Allow downsampling of output from a MediaStream video track to arbitrary max video size.

content/renderer/media/media_stream_video_source.cc

 // Copyright 2014 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/renderer/media/media_stream_video_source.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 
@@ skipping 31 matching lines @@
 const int MediaStreamVideoSource::kDefaultWidth = 640;
 const int MediaStreamVideoSource::kDefaultHeight = 480;
 const int MediaStreamVideoSource::kDefaultFrameRate = 30;
 
 namespace {
 
 // Google-specific key prefix. Constraints with this prefix are ignored if they
 // are unknown.
 const char kGooglePrefix[] = "goog";
 
-// MediaStreamVideoSource supports cropping of video frames but only up to
-// kMaxCropFactor. Ie - if a constraint is set to maxHeight 360, an original
-// input frame height of max 360 * kMaxCropFactor pixels is accepted.
-const int kMaxCropFactor = 2;
-
 // Returns true if |constraint| has mandatory constraints.
 bool HasMandatoryConstraints(const blink::WebMediaConstraints& constraints) {
   blink::WebVector<blink::WebMediaConstraint> mandatory_constraints;
   constraints.getMandatoryConstraints(mandatory_constraints);
   return !mandatory_constraints.isEmpty();
 }
 
 // Retrieve the desired max width and height from |constraints|. If not set,
 // the |desired_width| and |desired_height| are set to
 // std::numeric_limits<int>::max();
@@ skipping 97 matching lines @@
 
   int value;
   if (!base::StringToInt(constraint_value, &value)) {
     DLOG(WARNING) << "Can't parse MediaStream constraint. Name:"
                   <<  constraint_name << " Value:" << constraint_value;
     return false;
   }
   if (constraint_name == MediaStreamVideoSource::kMinWidth) {
     return (value <= format->frame_size.width());
   } else if (constraint_name == MediaStreamVideoSource::kMaxWidth) {
-    return (value * kMaxCropFactor >= format->frame_size.width());
+    return value > 0;

[mcasas, 2014/05/30 13:31:58]

Shouldn't we:
return value > kMinimumPossibleFrameWidth?

(Assuming |kMinimumPossibleFrameWidth| exists).

   } else if (constraint_name == MediaStreamVideoSource::kMinHeight) {
     return (value <= format->frame_size.height());
   } else if (constraint_name == MediaStreamVideoSource::kMaxHeight) {
-     return (value * kMaxCropFactor >= format->frame_size.height());
+     return value > 0;

[mcasas, 2014/05/30 13:31:58]

return value > kMaximumPossibleFrameWidth?

(Assuming |kMaximumPossibleFrameWidth| exists).

   } else if (constraint_name == MediaStreamVideoSource::kMinFrameRate) {
     return (value <= format->frame_rate);
   } else if (constraint_name == MediaStreamVideoSource::kMaxFrameRate) {
     if (value == 0) {
       // The frame rate is set by constraint.
       // Don't allow 0 as frame rate if it is a mandatory constraint.
       // Set the frame rate to 1 if it is not mandatory.
       if (mandatory) {
         return false;
       } else {
@@ skipping 385 matching lines @@
     : track(track),
       frame_callback(frame_callback),
       constraints(constraints),
       callback(callback) {
 }
 
 MediaStreamVideoSource::RequestedConstraints::~RequestedConstraints() {
 }
 
 }  // namespace content