, kMaxFrameCount);
     fifo.Consume(bus.get(), 0, bus->frames());
-    EXPECT_EQ(fifo.frames(), 0);
+    EXPECT_EQ(fifo.frames(), 0u);
     fifo.Push(bus.get());
     EXPECT_EQ(fifo.frames(), kMaxFrameCount);
   }
 }
 
+TEST_F(AudioFifoTest, ConsumeWithStartFrame) {
+  static constexpr int kChannels = 2;
+  static constexpr size_t kMaxFrameCount = 128;
+  AudioFifo fifo(kChannels, kMaxFrameCount);
+  std::unique_ptr<AudioBus> bus = AudioBus::Create(kChannels, kMaxFrameCount);
+
+  // Fill the fifo with `kTestValue`.
+  static constexpr float kTestValue = 0.5f;
+  for (auto channel : bus->AllChannels()) {
+    std::ranges::fill(channel, kTestValue);
+  }
+  fifo.Push(bus.get());
+
+  static constexpr size_t kOffset = 10;
+  static constexpr size_t kCount = 5;
+
+  // Fill `output_bus` with an offset.
+  bus->Zero();
+  fifo.Consume(bus.get(), kOffset, kCount);
+
+  // `kTestValue` should only be present at `kOffset`, for `kCount` values.
+  for (auto channel : bus->AllChannels()) {
+    VerifyValue(channel.first(kOffset), 0);
+    VerifyValue(channel.subspan(kOffset, kCount), kTestValue);
+    VerifyValue(channel.subspan(kOffset + kCount), 0);
+  }
+}
+
 // Verify that the frames() method of the FIFO works as intended while
 // appending and removing audio bus elements to/from the FIFO.
 TEST_F(AudioFifoTest, FramesInFifo) {
-  static const int kChannels = 2;
+  static constexpr int kChannels = 2;
-  static const int kMaxFrameCount = 64;
+  static constexpr size_t kMaxFrameCount = 64;
   AudioFifo fifo(kChannels, kMaxFrameCount);
 
   // Fill up the FIFO and verify that the size grows as it should while adding
   // one audio frame each time.
   std::unique_ptr<AudioBus> bus = AudioBus::Create(kChannels, 1);
-  int n = 0;
+  size_t n = 0;
   while (fifo.frames() < kMaxFrameCount) {
     fifo.Push(bus.get());
     EXPECT_EQ(fifo.frames(), ++n);
@@ -113,22 +138,22 @@ TEST_F(AudioFifoTest, FramesInFifo) {
 
   // Empty the FIFO and verify that the size decreases as it should.
   // Reduce the size of the FIFO by one frame each time.
-  while (fifo.frames() > 0) {
+  while (fifo.frames() > 0u) {
     fifo.Consume(bus.get(), 0, bus->frames());
     EXPECT_EQ(fifo.frames(), --n);
   }
-  EXPECT_EQ(fifo.frames(), 0);
+  EXPECT_EQ(fifo.frames(), 0u);
 
   // Verify that a steady-state size of #frames in the FIFO is maintained
-  // during a sequence of Push/Consume calls which involves wrapping. We ensure
+  // during a sequence of Push/Consume calls which involves wrapping. We
-  // wrapping by selecting a buffer size which does divides the FIFO size
+  // ensure wrapping by selecting a buffer size which does divides the FIFO
-  // with a remainder of one.
+  // size with a remainder of one.
   std::unique_ptr<AudioBus> bus2 =
       AudioBus::Create(kChannels, (kMaxFrameCount / 4) - 1);
-  const int frames_in_fifo = bus2->frames();
+  const size_t frames_in_fifo = static_cast<size_t>(bus2->frames());
   fifo.Push(bus2.get());
   EXPECT_EQ(fifo.frames(), frames_in_fifo);
-  for (n = 0; n < kMaxFrameCount; ++n) {
+  for (n = 0u; n < kMaxFrameCount; ++n) {
     fifo.Push(bus2.get());
     fifo.Consume(bus2.get(), 0, frames_in_fifo);
     EXPECT_EQ(fifo.frames(), frames_in_fifo);
@@ -139,24 +164,23 @@ TEST_F(AudioFifoTest, FramesInFifo) {
 // to the FIFO is correctly retrieved, i.e., that the order is correct and the
 // values are correct.
 TEST_F(AudioFifoTest, VerifyDataValues) {
-  static const int kChannels = 2;
+  static constexpr int kChannels = 2;
-  static const int kFrameCount = 2;
+  static constexpr size_t kFrameCount = 2;
-  static const int kFifoFrameCount = 5 * kFrameCount;
+  static constexpr size_t kFifoFrameCount = 5 * kFrameCount;
 
   AudioFifo fifo(kChannels, kFifoFrameCount);
   std::unique_ptr<AudioBus> bus = AudioBus::Create(kChannels, kFrameCount);
-  EXPECT_EQ(fifo.frames(), 0);
-  EXPECT_EQ(bus->frames(), kFrameCount);
 
   // Start by filling up the FIFO with audio frames. The first audio frame
   // will contain all 1's, the second all 2's etc. All channels contain the
   // same value.
   int value = 1;
   while (fifo.frames() < kFifoFrameCount) {
-    for (int j = 0; j < bus->channels(); ++j)
+    for (auto channel : bus->AllChannels()) {
-      std::fill(bus->channel(j), bus->channel(j) + bus->frames(), value);
+      std::ranges::fill(channel, value);
+    }
     fifo.Push(bus.get());
-    EXPECT_EQ(fifo.frames(), bus->frames() * value);
+    EXPECT_EQ(fifo.frames(), static_cast<size_t>(bus->frames() * value));
     ++value;
   }
 
@@ -169,36 +193,39 @@ TEST_F(AudioFifoTest, VerifyDataValues) {
   // It means that we shall read out the same value two times in row.
   value = 1;
   int n = 1;
-  const int frames_to_consume = bus->frames() / 2;
+  const size_t frames_to_consume = bus->frames() / 2;
   while (fifo.frames() > 0) {
     fifo.Consume(bus.get(), 0, frames_to_consume);
-    for (int j = 0; j < bus->channels(); ++j)
+    for (auto channel : bus->AllChannels()) {
-      VerifyValue(bus->channel(j), frames_to_consume, value);
+      VerifyValue(channel.first(frames_to_consume), value);
-    if (n++ % 2 == 0)
+    }
+    if (n++ % 2 == 0) {
       ++value;  // counts 1, 1, 2, 2, 3, 3,...
+    }
   }
 
   // FIFO should be empty now.
-  EXPECT_EQ(fifo.frames(), 0);
+  EXPECT_EQ(fifo.frames(), 0u);
 
   // Push one audio bus to the FIFO and fill it with 1's.
   value = 1;
-  for (int j = 0; j < bus->channels(); ++j)
+  for (auto channel : bus->AllChannels()) {
-    std::fill(bus->channel(j), bus->channel(j) + bus->frames(), value);
+    std::ranges::fill(channel, value);
+  }
   fifo.Push(bus.get());
-  EXPECT_EQ(fifo.frames(), bus->frames());
+  EXPECT_EQ(fifo.frames(), static_cast<size_t>(bus->frames()));
 
   // Keep calling Consume/Push a few rounds and verify that we read out the
-  // correct values. The number of elements shall be fixed (kFrameCount) during
+  // correct values. The number of elements shall be fixed (kFrameCount)
-  // this phase.
+  // during this phase.
-  for (int i = 0; i < 5 * kFifoFrameCount; i++) {
+  for (size_t i = 0; i < 5 * kFifoFrameCount; i++) {
     fifo.Consume(bus.get(), 0, bus->frames());
-    for (int j = 0; j < bus->channels(); ++j) {
+    for (auto channel : bus->AllChannels()) {
-      VerifyValue(bus->channel(j), bus->channels(), value);
+      VerifyValue(channel, value);
-      std::fill(bus->channel(j), bus->channel(j) + bus->frames(), value + 1);
+      std::ranges::fill(channel, value + 1);
     }
     fifo.Push(bus.get());
-    EXPECT_EQ(fifo.frames(), bus->frames());
+    EXPECT_EQ(fifo.frames(), static_cast<size_t>(bus->frames()));
     ++value;
   }
 }

media/webrtc/audio_processor.cc

@@ -178,7 +178,8 @@ class AudioProcessorCaptureFifo {
     }
 
     if (fifo_) {
-      CHECK_LT(fifo_->frames(), destination_->bus()->frames());
+      CHECK_LT(fifo_->frames(),
+               static_cast<size_t>(destination_->bus()->frames()));
       next_audio_delay_ =
           audio_delay + fifo_->frames() * base::Seconds(1) / sample_rate_;
       fifo_->Push(source_to_push);
@@ -195,8 +196,10 @@ class AudioProcessorCaptureFifo {
   bool Consume(AudioProcessorCaptureBus** destination,
                base::TimeDelta* audio_delay) {
     if (fifo_) {
-      if (fifo_->frames() < destination_->bus()->frames())
+      if (fifo_->frames() <
+          static_cast<size_t>(destination_->bus()->frames())) {
         return false;
+      }
 
       fifo_->Consume(destination_->bus(), 0, destination_->bus()->frames());
       *audio_delay = next_audio_delay_;

third_party/blink/renderer/modules/mediarecorder/audio_track_opus_encoder.cc

@@ -187,8 +187,9 @@ void AudioTrackOpusEncoder::EncodeAudio(
 
   // Wait to have enough |input_bus|s to guarantee a satisfactory conversion,
   // accounting for multiple calls to ProvideInput().
-  while (fifo_->frames() >= converter_->GetMaxInputFramesRequested(
+  while (fifo_->frames() >=
-                                kOpusPreferredFramesPerBuffer)) {
+         static_cast<size_t>(converter_->GetMaxInputFramesRequested(
+             kOpusPreferredFramesPerBuffer))) {
     std::unique_ptr<media::AudioBus> audio_bus = media::AudioBus::Create(
         converted_params_.channels(), kOpusPreferredFramesPerBuffer);
     converter_->Convert(audio_bus.get());

third_party/blink/renderer/modules/mediastream/webaudio_media_stream_audio_sink.cc

@@ -218,7 +218,7 @@ double WebAudioMediaStreamAudioSink::ProvideInput(
       media::AudioTimestampHelper::FramesToTime(
           frames_delayed + fifo_->frames(), source_params_.sample_rate())
           .InMillisecondsF());
-  if (fifo_->frames() >= audio_bus->frames()) {
+  if (fifo_->frames() >= static_cast<size_t>(audio_bus->frames())) {
     fifo_->Consume(audio_bus, 0, audio_bus->frames());
     TRACE_COUNTER_ID1(TRACE_DISABLED_BY_DEFAULT("mediastream"),
                       "WebAudioMediaStreamAudioSink fifo space", this,