108 lines
3.3 KiB
C++
108 lines
3.3 KiB
C++
// Copyright 2017 Google Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#include "packager/media/formats/webvtt/webvtt_segmenter.h"
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namespace shaka {
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namespace media {
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namespace {
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const size_t kStreamIndex = 0;
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}
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WebVttSegmenter::WebVttSegmenter(uint64_t segment_duration_ms)
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: segment_duration_ms_(segment_duration_ms) {}
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Status WebVttSegmenter::InitializeInternal() {
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return Status::OK;
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}
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Status WebVttSegmenter::Process(std::unique_ptr<StreamData> stream_data) {
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switch (stream_data->stream_data_type) {
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case StreamDataType::kStreamInfo:
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return DispatchStreamInfo(kStreamIndex,
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std::move(stream_data->stream_info));
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case StreamDataType::kTextSample:
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return OnTextSample(stream_data->text_sample);
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default:
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return Status(error::INTERNAL_ERROR,
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"Invalid stream data type for this handler");
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}
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}
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Status WebVttSegmenter::OnFlushRequest(size_t input_stream_index) {
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Status status;
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while (status.ok() && samples_.size()) {
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status.Update(OnSegmentEnd());
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}
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return status.ok() ? FlushAllDownstreams() : status;
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}
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Status WebVttSegmenter::OnTextSample(std::shared_ptr<const TextSample> sample) {
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const uint64_t start_segment = sample->start_time() / segment_duration_ms_;
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// Find the last segment that overlaps the sample. Adjust the sample by one
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// ms (smallest time unit) in case |EndTime| falls on the segment boundary.
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DCHECK_GT(sample->duration(), 0u);
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const uint64_t ending_segment =
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(sample->EndTime() - 1) / segment_duration_ms_;
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DCHECK_GE(ending_segment, start_segment);
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// Samples must always be advancing. If a sample comes in out of order,
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// skip the sample.
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if (samples_.size() && samples_.top().segment > start_segment) {
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LOG(WARNING) << "New sample has arrived out of order. Skipping sample "
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<< "as segment start is " << start_segment << " and segment "
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<< "head is " << samples_.top().segment << ".";
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return Status::OK;
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}
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for (uint64_t segment = start_segment; segment <= ending_segment; segment++) {
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WebVttSegmentedTextSample seg_sample;
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seg_sample.segment = segment;
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seg_sample.sample = sample;
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samples_.push(seg_sample);
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}
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Status status;
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while (status.ok() && samples_.size() &&
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samples_.top().segment < start_segment) {
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// WriteNextSegment will pop elements from |samples_| which will
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// eventually allow the loop to exit.
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status.Update(OnSegmentEnd());
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}
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return status;
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}
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Status WebVttSegmenter::OnSegmentEnd() {
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DCHECK(samples_.size());
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const uint64_t segment = samples_.top().segment;
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Status status;
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while (status.ok() && samples_.size() && samples_.top().segment == segment) {
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status.Update(
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DispatchTextSample(kStreamIndex, std::move(samples_.top().sample)));
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samples_.pop();
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}
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// Only send the segment info if all the samples were accepted.
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if (status.ok()) {
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std::shared_ptr<SegmentInfo> info = std::make_shared<SegmentInfo>();
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info->start_timestamp = segment * segment_duration_ms_;
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info->duration = segment_duration_ms_;
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status.Update(DispatchSegmentInfo(kStreamIndex, std::move(info)));
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}
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return status;
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}
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} // namespace media
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} // namespace shaka
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