Update audio code to use size_t more correctly,

webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc

 /*
  *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 20 matching lines @@
       vad(NULL) {
 }
 
 bool AudioEncoderCng::Config::IsOk() const {
   if (num_channels != 1)
     return false;
   if (!speech_encoder)
     return false;
   if (num_channels != speech_encoder->NumChannels())
     return false;
-  if (sid_frame_interval_ms < speech_encoder->Max10MsFramesInAPacket() * 10)
+  if (sid_frame_interval_ms <
+      static_cast<int>(speech_encoder->Max10MsFramesInAPacket() * 10))
     return false;
   if (num_cng_coefficients > WEBRTC_CNG_MAX_LPC_ORDER ||
       num_cng_coefficients <= 0)
     return false;
   return true;
 }
 
 AudioEncoderCng::AudioEncoderCng(const Config& config)
     : speech_encoder_(config.speech_encoder),
       cng_payload_type_(config.payload_type),
@@ skipping 30 matching lines @@
   return 1;
 }
 
 size_t AudioEncoderCng::MaxEncodedBytes() const {
   const size_t max_encoded_bytes_active = speech_encoder_->MaxEncodedBytes();
   const size_t max_encoded_bytes_passive =
       rtc::CheckedDivExact(kMaxFrameSizeMs, 10) * SamplesPer10msFrame();
   return std::max(max_encoded_bytes_active, max_encoded_bytes_passive);
 }
 
-int AudioEncoderCng::Num10MsFramesInNextPacket() const {
+size_t AudioEncoderCng::Num10MsFramesInNextPacket() const {
   return speech_encoder_->Num10MsFramesInNextPacket();
 }
 
-int AudioEncoderCng::Max10MsFramesInAPacket() const {
+size_t AudioEncoderCng::Max10MsFramesInAPacket() const {
   return speech_encoder_->Max10MsFramesInAPacket();
 }
 
 int AudioEncoderCng::GetTargetBitrate() const {
   return speech_encoder_->GetTargetBitrate();
 }
 
 void AudioEncoderCng::SetTargetBitrate(int bits_per_second) {
   speech_encoder_->SetTargetBitrate(bits_per_second);
 }
@@ skipping 10 matching lines @@
     size_t max_encoded_bytes,
     uint8_t* encoded) {
   CHECK_GE(max_encoded_bytes, static_cast<size_t>(num_cng_coefficients_ + 1));
   const size_t samples_per_10ms_frame = SamplesPer10msFrame();
   CHECK_EQ(speech_buffer_.size(),
            rtp_timestamps_.size() * samples_per_10ms_frame);
   rtp_timestamps_.push_back(rtp_timestamp);
   for (size_t i = 0; i < samples_per_10ms_frame; ++i) {
     speech_buffer_.push_back(audio[i]);
   }
-  const int frames_to_encode = speech_encoder_->Num10MsFramesInNextPacket();
-  if (rtp_timestamps_.size() < static_cast<size_t>(frames_to_encode)) {
+  const size_t frames_to_encode = speech_encoder_->Num10MsFramesInNextPacket();
+  if (rtp_timestamps_.size() < frames_to_encode) {
     return EncodedInfo();
   }
-  CHECK_LE(frames_to_encode * 10, kMaxFrameSizeMs)
+  CHECK_LE(static_cast<int>(frames_to_encode * 10), kMaxFrameSizeMs)
       << "Frame size cannot be larger than " << kMaxFrameSizeMs
       << " ms when using VAD/CNG.";
 
   // Group several 10 ms blocks per VAD call. Call VAD once or twice using the
   // following split sizes:
   // 10 ms = 10 + 0 ms; 20 ms = 20 + 0 ms; 30 ms = 30 + 0 ms;
   // 40 ms = 20 + 20 ms; 50 ms = 30 + 20 ms; 60 ms = 30 + 30 ms.
-  int blocks_in_first_vad_call =
+  size_t blocks_in_first_vad_call =
       (frames_to_encode > 3 ? 3 : frames_to_encode);
   if (frames_to_encode == 4)
     blocks_in_first_vad_call = 2;
   CHECK_GE(frames_to_encode, blocks_in_first_vad_call);
-  const int blocks_in_second_vad_call =
+  const size_t blocks_in_second_vad_call =
       frames_to_encode - blocks_in_first_vad_call;
 
   // Check if all of the buffer is passive speech. Start with checking the first
   // block.
   Vad::Activity activity = vad_->VoiceActivity(
       &speech_buffer_[0], samples_per_10ms_frame * blocks_in_first_vad_call,
       SampleRateHz());
   if (activity == Vad::kPassive && blocks_in_second_vad_call > 0) {
     // Only check the second block if the first was passive.
     activity = vad_->VoiceActivity(
@@ skipping 21 matching lines @@
 
   speech_buffer_.erase(
       speech_buffer_.begin(),
       speech_buffer_.begin() + frames_to_encode * samples_per_10ms_frame);
   rtp_timestamps_.erase(rtp_timestamps_.begin(),
                         rtp_timestamps_.begin() + frames_to_encode);
   return info;
 }
 
 AudioEncoder::EncodedInfo AudioEncoderCng::EncodePassive(
-    int frames_to_encode,
+    size_t frames_to_encode,
     size_t max_encoded_bytes,
     uint8_t* encoded) {
   bool force_sid = last_frame_active_;
   bool output_produced = false;
   const size_t samples_per_10ms_frame = SamplesPer10msFrame();
   CHECK_GE(max_encoded_bytes, frames_to_encode * samples_per_10ms_frame);
   AudioEncoder::EncodedInfo info;
-  for (int i = 0; i < frames_to_encode; ++i) {
-    int16_t encoded_bytes_tmp = 0;
+  for (size_t i = 0; i < frames_to_encode; ++i) {
+    // It's important not to pass &info.encoded_bytes directly to
+    // WebRtcCng_Encode(), since later loop iterations may return zero in that
+    // value, in which case we don't want to overwrite any value from an earlier
+    // iteration.

[kwiberg-webrtc, 2015/08/06 09:14:25]

Not sure the comment says anything that isn't already obvious, but since you
bothered to write it I guess I'm wrong. :-)

[Peter Kasting, 2015/08/06 18:38:50]

I wrote it because I did the wrong thing here originally, got bitten by test
failures as a result, and required a couple hours to track down the actual bug
:P

+    size_t encoded_bytes_tmp = 0;
     CHECK_GE(WebRtcCng_Encode(cng_inst_.get(),
                               &speech_buffer_[i * samples_per_10ms_frame],
-                              static_cast<int16_t>(samples_per_10ms_frame),
+                              samples_per_10ms_frame,
                               encoded, &encoded_bytes_tmp, force_sid), 0);
     if (encoded_bytes_tmp > 0) {
       CHECK(!output_produced);
-      info.encoded_bytes = static_cast<size_t>(encoded_bytes_tmp);
+      info.encoded_bytes = encoded_bytes_tmp;
       output_produced = true;
       force_sid = false;
     }
   }
   info.encoded_timestamp = rtp_timestamps_.front();
   info.payload_type = cng_payload_type_;
   info.send_even_if_empty = true;
   info.speech = false;
   return info;
 }
 
 AudioEncoder::EncodedInfo AudioEncoderCng::EncodeActive(
-    int frames_to_encode,
+    size_t frames_to_encode,
     size_t max_encoded_bytes,
     uint8_t* encoded) {
   const size_t samples_per_10ms_frame = SamplesPer10msFrame();
   AudioEncoder::EncodedInfo info;
-  for (int i = 0; i < frames_to_encode; ++i) {
+  for (size_t i = 0; i < frames_to_encode; ++i) {
     info = speech_encoder_->Encode(
         rtp_timestamps_.front(), &speech_buffer_[i * samples_per_10ms_frame],
         samples_per_10ms_frame, max_encoded_bytes, encoded);
     if (i + 1 == frames_to_encode) {
       CHECK_GT(info.encoded_bytes, 0u) << "Encoder didn't deliver data.";
     } else {
       CHECK_EQ(info.encoded_bytes, 0u) << "Encoder delivered data too early.";
     }
   }
   return info;
 }
 
 size_t AudioEncoderCng::SamplesPer10msFrame() const {
   return rtc::CheckedDivExact(10 * SampleRateHz(), 1000);
 }
 
 }  // namespace webrtc