Adding third_party/openh264 build files for encoding

third_party/openh264/testing/i420_utils.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "third_party/openh264/testing/i420_utils.h"
+
+#include <limits>
+
+namespace openh264 {
+
+static int ClampIntRange(int x, int min, int max) {
+  return (x >= min && x <= max) ? x : (x > max ? max : min);
+}
+
+void RgbToYuv(uint8_t r, uint8_t g, uint8_t b,
+              uint8_t* y, uint8_t* u, uint8_t* v) {
+  int R = r;
+  int G = g;
+  int B = b;
+  *y = ClampIntRange(
+      (R *  2104 + G *  4130 + B *  802 + 4096 +  131072) >> 13, 16, 235);
+  *u = ClampIntRange(
+      (R * -1214 + G * -2384 + B * 3598 + 4096 + 1048576) >> 13, 16, 240);
+  *v = ClampIntRange(
+      (R *  3598 + G * -3013 + B * -585 + 4096 + 1048576) >> 13, 16, 240);
+}
+
+void YuvToRgb(uint8_t y, uint8_t u, uint8_t v,
+              uint8_t* r, uint8_t* g, uint8_t* b) {
+  int Y = y;
+  int U = u;
+  int V = v;
+  *r = ClampIntRange(
+      (Y * 9538             + V * 13074 + 4096 - 1826058) >> 13, 0, 255);
+  *g = ClampIntRange(
+      (Y * 9538 + U * -3209 + V * -6660 + 4096 + 1110639) >> 13, 0, 255);
+  *b = ClampIntRange(
+      (Y * 9538 + U * 16525 + V * -2    + 4096 - 2267650) >> 13, 0, 255);
+}
+
+void CreateRgbFrame(webrtc::VideoFrame* video_frame, int width, int height,
+                    uint8_t r, uint8_t g, uint8_t b) {
+  uint8_t y, u, v;
+  RgbToYuv(r, g, b, &y, &u, &v);
+  video_frame->CreateEmptyFrame(width, height, width, (width + 1) / 2,
+                                (width + 1) / 2);
+  memset(video_frame->buffer(webrtc::kYPlane), y,

[torbjorng, 2015/11/18 14:41:09]

Slightly ignorant comment: Should we really copy allocated_size, not actual
size?

[hbos_chromium, 2015/11/18 15:55:04]

I must admit basing this code off of
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/libjin....
Looking at allocated_size(), buffer() and VideoFrameBuffer::data() though it
looks like this is the correct size to use.

+         video_frame->allocated_size(webrtc::kYPlane));
+  memset(video_frame->buffer(webrtc::kUPlane), u,
+         video_frame->allocated_size(webrtc::kUPlane));
+  memset(video_frame->buffer(webrtc::kVPlane), v,
+         video_frame->allocated_size(webrtc::kVPlane));
+}
+
+}  // namespace openh264