[Chromecast] Make ALSA rendering delay either accurate or kNoTimestamp

chromecast/media/cma/backend/multizone_backend_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdint.h>
 #include <stdlib.h>
 
 #include <algorithm>
 #include <limits>
 #include <memory>
@@ skipping 23 matching lines @@
 namespace media {
 
 class MultizoneBackendTest;
 
 namespace {
 
 const int64_t kMicrosecondsPerSecond = 1000 * 1000;
 // Total length of test, in microseconds.
 const int64_t kPushTimeUs = 2 * kMicrosecondsPerSecond;
 const int64_t kStartPts = 0;
-const int64_t kRenderingDelayGracePeriodUs = 250 * 1000;
 const int64_t kMaxRenderingDelayErrorUs = 200;
 const int kNumEffectsStreams = 1;
+const int64_t kNoTimestamp = std::numeric_limits<int64_t>::min();
 
 void IgnoreEos() {}
 
 class BufferFeeder : public MediaPipelineBackend::Decoder::Delegate {
  public:
   BufferFeeder(const AudioConfig& config,
                bool effects_only,
                const base::Closure& eos_cb);
   ~BufferFeeder() override {}
 
@@ skipping 107 matching lines @@
       max_positive_rendering_delay_error_us_(0),
       max_negative_rendering_delay_error_us_(0),
       total_rendering_delay_error_us_(0),
       sample_count_(0),
       feeding_completed_(false),
       task_runner_(new TaskRunnerImpl()),
       decoder_(nullptr),
       push_limit_us_(effects_only_ ? 0 : kPushTimeUs),
       last_push_length_us_(0),
       pushed_us_(0),
-      next_push_playback_timestamp_(0) {
+      next_push_playback_timestamp_(kNoTimestamp) {
   CHECK(!eos_cb_.is_null());
 }
 
 void BufferFeeder::Initialize() {
   MediaPipelineDeviceParams params(
       MediaPipelineDeviceParams::kModeIgnorePts,
       effects_only_ ? MediaPipelineDeviceParams::kAudioStreamSoundEffects
                     : MediaPipelineDeviceParams::kAudioStreamNormal,
       task_runner_.get());
   backend_.reset(CastMediaShlib::CreateMediaPipelineBackend(params));
@@ skipping 54 matching lines @@
 }
 
 void BufferFeeder::OnPushBufferComplete(BufferStatus status) {
   DCHECK(thread_checker_.CalledOnValidThread());
   pending_buffer_ = nullptr;
   ASSERT_NE(status, MediaPipelineBackend::kBufferFailed);
 
   if (!effects_only_) {
     MediaPipelineBackend::AudioDecoder::RenderingDelay delay =
         decoder_->GetRenderingDelay();
-    int64_t expected_next_push_playback_timestamp =
-        next_push_playback_timestamp_ + last_push_length_us_;
-    next_push_playback_timestamp_ =
-        delay.timestamp_microseconds + delay.delay_microseconds;
-    // Check rendering delay accuracy only if we have pushed more than
-    // kRenderingDelayGracePeriodUs of data.
-    if (pushed_us_ > kRenderingDelayGracePeriodUs) {
-      int64_t error =
-          next_push_playback_timestamp_ - expected_next_push_playback_timestamp;
-      max_rendering_delay_error_us_ =
-          std::max(max_rendering_delay_error_us_, std::abs(error));
-      total_rendering_delay_error_us_ += std::abs(error);
-      if (error >= 0) {
-        max_positive_rendering_delay_error_us_ =
-            std::max(max_positive_rendering_delay_error_us_, error);
+
+    if (delay.timestamp_microseconds != kNoTimestamp) {
+      if (next_push_playback_timestamp_ == kNoTimestamp) {
+        next_push_playback_timestamp_ =
+            delay.timestamp_microseconds + delay.delay_microseconds;
       } else {
-        max_negative_rendering_delay_error_us_ =
-            std::min(max_negative_rendering_delay_error_us_, error);
+        int64_t expected_next_push_playback_timestamp =
+            next_push_playback_timestamp_ + last_push_length_us_;
+        next_push_playback_timestamp_ =
+            delay.timestamp_microseconds + delay.delay_microseconds;
+        int64_t error = next_push_playback_timestamp_ -
+                        expected_next_push_playback_timestamp;
+        max_rendering_delay_error_us_ =
+            std::max(max_rendering_delay_error_us_, std::abs(error));
+        total_rendering_delay_error_us_ += std::abs(error);
+        if (error >= 0) {
+          max_positive_rendering_delay_error_us_ =
+              std::max(max_positive_rendering_delay_error_us_, error);
+        } else {
+          max_negative_rendering_delay_error_us_ =
+              std::min(max_negative_rendering_delay_error_us_, error);
+        }
+        sample_count_++;
       }
-      sample_count_++;
     }
   }
   pushed_us_ += last_push_length_us_;
 
   if (feeding_completed_)
     return;
 
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(&BufferFeeder::FeedBuffer, base::Unretained(this)));
 }
@@ skipping 79 matching lines @@
                                           32000,
                                           44100,
                                           48000));
 
 INSTANTIATE_TEST_CASE_P(Optional,
                         MultizoneBackendTest,
                         ::testing::Values(64000, 88200, 96000));
 
 }  // namespace media
 }  // namespace chromecast