Move talk/media to webrtc/media

talk/media/webrtc/simulcast.cc

-/*
- * libjingle
- * Copyright 2014 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.
- */
-
-#include <stdio.h>
-
-#include "talk/media/base/streamparams.h"
-#include "talk/media/webrtc/simulcast.h"
-#include "webrtc/base/arraysize.h"
-#include "webrtc/base/common.h"
-#include "webrtc/base/logging.h"
-#include "webrtc/system_wrappers/include/field_trial.h"
-
-namespace cricket {
-
-struct SimulcastFormat {
-  int width;
-  int height;
-  // The maximum number of simulcast layers can be used for
-  // resolutions at |widthxheigh|.
-  size_t max_layers;
-  // The maximum bitrate for encoding stream at |widthxheight|, when we are
-  // not sending the next higher spatial stream.
-  int max_bitrate_kbps;
-  // The target bitrate for encoding stream at |widthxheight|, when this layer
-  // is not the highest layer (i.e., when we are sending another higher spatial
-  // stream).
-  int target_bitrate_kbps;
-  // The minimum bitrate needed for encoding stream at |widthxheight|.
-  int min_bitrate_kbps;
-};
-
-// These tables describe from which resolution we can use how many
-// simulcast layers at what bitrates (maximum, target, and minimum).
-// Important!! Keep this table from high resolution to low resolution.
-const SimulcastFormat kSimulcastFormats[] = {
-  {1920, 1080, 3, 5000, 4000, 800},
-  {1280, 720, 3,  2500, 2500, 600},
-  {960, 540, 3, 900, 900, 450},
-  {640, 360, 2, 700, 500, 150},
-  {480, 270, 2, 450, 350, 150},
-  {320, 180, 1, 200, 150, 30},
-  {0, 0, 1, 200, 150, 30}
-};
-
-// Multiway: Number of temporal layers for each simulcast stream, for maximum
-// possible number of simulcast streams |kMaxSimulcastStreams|. The array
-// goes from lowest resolution at position 0 to highest resolution.
-// For example, first three elements correspond to say: QVGA, VGA, WHD.
-static const int
-    kDefaultConferenceNumberOfTemporalLayers[webrtc::kMaxSimulcastStreams] =
-    {3, 3, 3, 3};
-
-void GetSimulcastSsrcs(const StreamParams& sp, std::vector<uint32_t>* ssrcs) {
-  const SsrcGroup* sim_group = sp.get_ssrc_group(kSimSsrcGroupSemantics);
-  if (sim_group) {
-    ssrcs->insert(
-        ssrcs->end(), sim_group->ssrcs.begin(), sim_group->ssrcs.end());
-  }
-}
-
-void MaybeExchangeWidthHeight(int* width, int* height) {
-  // |kSimulcastFormats| assumes |width| >= |height|. If not, exchange them
-  // before comparing.
-  if (*width < *height) {
-    int temp = *width;
-    *width = *height;
-    *height = temp;
-  }
-}
-
-int FindSimulcastFormatIndex(int width, int height) {
-  MaybeExchangeWidthHeight(&width, &height);
-
-  for (int i = 0; i < arraysize(kSimulcastFormats); ++i) {
-    if (width >= kSimulcastFormats[i].width &&
-        height >= kSimulcastFormats[i].height) {
-      return i;
-    }
-  }
-  return -1;
-}
-
-int FindSimulcastFormatIndex(int width, int height, size_t max_layers) {
-  MaybeExchangeWidthHeight(&width, &height);
-
-  for (int i = 0; i < arraysize(kSimulcastFormats); ++i) {
-    if (width >= kSimulcastFormats[i].width &&
-        height >= kSimulcastFormats[i].height &&
-        max_layers == kSimulcastFormats[i].max_layers) {
-      return i;
-    }
-  }
-  return -1;
-}
-
-// Simulcast stream width and height must both be dividable by
-// |2 ^ simulcast_layers - 1|.
-int NormalizeSimulcastSize(int size, size_t simulcast_layers) {
-  const int base2_exponent = static_cast<int>(simulcast_layers) - 1;
-  return ((size >> base2_exponent) << base2_exponent);
-}
-
-size_t FindSimulcastMaxLayers(int width, int height) {
-  int index = FindSimulcastFormatIndex(width, height);
-  if (index == -1) {
-    return -1;
-  }
-  return kSimulcastFormats[index].max_layers;
-}
-
-// TODO(marpan): Investigate if we should return 0 instead of -1 in
-// FindSimulcast[Max/Target/Min]Bitrate functions below, since the
-// codec struct max/min/targeBitrates are unsigned.
-int FindSimulcastMaxBitrateBps(int width, int height, size_t max_layers) {
-  const int format_index = FindSimulcastFormatIndex(width, height);
-  if (format_index == -1) {
-    return -1;
-  }
-  return kSimulcastFormats[format_index].max_bitrate_kbps * 1000;
-}
-
-int FindSimulcastTargetBitrateBps(int width,
-                                  int height,
-                                  size_t max_layers) {
-  const int format_index = FindSimulcastFormatIndex(width, height);
-  if (format_index == -1) {
-    return -1;
-  }
-  return kSimulcastFormats[format_index].target_bitrate_kbps * 1000;
-}
-
-int FindSimulcastMinBitrateBps(int width, int height, size_t max_layers) {
-  const int format_index = FindSimulcastFormatIndex(width, height);
-  if (format_index == -1) {
-    return -1;
-  }
-  return kSimulcastFormats[format_index].min_bitrate_kbps * 1000;
-}
-
-bool SlotSimulcastMaxResolution(size_t max_layers, int* width, int* height) {
-  int index = FindSimulcastFormatIndex(*width, *height, max_layers);
-  if (index == -1) {
-    LOG(LS_ERROR) << "SlotSimulcastMaxResolution";
-    return false;
-  }
-
-  *width = kSimulcastFormats[index].width;
-  *height = kSimulcastFormats[index].height;
-  LOG(LS_INFO) << "SlotSimulcastMaxResolution to width:" << *width
-               << " height:" << *height;
-  return true;
-}
-
-int GetTotalMaxBitrateBps(const std::vector<webrtc::VideoStream>& streams) {
-  int total_max_bitrate_bps = 0;
-  for (size_t s = 0; s < streams.size() - 1; ++s) {
-    total_max_bitrate_bps += streams[s].target_bitrate_bps;
-  }
-  total_max_bitrate_bps += streams.back().max_bitrate_bps;
-  return total_max_bitrate_bps;
-}
-
-std::vector<webrtc::VideoStream> GetSimulcastConfig(
-    size_t max_streams,
-    int width,
-    int height,
-    int max_bitrate_bps,
-    int max_qp,
-    int max_framerate) {
-  size_t simulcast_layers = FindSimulcastMaxLayers(width, height);
-  if (simulcast_layers > max_streams) {
-    // If the number of SSRCs in the group differs from our target
-    // number of simulcast streams for current resolution, switch down
-    // to a resolution that matches our number of SSRCs.
-    if (!SlotSimulcastMaxResolution(max_streams, &width, &height)) {
-      return std::vector<webrtc::VideoStream>();
-    }
-    simulcast_layers = max_streams;
-  }
-  std::vector<webrtc::VideoStream> streams;
-  streams.resize(simulcast_layers);
-
-  // Format width and height has to be divisible by |2 ^ number_streams - 1|.
-  width = NormalizeSimulcastSize(width, simulcast_layers);
-  height = NormalizeSimulcastSize(height, simulcast_layers);
-
-  // Add simulcast sub-streams from lower resolution to higher resolutions.
-  // Add simulcast streams, from highest resolution (|s| = number_streams -1)
-  // to lowest resolution at |s| = 0.
-  for (size_t s = simulcast_layers - 1;; --s) {
-    streams[s].width = width;
-    streams[s].height = height;
-    // TODO(pbos): Fill actual temporal-layer bitrate thresholds.
-    streams[s].temporal_layer_thresholds_bps.resize(
-        kDefaultConferenceNumberOfTemporalLayers[s] - 1);
-    streams[s].max_bitrate_bps =
-        FindSimulcastMaxBitrateBps(width, height, simulcast_layers);
-    streams[s].target_bitrate_bps =
-        FindSimulcastTargetBitrateBps(width, height, simulcast_layers);
-    streams[s].min_bitrate_bps =
-        FindSimulcastMinBitrateBps(width, height, simulcast_layers);
-    streams[s].max_qp = max_qp;
-    streams[s].max_framerate = max_framerate;
-    width /= 2;
-    height /= 2;
-    if (s == 0) {
-      break;
-    }
-  }
-
-  // Spend additional bits to boost the max stream.
-  int bitrate_left_bps = max_bitrate_bps - GetTotalMaxBitrateBps(streams);
-  if (bitrate_left_bps > 0) {
-    streams.back().max_bitrate_bps += bitrate_left_bps;
-  }
-
-  return streams;
-}
-
-static const int kScreenshareMinBitrateKbps = 50;
-static const int kScreenshareMaxBitrateKbps = 6000;
-static const int kScreenshareDefaultTl0BitrateKbps = 200;
-static const int kScreenshareDefaultTl1BitrateKbps = 1000;
-
-static const char* kScreencastLayerFieldTrialName =
-    "WebRTC-ScreenshareLayerRates";
-
-ScreenshareLayerConfig::ScreenshareLayerConfig(int tl0_bitrate, int tl1_bitrate)
-    : tl0_bitrate_kbps(tl0_bitrate), tl1_bitrate_kbps(tl1_bitrate) {
-}
-
-ScreenshareLayerConfig ScreenshareLayerConfig::GetDefault() {
-  std::string group =
-      webrtc::field_trial::FindFullName(kScreencastLayerFieldTrialName);
-
-  ScreenshareLayerConfig config(kScreenshareDefaultTl0BitrateKbps,
-                                kScreenshareDefaultTl1BitrateKbps);
-  if (!group.empty() && !FromFieldTrialGroup(group, &config)) {
-    LOG(LS_WARNING) << "Unable to parse WebRTC-ScreenshareLayerRates"
-                       " field trial group: '" << group << "'.";
-  }
-  return config;
-}
-
-bool ScreenshareLayerConfig::FromFieldTrialGroup(
-    const std::string& group,
-    ScreenshareLayerConfig* config) {
-  // Parse field trial group name, containing bitrates for tl0 and tl1.
-  int tl0_bitrate;
-  int tl1_bitrate;
-  if (sscanf(group.c_str(), "%d-%d", &tl0_bitrate, &tl1_bitrate) != 2) {
-    return false;
-  }
-
-  // Sanity check.
-  if (tl0_bitrate < kScreenshareMinBitrateKbps ||
-      tl0_bitrate > kScreenshareMaxBitrateKbps ||
-      tl1_bitrate < kScreenshareMinBitrateKbps ||
-      tl1_bitrate > kScreenshareMaxBitrateKbps || tl0_bitrate > tl1_bitrate) {
-    return false;
-  }
-
-  config->tl0_bitrate_kbps = tl0_bitrate;
-  config->tl1_bitrate_kbps = tl1_bitrate;
-
-  return true;
-}
-
-}  // namespace cricket