Move ContentVideoCaptureDeviceCore from src/content to src/media

content/browser/media/capture/video_capture_oracle.cc

-// Copyright (c) 2013 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 "content/browser/media/capture/video_capture_oracle.h"
-
-#include <algorithm>
-
-#include "base/format_macros.h"
-#include "base/strings/stringprintf.h"
-
-namespace content {
-
-namespace {
-
-// This value controls how many redundant, timer-base captures occur when the
-// content is static. Redundantly capturing the same frame allows iterative
-// quality enhancement, and also allows the buffer to fill in "buffered mode".
-//
-// TODO(nick): Controlling this here is a hack and a layering violation, since
-// it's a strategy specific to the WebRTC consumer, and probably just papers
-// over some frame dropping and quality bugs. It should either be controlled at
-// a higher level, or else redundant frame generation should be pushed down
-// further into the WebRTC encoding stack.
-const int kNumRedundantCapturesOfStaticContent = 200;
-
-// Given the amount of time between frames, compare to the expected amount of
-// time between frames at |frame_rate| and return the fractional difference.
-double FractionFromExpectedFrameRate(base::TimeDelta delta, int frame_rate) {
-  DCHECK_GT(frame_rate, 0);
-  const base::TimeDelta expected_delta =
-      base::TimeDelta::FromSeconds(1) / frame_rate;
-  return (delta - expected_delta).InMillisecondsF() /
-      expected_delta.InMillisecondsF();
-}
-
-}  // anonymous namespace
-
-VideoCaptureOracle::VideoCaptureOracle(base::TimeDelta min_capture_period)
-    : next_frame_number_(0),
-      last_delivered_frame_number_(-1),
-      smoothing_sampler_(min_capture_period,
-                         kNumRedundantCapturesOfStaticContent),
-      content_sampler_(min_capture_period) {
-}
-
-VideoCaptureOracle::~VideoCaptureOracle() {}
-
-bool VideoCaptureOracle::ObserveEventAndDecideCapture(
-    Event event,
-    const gfx::Rect& damage_rect,
-    base::TimeTicks event_time) {
-  DCHECK_GE(event, 0);
-  DCHECK_LT(event, kNumEvents);
-  if (event_time < last_event_time_[event]) {
-    LOG(WARNING) << "Event time is not monotonically non-decreasing.  "
-                 << "Deciding not to capture this frame.";
-    return false;
-  }
-  last_event_time_[event] = event_time;
-
-  bool should_sample = false;
-  duration_of_next_frame_ = base::TimeDelta();
-  switch (event) {
-    case kCompositorUpdate:
-      smoothing_sampler_.ConsiderPresentationEvent(event_time);
-      content_sampler_.ConsiderPresentationEvent(damage_rect, event_time);
-      if (content_sampler_.HasProposal()) {
-        should_sample = content_sampler_.ShouldSample();
-        if (should_sample) {
-          event_time = content_sampler_.frame_timestamp();
-          duration_of_next_frame_ = content_sampler_.sampling_period();
-        }
-      } else {
-        should_sample = smoothing_sampler_.ShouldSample();
-        if (should_sample)
-          duration_of_next_frame_ = smoothing_sampler_.min_capture_period();
-      }
-      break;
-    case kTimerPoll:
-      // While the timer is firing, only allow a sampling if there are none
-      // currently in-progress.
-      if (last_delivered_frame_number_ == (next_frame_number_ - 1)) {
-        should_sample = smoothing_sampler_.IsOverdueForSamplingAt(event_time);
-        if (should_sample)
-          duration_of_next_frame_ = smoothing_sampler_.min_capture_period();
-      }
-      break;
-    case kNumEvents:
-      NOTREACHED();
-      break;
-  }
-
-  SetFrameTimestamp(next_frame_number_, event_time);
-  return should_sample;
-}
-
-int VideoCaptureOracle::RecordCapture() {
-  smoothing_sampler_.RecordSample();
-  content_sampler_.RecordSample(GetFrameTimestamp(next_frame_number_));
-  return next_frame_number_++;
-}
-
-bool VideoCaptureOracle::CompleteCapture(int frame_number,
-                                         bool capture_was_successful,
-                                         base::TimeTicks* frame_timestamp) {
-  // Drop frame if previous frame number is higher.
-  if (last_delivered_frame_number_ > frame_number) {
-    LOG_IF(WARNING, capture_was_successful)
-        << "Out of order frame delivery detected (have #" << frame_number
-        << ", last was #" << last_delivered_frame_number_
-        << ").  Dropping frame.";
-    return false;
-  }
-  DCHECK_NE(last_delivered_frame_number_, frame_number);
-  last_delivered_frame_number_ = frame_number;
-
-  if (!capture_was_successful) {
-    VLOG(2) << "Capture of frame #" << frame_number << " was not successful.";
-    return false;
-  }
-
-  *frame_timestamp = GetFrameTimestamp(frame_number);
-
-  // If enabled, log a measurement of how this frame timestamp has incremented
-  // in relation to an ideal increment.
-  if (VLOG_IS_ON(2) && frame_number > 0) {
-    const base::TimeDelta delta =
-        *frame_timestamp - GetFrameTimestamp(frame_number - 1);
-    if (content_sampler_.HasProposal()) {
-      const double estimated_frame_rate =
-          1000000.0 / content_sampler_.detected_period().InMicroseconds();
-      const int rounded_frame_rate =
-          static_cast<int>(estimated_frame_rate + 0.5);
-      VLOG(2) << base::StringPrintf(
-          "Captured #%d: delta=%" PRId64 " usec"
-          ", now locked into {%s}, %+0.1f%% slower than %d FPS",
-          frame_number,
-          delta.InMicroseconds(),
-          content_sampler_.detected_region().ToString().c_str(),
-          100.0 * FractionFromExpectedFrameRate(delta, rounded_frame_rate),
-          rounded_frame_rate);
-    } else {
-      VLOG(2) << base::StringPrintf(
-          "Captured #%d: delta=%" PRId64 " usec"
-          ", d/30fps=%+0.1f%%, d/25fps=%+0.1f%%, d/24fps=%+0.1f%%",
-          frame_number,
-          delta.InMicroseconds(),
-          100.0 * FractionFromExpectedFrameRate(delta, 30),
-          100.0 * FractionFromExpectedFrameRate(delta, 25),
-          100.0 * FractionFromExpectedFrameRate(delta, 24));
-    }
-  }
-
-  return !frame_timestamp->is_null();
-}
-
-base::TimeTicks VideoCaptureOracle::GetFrameTimestamp(int frame_number) const {
-  DCHECK_LE(frame_number, next_frame_number_);
-  DCHECK_LT(next_frame_number_ - frame_number, kMaxFrameTimestamps);
-  return frame_timestamps_[frame_number % kMaxFrameTimestamps];
-}
-
-void VideoCaptureOracle::SetFrameTimestamp(int frame_number,
-                                           base::TimeTicks timestamp) {
-  frame_timestamps_[frame_number % kMaxFrameTimestamps] = timestamp;
-}
-
-}  // namespace content