Delete unused methods of the VideoProcessing class. And fix a typo.

webrtc/modules/video_processing/deflickering.cc

-/*
- *  Copyright (c) 2011 The WebRTC 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 "webrtc/modules/video_processing/deflickering.h"
-
-#include <math.h>
-#include <stdlib.h>
-
-#include "webrtc/base/logging.h"
-#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
-#include "webrtc/system_wrappers/include/sort.h"
-
-namespace webrtc {
-
-// Detection constants
-// (Q4) Maximum allowed deviation for detection.
-enum { kFrequencyDeviation = 39 };
-// (Q4) Minimum frequency that can be detected.
-enum { kMinFrequencyToDetect = 32 };
-// Number of flickers before we accept detection
-enum { kNumFlickerBeforeDetect = 2 };
-enum { kmean_valueScaling = 4 };  // (Q4) In power of 2
-// Dead-zone region in terms of pixel values
-enum { kZeroCrossingDeadzone = 10 };
-// Deflickering constants.
-// Compute the quantiles over 1 / DownsamplingFactor of the image.
-enum { kDownsamplingFactor = 8 };
-enum { kLog2OfDownsamplingFactor = 3 };
-
-// To generate in Matlab:
-// >> probUW16 = round(2^11 *
-//     [0.05,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,0.95,0.97]);
-// >> fprintf('%d, ', probUW16)
-// Resolution reduced to avoid overflow when multiplying with the
-// (potentially) large number of pixels.
-const uint16_t VPMDeflickering::prob_uw16_[kNumProbs] = {
-    102,  205,  410,  614,  819,  1024,
-    1229, 1434, 1638, 1843, 1946, 1987};  // <Q11>
-
-// To generate in Matlab:
-// >> numQuants = 14; maxOnlyLength = 5;
-// >> weightUW16 = round(2^15 *
-//    [linspace(0.5, 1.0, numQuants - maxOnlyLength)]);
-// >> fprintf('%d, %d,\n ', weightUW16);
-const uint16_t VPMDeflickering::weight_uw16_[kNumQuants - kMaxOnlyLength] = {
-    16384, 18432, 20480, 22528, 24576, 26624, 28672, 30720, 32768};  // <Q15>
-
-VPMDeflickering::VPMDeflickering() {
-  Reset();
-}
-
-VPMDeflickering::~VPMDeflickering() {}
-
-void VPMDeflickering::Reset() {
-  mean_buffer_length_ = 0;
-  detection_state_ = 0;
-  frame_rate_ = 0;
-
-  memset(mean_buffer_, 0, sizeof(int32_t) * kMeanBufferLength);
-  memset(timestamp_buffer_, 0, sizeof(int32_t) * kMeanBufferLength);
-
-  // Initialize the history with a uniformly distributed histogram.
-  quant_hist_uw8_[0][0] = 0;
-  quant_hist_uw8_[0][kNumQuants - 1] = 255;
-  for (int32_t i = 0; i < kNumProbs; i++) {
-    // Unsigned round. <Q0>
-    quant_hist_uw8_[0][i + 1] =
-        static_cast<uint8_t>((prob_uw16_[i] * 255 + (1 << 10)) >> 11);
-  }
-
-  for (int32_t i = 1; i < kFrameHistory_size; i++) {
-    memcpy(quant_hist_uw8_[i], quant_hist_uw8_[0],
-           sizeof(uint8_t) * kNumQuants);
-  }
-}
-
-int32_t VPMDeflickering::ProcessFrame(VideoFrame* frame,
-                                      VideoProcessing::FrameStats* stats) {
-  assert(frame);
-  uint32_t frame_memory;
-  uint8_t quant_uw8[kNumQuants];
-  uint8_t maxquant_uw8[kNumQuants];
-  uint8_t minquant_uw8[kNumQuants];
-  uint16_t target_quant_uw16[kNumQuants];
-  uint16_t increment_uw16;
-  uint8_t map_uw8[256];
-
-  uint16_t tmp_uw16;
-  uint32_t tmp_uw32;
-  int width = frame->width();
-  int height = frame->height();
-
-  if (frame->IsZeroSize()) {
-    return VPM_GENERAL_ERROR;
-  }
-
-  // Stricter height check due to subsampling size calculation below.
-  if (height < 2) {
-    LOG(LS_ERROR) << "Invalid frame size.";
-    return VPM_GENERAL_ERROR;
-  }
-
-  if (!VideoProcessing::ValidFrameStats(*stats)) {
-    return VPM_GENERAL_ERROR;
-  }
-
-  if (PreDetection(frame->timestamp(), *stats) == -1)
-    return VPM_GENERAL_ERROR;
-
-  // Flicker detection
-  int32_t det_flicker = DetectFlicker();
-  if (det_flicker < 0) {
-    return VPM_GENERAL_ERROR;
-  } else if (det_flicker != 1) {
-    return 0;
-  }
-
-  // Size of luminance component.
-  const uint32_t y_size = height * width;
-
-  const uint32_t y_sub_size =
-      width * (((height - 1) >> kLog2OfDownsamplingFactor) + 1);
-  uint8_t* y_sorted = new uint8_t[y_sub_size];
-  uint32_t sort_row_idx = 0;
-  for (int i = 0; i < height; i += kDownsamplingFactor) {
-    memcpy(y_sorted + sort_row_idx * width, frame->buffer(kYPlane) + i * width,
-           width);
-    sort_row_idx++;
-  }
-
-  webrtc::Sort(y_sorted, y_sub_size, webrtc::TYPE_UWord8);
-
-  uint32_t prob_idx_uw32 = 0;
-  quant_uw8[0] = 0;
-  quant_uw8[kNumQuants - 1] = 255;
-
-  // Ensure we won't get an overflow below.
-  // In practice, the number of subsampled pixels will not become this large.
-  if (y_sub_size > (1 << 21) - 1) {
-    LOG(LS_ERROR) << "Subsampled number of pixels too large.";
-    return -1;
-  }
-
-  for (int32_t i = 0; i < kNumProbs; i++) {
-    // <Q0>.
-    prob_idx_uw32 = WEBRTC_SPL_UMUL_32_16(y_sub_size, prob_uw16_[i]) >> 11;
-    quant_uw8[i + 1] = y_sorted[prob_idx_uw32];
-  }
-
-  delete[] y_sorted;
-  y_sorted = NULL;
-
-  // Shift history for new frame.
-  memmove(quant_hist_uw8_[1], quant_hist_uw8_[0],
-          (kFrameHistory_size - 1) * kNumQuants * sizeof(uint8_t));
-  // Store current frame in history.
-  memcpy(quant_hist_uw8_[0], quant_uw8, kNumQuants * sizeof(uint8_t));
-
-  // We use a frame memory equal to the ceiling of half the frame rate to
-  // ensure we capture an entire period of flicker.
-  frame_memory = (frame_rate_ + (1 << 5)) >> 5;  // Unsigned ceiling. <Q0>
-                                                 // frame_rate_ in Q4.
-  if (frame_memory > kFrameHistory_size) {
-    frame_memory = kFrameHistory_size;
-  }
-
-  // Get maximum and minimum.
-  for (int32_t i = 0; i < kNumQuants; i++) {
-    maxquant_uw8[i] = 0;
-    minquant_uw8[i] = 255;
-    for (uint32_t j = 0; j < frame_memory; j++) {
-      if (quant_hist_uw8_[j][i] > maxquant_uw8[i]) {
-        maxquant_uw8[i] = quant_hist_uw8_[j][i];
-      }
-
-      if (quant_hist_uw8_[j][i] < minquant_uw8[i]) {
-        minquant_uw8[i] = quant_hist_uw8_[j][i];
-      }
-    }
-  }
-
-  // Get target quantiles.
-  for (int32_t i = 0; i < kNumQuants - kMaxOnlyLength; i++) {
-    // target = w * maxquant_uw8 + (1 - w) * minquant_uw8
-    // Weights w = |weight_uw16_| are in Q15, hence the final output has to be
-    // right shifted by 8 to end up in Q7.
-    target_quant_uw16[i] = static_cast<uint16_t>(
-        (weight_uw16_[i] * maxquant_uw8[i] +
-         ((1 << 15) - weight_uw16_[i]) * minquant_uw8[i]) >>
-        8);  // <Q7>
-  }
-
-  for (int32_t i = kNumQuants - kMaxOnlyLength; i < kNumQuants; i++) {
-    target_quant_uw16[i] = ((uint16_t)maxquant_uw8[i]) << 7;
-  }
-
-  // Compute the map from input to output pixels.
-  uint16_t mapUW16;  // <Q7>
-  for (int32_t i = 1; i < kNumQuants; i++) {
-    // As quant and targetQuant are limited to UWord8, it's safe to use Q7 here.
-    tmp_uw32 =
-        static_cast<uint32_t>(target_quant_uw16[i] - target_quant_uw16[i - 1]);
-    tmp_uw16 = static_cast<uint16_t>(quant_uw8[i] - quant_uw8[i - 1]);  // <Q0>
-
-    if (tmp_uw16 > 0) {
-      increment_uw16 =
-          static_cast<uint16_t>(WebRtcSpl_DivU32U16(tmp_uw32,
-                                                    tmp_uw16));  // <Q7>
-    } else {
-      // The value is irrelevant; the loop below will only iterate once.
-      increment_uw16 = 0;
-    }
-
-    mapUW16 = target_quant_uw16[i - 1];
-    for (uint32_t j = quant_uw8[i - 1]; j < (uint32_t)(quant_uw8[i] + 1); j++) {
-      // Unsigned round. <Q0>
-      map_uw8[j] = (uint8_t)((mapUW16 + (1 << 6)) >> 7);
-      mapUW16 += increment_uw16;
-    }
-  }
-
-  // Map to the output frame.
-  uint8_t* buffer = frame->buffer(kYPlane);
-  for (uint32_t i = 0; i < y_size; i++) {
-    buffer[i] = map_uw8[buffer[i]];
-  }
-
-  // Frame was altered, so reset stats.
-  VideoProcessing::ClearFrameStats(stats);
-
-  return VPM_OK;
-}
-
-/**
-   Performs some pre-detection operations. Must be called before
-   DetectFlicker().
-
-   \param[in] timestamp Timestamp of the current frame.
-   \param[in] stats     Statistics of the current frame.
-
-   \return 0: Success\n
-           2: Detection not possible due to flickering frequency too close to
-              zero.\n
-          -1: Error
-*/
-int32_t VPMDeflickering::PreDetection(
-    const uint32_t timestamp,
-    const VideoProcessing::FrameStats& stats) {
-  int32_t mean_val;  // Mean value of frame (Q4)
-  uint32_t frame_rate = 0;
-  int32_t meanBufferLength;  // Temp variable.
-
-  mean_val = ((stats.sum << kmean_valueScaling) / stats.num_pixels);
-  // Update mean value buffer.
-  // This should be done even though we might end up in an unreliable detection.
-  memmove(mean_buffer_ + 1, mean_buffer_,
-          (kMeanBufferLength - 1) * sizeof(int32_t));
-  mean_buffer_[0] = mean_val;
-
-  // Update timestamp buffer.
-  // This should be done even though we might end up in an unreliable detection.
-  memmove(timestamp_buffer_ + 1, timestamp_buffer_,
-          (kMeanBufferLength - 1) * sizeof(uint32_t));
-  timestamp_buffer_[0] = timestamp;
-
-  /* Compute current frame rate (Q4) */
-  if (timestamp_buffer_[kMeanBufferLength - 1] != 0) {
-    frame_rate = ((90000 << 4) * (kMeanBufferLength - 1));
-    frame_rate /=
-        (timestamp_buffer_[0] - timestamp_buffer_[kMeanBufferLength - 1]);
-  } else if (timestamp_buffer_[1] != 0) {
-    frame_rate = (90000 << 4) / (timestamp_buffer_[0] - timestamp_buffer_[1]);
-  }
-
-  /* Determine required size of mean value buffer (mean_buffer_length_) */
-  if (frame_rate == 0) {
-    meanBufferLength = 1;
-  } else {
-    meanBufferLength =
-        (kNumFlickerBeforeDetect * frame_rate) / kMinFrequencyToDetect;
-  }
-  /* Sanity check of buffer length */
-  if (meanBufferLength >= kMeanBufferLength) {
-    /* Too long buffer. The flickering frequency is too close to zero, which
-     * makes the estimation unreliable.
-     */
-    mean_buffer_length_ = 0;
-    return 2;
-  }
-  mean_buffer_length_ = meanBufferLength;
-
-  if ((timestamp_buffer_[mean_buffer_length_ - 1] != 0) &&
-      (mean_buffer_length_ != 1)) {
-    frame_rate = ((90000 << 4) * (mean_buffer_length_ - 1));
-    frame_rate /=
-        (timestamp_buffer_[0] - timestamp_buffer_[mean_buffer_length_ - 1]);
-  } else if (timestamp_buffer_[1] != 0) {
-    frame_rate = (90000 << 4) / (timestamp_buffer_[0] - timestamp_buffer_[1]);
-  }
-  frame_rate_ = frame_rate;
-
-  return VPM_OK;
-}
-
-/**
-   This function detects flicker in the video stream. As a side effect the
-   mean value buffer is updated with the new mean value.
-
-   \return 0: No flickering detected\n
-           1: Flickering detected\n
-           2: Detection not possible due to unreliable frequency interval
-          -1: Error
-*/
-int32_t VPMDeflickering::DetectFlicker() {
-  uint32_t i;
-  int32_t freqEst;  // (Q4) Frequency estimate to base detection upon
-  int32_t ret_val = -1;
-
-  /* Sanity check for mean_buffer_length_ */
-  if (mean_buffer_length_ < 2) {
-    /* Not possible to estimate frequency */
-    return 2;
-  }
-  // Count zero crossings with a dead zone to be robust against noise. If the
-  // noise std is 2 pixel this corresponds to about 95% confidence interval.
-  int32_t deadzone = (kZeroCrossingDeadzone << kmean_valueScaling);  // Q4
-  int32_t meanOfBuffer = 0;  // Mean value of mean value buffer.
-  int32_t numZeros = 0;      // Number of zeros that cross the dead-zone.
-  int32_t cntState = 0;      // State variable for zero crossing regions.
-  int32_t cntStateOld = 0;   // Previous state for zero crossing regions.
-
-  for (i = 0; i < mean_buffer_length_; i++) {
-    meanOfBuffer += mean_buffer_[i];
-  }
-  meanOfBuffer += (mean_buffer_length_ >> 1);  // Rounding, not truncation.
-  meanOfBuffer /= mean_buffer_length_;
-
-  // Count zero crossings.
-  cntStateOld = (mean_buffer_[0] >= (meanOfBuffer + deadzone));
-  cntStateOld -= (mean_buffer_[0] <= (meanOfBuffer - deadzone));
-  for (i = 1; i < mean_buffer_length_; i++) {
-    cntState = (mean_buffer_[i] >= (meanOfBuffer + deadzone));
-    cntState -= (mean_buffer_[i] <= (meanOfBuffer - deadzone));
-    if (cntStateOld == 0) {
-      cntStateOld = -cntState;
-    }
-    if (((cntState + cntStateOld) == 0) && (cntState != 0)) {
-      numZeros++;
-      cntStateOld = cntState;
-    }
-  }
-  // END count zero crossings.
-
-  /* Frequency estimation according to:
-  * freqEst = numZeros * frame_rate / 2 / mean_buffer_length_;
-  *
-  * Resolution is set to Q4
-  */
-  freqEst = ((numZeros * 90000) << 3);
-  freqEst /=
-      (timestamp_buffer_[0] - timestamp_buffer_[mean_buffer_length_ - 1]);
-
-  /* Translate frequency estimate to regions close to 100 and 120 Hz */
-  uint8_t freqState = 0;  // Current translation state;
-                          // (0) Not in interval,
-                          // (1) Within valid interval,
-                          // (2) Out of range
-  int32_t freqAlias = freqEst;
-  if (freqEst > kMinFrequencyToDetect) {
-    uint8_t aliasState = 1;
-    while (freqState == 0) {
-      /* Increase frequency */
-      freqAlias += (aliasState * frame_rate_);
-      freqAlias += ((freqEst << 1) * (1 - (aliasState << 1)));
-      /* Compute state */
-      freqState = (abs(freqAlias - (100 << 4)) <= kFrequencyDeviation);
-      freqState += (abs(freqAlias - (120 << 4)) <= kFrequencyDeviation);
-      freqState += 2 * (freqAlias > ((120 << 4) + kFrequencyDeviation));
-      /* Switch alias state */
-      aliasState++;
-      aliasState &= 0x01;
-    }
-  }
-  /* Is frequency estimate within detection region? */
-  if (freqState == 1) {
-    ret_val = 1;
-  } else if (freqState == 0) {
-    ret_val = 2;
-  } else {
-    ret_val = 0;
-  }
-  return ret_val;
-}
-
-}  // namespace webrtc