// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROMECAST_STARBOARD_MEDIA_MEDIA_MEDIA_PIPELINE_BACKEND_STARBOARD_H_
#define CHROMECAST_STARBOARD_MEDIA_MEDIA_MEDIA_PIPELINE_BACKEND_STARBOARD_H_
#include <optional>
#include "base/memory/weak_ptr.h"
#include "base/task/sequenced_task_runner.h"
#include "chromecast/public/graphics_types.h"
#include "chromecast/public/media/media_pipeline_device_params.h"
#include "chromecast/starboard/media/media/starboard_api_wrapper.h"
#include "chromecast/starboard/media/media/starboard_audio_decoder.h"
#include "chromecast/starboard/media/media/starboard_video_decoder.h"
#include "chromecast/starboard/media/media/starboard_video_plane.h"
namespace chromecast {
namespace media {
// A backend that uses starboard for decoding/rendering.
//
// Public functions and the destructor must be called on the sequence that
// consntructed the MediaPipelineBackendStarboard.
class MediaPipelineBackendStarboard : public MediaPipelineBackend {
public:
MediaPipelineBackendStarboard(const MediaPipelineDeviceParams& params,
StarboardVideoPlane* video_plane);
~MediaPipelineBackendStarboard() override;
// For testing purposes, `starboard` will be used to call starboard functions.
void TestOnlySetStarboardApiWrapper(
std::unique_ptr<StarboardApiWrapper> starboard);
// MediaPipelineBackend implementation:
AudioDecoder* CreateAudioDecoder() override;
VideoDecoder* CreateVideoDecoder() override;
bool Initialize() override;
bool Start(int64_t start_pts) override;
void Stop() override;
bool Pause() override;
bool Resume() override;
int64_t GetCurrentPts() override;
bool SetPlaybackRate(float rate) override;
// StarboardVideoPlane::Delegate implementation:
private:
// Represents the state of the backend. See the documentation of
// media_pipeline_backend.h for more information about valid transitions
// between states.
enum class State {
kUninitialized,
kInitialized,
kPlaying,
kPaused,
};
// Called when the video plane's geometry changes. This means that we need to
// update the SbPlayer's bounds.
//
// Expects that `display_rect` is in display coordinates, NOT (physical)
// screen coordinates.
//
// This function must be called on media_task_runner_.
void OnGeometryChanged(const RectF& display_rect,
StarboardVideoPlane::Transform transform);
// Creates the starboard player object.
void CreatePlayer();
// Called when a starboard audio or video decoder needs more samples. This
// occurs after either:
// 1. A sample has been decoded, or
// 2. A seek has finished
//
// For case 1, we notify the relevant decoder that the sample has been
// decoded. For case 2, we re-initialize the decoder, meaning it will start
// pushing buffers to starboard again.
void OnSampleDecoded(void* player,
StarboardMediaType type,
StarboardDecoderState decoder_state,
int ticket);
// Called when a sample can be deallocated. The decoders handle the actual
// deallocation.
void DeallocateSample(void* player, const void* sample_buffer);
// Called when the SbPlayer's state has changed.
void OnPlayerStatus(void* player, StarboardPlayerState state, int ticket);
// Called when the SbPlayer has encountered an error.
void OnPlayerError(void* player,
StarboardPlayerError error,
const std::string& message);
// Called when starboard has started. This must be called on the media task
// runner.
void OnStarboardStarted();
// Performs the actual play logic by setting the playback rate to a non-zero
// value. player_ must not be null when this is called.
void DoPlay();
// Performs the actual pause logic by setting the playback rate to 0. player_
// must not be null when this is called.
void DoPause();
// Seeks to last_seek_pts_ and increments seek_ticket_.
void DoSeek();
// A pure function that calls OnSampleDecoded. `context` is a pointer to a
// MediaPipelineBackendStarboard object. The rest of the arguments are
// forwarded to OnSampleDecoded.
static void CallOnSampleDecoded(void* player,
void* context,
StarboardMediaType type,
StarboardDecoderState decoder_state,
int ticket);
// Called by starboard when a sample can be deallocated. Note that this may be
// called after CallOnSampleDecoded is called for a given sample, meaning that
// the sample needs to outlive the call to CallOnSampleDecoded.
static void CallDeallocateSample(void* player,
void* context,
const void* sample_buffer);
// Called by starboard when the player's status changes. Notably, this will be
// called with state kStarboardPlayerStateEndOfStream when the end of stream
// buffer has been rendered.
static void CallOnPlayerStatus(void* player,
void* context,
StarboardPlayerState state,
int ticket);
// Called by starboard when there is a player error.
static void CallOnPlayerError(void* player,
void* context,
StarboardPlayerError error,
const char* message);
StarboardPlayerCallbackHandler player_callback_handler_ = {
/*context=*/this, &CallOnSampleDecoded,
&CallDeallocateSample, &CallOnPlayerStatus,
&CallOnPlayerError,
};
// Calls to Starboard are made through this struct, to allow tests to mock
// their behavior (and not rely on Starboard).
std::unique_ptr<StarboardApiWrapper> starboard_;
State state_ = State::kUninitialized;
float playback_rate_ = 1.0;
int64_t last_seek_pts_ = -1;
// Ticket representing the last seek. This is necessary to recognize callbacks
// from old seeks, which are no longer relevant.
int seek_ticket_ = 0;
scoped_refptr<base::SequencedTaskRunner> media_task_runner_;
// An opaque handle to the SbPlayer.
void* player_ = nullptr;
std::optional<StarboardAudioDecoder> audio_decoder_;
std::optional<StarboardVideoDecoder> video_decoder_;
std::optional<RectF> pending_geometry_change_;
StarboardVideoPlane* video_plane_ = nullptr;
int64_t video_plane_callback_token_ = 0;
// If true, we should render frames immediately to minimize latency. This
// should be true when mirroring.
bool is_streaming_ = false;
// This must be destructed first.
base::WeakPtrFactory<MediaPipelineBackendStarboard> weak_factory_{this};
};
} // namespace media
} // namespace chromecast
#endif // CHROMECAST_STARBOARD_MEDIA_MEDIA_MEDIA_PIPELINE_BACKEND_STARBOARD_H_
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