text: // libjingle
  // Copyright 2004 Google Inc.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are met:
  //
  //  1. Redistributions of source code must retain the above copyright notice,
  //     this list of conditions and the following disclaimer.
  //  2. Redistributions in binary form must reproduce the above copyright notice,
  //     this list of conditions and the following disclaimer in the documentation
  //     and/or other materials provided with the distribution.
  //  3. The name of the author may not be used to endorse or promote products
  //     derived from this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
  // EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  // OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  // OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  // ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  //
  // Common definition for video, including fourcc and VideoFormat.
  
  #ifndef TALK_MEDIA_BASE_VIDEOCOMMON_H_
  #define TALK_MEDIA_BASE_VIDEOCOMMON_H_
  
  #include <string>
  
  #include "talk/base/basictypes.h"
  #include "talk/base/timeutils.h"
  
  namespace cricket {
  
  // TODO(janahan): For now, a hard-coded ssrc is used as the video ssrc.
  // This is because when the video frame is passed to the mediaprocessor for
  // processing, it doesn't have the correct ssrc. Since currently only Tx
  // Video processing is supported, this is ok. When we switch over to trigger
  // from capturer, this should be fixed and this const removed.
  const uint32 kDummyVideoSsrc = 0xFFFFFFFF;
  
  // Minimum interval is 10k fps.
  #define FPS_TO_INTERVAL(fps) \
      (fps ? talk_base::kNumNanosecsPerSec / fps : \
      talk_base::kNumNanosecsPerSec / 10000)
  
  //////////////////////////////////////////////////////////////////////////////
  // Definition of FourCC codes
  //////////////////////////////////////////////////////////////////////////////
  // Convert four characters to a FourCC code.
  // Needs to be a macro otherwise the OS X compiler complains when the kFormat*
  // constants are used in a switch.
  #define FOURCC(a, b, c, d) ( \
      (static_cast<uint32>(a)) | (static_cast<uint32>(b) << 8) | \
      (static_cast<uint32>(c) << 16) | (static_cast<uint32>(d) << 24))
  
  // Some pages discussing FourCC codes:
  //   http://www.fourcc.org/yuv.php
  //   http://v4l2spec.bytesex.org/spec/book1.htm
  //   http://developer.apple.com/quicktime/icefloe/dispatch020.html
  //   http://msdn.microsoft.com/library/windows/desktop/dd206750.aspx#nv12
  
  enum FourCC {
    // Canonical fourcc codes used in our code.
    FOURCC_I420 = FOURCC('I', '4', '2', '0'),
    FOURCC_I422 = FOURCC('I', '4', '2', '2'),
    FOURCC_I444 = FOURCC('I', '4', '4', '4'),
    FOURCC_I411 = FOURCC('I', '4', '1', '1'),
    FOURCC_I400 = FOURCC('I', '4', '0', '0'),
    FOURCC_YU12 = FOURCC('Y', 'U', '1', '2'),  // Linux version of I420.
    FOURCC_YV12 = FOURCC('Y', 'V', '1', '2'),
    FOURCC_YV16 = FOURCC('Y', 'V', '1', '6'),
    FOURCC_YV24 = FOURCC('Y', 'V', '2', '4'),
    FOURCC_YUY2 = FOURCC('Y', 'U', 'Y', '2'),
    FOURCC_UYVY = FOURCC('U', 'Y', 'V', 'Y'),
    FOURCC_M420 = FOURCC('M', '4', '2', '0'),
    FOURCC_Q420 = FOURCC('Q', '4', '2', '0'),
    FOURCC_V210 = FOURCC('V', '2', '1', '0'),
    FOURCC_24BG = FOURCC('2', '4', 'B', 'G'),
    FOURCC_ABGR = FOURCC('A', 'B', 'G', 'R'),
    FOURCC_BGRA = FOURCC('B', 'G', 'R', 'A'),
    FOURCC_ARGB = FOURCC('A', 'R', 'G', 'B'),
    FOURCC_RGBP = FOURCC('R', 'G', 'B', 'P'),  // bgr565.
    FOURCC_RGBO = FOURCC('R', 'G', 'B', 'O'),  // abgr1555.
    FOURCC_R444 = FOURCC('R', '4', '4', '4'),  // argb4444.
    FOURCC_RAW  = FOURCC('r', 'a', 'w', ' '),
    FOURCC_NV21 = FOURCC('N', 'V', '2', '1'),
    FOURCC_NV12 = FOURCC('N', 'V', '1', '2'),
    FOURCC_MJPG = FOURCC('M', 'J', 'P', 'G'),
    FOURCC_H264 = FOURCC('H', '2', '6', '4'),
    // Next four are Bayer RGB formats. The four characters define the order of
    // the colours in each 2x2 pixel grid, going left-to-right and top-to-bottom.
    FOURCC_RGGB = FOURCC('R', 'G', 'G', 'B'),
    FOURCC_BGGR = FOURCC('B', 'G', 'G', 'R'),
    FOURCC_GRBG = FOURCC('G', 'R', 'B', 'G'),
    FOURCC_GBRG = FOURCC('G', 'B', 'R', 'G'),
  
    // Aliases for canonical fourcc codes, replaced with their canonical
    // equivalents by CanonicalFourCC().
    FOURCC_IYUV = FOURCC('I', 'Y', 'U', 'V'),  // Alias for I420.
    FOURCC_YU16 = FOURCC('Y', 'U', '1', '6'),  // Alias for I422.
    FOURCC_YU24 = FOURCC('Y', 'U', '2', '4'),  // Alias for I444.
    FOURCC_YUYV = FOURCC('Y', 'U', 'Y', 'V'),  // Alias for YUY2.
    FOURCC_YUVS = FOURCC('y', 'u', 'v', 's'),  // Alias for YUY2 on Mac.
    FOURCC_HDYC = FOURCC('H', 'D', 'Y', 'C'),  // Alias for UYVY.
    FOURCC_2VUY = FOURCC('2', 'v', 'u', 'y'),  // Alias for UYVY.
    FOURCC_JPEG = FOURCC('J', 'P', 'E', 'G'),  // Alias for MJPG.
    FOURCC_DMB1 = FOURCC('d', 'm', 'b', '1'),  // Alias for MJPG on Mac.
    FOURCC_BA81 = FOURCC('B', 'A', '8', '1'),  // Alias for BGGR.
    FOURCC_RGB3 = FOURCC('R', 'G', 'B', '3'),  // Alias for RAW.
    FOURCC_BGR3 = FOURCC('B', 'G', 'R', '3'),  // Alias for 24BG.
  
    // Match any fourcc.
    FOURCC_ANY  = 0xFFFFFFFF,
  };
  
  // Converts fourcc aliases into canonical ones.
  uint32 CanonicalFourCC(uint32 fourcc);
  
  // Get FourCC code as a string.
  inline std::string GetFourccName(uint32 fourcc) {
    std::string name;
    name.push_back(static_cast<char>(fourcc & 0xFF));
    name.push_back(static_cast<char>((fourcc >> 8) & 0xFF));
    name.push_back(static_cast<char>((fourcc >> 16) & 0xFF));
    name.push_back(static_cast<char>((fourcc >> 24) & 0xFF));
    return name;
  }
  
  void ComputeScale(int frame_width, int frame_height,
                    int* scaled_width, int* scaled_height);
  
  // Compute the frame size that conversion should crop to based on aspect ratio.
  // Ensures size is multiple of 2 due to I420 and conversion limitations.
  void ComputeCrop(int cropped_format_width, int cropped_format_height,
                   int frame_width, int frame_height,
                   int pixel_width, int pixel_height,
                   int rotation,
                   int* cropped_width, int* cropped_height);
  
  //////////////////////////////////////////////////////////////////////////////
  // Definition of VideoFormat.
  //////////////////////////////////////////////////////////////////////////////
  
  // VideoFormat with Plain Old Data for global variables.
  struct VideoFormatPod {
    int width;  // Number of pixels.
    int height;  // Number of pixels.
    int64 interval;  // Nanoseconds.
    uint32 fourcc;  // Color space. FOURCC_ANY means that any color space is OK.
  };
  
  struct VideoFormat : VideoFormatPod {
    static const int64 kMinimumInterval =
        talk_base::kNumNanosecsPerSec / 10000;  // 10k fps.
  
    VideoFormat() {
      Construct(0, 0, 0, 0);
    }
  
    VideoFormat(int w, int h, int64 interval_ns, uint32 cc) {
      Construct(w, h, interval_ns, cc);
    }
  
    explicit VideoFormat(const VideoFormatPod& format) {
      Construct(format.width, format.height, format.interval, format.fourcc);
    }
  
    void Construct(int w, int h, int64 interval_ns, uint32 cc) {
      width = w;
      height = h;
      interval = interval_ns;
      fourcc = cc;
    }
  
    static int64 FpsToInterval(int fps) {
      return fps ? talk_base::kNumNanosecsPerSec / fps : kMinimumInterval;
    }
  
    static int IntervalToFps(int64 interval) {
      // Normalize the interval first.
      interval = talk_base::_max(interval, kMinimumInterval);
      return static_cast<int>(talk_base::kNumNanosecsPerSec / interval);
    }
  
    bool operator==(const VideoFormat& format) const {
      return width == format.width && height == format.height &&
          interval == format.interval && fourcc == format.fourcc;
    }
  
    bool operator!=(const VideoFormat& format) const {
      return !(*this == format);
    }
  
    bool operator<(const VideoFormat& format) const {
      return (fourcc < format.fourcc) ||
          (fourcc == format.fourcc && width < format.width) ||
          (fourcc == format.fourcc && width == format.width &&
              height < format.height) ||
          (fourcc == format.fourcc && width == format.width &&
              height == format.height && interval > format.interval);
    }
  
    int framerate() const { return IntervalToFps(interval); }
  
    // Check if both width and height are 0.
    bool IsSize0x0() const { return 0 == width && 0 == height; }
  
    // Check if this format is less than another one by comparing the resolution
    // and frame rate.
    bool IsPixelRateLess(const VideoFormat& format) const {
      return width * height * framerate() <
          format.width * format.height * format.framerate();
    }
  
    // Get a string presentation in the form of "fourcc width x height x fps"
    std::string ToString() const;
  };
  
  }  // namespace cricket
  
  #endif  // TALK_MEDIA_BASE_VIDEOCOMMON_H_
  