datarate_test.cc

/*
 *  Copyright (c) 2012 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */
#include "third_party/googletest/src/include/gtest/gtest.h"
#include "test/codec_factory.h"
#include "test/encode_test_driver.h"
#include "test/i420_video_source.h"
#include "test/util.h"

namespace {

class DatarateTest : public ::libvpx_test::EncoderTest,
    public ::libvpx_test::CodecTestWithParam<libvpx_test::TestMode> {
 public:
  DatarateTest() : EncoderTest(GET_PARAM(0)) {}

 protected:
  virtual void SetUp() {
    InitializeConfig();
    SetMode(GET_PARAM(1));
    ResetModel();
  }

  virtual void ResetModel() {
    last_pts_ = 0;
    bits_in_buffer_model_ = cfg_.rc_target_bitrate * cfg_.rc_buf_initial_sz;
    frame_number_ = 0;
    first_drop_ = 0;
    bits_total_ = 0;
    duration_ = 0.0;
  }

  virtual void PreEncodeFrameHook(::libvpx_test::VideoSource *video,
                                  ::libvpx_test::Encoder *encoder) {
    const vpx_rational_t tb = video->timebase();
    timebase_ = static_cast<double>(tb.num) / tb.den;
    duration_ = 0;
  }

  virtual void FramePktHook(const vpx_codec_cx_pkt_t *pkt) {
    // Time since last timestamp = duration.
    vpx_codec_pts_t duration = pkt->data.frame.pts - last_pts_;

    // TODO(jimbankoski): Remove these lines when the issue:
    // http://code.google.com/p/webm/issues/detail?id=496 is fixed.
    // For now the codec assumes buffer starts at starting buffer rate
    // plus one frame's time.
    if (last_pts_ == 0)
      duration = 1;

    // Add to the buffer the bits we'd expect from a constant bitrate server.
    bits_in_buffer_model_ += duration * timebase_ * cfg_.rc_target_bitrate
        * 1000;

    /* Test the buffer model here before subtracting the frame. Do so because
     * the way the leaky bucket model works in libvpx is to allow the buffer to
     * empty - and then stop showing frames until we've got enough bits to
     * show one. As noted in comment below (issue 495), this does not currently
     * apply to key frames. For now exclude key frames in condition below. */
    bool key_frame = (pkt->data.frame.flags & VPX_FRAME_IS_KEY) ? true: false;
    if (!key_frame) {
      ASSERT_GE(bits_in_buffer_model_, 0) << "Buffer Underrun at frame "
          << pkt->data.frame.pts;
    }