media/base/video_capture_types.h

   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 #ifndef MEDIA_BASE_VIDEO_CAPTURE_TYPES_H_
   6 #define MEDIA_BASE_VIDEO_CAPTURE_TYPES_H_
   7
   8 #include <vector>
   9
  10 #include "media/base/media_export.h"
  11 #include "ui/gfx/geometry/size.h"
  12
  13 namespace media {
  14
  15 // TODO(wjia): this type should be defined in a common place and
  16 // shared with device manager.
  17 typedef int VideoCaptureSessionId;
  18
  19 // Color formats from camera. This list is sorted in order of preference.
  20 enum VideoPixelFormat {
  21   PIXEL_FORMAT_I420,
  22   PIXEL_FORMAT_YV12,
  23   PIXEL_FORMAT_NV12,
  24   PIXEL_FORMAT_NV21,
  25   PIXEL_FORMAT_UYVY,
  26   PIXEL_FORMAT_YUY2,
  27   PIXEL_FORMAT_RGB24,
  28   PIXEL_FORMAT_RGB32,
  29   PIXEL_FORMAT_ARGB,
  30   PIXEL_FORMAT_MJPEG,
  31   PIXEL_FORMAT_TEXTURE,  // Capture format as a GL texture.
  32   PIXEL_FORMAT_GPUMEMORYBUFFER,
  33   PIXEL_FORMAT_UNKNOWN,  // Color format not set.
  34   PIXEL_FORMAT_MAX,
  35 };
  36
  37 // Policies for capture devices that have source content that varies in size.
  38 // It is up to the implementation how the captured content will be transformed
  39 // (e.g., scaling and/or letterboxing) in order to produce video frames that
  40 // strictly adheree to one of these policies.
  41 enum ResolutionChangePolicy {
  42   // Capture device outputs a fixed resolution all the time. The resolution of
  43   // the first frame is the resolution for all frames.
  44   RESOLUTION_POLICY_FIXED_RESOLUTION,
  45
  46   // Capture device is allowed to output frames of varying resolutions. The
  47   // width and height will not exceed the maximum dimensions specified. The
  48   // aspect ratio of the frames will match the aspect ratio of the maximum
  49   // dimensions as closely as possible.
  50   RESOLUTION_POLICY_FIXED_ASPECT_RATIO,
  51
  52   // Capture device is allowed to output frames of varying resolutions not
  53   // exceeding the maximum dimensions specified.
  54   RESOLUTION_POLICY_ANY_WITHIN_LIMIT,
  55
  56   RESOLUTION_POLICY_LAST,
  57 };
  58
  59 // Some drivers use rational time per frame instead of float frame rate, this
  60 // constant k is used to convert between both: A fps -> [k/k*A] seconds/frame.
  61 const int kFrameRatePrecision = 10000;
  62
  63 // Video capture format specification.
  64 // This class is used by the video capture device to specify the format of every
  65 // frame captured and returned to a client. It is also used to specify a
  66 // supported capture format by a device.
  67 class MEDIA_EXPORT VideoCaptureFormat {
  68  public:
  69   VideoCaptureFormat();
  70   VideoCaptureFormat(const gfx::Size& frame_size,
  71                      float frame_rate,
  72                      VideoPixelFormat pixel_format);
  73
  74   std::string ToString() const;
  75   static std::string PixelFormatToString(VideoPixelFormat format);
  76
  77   // Returns the required buffer size to hold an image of a given
  78   // VideoCaptureFormat with no padding and tightly packed.
  79   size_t ImageAllocationSize() const;
  80
  81   // Checks that all values are in the expected range. All limits are specified
  82   // in media::Limits.
  83   bool IsValid() const;
  84
  85   bool operator==(const VideoCaptureFormat& other) const {
  86     return frame_size == other.frame_size &&
  87         frame_rate == other.frame_rate &&
  88         pixel_format == other.pixel_format;
  89   }
  90
  91   gfx::Size frame_size;
  92   float frame_rate;
  93   VideoPixelFormat pixel_format;
  94 };
  95
  96 typedef std::vector<VideoCaptureFormat> VideoCaptureFormats;
  97
  98 // Parameters for starting video capture.
  99 // This class is used by the client of a video capture device to specify the
 100 // format of frames in which the client would like to have captured frames
 101 // returned.
 102 class MEDIA_EXPORT VideoCaptureParams {
 103  public:
 104   VideoCaptureParams();
 105
 106   bool operator==(const VideoCaptureParams& other) const {
 107     return requested_format == other.requested_format &&
 108         resolution_change_policy == other.resolution_change_policy;
 109   }
 110
 111   // Requests a resolution and format at which the capture will occur.
 112   VideoCaptureFormat requested_format;
 113
 114   // Policy for resolution change.
 115   ResolutionChangePolicy resolution_change_policy;
 116 };
 117
 118 }  // namespace media
 119
 120 #endif  // MEDIA_BASE_VIDEO_CAPTURE_TYPES_H_