shaka-packager/packager/media/chunking/chunking_handler.cc

253 lines
9.8 KiB
C++

// Copyright 2017 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#include "packager/media/chunking/chunking_handler.h"
#include "packager/base/logging.h"
#include "packager/base/threading/platform_thread.h"
#include "packager/media/base/media_sample.h"
namespace {
int64_t kThreadIdUnset = -1;
int64_t kTimeStampToDispatchAllSamples = -1;
} // namespace
namespace shaka {
namespace media {
ChunkingHandler::ChunkingHandler(const ChunkingOptions& chunking_options)
: chunking_options_(chunking_options), thread_id_(kThreadIdUnset) {
CHECK_NE(chunking_options.segment_duration_in_seconds, 0u);
}
ChunkingHandler::~ChunkingHandler() {}
Status ChunkingHandler::InitializeInternal() {
segment_info_.resize(num_input_streams());
subsegment_info_.resize(num_input_streams());
time_scales_.resize(num_input_streams());
last_sample_end_timestamps_.resize(num_input_streams());
return Status::OK;
}
Status ChunkingHandler::Process(std::unique_ptr<StreamData> stream_data) {
switch (stream_data->stream_data_type) {
case StreamDataType::kStreamInfo: {
// Make sure the inputs come from the same thread.
const int64_t thread_id =
static_cast<int64_t>(base::PlatformThread::CurrentId());
int64_t expected = kThreadIdUnset;
if (!thread_id_.compare_exchange_strong(expected, thread_id) &&
expected != thread_id) {
return Status(error::CHUNKING_ERROR,
"Inputs should come from the same thread.");
}
const auto time_scale = stream_data->stream_info->time_scale();
// The video stream is treated as the main stream. If there is only one
// stream, it is the main stream.
const bool is_main_stream =
main_stream_index_ == -1 &&
(stream_data->stream_info->stream_type() == kStreamVideo ||
num_input_streams() == 1);
if (is_main_stream) {
main_stream_index_ = stream_data->stream_index;
segment_duration_ =
chunking_options_.segment_duration_in_seconds * time_scale;
subsegment_duration_ =
chunking_options_.subsegment_duration_in_seconds * time_scale;
} else if (stream_data->stream_info->stream_type() == kStreamVideo) {
return Status(error::CHUNKING_ERROR,
"Only one video stream is allowed per chunking handler.");
}
time_scales_[stream_data->stream_index] = time_scale;
break;
}
case StreamDataType::kSegmentInfo:
VLOG(3) << "Drop existing segment info.";
return Status::OK;
case StreamDataType::kMediaSample: {
const int stream_index = stream_data->stream_index;
DCHECK_NE(time_scales_[stream_index], 0u)
<< "kStreamInfo should arrive before kMediaSample";
if (stream_index != main_stream_index_) {
if (!stream_data->media_sample->is_key_frame()) {
return Status(error::CHUNKING_ERROR,
"All non video samples should be key frames.");
}
// Cache non main stream samples, since we don't know yet whether these
// samples belong to the current or next segment.
non_main_samples_.push_back(std::move(stream_data));
// The streams are expected to be synchronized, so we don't expect to
// see a lot of samples before seeing video samples.
const size_t kMaxSamplesPerStreamBeforeVideoSample = 5u;
if (non_main_samples_.size() >
num_input_streams() * kMaxSamplesPerStreamBeforeVideoSample) {
return Status(error::CHUNKING_ERROR,
"Too many non video samples before video sample.");
}
return Status::OK;
}
const MediaSample* sample = stream_data->media_sample.get();
Status status = ProcessMediaSample(sample);
if (!status.ok())
return status;
// Discard samples before segment start.
if (!segment_info_[stream_index])
return Status::OK;
last_sample_end_timestamps_[stream_index] =
sample->dts() + sample->duration();
break;
}
default:
VLOG(3) << "Stream data type "
<< static_cast<int>(stream_data->stream_data_type) << " ignored.";
break;
}
return Dispatch(std::move(stream_data));
}
Status ChunkingHandler::FlushStream(int input_stream_index) {
if (segment_info_[input_stream_index]) {
Status status;
if (input_stream_index != main_stream_index_) {
status = DispatchNonMainSamples(kTimeStampToDispatchAllSamples);
if (!status.ok())
return status;
}
auto& segment_info = segment_info_[input_stream_index];
if (segment_info->start_timestamp != -1) {
segment_info->duration = last_sample_end_timestamps_[input_stream_index] -
segment_info->start_timestamp;
status = DispatchSegmentInfo(input_stream_index, std::move(segment_info));
if (!status.ok())
return status;
}
}
return MediaHandler::FlushStream(input_stream_index);
}
Status ChunkingHandler::ProcessMediaSample(const MediaSample* sample) {
const bool is_key_frame = sample->is_key_frame();
const int64_t timestamp = sample->dts();
// Check if we need to terminate the current (sub)segment.
bool new_segment = false;
bool new_subsegment = false;
if (is_key_frame || !chunking_options_.segment_sap_aligned) {
const int64_t segment_index = timestamp / segment_duration_;
if (segment_index != current_segment_index_) {
current_segment_index_ = segment_index;
new_segment = true;
}
}
if (!new_segment && subsegment_duration_ > 0 &&
(is_key_frame || !chunking_options_.subsegment_sap_aligned)) {
const int64_t subsegment_index =
(timestamp - segment_info_[main_stream_index_]->start_timestamp) /
subsegment_duration_;
if (subsegment_index != current_subsegment_index_) {
current_subsegment_index_ = subsegment_index;
new_subsegment = true;
}
}
Status status;
if (new_segment || new_subsegment) {
// Dispatch the samples before |timestamp| - See the implemention on how we
// determine if a sample is before |timestamp|..
status.Update(DispatchNonMainSamples(timestamp));
}
if (new_segment) {
status.Update(DispatchSegmentInfoForAllStreams());
segment_info_[main_stream_index_]->start_timestamp = timestamp;
}
if (subsegment_duration_ > 0 && (new_segment || new_subsegment)) {
status.Update(DispatchSubsegmentInfoForAllStreams());
subsegment_info_[main_stream_index_]->start_timestamp = timestamp;
}
if (!status.ok())
return status;
// Dispatch non-main samples for the next segment.
return DispatchNonMainSamples(kTimeStampToDispatchAllSamples);
}
Status ChunkingHandler::DispatchNonMainSamples(int64_t timestamp_threshold) {
Status status;
while (status.ok() && !non_main_samples_.empty()) {
DCHECK_EQ(non_main_samples_.front()->stream_data_type,
StreamDataType::kMediaSample);
const int stream_index = non_main_samples_.front()->stream_index;
const MediaSample* sample = non_main_samples_.front()->media_sample.get();
// If the portion of the sample before |timestamp_threshold| is bigger than
// the other portion, we consider it part of the current segment.
const int64_t timestamp = sample->dts() + sample->duration() / 2;
const bool stop =
(timestamp_threshold != kTimeStampToDispatchAllSamples &&
(static_cast<double>(timestamp) / time_scales_[stream_index]) >
(static_cast<double>(timestamp_threshold) /
time_scales_[main_stream_index_]));
VLOG(3) << "Sample ts: " << sample->dts() << " "
<< " duration: " << sample->duration()
<< " scale: " << time_scales_[stream_index] << "\n"
<< " threshold: " << timestamp_threshold
<< " scale: " << time_scales_[main_stream_index_]
<< (stop ? " stop "
: (segment_info_[stream_index] ? " dispatch "
: " discard "));
if (stop)
break;
// Only dispatch samples if the segment has started, otherwise discard
// them.
if (segment_info_[stream_index]) {
if (segment_info_[stream_index]->start_timestamp == -1)
segment_info_[stream_index]->start_timestamp = sample->dts();
if (subsegment_info_[stream_index] &&
subsegment_info_[stream_index]->start_timestamp == -1) {
subsegment_info_[stream_index]->start_timestamp = sample->dts();
}
last_sample_end_timestamps_[stream_index] =
sample->dts() + sample->duration();
status.Update(Dispatch(std::move(non_main_samples_.front())));
}
non_main_samples_.pop_front();
}
return status;
}
Status ChunkingHandler::DispatchSegmentInfoForAllStreams() {
Status status;
for (size_t i = 0; i < segment_info_.size() && status.ok(); ++i) {
if (segment_info_[i] && segment_info_[i]->start_timestamp != -1) {
segment_info_[i]->duration =
last_sample_end_timestamps_[i] - segment_info_[i]->start_timestamp;
status.Update(DispatchSegmentInfo(i, std::move(segment_info_[i])));
}
segment_info_[i].reset(new SegmentInfo);
subsegment_info_[i].reset();
}
return status;
}
Status ChunkingHandler::DispatchSubsegmentInfoForAllStreams() {
Status status;
for (size_t i = 0; i < subsegment_info_.size() && status.ok(); ++i) {
if (subsegment_info_[i] && subsegment_info_[i]->start_timestamp != -1) {
subsegment_info_[i]->duration =
last_sample_end_timestamps_[i] - subsegment_info_[i]->start_timestamp;
status.Update(DispatchSegmentInfo(i, std::move(subsegment_info_[i])));
}
subsegment_info_[i].reset(new SegmentInfo);
subsegment_info_[i]->is_subsegment = true;
}
return status;
}
} // namespace media
} // namespace shaka