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* 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/videocommon.h"
#include "webrtc/rtc_base/constructormagic.h"
#include "webrtc/rtc_base/criticalsection.h"
#include "webrtc/rtc_base/optional.h"
namespace cricket {
// VideoAdapter adapts an input video frame to an output frame based on the
// specified input and output formats. The adaptation includes dropping frames
// to reduce frame rate and scaling frames.
// VideoAdapter is thread safe.
class VideoAdapter {
// The output frames will have height and width that is divisible by
// |required_resolution_alignment|.
explicit VideoAdapter(int required_resolution_alignment);
virtual ~VideoAdapter();
// Return the adapted resolution and cropping parameters given the
// input resolution. The input frame should first be cropped, then
// scaled to the final output resolution. Returns true if the frame
// should be adapted, and false if it should be dropped.
bool AdaptFrameResolution(int in_width,
int in_height,
int64_t in_timestamp_ns,
int* cropped_width,
int* cropped_height,
int* out_width,
int* out_height);
// Requests the output frame size and frame interval from
// |AdaptFrameResolution| to not be larger than |format|. Also, the input
// frame size will be cropped to match the requested aspect ratio. The
// requested aspect ratio is orientation agnostic and will be adjusted to
// maintain the input orientation, so it doesn't matter if e.g. 1280x720 or
// 720x1280 is requested.
void OnOutputFormatRequest(const VideoFormat& format);
// Requests the output frame size from |AdaptFrameResolution| to have as close
// as possible to |target_pixel_count| pixels (if set) but no more than
// |max_pixel_count|.
// |max_framerate_fps| is essentially analogous to |max_pixel_count|, but for
// framerate rather than resolution.
// Set |max_pixel_count| and/or |max_framerate_fps| to
// std::numeric_limit<int>::max() if no upper limit is desired.
void OnResolutionFramerateRequest(
const rtc::Optional<int>& target_pixel_count,
int max_pixel_count,
int max_framerate_fps);
// Determine if frame should be dropped based on input fps and requested fps.
bool KeepFrame(int64_t in_timestamp_ns);
int frames_in_; // Number of input frames.
int frames_out_; // Number of output frames.
int frames_scaled_; // Number of frames scaled.
int adaption_changes_; // Number of changes in scale factor.
int previous_width_; // Previous adapter output width.
int previous_height_; // Previous adapter output height.
// Resolution must be divisible by this factor.
const int required_resolution_alignment_;
// The target timestamp for the next frame based on requested format.
rtc::Optional<int64_t> next_frame_timestamp_ns_ GUARDED_BY(critical_section_);
// Max number of pixels requested via calls to OnOutputFormatRequest,
// OnResolutionRequest respectively.
// The adapted output format is the minimum of these.
rtc::Optional<VideoFormat> requested_format_ GUARDED_BY(critical_section_);
int resolution_request_target_pixel_count_ GUARDED_BY(critical_section_);
int resolution_request_max_pixel_count_ GUARDED_BY(critical_section_);
int max_framerate_request_ GUARDED_BY(critical_section_);
// The critical section to protect the above variables.
rtc::CriticalSection critical_section_;
} // namespace cricket