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/*
* Copyright (c) 2019 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.
*/
#ifndef API_VIDEO_CODECS_VP8_FRAME_BUFFER_CONTROLLER_H_
#define API_VIDEO_CODECS_VP8_FRAME_BUFFER_CONTROLLER_H_
#include <array>
#include <cstddef>
#include <cstdint>
#include <memory>
#include <vector>
#include "absl/types/optional.h"
#include "api/fec_controller_override.h"
#include "api/video_codecs/video_codec.h"
#include "api/video_codecs/video_encoder.h"
#include "api/video_codecs/vp8_frame_config.h"
namespace webrtc {
// Some notes on the prerequisites of the TemporalLayers interface.
// * Vp8FrameBufferController is not thread safe, synchronization is the
// caller's responsibility.
// * The encoder is assumed to encode all frames in order, and callbacks to
// PopulateCodecSpecific() / OnEncodeDone() must happen in the same order.
//
// This means that in the case of pipelining encoders, it is OK to have a chain
// of calls such as this:
// - NextFrameConfig(timestampA)
// - NextFrameConfig(timestampB)
// - PopulateCodecSpecific(timestampA, ...)
// - NextFrameConfig(timestampC)
// - OnEncodeDone(timestampA, 1234, ...)
// - NextFrameConfig(timestampC)
// - OnEncodeDone(timestampB, 0, ...)
// - OnEncodeDone(timestampC, 1234, ...)
// Note that NextFrameConfig() for a new frame can happen before
// OnEncodeDone() for a previous one, but calls themselves must be both
// synchronized (e.g. run on a task queue) and in order (per type).
//
// TODO(eladalon): Revise comment (referring to PopulateCodecSpecific in this
// context is not very meaningful).
struct CodecSpecificInfo;
// Each member represents an override of the VPX configuration if the optional
// value is set.
struct Vp8EncoderConfig {
struct TemporalLayerConfig {
bool operator!=(const TemporalLayerConfig& other) const {
return ts_number_layers != other.ts_number_layers ||
ts_target_bitrate != other.ts_target_bitrate ||
ts_rate_decimator != other.ts_rate_decimator ||
ts_periodicity != other.ts_periodicity ||
ts_layer_id != other.ts_layer_id;
}
static constexpr size_t kMaxPeriodicity = 16;
static constexpr size_t kMaxLayers = 5;
// Number of active temporal layers. Set to 0 if not used.
uint32_t ts_number_layers;
// Arrays of length `ts_number_layers`, indicating (cumulative) target
// bitrate and rate decimator (e.g. 4 if every 4th frame is in the given
// layer) for each active temporal layer, starting with temporal id 0.
std::array<uint32_t, kMaxLayers> ts_target_bitrate;
std::array<uint32_t, kMaxLayers> ts_rate_decimator;
// The periodicity of the temporal pattern. Set to 0 if not used.
uint32_t ts_periodicity;
// Array of length `ts_periodicity` indicating the sequence of temporal id's
// to assign to incoming frames.
std::array<uint32_t, kMaxPeriodicity> ts_layer_id;
};
absl::optional<TemporalLayerConfig> temporal_layer_config;
// Target bitrate, in bps.
absl::optional<uint32_t> rc_target_bitrate;
// Clamp QP to max. Use 0 to disable clamping.
absl::optional<uint32_t> rc_max_quantizer;
// Error resilience mode.
absl::optional<uint32_t> g_error_resilient;
// If set to true, all previous configuration overrides should be reset.
bool reset_previous_configuration_overrides = false;
};
// This interface defines a way of delegating the logic of buffer management.
// Multiple streams may be controlled by a single controller, demuxing between
// them using stream_index.
class Vp8FrameBufferController {
public:
virtual ~Vp8FrameBufferController() = default;
// Set limits on QP.
// The limits are suggestion-only; the controller is allowed to exceed them.
virtual void SetQpLimits(size_t stream_index, int min_qp, int max_qp) = 0;
// Number of streamed controlled by `this`.
virtual size_t StreamCount() const = 0;
// If this method returns true, the encoder is free to drop frames for
// instance in an effort to uphold encoding bitrate.
// If this return false, the encoder must not drop any frames unless:
// 1. Requested to do so via Vp8FrameConfig.drop_frame
// 2. The frame to be encoded is requested to be a keyframe
// 3. The encoder detected a large overshoot and decided to drop and then
// re-encode the image at a low bitrate. In this case the encoder should
// call OnFrameDropped() once to indicate drop, and then call
// OnEncodeDone() again when the frame has actually been encoded.
virtual bool SupportsEncoderFrameDropping(size_t stream_index) const = 0;
// New target bitrate for a stream (each entry in
// `bitrates_bps` is for another temporal layer).
virtual void OnRatesUpdated(size_t stream_index,
const std::vector<uint32_t>& bitrates_bps,
int framerate_fps) = 0;
// Called by the encoder before encoding a frame. Returns a set of overrides
// the controller wishes to enact in the encoder's configuration.
// If a value is not overridden, previous overrides are still in effect.
// However, if `Vp8EncoderConfig::reset_previous_configuration_overrides`
// is set to `true`, all previous overrides are reset.
virtual Vp8EncoderConfig UpdateConfiguration(size_t stream_index) = 0;
// Returns the recommended VP8 encode flags needed.
// The timestamp may be used as both a time and a unique identifier, and so
// the caller must make sure no two frames use the same timestamp.
// The timestamp uses a 90kHz RTP clock.
// After calling this method, first call the actual encoder with the provided
// frame configuration, and then OnEncodeDone() below.
virtual Vp8FrameConfig NextFrameConfig(size_t stream_index,
uint32_t rtp_timestamp) = 0;
// Called after the encode step is done. `rtp_timestamp` must match the
// parameter use in the NextFrameConfig() call.
// `is_keyframe` must be true iff the encoder decided to encode this frame as
// a keyframe.
// If `info` is not null, the encoder may update `info` with codec specific
// data such as temporal id. `qp` should indicate the frame-level QP this
// frame was encoded at. If the encoder does not support extracting this, `qp`
// should be set to 0.
virtual void OnEncodeDone(size_t stream_index,
uint32_t rtp_timestamp,
size_t size_bytes,
bool is_keyframe,
int qp,
CodecSpecificInfo* info) = 0;
// Called when a frame is dropped by the encoder.
virtual void OnFrameDropped(size_t stream_index, uint32_t rtp_timestamp) = 0;
// Called by the encoder when the packet loss rate changes.
// `packet_loss_rate` runs between 0.0 (no loss) and 1.0 (everything lost).
virtual void OnPacketLossRateUpdate(float packet_loss_rate) = 0;
// Called by the encoder when the round trip time changes.
virtual void OnRttUpdate(int64_t rtt_ms) = 0;
// Called when a loss notification is received.
virtual void OnLossNotification(
const VideoEncoder::LossNotification& loss_notification) = 0;
};
// Interface for a factory of Vp8FrameBufferController instances.
class Vp8FrameBufferControllerFactory {
public:
virtual ~Vp8FrameBufferControllerFactory() = default;
// Clones oneself. (Avoids Vp8FrameBufferControllerFactoryFactory.)
virtual std::unique_ptr<Vp8FrameBufferControllerFactory> Clone() const = 0;
// Create a Vp8FrameBufferController instance.
virtual std::unique_ptr<Vp8FrameBufferController> Create(
const VideoCodec& codec,
const VideoEncoder::Settings& settings,
FecControllerOverride* fec_controller_override) = 0;
};
} // namespace webrtc
#endif // API_VIDEO_CODECS_VP8_FRAME_BUFFER_CONTROLLER_H_