1/*
2 *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#include "webrtc/common_video/libyuv/include/scaler.h"
12
13#include <algorithm>
14
15// NOTE(ajm): Path provided by gyp.
16#include "libyuv.h"  // NOLINT
17
18namespace webrtc {
19
20Scaler::Scaler()
21    : method_(kScaleBox),
22      src_width_(0),
23      src_height_(0),
24      dst_width_(0),
25      dst_height_(0),
26      set_(false) {}
27
28Scaler::~Scaler() {}
29
30int Scaler::Set(int src_width, int src_height,
31                int dst_width, int dst_height,
32                VideoType src_video_type, VideoType dst_video_type,
33                ScaleMethod method) {
34  set_ = false;
35  if (src_width < 1 || src_height < 1 || dst_width < 1 || dst_height < 1)
36    return -1;
37
38  if (!SupportedVideoType(src_video_type, dst_video_type))
39    return -1;
40
41  src_width_ = src_width;
42  src_height_ = src_height;
43  dst_width_ = dst_width;
44  dst_height_ = dst_height;
45  method_ = method;
46  set_ = true;
47  return 0;
48}
49
50int Scaler::Scale(const VideoFrame& src_frame, VideoFrame* dst_frame) {
51  assert(dst_frame);
52  if (src_frame.IsZeroSize())
53    return -1;
54  if (!set_)
55    return -2;
56
57  // Making sure that destination frame is of sufficient size.
58  dst_frame->set_video_frame_buffer(
59      buffer_pool_.CreateBuffer(dst_width_, dst_height_));
60
61  // We want to preserve aspect ratio instead of stretching the frame.
62  // Therefore, we need to crop the source frame. Calculate the largest center
63  // aligned region of the source frame that can be used.
64  const int cropped_src_width =
65      std::min(src_width_, dst_width_ * src_height_ / dst_height_);
66  const int cropped_src_height =
67      std::min(src_height_, dst_height_ * src_width_ / dst_width_);
68  // Make sure the offsets are even to avoid rounding errors for the U/V planes.
69  const int src_offset_x = ((src_width_ - cropped_src_width) / 2) & ~1;
70  const int src_offset_y = ((src_height_ - cropped_src_height) / 2) & ~1;
71
72  const uint8_t* y_ptr = src_frame.buffer(kYPlane) +
73                         src_offset_y * src_frame.stride(kYPlane) +
74                         src_offset_x;
75  const uint8_t* u_ptr = src_frame.buffer(kUPlane) +
76                         src_offset_y / 2 * src_frame.stride(kUPlane) +
77                         src_offset_x / 2;
78  const uint8_t* v_ptr = src_frame.buffer(kVPlane) +
79                         src_offset_y / 2 * src_frame.stride(kVPlane) +
80                         src_offset_x / 2;
81
82  return libyuv::I420Scale(y_ptr,
83                           src_frame.stride(kYPlane),
84                           u_ptr,
85                           src_frame.stride(kUPlane),
86                           v_ptr,
87                           src_frame.stride(kVPlane),
88                           cropped_src_width, cropped_src_height,
89                           dst_frame->buffer(kYPlane),
90                           dst_frame->stride(kYPlane),
91                           dst_frame->buffer(kUPlane),
92                           dst_frame->stride(kUPlane),
93                           dst_frame->buffer(kVPlane),
94                           dst_frame->stride(kVPlane),
95                           dst_width_, dst_height_,
96                           libyuv::FilterMode(method_));
97}
98
99bool Scaler::SupportedVideoType(VideoType src_video_type,
100                                VideoType dst_video_type) {
101  if (src_video_type != dst_video_type)
102    return false;
103
104  if ((src_video_type == kI420) || (src_video_type == kIYUV) ||
105      (src_video_type == kYV12))
106    return true;
107
108  return false;
109}
110
111}  // namespace webrtc
112