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- // Copyright 2017 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 "media/capabilities/bucket_utility.h"
- #include <algorithm>
- #include <cmath>
- #include <iterator>
- #include "base/check_op.h"
- namespace {
- // TODO(chcunningham): Find some authoritative list of frame rates.
- // Framerates in this list go way beyond typical values to account for changes
- // to playback rate.
- const int kFrameRateBuckets[] = {5, 10, 20, 25, 30, 40, 50, 60,
- 70, 80, 90, 100, 120, 150, 200, 250,
- 300, 350, 400, 450, 500, 550, 600, 650,
- 700, 750, 800, 850, 900, 950, 1000, 1500};
- // A mix of width and height dimensions for common and not-so-common resolutions
- // spanning 50p -> 12K.
- // TODO(chcunningham): Ponder these a bit more.
- const int kSizeBuckets[] = {
- 50, 100, 144, 240, 256, 280, 360, 426, 480, 640, 720,
- 854, 960, 1080, 1280, 1440, 1920, 2160, 2560, 2880, 3160, 3840,
- 4128, 4320, 5120, 6144, 7360, 7680, 8000, 9000, 10000, 11000, 11520};
- // Pixel buckets that are used to quantize the resolution to limit the amount of
- // information that is stored and exposed through the API. The pixel size
- // indices are used for logging, the pixel size buckets can therefore not be
- // changed unless the corresponding logging code is updated.
- constexpr int kWebrtcPixelsBuckets[] = {1280 * 720, 1920 * 1080, 2560 * 1440,
- 3840 * 2160};
- // The boundaries between buckets are calculated as the point between the two
- // buckets.
- constexpr int kWebrtcPixelsBoundaries[] = {
- (kWebrtcPixelsBuckets[0] + kWebrtcPixelsBuckets[1]) / 2,
- (kWebrtcPixelsBuckets[1] + kWebrtcPixelsBuckets[2]) / 2,
- (kWebrtcPixelsBuckets[2] + kWebrtcPixelsBuckets[3]) / 2};
- // Static assert to make sure that `kWebrtcPixelsBoundaries[]` is updated if new
- // pixel sizes are added to kWebrtcPixelsBuckets[]`.
- static_assert(std::size(kWebrtcPixelsBoundaries) + 1 ==
- std::size(kWebrtcPixelsBuckets));
- } // namespace
- namespace media {
- gfx::Size GetSizeBucket(const gfx::Size& raw_size) {
- // If either dimension is less than 75% of the min size bucket, return an
- // empty size. Empty |natural_size_| will signal ShouldBeReporting() to return
- // false.
- const double kMinSizeBucketPercent = .75;
- if (raw_size.width() < kMinSizeBucketPercent * kSizeBuckets[0] ||
- raw_size.height() < kMinSizeBucketPercent * kSizeBuckets[0]) {
- return gfx::Size();
- }
- // Round width and height to first bucket >= |raw_size| dimensions. See
- // explanation in header file.
- const int* width_bound = std::lower_bound(
- std::begin(kSizeBuckets), std::end(kSizeBuckets), raw_size.width());
- const int* height_bound = std::lower_bound(
- std::begin(kSizeBuckets), std::end(kSizeBuckets), raw_size.height());
- // If no bucket is larger than the raw dimension, just use the last bucket.
- if (width_bound == std::end(kSizeBuckets))
- --width_bound;
- if (height_bound == std::end(kSizeBuckets))
- --height_bound;
- return gfx::Size(*width_bound, *height_bound);
- }
- int GetFpsBucket(double raw_fps) {
- int rounded_fps = std::round(raw_fps);
- // Find the first bucket that is strictly > than |rounded_fps|.
- const int* upper_bound =
- std::upper_bound(std::begin(kFrameRateBuckets),
- std::end(kFrameRateBuckets), std::round(rounded_fps));
- // If no bucket is larger than |rounded_fps|, just used the last bucket;
- if (upper_bound == std::end(kFrameRateBuckets))
- return *(upper_bound - 1);
- // Return early if its the first bucket.
- if (upper_bound == std::begin(kFrameRateBuckets))
- return *upper_bound;
- int higher_bucket = *upper_bound;
- int previous_bucket = *(upper_bound - 1);
- if (std::abs(previous_bucket - rounded_fps) <
- std::abs(higher_bucket - rounded_fps)) {
- return previous_bucket;
- }
- return higher_bucket;
- }
- int GetWebrtcPixelsBucket(int pixels) {
- return kWebrtcPixelsBuckets[GetWebrtcPixelsBucketIndex(pixels)];
- }
- int GetWebrtcPixelsBucketIndex(int pixels) {
- const int* pixels_bucket_it =
- std::lower_bound(std::begin(kWebrtcPixelsBoundaries),
- std::end(kWebrtcPixelsBoundaries), pixels);
- // The output from std::lower_bound is in the range [begin, end], hence the
- // subtraction below is well defined.
- int pixels_bucket_index =
- std::distance(std::begin(kWebrtcPixelsBoundaries), pixels_bucket_it);
- DCHECK_GE(pixels_bucket_index, 0);
- DCHECK_LT(pixels_bucket_index,
- static_cast<int>(std::size(kWebrtcPixelsBuckets)));
- return pixels_bucket_index;
- }
- } // namespace media
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