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// Copyright (c) 2012-2017 VideoStitch SAS
// Copyright (c) 2018 stitchEm
#include "bufferedReader.hpp"
namespace VideoStitch {
namespace Core {
PotentialValue<Buffer> allocate(size_t size, GPU::HostBuffer<unsigned char>) {
auto host =
GPU::HostBuffer<unsigned char>::allocate(size, "Input Frames", GPUHostAllocPinned | GPUHostAllocHostWriteOnly);
FAIL_RETURN(host.status());
return Buffer{host.value()};
}
PotentialValue<Buffer> allocate(size_t size, GPU::Buffer<unsigned char>) {
auto device = GPU::Buffer<unsigned char>::allocate(size, "Input Frames");
FAIL_RETURN(device.status());
return Buffer{device.value()};
}
template <typename buffer_t>
PotentialValue<std::vector<Buffer>> allocateBuffers(const Input::VideoReader::Spec& readerSpec, unsigned numBuffers) {
std::vector<Buffer> buffers;
auto tryAllocatingBuffers = [&]() -> Status {
for (unsigned i = 0; i < numBuffers; i++) {
PotentialValue<Buffer> buf = allocate(readerSpec.frameDataSize, buffer_t());
FAIL_RETURN(buf.status());
buffers.push_back(buf.value());
}
return Status::OK();
};
Status allocationStatus = tryAllocatingBuffers();
if (!allocationStatus.ok()) {
for (auto buf : buffers) {
buf.release();
}
return allocationStatus;
}
return buffers;
}
BufferedReader::BufferedReader(std::shared_ptr<Input::VideoReader> delegate, std::vector<Buffer> buffers)
: lastLoadedFrame(), delegate(delegate) {
lastLoadedFrame.readerStatus = Input::ReadStatus::fromCode<Input::ReadStatusCode::TryAgain>();
for (auto buf : buffers) {
// no need to lock, haven't started yet
availableBuffers.push(buf);
}
start();
}
Potential<BufferedReader> BufferedReader::create(std::shared_ptr<Input::VideoReader> reader,
unsigned preloadCacheSize) {
FAIL_RETURN(GPU::useDefaultBackendDevice());
// one buffer for async loading
// another buffer for the last loaded frame, which needs to be kept for possible reloads and thus is unavailable for
// preloading
unsigned minNumBuffers = 2;
unsigned numBuffers = preloadCacheSize + minNumBuffers;
switch (reader->getSpec().addressSpace) {
case Host: {
auto buffers = allocateBuffers<GPU::HostBuffer<unsigned char>>(reader->getSpec(), numBuffers);
FAIL_RETURN(buffers.status());
return new BufferedReader(reader, buffers.value());
}
case Device: {
auto buffers = allocateBuffers<GPU::Buffer<unsigned char>>(reader->getSpec(), numBuffers);
FAIL_RETURN(buffers.status());
return new BufferedReader(reader, buffers.value());
}
}
assert(false);
return Status::OK();
}
BufferedReader::~BufferedReader() {
{
std::lock_guard<std::mutex> la(availableMutex);
stoppingAvailable = true;
}
availableCV.notify_all();
{
std::lock_guard<std::mutex> ll(loadedMutex);
stoppingLoaded = true;
}
loadedCV.notify_all();
{
// make sure any outstanding load have finished
std::lock_guard<std::mutex> loadingLock(loadedMutex);
// flush reload frame so it can be released
updateCurrentFrame({Input::ReadStatus::fromCode<Input::ReadStatusCode::EndOfFile>(), 0, Buffer()});
}
// wait for background reading to wind down
join();
{
std::lock_guard<std::mutex> la(availableMutex);
while (!availableBuffers.empty()) {
availableBuffers.front().release();
availableBuffers.pop();
}
}
{
std::lock_guard<std::mutex> ll(loadedMutex);
while (!loadedFrames.empty()) {
auto loaded = std::move(loadedFrames.front());
loadedFrames.pop();
loaded.buffer.release();
}
}
}
void BufferedReader::run() {
GPU::useDefaultBackendDevice();
for (;;) {
Buffer frame;
{
std::unique_lock<std::mutex> lock(availableMutex);
availableCV.wait(lock, [&]() { return !availableBuffers.empty() || stoppingAvailable; });
// queue has stopped, wind down reading as well
if (stoppingAvailable) {
return;
}
frame = availableBuffers.front();
availableBuffers.pop();
}
{
mtime_t date;
Input::ReadStatus readStatus;
std::lock_guard<std::mutex> lock(delegateMutex);
readStatus = delegate->readFrame(date, frame.rawPtr());
{
InputFrame loaded{readStatus, date, frame};
std::lock_guard<std::mutex> lock(loadedMutex);
loadedFrames.push(std::move(loaded));
}
}
loadedCV.notify_one();
}
}
Status BufferedReader::seekFrame(frameid_t seekFrame) {
// block readFrame
std::lock_guard<std::mutex> delegateLock(delegateMutex);
// block loading
std::lock_guard<std::mutex> loadingLock(loadedMutex);
if (stoppingLoaded) {
return Status::OK();
}
std::vector<InputFrame> localLoadedFrames;
while (!loadedFrames.empty()) {
InputFrame loaded = std::move(loadedFrames.front());
loadedFrames.pop();
localLoadedFrames.push_back(std::move(loaded));
}
bool seekTargetFrameIsCached = false;
// TODO API to convert frame ID (used by seek) <--> date (used by readFrame) ?
mtime_t seekDate =
(mtime_t)((double)seekFrame * 1000000.0 * (double)getSpec().frameRate.den / (double)getSpec().frameRate.num);
for (auto& frame : localLoadedFrames) {
mtime_t frameDate = frame.date;
if (frameDate == seekDate) {
seekTargetFrameIsCached = true;
}
if (seekTargetFrameIsCached) {
loadedFrames.push(std::move(frame));
} else {
makeBufferAvailable(frame.buffer);
}
}
if (seekTargetFrameIsCached) {
return Status::OK();
}
return delegate->seekFrame(seekFrame);
}
void BufferedReader::makeBufferAvailable(Buffer buf) {
{
std::lock_guard<std::mutex> la(availableMutex);
availableBuffers.push(buf);
}
availableCV.notify_one();
}
InputFrame BufferedReader::fetchLoadedFrame() {
std::unique_lock<std::mutex> lock(loadedMutex);
loadedCV.wait(lock, [&]() { return !loadedFrames.empty() || stoppingLoaded; });
// queue has stopped, wind down reading as well
if (stoppingLoaded) {
return {Input::ReadStatus::fromCode<Input::ReadStatusCode::EndOfFile>(), -1, Core::Buffer()};
}
InputFrame loaded = std::move(loadedFrames.front());
loadedFrames.pop();
return loaded;
}
InputFrame BufferedReader::load() {
InputFrame loadedFrame = fetchLoadedFrame();
updateCurrentFrame(loadedFrame);
return loadedFrame;
}
InputFrame BufferedReader::reload() {
std::lock_guard<std::recursive_mutex> lock(borrowedMutex);
borrowed[lastLoadedFrame.buffer]++;
return lastLoadedFrame;
}
void BufferedReader::updateCurrentFrame(InputFrame frame) {
std::lock_guard<std::recursive_mutex> lock(borrowedMutex);
InputFrame lastFrame = lastLoadedFrame;
lastLoadedFrame = frame;
// 1st borrow for the frame that load() returns
// 2nd: keep it around for possible reloads
borrowed[lastLoadedFrame.buffer] = 2;
releaseBuffer(lastFrame.buffer);
}
void BufferedReader::releaseBuffer(Buffer frame) {
std::lock_guard<std::recursive_mutex> lock(borrowedMutex);
if (frame.rawPtr()) {
borrowed[frame]--;
if (borrowed[frame] == 0) {
makeBufferAvailable(frame);
borrowed.erase(frame);
}
}
}
} // namespace Core
} // namespace VideoStitch