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VideoCacheThread.h
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// Copyright (c) 2008-2025 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
#ifndef OPENSHOT_VIDEO_CACHE_THREAD_H
#define OPENSHOT_VIDEO_CACHE_THREAD_H
#include "ReaderBase.h"
#include <AppConfig.h>
#include <juce_audio_basics/juce_audio_basics.h>
#include <memory>
namespace openshot
{
using juce::Thread;
class VideoCacheThread : public Thread
{
public:
VideoCacheThread();
~VideoCacheThread() override;
bool isReady();
void Play() {};
void Stop() {};
void setSpeed(int new_speed);
int getSpeed() const { return speed; }
void Seek(int64_t new_position);
void Seek(int64_t new_position, bool start_preroll);
bool StartThread();
bool StopThread(int timeoutMs = 0);
void Reader(ReaderBase* new_reader) { reader = new_reader; Play(); }
protected:
void run() override;
int64_t getBytes(int width, int height, int sample_rate, int channels, float fps);
//---------- Helper functions, broken out for clarity & unit testing ----------
int computeDirection() const;
void handleUserSeek(int64_t playhead, int dir);
bool clearCacheIfPaused(int64_t playhead, bool paused, CacheBase* cache);
void computeWindowBounds(int64_t playhead,
int dir,
int64_t ahead_count,
int64_t timeline_end,
int64_t& window_begin,
int64_t& window_end) const;
bool prefetchWindow(CacheBase* cache,
int64_t window_begin,
int64_t window_end,
int dir,
ReaderBase* reader);
//---------- Internal state ----------
std::shared_ptr<Frame> last_cached_frame;
int speed;
int last_speed;
int last_dir;
bool userSeeked;
int64_t requested_display_frame;
int64_t current_display_frame;
int64_t cached_frame_count;
int64_t min_frames_ahead;
int64_t timeline_max_frame;
ReaderBase* reader;
bool force_directional_cache;
int64_t last_cached_index;
};
} // namespace openshot
#endif // OPENSHOT_VIDEO_CACHE_THREAD_H
ReaderBase.h
Header file for ReaderBase class.
openshot::CacheBase
All cache managers in libopenshot are based on this CacheBase class.
Definition CacheBase.h:35
openshot::ReaderBase
This abstract class is the base class, used by all readers in libopenshot.
Definition ReaderBase.h:76
openshot::Thread
openshot::VideoCacheThread::StopThread
bool StopThread(int timeoutMs=0)
Stop the cache thread (wait up to timeoutMs ms). Returns true if it stopped.
Definition VideoCacheThread.cpp:96
openshot::VideoCacheThread::setSpeed
void setSpeed(int new_speed)
Set playback speed/direction. Positive = forward, negative = rewind, zero = pause.
Definition VideoCacheThread.cpp:62
openshot::VideoCacheThread::force_directional_cache
bool force_directional_cache
(Reserved for future use).
Definition VideoCacheThread.h:175
openshot::VideoCacheThread::prefetchWindow
bool prefetchWindow(CacheBase *cache, int64_t window_begin, int64_t window_end, int dir, ReaderBase *reader)
Prefetch all missing frames in [window_begin ... window_end] or [window_end ... window_begin].
Definition VideoCacheThread.cpp:177
openshot::VideoCacheThread::~VideoCacheThread
~VideoCacheThread() override
Definition VideoCacheThread.cpp:44
openshot::VideoCacheThread::requested_display_frame
int64_t requested_display_frame
Frame index the user requested.
Definition VideoCacheThread.h:167
openshot::VideoCacheThread::timeline_max_frame
int64_t timeline_max_frame
Highest valid frame index in the timeline.
Definition VideoCacheThread.h:172
openshot::VideoCacheThread::Play
void Play()
Play method is unimplemented.
Definition VideoCacheThread.h:44
openshot::VideoCacheThread::Stop
void Stop()
Stop method is unimplemented.
Definition VideoCacheThread.h:47
openshot::VideoCacheThread::clearCacheIfPaused
bool clearCacheIfPaused(int64_t playhead, bool paused, CacheBase *cache)
When paused and playhead is outside current cache, clear all frames.
Definition VideoCacheThread.cpp:141
openshot::VideoCacheThread::last_cached_index
int64_t last_cached_index
Index of the most recently cached frame.
Definition VideoCacheThread.h:177
openshot::VideoCacheThread::cached_frame_count
int64_t cached_frame_count
Estimated count of frames currently stored in cache.
Definition VideoCacheThread.h:169
openshot::VideoCacheThread::run
void run() override
Thread entry point: loops until threadShouldExit() is true.
Definition VideoCacheThread.cpp:221
openshot::VideoCacheThread::last_speed
int last_speed
Last non-zero speed (for tracking).
Definition VideoCacheThread.h:163
openshot::VideoCacheThread::isReady
bool isReady()
Definition VideoCacheThread.cpp:49
openshot::VideoCacheThread::current_display_frame
int64_t current_display_frame
Currently displayed frame (unused here, reserved).
Definition VideoCacheThread.h:168
openshot::VideoCacheThread::VideoCacheThread
VideoCacheThread()
Constructor: initializes member variables and assumes forward direction on first launch.
Definition VideoCacheThread.cpp:26
openshot::VideoCacheThread::Reader
void Reader(ReaderBase *new_reader)
Attach a ReaderBase (e.g. Timeline, FFmpegReader) and begin caching.
Definition VideoCacheThread.h:81
openshot::VideoCacheThread::handleUserSeek
void handleUserSeek(int64_t playhead, int dir)
If userSeeked is true, reset last_cached_index just behind the playhead.
Definition VideoCacheThread.cpp:135
openshot::VideoCacheThread::getBytes
int64_t getBytes(int width, int height, int sample_rate, int channels, float fps)
Estimate memory usage for a single frame (video + audio).
Definition VideoCacheThread.cpp:73
openshot::VideoCacheThread::reader
ReaderBase * reader
The source reader (e.g., Timeline, FFmpegReader).
Definition VideoCacheThread.h:174
openshot::VideoCacheThread::Seek
void Seek(int64_t new_position)
Seek to a specific frame (no preroll).
Definition VideoCacheThread.cpp:124
openshot::VideoCacheThread::getSpeed
int getSpeed() const
Definition VideoCacheThread.h:59
openshot::VideoCacheThread::userSeeked
bool userSeeked
True if Seek(..., true) was called (forces a cache reset).
Definition VideoCacheThread.h:165
openshot::VideoCacheThread::computeWindowBounds
void computeWindowBounds(int64_t playhead, int dir, int64_t ahead_count, int64_t timeline_end, int64_t &window_begin, int64_t &window_end) const
Compute the “window” of frames to cache around playhead.
Definition VideoCacheThread.cpp:155
openshot::VideoCacheThread::min_frames_ahead
int64_t min_frames_ahead
Minimum number of frames considered “ready” (pre-roll).
Definition VideoCacheThread.h:171
openshot::VideoCacheThread::last_dir
int last_dir
Last direction sign (+1 forward, –1 backward).
Definition VideoCacheThread.h:164
openshot::VideoCacheThread::StartThread
bool StartThread()
Start the cache thread at high priority. Returns true if it’s actually running.
Definition VideoCacheThread.cpp:87
openshot::VideoCacheThread::computeDirection
int computeDirection() const
Definition VideoCacheThread.cpp:129
openshot::VideoCacheThread::speed
int speed
Current playback speed (0=paused, >0 forward, <0 backward).
Definition VideoCacheThread.h:162
openshot::VideoCacheThread::last_cached_frame
std::shared_ptr< Frame > last_cached_frame
Last frame pointer added to cache.
Definition VideoCacheThread.h:160
openshot
This namespace is the default namespace for all code in the openshot library.
Definition Compressor.h:29