media/capture/video/win/capability_list_win.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "media/base/video_capture_types.h"
   6 #include "media/capture/video/win/capability_list_win.h"
   7
   8 #include <algorithm>
   9 #include <functional>
  10
  11 #include "base/logging.h"
  12
  13 namespace media {
  14
  15 static bool CompareCapability(const VideoCaptureFormat& requested,
  16                               const CapabilityWin& capability_lhs,
  17                               const CapabilityWin& capability_rhs) {
  18   const VideoCaptureFormat& lhs = capability_lhs.supported_format;
  19   const VideoCaptureFormat& rhs = capability_rhs.supported_format;
  20
  21   const int diff_height_lhs =
  22       std::abs(lhs.frame_size.height() - requested.frame_size.height());
  23   const int diff_height_rhs =
  24       std::abs(rhs.frame_size.height() - requested.frame_size.height());
  25   if (diff_height_lhs != diff_height_rhs)
  26     return diff_height_lhs < diff_height_rhs;
  27
  28   const int diff_width_lhs =
  29       std::abs(lhs.frame_size.width() - requested.frame_size.width());
  30   const int diff_width_rhs =
  31       std::abs(rhs.frame_size.width() - requested.frame_size.width());
  32   if (diff_width_lhs != diff_width_rhs)
  33     return diff_width_lhs < diff_width_rhs;
  34
  35   const float diff_fps_lhs = std::fabs(lhs.frame_rate - requested.frame_rate);
  36   const float diff_fps_rhs = std::fabs(rhs.frame_rate - requested.frame_rate);
  37   if (diff_fps_lhs != diff_fps_rhs)
  38     return diff_fps_lhs < diff_fps_rhs;
  39
  40   return VideoCaptureFormat::ComparePixelFormatPreference(lhs.pixel_format,
  41                                                           rhs.pixel_format);
  42 }
  43
  44 const CapabilityWin& GetBestMatchedCapability(
  45     const VideoCaptureFormat& requested,
  46     const CapabilityList& capabilities) {
  47   DCHECK(!capabilities.empty());
  48   const CapabilityWin* best_match = &(*capabilities.begin());
  49   for (const CapabilityWin& capability : capabilities) {
  50     if (CompareCapability(requested, capability, *best_match))
  51       best_match = &capability;
  52   }
  53   return *best_match;
  54 }
  55
  56 }  // namespace media