| /* |
| * Copyright (c) 2010 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/media/base/videoadapter.h" |
| |
| #include <algorithm> |
| #include <cmath> |
| #include <cstdlib> |
| #include <limits> |
| |
| #include "webrtc/base/arraysize.h" |
| #include "webrtc/base/checks.h" |
| #include "webrtc/base/logging.h" |
| #include "webrtc/base/optional.h" |
| #include "webrtc/media/base/mediaconstants.h" |
| #include "webrtc/media/base/videocommon.h" |
| |
| namespace { |
| struct Fraction { |
| int numerator; |
| int denominator; |
| |
| // Determines number of output pixels if both width and height of an input of |
| // |input_pixels| pixels is scaled with the fraction numerator / denominator. |
| int scale_pixel_count(int input_pixels) { |
| return (numerator * numerator * input_pixels) / (denominator * denominator); |
| } |
| }; |
| |
| // Round |value_to_round| to a multiple of |multiple|. Prefer rounding upwards, |
| // but never more than |max_value|. |
| int roundUp(int value_to_round, int multiple, int max_value) { |
| const int rounded_value = |
| (value_to_round + multiple - 1) / multiple * multiple; |
| return rounded_value <= max_value ? rounded_value |
| : (max_value / multiple * multiple); |
| } |
| |
| // Generates a scale factor that makes |input_pixels| close to |target_pixels|, |
| // but no higher than |max_pixels|. |
| Fraction FindScale(int input_pixels, int target_pixels, int max_pixels) { |
| // This function only makes sense for a positive target. |
| RTC_DCHECK_GT(target_pixels, 0); |
| RTC_DCHECK_GT(max_pixels, 0); |
| RTC_DCHECK_GE(max_pixels, target_pixels); |
| |
| // Don't scale up original. |
| if (target_pixels >= input_pixels) |
| return Fraction{1, 1}; |
| |
| Fraction current_scale = Fraction{1, 1}; |
| Fraction best_scale = Fraction{1, 1}; |
| // The minimum (absolute) difference between the number of output pixels and |
| // the target pixel count. |
| int min_pixel_diff = std::numeric_limits<int>::max(); |
| if (input_pixels <= max_pixels) { |
| // Start condition for 1/1 case, if it is less than max. |
| min_pixel_diff = std::abs(input_pixels - target_pixels); |
| } |
| |
| // Alternately scale down by 2/3 and 3/4. This results in fractions which are |
| // effectively scalable. For instance, starting at 1280x720 will result in |
| // the series (3/4) => 960x540, (1/2) => 640x360, (3/8) => 480x270, |
| // (1/4) => 320x180, (3/16) => 240x125, (1/8) => 160x90. |
| while (current_scale.scale_pixel_count(input_pixels) > target_pixels) { |
| if (current_scale.numerator % 3 == 0 && |
| current_scale.denominator % 2 == 0) { |
| // Multiply by 2/3. |
| current_scale.numerator /= 3; |
| current_scale.denominator /= 2; |
| } else { |
| // Multiply by 3/4. |
| current_scale.numerator *= 3; |
| current_scale.denominator *= 4; |
| } |
| |
| int output_pixels = current_scale.scale_pixel_count(input_pixels); |
| if (output_pixels <= max_pixels) { |
| int diff = std::abs(target_pixels - output_pixels); |
| if (diff < min_pixel_diff) { |
| min_pixel_diff = diff; |
| best_scale = current_scale; |
| } |
| } |
| } |
| |
| return best_scale; |
| } |
| } // namespace |
| |
| namespace cricket { |
| |
| VideoAdapter::VideoAdapter(int required_resolution_alignment) |
| : frames_in_(0), |
| frames_out_(0), |
| frames_scaled_(0), |
| adaption_changes_(0), |
| previous_width_(0), |
| previous_height_(0), |
| required_resolution_alignment_(required_resolution_alignment), |
| resolution_request_target_pixel_count_(std::numeric_limits<int>::max()), |
| resolution_request_max_pixel_count_(std::numeric_limits<int>::max()), |
| max_framerate_request_(std::numeric_limits<int>::max()) {} |
| |
| VideoAdapter::VideoAdapter() : VideoAdapter(1) {} |
| |
| VideoAdapter::~VideoAdapter() {} |
| |
| bool VideoAdapter::KeepFrame(int64_t in_timestamp_ns) { |
| rtc::CritScope cs(&critical_section_); |
| if (max_framerate_request_ <= 0) |
| return false; |
| |
| int64_t frame_interval_ns = |
| requested_format_ ? requested_format_->interval : 0; |
| |
| // If |max_framerate_request_| is not set, it will default to maxint, which |
| // will lead to a frame_interval_ns rounded to 0. |
| frame_interval_ns = std::max<int64_t>( |
| frame_interval_ns, rtc::kNumNanosecsPerSec / max_framerate_request_); |
| |
| if (frame_interval_ns <= 0) { |
| // Frame rate throttling not enabled. |
| return true; |
| } |
| |
| if (next_frame_timestamp_ns_) { |
| // Time until next frame should be outputted. |
| const int64_t time_until_next_frame_ns = |
| (*next_frame_timestamp_ns_ - in_timestamp_ns); |
| |
| // Continue if timestamp is within expected range. |
| if (std::abs(time_until_next_frame_ns) < 2 * frame_interval_ns) { |
| // Drop if a frame shouldn't be outputted yet. |
| if (time_until_next_frame_ns > 0) |
| return false; |
| // Time to output new frame. |
| *next_frame_timestamp_ns_ += frame_interval_ns; |
| return true; |
| } |
| } |
| |
| // First timestamp received or timestamp is way outside expected range, so |
| // reset. Set first timestamp target to just half the interval to prefer |
| // keeping frames in case of jitter. |
| next_frame_timestamp_ns_ = |
| rtc::Optional<int64_t>(in_timestamp_ns + frame_interval_ns / 2); |
| return true; |
| } |
| |
| bool VideoAdapter::AdaptFrameResolution(int in_width, |
| int in_height, |
| int64_t in_timestamp_ns, |
| int* cropped_width, |
| int* cropped_height, |
| int* out_width, |
| int* out_height) { |
| rtc::CritScope cs(&critical_section_); |
| ++frames_in_; |
| |
| // The max output pixel count is the minimum of the requests from |
| // OnOutputFormatRequest and OnResolutionRequest. |
| int max_pixel_count = resolution_request_max_pixel_count_; |
| if (requested_format_) { |
| max_pixel_count = std::min( |
| max_pixel_count, requested_format_->width * requested_format_->height); |
| } |
| int target_pixel_count = |
| std::min(resolution_request_target_pixel_count_, max_pixel_count); |
| |
| // Drop the input frame if necessary. |
| if (max_pixel_count <= 0 || !KeepFrame(in_timestamp_ns)) { |
| // Show VAdapt log every 90 frames dropped. (3 seconds) |
| if ((frames_in_ - frames_out_) % 90 == 0) { |
| // TODO(fbarchard): Reduce to LS_VERBOSE when adapter info is not needed |
| // in default calls. |
| LOG(LS_INFO) << "VAdapt Drop Frame: scaled " << frames_scaled_ |
| << " / out " << frames_out_ |
| << " / in " << frames_in_ |
| << " Changes: " << adaption_changes_ |
| << " Input: " << in_width |
| << "x" << in_height |
| << " timestamp: " << in_timestamp_ns |
| << " Output: i" |
| << (requested_format_ ? requested_format_->interval : 0); |
| } |
| |
| // Drop frame. |
| return false; |
| } |
| |
| // Calculate how the input should be cropped. |
| if (!requested_format_ || |
| requested_format_->width == 0 || requested_format_->height == 0) { |
| *cropped_width = in_width; |
| *cropped_height = in_height; |
| } else { |
| // Adjust |requested_format_| orientation to match input. |
| if ((in_width > in_height) != |
| (requested_format_->width > requested_format_->height)) { |
| std::swap(requested_format_->width, requested_format_->height); |
| } |
| const float requested_aspect = |
| requested_format_->width / |
| static_cast<float>(requested_format_->height); |
| *cropped_width = |
| std::min(in_width, static_cast<int>(in_height * requested_aspect)); |
| *cropped_height = |
| std::min(in_height, static_cast<int>(in_width / requested_aspect)); |
| } |
| const Fraction scale = FindScale((*cropped_width) * (*cropped_height), |
| target_pixel_count, max_pixel_count); |
| // Adjust cropping slightly to get even integer output size and a perfect |
| // scale factor. Make sure the resulting dimensions are aligned correctly |
| // to be nice to hardware encoders. |
| *cropped_width = |
| roundUp(*cropped_width, |
| scale.denominator * required_resolution_alignment_, in_width); |
| *cropped_height = |
| roundUp(*cropped_height, |
| scale.denominator * required_resolution_alignment_, in_height); |
| RTC_DCHECK_EQ(0, *cropped_width % scale.denominator); |
| RTC_DCHECK_EQ(0, *cropped_height % scale.denominator); |
| |
| // Calculate final output size. |
| *out_width = *cropped_width / scale.denominator * scale.numerator; |
| *out_height = *cropped_height / scale.denominator * scale.numerator; |
| RTC_DCHECK_EQ(0, *out_width % required_resolution_alignment_); |
| RTC_DCHECK_EQ(0, *out_height % required_resolution_alignment_); |
| |
| ++frames_out_; |
| if (scale.numerator != scale.denominator) |
| ++frames_scaled_; |
| |
| if (previous_width_ && (previous_width_ != *out_width || |
| previous_height_ != *out_height)) { |
| ++adaption_changes_; |
| LOG(LS_INFO) << "Frame size changed: scaled " << frames_scaled_ << " / out " |
| << frames_out_ << " / in " << frames_in_ |
| << " Changes: " << adaption_changes_ << " Input: " << in_width |
| << "x" << in_height |
| << " Scale: " << scale.numerator << "/" << scale.denominator |
| << " Output: " << *out_width << "x" << *out_height << " i" |
| << (requested_format_ ? requested_format_->interval : 0); |
| } |
| |
| previous_width_ = *out_width; |
| previous_height_ = *out_height; |
| |
| return true; |
| } |
| |
| void VideoAdapter::OnOutputFormatRequest(const VideoFormat& format) { |
| rtc::CritScope cs(&critical_section_); |
| requested_format_ = rtc::Optional<VideoFormat>(format); |
| next_frame_timestamp_ns_ = rtc::Optional<int64_t>(); |
| } |
| |
| void VideoAdapter::OnResolutionFramerateRequest( |
| const rtc::Optional<int>& target_pixel_count, |
| int max_pixel_count, |
| int max_framerate_fps) { |
| rtc::CritScope cs(&critical_section_); |
| resolution_request_max_pixel_count_ = max_pixel_count; |
| resolution_request_target_pixel_count_ = |
| target_pixel_count.value_or(resolution_request_max_pixel_count_); |
| max_framerate_request_ = max_framerate_fps; |
| } |
| |
| } // namespace cricket |
