428 lines
18 KiB
C++
428 lines
18 KiB
C++
/*
|
|
* Copyright (c) 2014 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_VIDEO_ENCODER_H_
|
|
#define API_VIDEO_CODECS_VIDEO_ENCODER_H_
|
|
|
|
#include <limits>
|
|
#include <memory>
|
|
#include <string>
|
|
#include <vector>
|
|
|
|
#include "absl/container/inlined_vector.h"
|
|
#include "absl/types/optional.h"
|
|
#include "api/fec_controller_override.h"
|
|
#include "api/units/data_rate.h"
|
|
#include "api/video/encoded_image.h"
|
|
#include "api/video/video_bitrate_allocation.h"
|
|
#include "api/video/video_codec_constants.h"
|
|
#include "api/video/video_frame.h"
|
|
#include "api/video_codecs/video_codec.h"
|
|
#include "rtc_base/checks.h"
|
|
#include "rtc_base/system/rtc_export.h"
|
|
|
|
namespace webrtc {
|
|
|
|
// TODO(pbos): Expose these through a public (root) header or change these APIs.
|
|
struct CodecSpecificInfo;
|
|
|
|
constexpr int kDefaultMinPixelsPerFrame = 320 * 180;
|
|
|
|
class RTC_EXPORT EncodedImageCallback {
|
|
public:
|
|
virtual ~EncodedImageCallback() {}
|
|
|
|
struct Result {
|
|
enum Error {
|
|
OK,
|
|
|
|
// Failed to send the packet.
|
|
ERROR_SEND_FAILED,
|
|
};
|
|
|
|
explicit Result(Error error) : error(error) {}
|
|
Result(Error error, uint32_t frame_id) : error(error), frame_id(frame_id) {}
|
|
|
|
Error error;
|
|
|
|
// Frame ID assigned to the frame. The frame ID should be the same as the ID
|
|
// seen by the receiver for this frame. RTP timestamp of the frame is used
|
|
// as frame ID when RTP is used to send video. Must be used only when
|
|
// error=OK.
|
|
uint32_t frame_id = 0;
|
|
|
|
// Tells the encoder that the next frame is should be dropped.
|
|
bool drop_next_frame = false;
|
|
};
|
|
|
|
// Used to signal the encoder about reason a frame is dropped.
|
|
// kDroppedByMediaOptimizations - dropped by MediaOptimizations (for rate
|
|
// limiting purposes).
|
|
// kDroppedByEncoder - dropped by encoder's internal rate limiter.
|
|
enum class DropReason : uint8_t {
|
|
kDroppedByMediaOptimizations,
|
|
kDroppedByEncoder
|
|
};
|
|
|
|
// Callback function which is called when an image has been encoded.
|
|
virtual Result OnEncodedImage(
|
|
const EncodedImage& encoded_image,
|
|
const CodecSpecificInfo* codec_specific_info) = 0;
|
|
|
|
virtual void OnDroppedFrame(DropReason reason) {}
|
|
};
|
|
|
|
class RTC_EXPORT VideoEncoder {
|
|
public:
|
|
struct QpThresholds {
|
|
QpThresholds(int l, int h) : low(l), high(h) {}
|
|
QpThresholds() : low(-1), high(-1) {}
|
|
int low;
|
|
int high;
|
|
};
|
|
|
|
// Quality scaling is enabled if thresholds are provided.
|
|
struct RTC_EXPORT ScalingSettings {
|
|
private:
|
|
// Private magic type for kOff, implicitly convertible to
|
|
// ScalingSettings.
|
|
struct KOff {};
|
|
|
|
public:
|
|
// TODO(nisse): Would be nicer if kOff were a constant ScalingSettings
|
|
// rather than a magic value. However, absl::optional is not trivially copy
|
|
// constructible, and hence a constant ScalingSettings needs a static
|
|
// initializer, which is strongly discouraged in Chrome. We can hopefully
|
|
// fix this when we switch to absl::optional or std::optional.
|
|
static constexpr KOff kOff = {};
|
|
|
|
ScalingSettings(int low, int high);
|
|
ScalingSettings(int low, int high, int min_pixels);
|
|
ScalingSettings(const ScalingSettings&);
|
|
ScalingSettings(KOff); // NOLINT(runtime/explicit)
|
|
~ScalingSettings();
|
|
|
|
absl::optional<QpThresholds> thresholds;
|
|
|
|
// We will never ask for a resolution lower than this.
|
|
// TODO(kthelgason): Lower this limit when better testing
|
|
// on MediaCodec and fallback implementations are in place.
|
|
// See https://bugs.chromium.org/p/webrtc/issues/detail?id=7206
|
|
int min_pixels_per_frame = kDefaultMinPixelsPerFrame;
|
|
|
|
private:
|
|
// Private constructor; to get an object without thresholds, use
|
|
// the magic constant ScalingSettings::kOff.
|
|
ScalingSettings();
|
|
};
|
|
|
|
// Bitrate limits for resolution.
|
|
struct ResolutionBitrateLimits {
|
|
ResolutionBitrateLimits(int frame_size_pixels,
|
|
int min_start_bitrate_bps,
|
|
int min_bitrate_bps,
|
|
int max_bitrate_bps)
|
|
: frame_size_pixels(frame_size_pixels),
|
|
min_start_bitrate_bps(min_start_bitrate_bps),
|
|
min_bitrate_bps(min_bitrate_bps),
|
|
max_bitrate_bps(max_bitrate_bps) {}
|
|
// Size of video frame, in pixels, the bitrate thresholds are intended for.
|
|
int frame_size_pixels = 0;
|
|
// Recommended minimum bitrate to start encoding.
|
|
int min_start_bitrate_bps = 0;
|
|
// Recommended minimum bitrate.
|
|
int min_bitrate_bps = 0;
|
|
// Recommended maximum bitrate.
|
|
int max_bitrate_bps = 0;
|
|
|
|
bool operator==(const ResolutionBitrateLimits& rhs) const;
|
|
bool operator!=(const ResolutionBitrateLimits& rhs) const {
|
|
return !(*this == rhs);
|
|
}
|
|
};
|
|
|
|
// Struct containing metadata about the encoder implementing this interface.
|
|
struct RTC_EXPORT EncoderInfo {
|
|
static constexpr uint8_t kMaxFramerateFraction =
|
|
std::numeric_limits<uint8_t>::max();
|
|
|
|
EncoderInfo();
|
|
EncoderInfo(const EncoderInfo&);
|
|
|
|
~EncoderInfo();
|
|
|
|
std::string ToString() const;
|
|
bool operator==(const EncoderInfo& rhs) const;
|
|
bool operator!=(const EncoderInfo& rhs) const { return !(*this == rhs); }
|
|
|
|
// Any encoder implementation wishing to use the WebRTC provided
|
|
// quality scaler must populate this field.
|
|
ScalingSettings scaling_settings;
|
|
|
|
// The width and height of the incoming video frames should be divisible
|
|
// by `requested_resolution_alignment`. If they are not, the encoder may
|
|
// drop the incoming frame.
|
|
// For example: With I420, this value would be a multiple of 2.
|
|
// Note that this field is unrelated to any horizontal or vertical stride
|
|
// requirements the encoder has on the incoming video frame buffers.
|
|
int requested_resolution_alignment;
|
|
|
|
// Same as above but if true, each simulcast layer should also be divisible
|
|
// by `requested_resolution_alignment`.
|
|
// Note that scale factors `scale_resolution_down_by` may be adjusted so a
|
|
// common multiple is not too large to avoid largely cropped frames and
|
|
// possibly with an aspect ratio far from the original.
|
|
// Warning: large values of scale_resolution_down_by could be changed
|
|
// considerably, especially if `requested_resolution_alignment` is large.
|
|
bool apply_alignment_to_all_simulcast_layers;
|
|
|
|
// If true, encoder supports working with a native handle (e.g. texture
|
|
// handle for hw codecs) rather than requiring a raw I420 buffer.
|
|
bool supports_native_handle;
|
|
|
|
// The name of this particular encoder implementation, e.g. "libvpx".
|
|
std::string implementation_name;
|
|
|
|
// If this field is true, the encoder rate controller must perform
|
|
// well even in difficult situations, and produce close to the specified
|
|
// target bitrate seen over a reasonable time window, drop frames if
|
|
// necessary in order to keep the rate correct, and react quickly to
|
|
// changing bitrate targets. If this method returns true, we disable the
|
|
// frame dropper in the media optimization module and rely entirely on the
|
|
// encoder to produce media at a bitrate that closely matches the target.
|
|
// Any overshooting may result in delay buildup. If this method returns
|
|
// false (default behavior), the media opt frame dropper will drop input
|
|
// frames if it suspect encoder misbehavior. Misbehavior is common,
|
|
// especially in hardware codecs. Disable media opt at your own risk.
|
|
bool has_trusted_rate_controller;
|
|
|
|
// If this field is true, the encoder uses hardware support and different
|
|
// thresholds will be used in CPU adaptation.
|
|
bool is_hardware_accelerated;
|
|
|
|
// For each spatial layer (simulcast stream or SVC layer), represented as an
|
|
// element in `fps_allocation` a vector indicates how many temporal layers
|
|
// the encoder is using for that spatial layer.
|
|
// For each spatial/temporal layer pair, the frame rate fraction is given as
|
|
// an 8bit unsigned integer where 0 = 0% and 255 = 100%.
|
|
//
|
|
// If the vector is empty for a given spatial layer, it indicates that frame
|
|
// rates are not defined and we can't count on any specific frame rate to be
|
|
// generated. Likely this indicates Vp8TemporalLayersType::kBitrateDynamic.
|
|
//
|
|
// The encoder may update this on a per-frame basis in response to both
|
|
// internal and external signals.
|
|
//
|
|
// Spatial layers are treated independently, but temporal layers are
|
|
// cumulative. For instance, if:
|
|
// fps_allocation[0][0] = kFullFramerate / 2;
|
|
// fps_allocation[0][1] = kFullFramerate;
|
|
// Then half of the frames are in the base layer and half is in TL1, but
|
|
// since TL1 is assumed to depend on the base layer, the frame rate is
|
|
// indicated as the full 100% for the top layer.
|
|
//
|
|
// Defaults to a single spatial layer containing a single temporal layer
|
|
// with a 100% frame rate fraction.
|
|
absl::InlinedVector<uint8_t, kMaxTemporalStreams>
|
|
fps_allocation[kMaxSpatialLayers];
|
|
|
|
// Recommended bitrate limits for different resolutions.
|
|
std::vector<ResolutionBitrateLimits> resolution_bitrate_limits;
|
|
|
|
// Obtains the limits from `resolution_bitrate_limits` that best matches the
|
|
// `frame_size_pixels`.
|
|
absl::optional<ResolutionBitrateLimits>
|
|
GetEncoderBitrateLimitsForResolution(int frame_size_pixels) const;
|
|
|
|
// If true, this encoder has internal support for generating simulcast
|
|
// streams. Otherwise, an adapter class will be needed.
|
|
// Even if true, the config provided to InitEncode() might not be supported,
|
|
// in such case the encoder should return
|
|
// WEBRTC_VIDEO_CODEC_ERR_SIMULCAST_PARAMETERS_NOT_SUPPORTED.
|
|
bool supports_simulcast;
|
|
|
|
// The list of pixel formats preferred by the encoder. It is assumed that if
|
|
// the list is empty and supports_native_handle is false, then {I420} is the
|
|
// preferred pixel format. The order of the formats does not matter.
|
|
absl::InlinedVector<VideoFrameBuffer::Type, kMaxPreferredPixelFormats>
|
|
preferred_pixel_formats;
|
|
|
|
// Indicates whether or not QP value encoder writes into frame/slice/tile
|
|
// header can be interpreted as average frame/slice/tile QP.
|
|
absl::optional<bool> is_qp_trusted;
|
|
};
|
|
|
|
struct RTC_EXPORT RateControlParameters {
|
|
RateControlParameters();
|
|
RateControlParameters(const VideoBitrateAllocation& bitrate,
|
|
double framerate_fps);
|
|
RateControlParameters(const VideoBitrateAllocation& bitrate,
|
|
double framerate_fps,
|
|
DataRate bandwidth_allocation);
|
|
virtual ~RateControlParameters();
|
|
|
|
// Target bitrate, per spatial/temporal layer.
|
|
// A target bitrate of 0bps indicates a layer should not be encoded at all.
|
|
VideoBitrateAllocation target_bitrate;
|
|
// Adjusted target bitrate, per spatial/temporal layer. May be lower or
|
|
// higher than the target depending on encoder behaviour.
|
|
VideoBitrateAllocation bitrate;
|
|
// Target framerate, in fps. A value <= 0.0 is invalid and should be
|
|
// interpreted as framerate target not available. In this case the encoder
|
|
// should fall back to the max framerate specified in `codec_settings` of
|
|
// the last InitEncode() call.
|
|
double framerate_fps;
|
|
// The network bandwidth available for video. This is at least
|
|
// `bitrate.get_sum_bps()`, but may be higher if the application is not
|
|
// network constrained.
|
|
DataRate bandwidth_allocation;
|
|
|
|
bool operator==(const RateControlParameters& rhs) const;
|
|
bool operator!=(const RateControlParameters& rhs) const;
|
|
};
|
|
|
|
struct LossNotification {
|
|
// The timestamp of the last decodable frame *prior* to the last received.
|
|
// (The last received - described below - might itself be decodable or not.)
|
|
uint32_t timestamp_of_last_decodable;
|
|
// The timestamp of the last received frame.
|
|
uint32_t timestamp_of_last_received;
|
|
// Describes whether the dependencies of the last received frame were
|
|
// all decodable.
|
|
// `false` if some dependencies were undecodable, `true` if all dependencies
|
|
// were decodable, and `nullopt` if the dependencies are unknown.
|
|
absl::optional<bool> dependencies_of_last_received_decodable;
|
|
// Describes whether the received frame was decodable.
|
|
// `false` if some dependency was undecodable or if some packet belonging
|
|
// to the last received frame was missed.
|
|
// `true` if all dependencies were decodable and all packets belonging
|
|
// to the last received frame were received.
|
|
// `nullopt` if no packet belonging to the last frame was missed, but the
|
|
// last packet in the frame was not yet received.
|
|
absl::optional<bool> last_received_decodable;
|
|
};
|
|
|
|
// Negotiated capabilities which the VideoEncoder may expect the other
|
|
// side to use.
|
|
struct Capabilities {
|
|
explicit Capabilities(bool loss_notification)
|
|
: loss_notification(loss_notification) {}
|
|
bool loss_notification;
|
|
};
|
|
|
|
struct Settings {
|
|
Settings(const Capabilities& capabilities,
|
|
int number_of_cores,
|
|
size_t max_payload_size)
|
|
: capabilities(capabilities),
|
|
number_of_cores(number_of_cores),
|
|
max_payload_size(max_payload_size) {}
|
|
|
|
Capabilities capabilities;
|
|
int number_of_cores;
|
|
size_t max_payload_size;
|
|
};
|
|
|
|
static VideoCodecVP8 GetDefaultVp8Settings();
|
|
static VideoCodecVP9 GetDefaultVp9Settings();
|
|
static VideoCodecH264 GetDefaultH264Settings();
|
|
#ifndef DISABLE_H265
|
|
static VideoCodecH265 GetDefaultH265Settings();
|
|
#endif
|
|
|
|
virtual ~VideoEncoder() {}
|
|
|
|
// Set a FecControllerOverride, through which the encoder may override
|
|
// decisions made by FecController.
|
|
// TODO(bugs.webrtc.org/10769): Update downstream, then make pure-virtual.
|
|
virtual void SetFecControllerOverride(
|
|
FecControllerOverride* fec_controller_override);
|
|
|
|
// Initialize the encoder with the information from the codecSettings
|
|
//
|
|
// Input:
|
|
// - codec_settings : Codec settings
|
|
// - settings : Settings affecting the encoding itself.
|
|
// Input for deprecated version:
|
|
// - number_of_cores : Number of cores available for the encoder
|
|
// - max_payload_size : The maximum size each payload is allowed
|
|
// to have. Usually MTU - overhead.
|
|
//
|
|
// Return value : Set bit rate if OK
|
|
// <0 - Errors:
|
|
// WEBRTC_VIDEO_CODEC_ERR_PARAMETER
|
|
// WEBRTC_VIDEO_CODEC_ERR_SIZE
|
|
// WEBRTC_VIDEO_CODEC_MEMORY
|
|
// WEBRTC_VIDEO_CODEC_ERROR
|
|
// TODO(bugs.webrtc.org/10720): After updating downstream projects and posting
|
|
// an announcement to discuss-webrtc, remove the three-parameters variant
|
|
// and make the two-parameters variant pure-virtual.
|
|
/* ABSL_DEPRECATED("bugs.webrtc.org/10720") */ virtual int32_t InitEncode(
|
|
const VideoCodec* codec_settings,
|
|
int32_t number_of_cores,
|
|
size_t max_payload_size);
|
|
virtual int InitEncode(const VideoCodec* codec_settings,
|
|
const VideoEncoder::Settings& settings);
|
|
|
|
// Register an encode complete callback object.
|
|
//
|
|
// Input:
|
|
// - callback : Callback object which handles encoded images.
|
|
//
|
|
// Return value : WEBRTC_VIDEO_CODEC_OK if OK, < 0 otherwise.
|
|
virtual int32_t RegisterEncodeCompleteCallback(
|
|
EncodedImageCallback* callback) = 0;
|
|
|
|
// Free encoder memory.
|
|
// Return value : WEBRTC_VIDEO_CODEC_OK if OK, < 0 otherwise.
|
|
virtual int32_t Release() = 0;
|
|
|
|
// Encode an image (as a part of a video stream). The encoded image
|
|
// will be returned to the user through the encode complete callback.
|
|
//
|
|
// Input:
|
|
// - frame : Image to be encoded
|
|
// - frame_types : Frame type to be generated by the encoder.
|
|
//
|
|
// Return value : WEBRTC_VIDEO_CODEC_OK if OK
|
|
// <0 - Errors:
|
|
// WEBRTC_VIDEO_CODEC_ERR_PARAMETER
|
|
// WEBRTC_VIDEO_CODEC_MEMORY
|
|
// WEBRTC_VIDEO_CODEC_ERROR
|
|
virtual int32_t Encode(const VideoFrame& frame,
|
|
const std::vector<VideoFrameType>* frame_types) = 0;
|
|
|
|
// Sets rate control parameters: bitrate, framerate, etc. These settings are
|
|
// instantaneous (i.e. not moving averages) and should apply from now until
|
|
// the next call to SetRates().
|
|
virtual void SetRates(const RateControlParameters& parameters) = 0;
|
|
|
|
// Inform the encoder when the packet loss rate changes.
|
|
//
|
|
// Input: - packet_loss_rate : The packet loss rate (0.0 to 1.0).
|
|
virtual void OnPacketLossRateUpdate(float packet_loss_rate);
|
|
|
|
// Inform the encoder when the round trip time changes.
|
|
//
|
|
// Input: - rtt_ms : The new RTT, in milliseconds.
|
|
virtual void OnRttUpdate(int64_t rtt_ms);
|
|
|
|
// Called when a loss notification is received.
|
|
virtual void OnLossNotification(const LossNotification& loss_notification);
|
|
|
|
// Returns meta-data about the encoder, such as implementation name.
|
|
// The output of this method may change during runtime. For instance if a
|
|
// hardware encoder fails, it may fall back to doing software encoding using
|
|
// an implementation with different characteristics.
|
|
virtual EncoderInfo GetEncoderInfo() const;
|
|
};
|
|
} // namespace webrtc
|
|
#endif // API_VIDEO_CODECS_VIDEO_ENCODER_H_
|