Update sink wants with ranges for both pixel count and frame rate.

webrtc/media/base/videoadapter.cc

Index: webrtc/media/base/videoadapter.cc
diff --git a/webrtc/media/base/videoadapter.cc b/webrtc/media/base/videoadapter.cc
index 660df8ad673e8f40668d8f150722cb21082073ee..f84114c9c1a60809f03d8e041b3f24106c7930b2 100644
--- a/webrtc/media/base/videoadapter.cc
+++ b/webrtc/media/base/videoadapter.cc
@@ -21,6 +21,7 @@
 #include "webrtc/base/optional.h"
 #include "webrtc/media/base/mediaconstants.h"
 #include "webrtc/media/base/videocommon.h"
+#include "webrtc/media/base/videosourceinterface.h"
 
 namespace {
 struct Fraction {
@@ -45,7 +46,10 @@ int roundUp(int value_to_round, int multiple, int max_value) {
 
 // Generates a scale factor that makes |input_pixels| close to |target_pixels|,
 // but no higher than |max_pixels|.
-Fraction FindScale(int input_pixels, int target_pixels, int max_pixels) {
+Fraction FindScale(int input_pixels,
+                   int target_pixels,
+                   int max_pixels,
+                   int min_pixels) {
   // This function only makes sense for a positive target.
   RTC_DCHECK_GT(target_pixels, 0);
   RTC_DCHECK_GT(max_pixels, 0);
@@ -82,6 +86,10 @@ Fraction FindScale(int input_pixels, int target_pixels, int max_pixels) {
     }
 
     int output_pixels = current_scale.scale_pixel_count(input_pixels);
+    if (output_pixels < min_pixels) {
+      // Don't violate lower bound;
+      break;
+    }
     if (output_pixels <= max_pixels) {
       int diff = std::abs(target_pixels - output_pixels);
       if (diff < min_pixel_diff) {
@@ -104,9 +112,7 @@ VideoAdapter::VideoAdapter(int required_resolution_alignment)
       adaption_changes_(0),
       previous_width_(0),
       previous_height_(0),
-      required_resolution_alignment_(required_resolution_alignment),
-      resolution_request_target_pixel_count_(std::numeric_limits<int>::max()),
-      resolution_request_max_pixel_count_(std::numeric_limits<int>::max()) {}
+      required_resolution_alignment_(required_resolution_alignment) {}
 
 VideoAdapter::VideoAdapter() : VideoAdapter(1) {}
 
@@ -114,21 +120,35 @@ VideoAdapter::~VideoAdapter() {}
 
 bool VideoAdapter::KeepFrame(int64_t in_timestamp_ns) {
   rtc::CritScope cs(&critical_section_);
-  if (!requested_format_ || requested_format_->interval == 0)
+
+  int64_t frame_interval_ns = 0;
+  if (requested_format_ && requested_format_->interval)
+    frame_interval_ns = requested_format_->interval;
+  // TODO(sprang): Take target/min into consideration when implementing smoother
+  // frame dropping.
+  if (requested_sink_wants_.framerate_fps_) {
+    frame_interval_ns = std::max<int64_t>(
+        frame_interval_ns,
+        rtc::kNumNanosecsPerSec / requested_sink_wants_.framerate_fps_->max);
+  }
+
+  if (frame_interval_ns <= 0) {
+    // Frame rate throttling not enabled.
     return true;
+  }
 
   if (next_frame_timestamp_ns_) {
     // Time until next frame should be outputted.
     const int64_t time_until_next_frame_ns =
         (*next_frame_timestamp_ns_ - in_timestamp_ns);
 
-    // Continue if timestamp is withing expected range.
-    if (std::abs(time_until_next_frame_ns) < 2 * requested_format_->interval) {
+    // Continue if timestamp is within expected range.
+    if (std::abs(time_until_next_frame_ns) < 2 * frame_interval_ns) {
       // Drop if a frame shouldn't be outputted yet.
       if (time_until_next_frame_ns > 0)
         return false;
       // Time to output new frame.
-      *next_frame_timestamp_ns_ += requested_format_->interval;
+      *next_frame_timestamp_ns_ += frame_interval_ns;
       return true;
     }
   }
@@ -137,7 +157,7 @@ bool VideoAdapter::KeepFrame(int64_t in_timestamp_ns) {
   // reset. Set first timestamp target to just half the interval to prefer
   // keeping frames in case of jitter.
   next_frame_timestamp_ns_ =
-      rtc::Optional<int64_t>(in_timestamp_ns + requested_format_->interval / 2);
+      rtc::Optional<int64_t>(in_timestamp_ns + frame_interval_ns / 2);
   return true;
 }
 
@@ -153,13 +173,19 @@ bool VideoAdapter::AdaptFrameResolution(int in_width,
 
   // The max output pixel count is the minimum of the requests from
   // OnOutputFormatRequest and OnResolutionRequest.
-  int max_pixel_count = resolution_request_max_pixel_count_;
+
+  rtc::VideoSinkWants::ValueRange requested_range =
+      requested_sink_wants_.pixel_count.value_or(
+          rtc::VideoSinkWants::ValueRange());
+  RTC_DCHECK_GE(requested_range.target, requested_range.min);
+  RTC_DCHECK_GE(requested_range.max, requested_range.target);
+  uint32_t max_pixel_count = requested_range.max;
   if (requested_format_) {
     max_pixel_count = std::min(
-        max_pixel_count, requested_format_->width * requested_format_->height);
+        max_pixel_count, static_cast<uint32_t>(requested_format_->width *
+                                               requested_format_->height));
   }
-  int target_pixel_count =
-      std::min(resolution_request_target_pixel_count_, max_pixel_count);
+  int target_pixel_count = std::min(requested_range.target, max_pixel_count);
 
   // Drop the input frame if necessary.
   if (max_pixel_count <= 0 || !KeepFrame(in_timestamp_ns)) {
@@ -201,8 +227,9 @@ bool VideoAdapter::AdaptFrameResolution(int in_width,
     *cropped_height =
         std::min(in_height, static_cast<int>(in_width / requested_aspect));
   }
-  const Fraction scale = FindScale((*cropped_width) * (*cropped_height),
-                                   target_pixel_count, max_pixel_count);
+  const Fraction scale =
+      FindScale((*cropped_width) * (*cropped_height), target_pixel_count,
+                max_pixel_count, requested_range.min);
   // Adjust cropping slightly to get even integer output size and a perfect
   // scale factor. Make sure the resulting dimensions are aligned correctly
   // to be nice to hardware encoders.
@@ -249,14 +276,9 @@ void VideoAdapter::OnOutputFormatRequest(const VideoFormat& format) {
   next_frame_timestamp_ns_ = rtc::Optional<int64_t>();
 }
 
-void VideoAdapter::OnResolutionRequest(
-    const rtc::Optional<int>& target_pixel_count,
-    const rtc::Optional<int>& max_pixel_count) {
+void VideoAdapter::OnSinkWantsUpdated(const rtc::VideoSinkWants& sink_wants) {

[nisse-webrtc, 2017/02/17 08:55:21]

I understand this change makes things look a little simpler, but it's not quite
the right level of abstraction. 

I think it's preferable to only pass and copy the entries of the SinkWants which
the video adapter needs, which would be everything but the |rotation_applied|
and |black_frames| flags. Using the Range type is fine, though.

[sprang_webrtc, 2017/02/20 15:48:35]

Fair enough. Just didn't want to pass along 6 optional<int> :)

   rtc::CritScope cs(&critical_section_);
-  resolution_request_max_pixel_count_ =
-      max_pixel_count.value_or(std::numeric_limits<int>::max());
-  resolution_request_target_pixel_count_ =
-      target_pixel_count.value_or(resolution_request_max_pixel_count_);
+  requested_sink_wants_ = sink_wants;
 }
 
 }  // namespace cricket