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 "build/build_config.h"
  11 #include "media/base/media_export.h"
  12 #include "ui/gfx/geometry/size.h"
  13
  14 namespace media {
  15
  16 // TODO(wjia): this type should be defined in a common place and
  17 // shared with device manager.
  18 typedef int VideoCaptureSessionId;
  19
  20 // Color formats from camera. This list is sorted in order of preference.
  21 // TODO(mcasas): Consider if this list can be merged with media::Format.
  22 // TODO(mcasas): http://crbug.com/504160 Consider making this an enum class.
  23 enum VideoPixelFormat {
  24   PIXEL_FORMAT_I420,
  25   PIXEL_FORMAT_YV12,
  26   PIXEL_FORMAT_NV12,
  27   PIXEL_FORMAT_NV21,
  28   PIXEL_FORMAT_UYVY,
  29   PIXEL_FORMAT_YUY2,
  30   PIXEL_FORMAT_RGB24,
  31   PIXEL_FORMAT_RGB32,
  32   PIXEL_FORMAT_ARGB,
  33   PIXEL_FORMAT_MJPEG,
  34   PIXEL_FORMAT_UNKNOWN,  // Color format not set.
  35   PIXEL_FORMAT_MAX = PIXEL_FORMAT_UNKNOWN,
  36 };
  37
  38 // Storage type for the pixels. In principle, all combinations of Storage and
  39 // Format are possible, though some are very typical, such as texture + ARGB,
  40 // and others are only available if the platform allows it e.g. GpuMemoryBuffer.
  41 // TODO(mcasas): http://crbug.com/504160 Consider making this an enum class.
  42 enum VideoPixelStorage {
  43   PIXEL_STORAGE_CPU,
  44   PIXEL_STORAGE_TEXTURE,
  45   PIXEL_STORAGE_GPUMEMORYBUFFER,
  46   PIXEL_STORAGE_MAX = PIXEL_STORAGE_GPUMEMORYBUFFER,
  47 };
  48
  49 // Policies for capture devices that have source content that varies in size.
  50 // It is up to the implementation how the captured content will be transformed
  51 // (e.g., scaling and/or letterboxing) in order to produce video frames that
  52 // strictly adheree to one of these policies.
  53 enum ResolutionChangePolicy {
  54   // Capture device outputs a fixed resolution all the time. The resolution of
  55   // the first frame is the resolution for all frames.
  56   RESOLUTION_POLICY_FIXED_RESOLUTION,
  57
  58   // Capture device is allowed to output frames of varying resolutions. The
  59   // width and height will not exceed the maximum dimensions specified. The
  60   // aspect ratio of the frames will match the aspect ratio of the maximum
  61   // dimensions as closely as possible.
  62   RESOLUTION_POLICY_FIXED_ASPECT_RATIO,
  63
  64   // Capture device is allowed to output frames of varying resolutions not
  65   // exceeding the maximum dimensions specified.
  66   RESOLUTION_POLICY_ANY_WITHIN_LIMIT,
  67
  68   // Must always be equal to largest entry in the enum.
  69   RESOLUTION_POLICY_LAST = RESOLUTION_POLICY_ANY_WITHIN_LIMIT,
  70 };
  71
  72 // Some drivers use rational time per frame instead of float frame rate, this
  73 // constant k is used to convert between both: A fps -> [k/k*A] seconds/frame.
  74 const int kFrameRatePrecision = 10000;
  75
  76 // Video capture format specification.
  77 // This class is used by the video capture device to specify the format of every
  78 // frame captured and returned to a client. It is also used to specify a
  79 // supported capture format by a device.
  80 struct MEDIA_EXPORT VideoCaptureFormat {
  81   VideoCaptureFormat();
  82   VideoCaptureFormat(const gfx::Size& frame_size,
  83                      float frame_rate,
  84                      VideoPixelFormat pixel_format);
  85   VideoCaptureFormat(const gfx::Size& frame_size,
  86                      float frame_rate,
  87                      VideoPixelFormat pixel_format,
  88                      VideoPixelStorage pixel_storage);
  89
  90   static std::string ToString(const VideoCaptureFormat& format);
  91   static std::string PixelFormatToString(VideoPixelFormat format);
  92   static std::string PixelStorageToString(VideoPixelStorage storage);
  93
  94   // Returns the required buffer size to hold an image of a given
  95   // VideoCaptureFormat with no padding and tightly packed.
  96   size_t ImageAllocationSize() const;
  97
  98   // Checks that all values are in the expected range. All limits are specified
  99   // in media::Limits.
 100   bool IsValid() const;
 101
 102   bool operator==(const VideoCaptureFormat& other) const {
 103     return frame_size == other.frame_size &&
 104         frame_rate == other.frame_rate &&
 105         pixel_format == other.pixel_format;
 106   }
 107
 108   gfx::Size frame_size;
 109   float frame_rate;
 110   VideoPixelFormat pixel_format;
 111   VideoPixelStorage pixel_storage;
 112 };
 113
 114 typedef std::vector<VideoCaptureFormat> VideoCaptureFormats;
 115
 116 // Parameters for starting video capture.
 117 // This class is used by the client of a video capture device to specify the
 118 // format of frames in which the client would like to have captured frames
 119 // returned.
 120 struct MEDIA_EXPORT VideoCaptureParams {
 121   VideoCaptureParams();
 122
 123   bool operator==(const VideoCaptureParams& other) const {
 124     return requested_format == other.requested_format &&
 125            use_gpu_memory_buffers == other.use_gpu_memory_buffers &&
 126            resolution_change_policy == other.resolution_change_policy;
 127   }
 128
 129   // Requests a resolution and format at which the capture will occur.
 130   VideoCaptureFormat requested_format;
 131
 132   // Policy for resolution change.
 133   ResolutionChangePolicy resolution_change_policy;
 134
 135   // Indication to the Driver to try to use GpuMemoryBuffers.
 136   bool use_gpu_memory_buffers;
 137 };
 138
 139 }  // namespace media
 140
 141 #endif  // MEDIA_BASE_VIDEO_CAPTURE_TYPES_H_