iSAC: Functions for importing and exporting bandwidth est. info

webrtc/modules/audio_coding/codecs/isac/unittest.cc

+/*
+ *  Copyright (c) 2015 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.
+ */
+
+#include <cmath>
+#include <sstream>
+#include <vector>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/base/buffer.h"
+#include "webrtc/base/checks.h"
+#include "webrtc/modules/audio_coding/codecs/isac/fix/interface/audio_encoder_isacfix.h"
+#include "webrtc/modules/audio_coding/codecs/isac/main/interface/audio_encoder_isac.h"
+#include "webrtc/test/testsupport/fileutils.h"
+
+namespace webrtc {
+
+namespace {
+
+std::vector<int16_t> LoadSpeechData() {

[hlundin-webrtc, 2015/06/26 10:35:15]

Consider using webrtc::test::InputAudioFile instead. (It is under
audio_coding/neteq/tools and should probably be moved elsewhere, but that is for
another time.)

[kwiberg-webrtc, 2015/06/28 03:17:41]

Done.

+  static const int kIsacNumberOfSamples = 32 * 60;  // 60 ms at 32 kHz
+  const std::string file_name =
+      webrtc::test::ResourcePath("audio_coding/testfile32kHz", "pcm");
+  FILE* input_file = fopen(file_name.c_str(), "rb");
+  CHECK(input_file);
+  std::vector<int16_t> speech_data(kIsacNumberOfSamples);
+  CHECK_EQ(kIsacNumberOfSamples,
+           static_cast<int32_t>(fread(speech_data.data(), sizeof(int16_t),
+                                      kIsacNumberOfSamples, input_file)));
+  CHECK_EQ(0, fclose(input_file));
+#ifndef WEBRTC_ARCH_LITTLE_ENDIAN
+#error "Need to convert samples from little-endian"
+#endif
+  return speech_data;
+}
+
+template <typename T>
+IsacBandwidthInfo GetBwInfo(typename T::instance_type* inst) {
+  IsacBandwidthInfo bi;
+  T::GetBandwidthInfo(inst, &bi);
+  CHECK(bi.in_use);
+  return bi;
+}
+
+std::string Str(const IsacBandwidthInfo& bi) {

[hlundin-webrtc, 2015/06/26 10:35:14]

The function name is a bit too compact. Consider ToString or BwInfoToString.

[kwiberg-webrtc, 2015/06/28 03:17:41]

Done.

+  CHECK(bi.in_use);
+  std::ostringstream o;
+  o << "(send_bw_avg: " << bi.send_bw_avg << ", "
+    << "send_max_delay_avg: " << bi.send_max_delay_avg << ", "
+    << "bottleneck_idx: " << bi.bottleneck_idx << ", "
+    << "jitter_info: " << bi.jitter_info << ")";
+  return o.str();
+}
+
+// Is the distance between a and b dist or less, and the relative distance
+// rdist or less?
+bool AlmostEqual(int a, int b, unsigned dist, double rdist) {
+  // d = |a-b|, because casting n-bit signed to n-bit unsigned leaves a value
+  // unchanged mod 2^n.
+  unsigned d = a > b ? static_cast<unsigned>(a) - static_cast<unsigned>(b)
+                     : static_cast<unsigned>(b) - static_cast<unsigned>(a);
+  return d <= dist && d <= rdist * std::min(std::abs(a), std::abs(b));
+}
+
+// Returns true if the two arguments are similar enough.
+bool Similar(const IsacBandwidthInfo& a, const IsacBandwidthInfo& b) {
+  return AlmostEqual(a.send_bw_avg, b.send_bw_avg, 1000, 0.07) &&
+         a.send_max_delay_avg == b.send_max_delay_avg &&
+         AlmostEqual(a.bottleneck_idx, b.bottleneck_idx, 1, 0.1) &&
+         a.jitter_info == b.jitter_info;
+}
+
+// Count the number of elements in the range [lower,upper).
+template <typename T>
+int CountRange(std::multiset<T> s, T lower, T upper) {
+  return std::distance(s.lower_bound(lower), s.lower_bound(upper));
+}
+
+template <typename T>
+rtc::Buffer Encode60Ms(typename T::instance_type* inst,
+                       const IsacBandwidthInfo* bi,
+                       const int16_t* speech_data) {
+  rtc::Buffer output(1000);
+  for (int i = 0;; ++i) {
+    if (bi)
+      T::SetBandwidthInfo(inst, bi);
+    int encoded_bytes = T::Encode(inst, speech_data, output.data());

[hlundin-webrtc, 2015/06/26 10:35:15]

What if encoded_bytes is too large for output?

[kwiberg-webrtc, 2015/06/28 03:17:41]

It shouldn't be. And some sanitizer bot would complain. But I'll CHECK it.

+    if (i == 5) {
+      output.SetSize(encoded_bytes);
+      return output;
+    }
+    CHECK_EQ(0, encoded_bytes);

[hlundin-webrtc, 2015/06/26 10:35:14]

CHECK is quite aggressive here. Consider using EXPECT instead.

[kwiberg-webrtc, 2015/06/28 03:17:41]

OK. Although I sort of doubt the rest of the run will be useful if we fail here.

[hlundin-webrtc, 2015/06/29 08:42:18]

Right. But a CHECK will kill the test binary, in this case all of
modules_unittests, so no more tests from that will be run (unless they are run
in a parallel-process fashion). I still think that ASSERT_* is better in tests.

[kwiberg-webrtc, 2015/06/29 11:53:48]

Mmmm, I didn't think things through enough to realize that's what a failing
CHECK would do---but given that, you're right of course. I'll replace all the
CHECKs, but turning them into ASSERTs would involve making subroutines such as
this one return void, which is too much of a mess, so I'll use EXPECTs.

+  }
+}
+
+template <typename T>
+void TestGetSetBandwidthInfo(const int16_t* speech_data) {
+  // Conjoined encoder/decoder pair:
+  typename T::instance_type* encdec;
+  EXPECT_EQ(0, T::Create(&encdec));

[hlundin-webrtc, 2015/06/26 10:35:15]

All the create and init calls should be ASSERT_EQ instead of EXPECT_EQ. It makes
little sense to continue with the test if they fail.

[kwiberg-webrtc, 2015/06/28 03:17:41]

Done.

+  EXPECT_EQ(0, T::EncoderInit(encdec, 0 /* adaptive mode */));
+  EXPECT_EQ(0, T::DecoderInit(encdec));
+
+  // Disjoint encoder/decoder pair:
+  typename T::instance_type* enc;
+  EXPECT_EQ(0, T::Create(&enc));
+  EXPECT_EQ(0, T::EncoderInit(enc, 0 /* adaptive mode */));
+  typename T::instance_type* dec;
+  EXPECT_EQ(0, T::Create(&dec));
+  EXPECT_EQ(0, T::DecoderInit(dec));
+
+  const int kSamplesPerPacket = 960;
+  std::multiset<int> send_bw_avg, bottleneck_idx;
+  for (int i = 0; i < 250; ++i) {
+    std::ostringstream ss;
+    ss << "i = " << i;
+    SCOPED_TRACE(ss.str());
+
+    // 1. Get BW info from decoders, and make sure they're similar enough.
+    auto bi1 = GetBwInfo<T>(encdec);
+    auto bi2 = GetBwInfo<T>(dec);
+    EXPECT_TRUE(Similar(bi1, bi2)) << "Not similar enough:\n  " << Str(bi1)
+                                   << "\n  " << Str(bi2);
+    send_bw_avg.insert(bi2.send_bw_avg);
+    bottleneck_idx.insert(bi2.bottleneck_idx);
+
+    // 2. Encode 6 * 10 ms. The separate encoder is given the BW info before
+    // each encode call.
+    auto bitstream1 = Encode60Ms<T>(encdec, nullptr, speech_data);
+    auto bitstream2 = Encode60Ms<T>(enc, &bi2, speech_data);
+
+    // 3. Deliver the encoded data to the decoders (but don't actually ask them
+    // to decode it; that's not necessary).
+    const int send_time = i * kSamplesPerPacket;
+    const int receive_time = send_time + kSamplesPerPacket / 10;  // 6 ms delay
+    EXPECT_EQ(
+        0, T::UpdateBwEstimate(encdec, bitstream1.data(), bitstream1.size(), 1,
+                               send_time, receive_time));
+    EXPECT_EQ(0, T::UpdateBwEstimate(dec, bitstream2.data(), bitstream2.size(),
+                                     1, send_time, receive_time));

[kwiberg-webrtc, 2015/06/25 14:52:43]

If I've understood correctly, this means that each packet is delivered 6 ms late
(and not, as I first assumed, that the packets spent 6 ms in flight), causing
the bw estimator to successively lower the bitrate until it reaches the lowest
allowed value.

[hlundin-webrtc, 2015/06/26 10:35:15]

I'm not so sure. The receive time should just be the local wall-clock, but with
the same frequency as the RTP timestamps (i.e., the send time). What you have is
just a constant offset between send_time and receive_time, which will likely not
trigger any BW actions. You will probably have to _increase_ the
offset for each packet in the loop to get some action. E.g.,

receive_time = last_receive_time + kSamplesPerPacket * 1.1;

[kwiberg-webrtc, 2015/06/27 23:43:43]

But I do get some action. First it keeps the bitrate at 20k for a dozen packets,
then it appears to decide corrective action is needed and gradually lowers it
(over a period of about 200 packets) until it reaches 10k (the minimum allowed
value), and then it stays there. My guess that it's seeing the 6 ms
send-to-receive difference as a delay that should be corrected is based on this
behavior.

[hlundin-webrtc, 2015/06/29 08:42:18]

Hmm. I still think that the BWE should ignore this constant offset between send
and receive timestamps. Please, try with another (wildly different) offset and
see if you get another behavior.

+  }
+
+  // Check that we see a good spread of send_bw_avg numbers.
+  EXPECT_EQ(CountRange(send_bw_avg, std::numeric_limits<int>::min(), 10000), 0);

[hlundin-webrtc, 2015/06/26 10:35:15]

EXPECT_EQ should have swapped parameters; expected value first. Four instances
in total.

[kwiberg-webrtc, 2015/06/28 03:17:41]

Done. For symmetry, I also swapped the EXPECT_GEs.

+  EXPECT_GE(CountRange(send_bw_avg, 10000, 11000), 37);
+  EXPECT_GE(CountRange(send_bw_avg, 11000, 12000), 14);
+  EXPECT_GE(CountRange(send_bw_avg, 12000, 13000), 14);
+  EXPECT_GE(CountRange(send_bw_avg, 13000, 14000), 10);
+  EXPECT_GE(CountRange(send_bw_avg, 14000, 15000), 15);
+  EXPECT_GE(CountRange(send_bw_avg, 15000, 16000), 12);
+  EXPECT_GE(CountRange(send_bw_avg, 16000, 17000), 10);
+  EXPECT_GE(CountRange(send_bw_avg, 17000, 18000), 12);
+  EXPECT_GE(CountRange(send_bw_avg, 18000, 19000), 7);
+  EXPECT_GE(CountRange(send_bw_avg, 19000, 20000), 40);
+  EXPECT_GE(CountRange(send_bw_avg, 20000, 21000), 34);
+  EXPECT_EQ(CountRange(send_bw_avg, 21000, std::numeric_limits<int>::max()), 0);
+
+  // Check that we see a good spread of bottleneck_idx numbers.
+  EXPECT_EQ(bottleneck_idx.count(7), 1u);
+  EXPECT_EQ(CountRange(bottleneck_idx, std::numeric_limits<int>::min(), 12), 1);
+  EXPECT_GE(bottleneck_idx.count(12), 37u);
+  EXPECT_GE(bottleneck_idx.count(13), 18u);
+  EXPECT_GE(bottleneck_idx.count(14), 18u);
+  EXPECT_GE(bottleneck_idx.count(15), 18u);
+  EXPECT_GE(bottleneck_idx.count(16), 20u);
+  EXPECT_GE(bottleneck_idx.count(17), 19u);
+  EXPECT_GE(bottleneck_idx.count(18), 40u);
+  EXPECT_GE(bottleneck_idx.count(19), 32u);
+  EXPECT_EQ(CountRange(bottleneck_idx, 20, std::numeric_limits<int>::max()), 0);
+}
+
+}  // namespace
+
+TEST(IsacCommonTest, GetSetBandwidthInfoFloat) {
+  TestGetSetBandwidthInfo<IsacFloat>(LoadSpeechData().data());
+}
+
+TEST(IsacCommonTest, GetSetBandwidthInfoFix) {
+  TestGetSetBandwidthInfo<IsacFix>(LoadSpeechData().data());
+}
+
+}  // namespace webrtc