91 lines
2.7 KiB
C++
91 lines
2.7 KiB
C++
// Copyright 2018 Google LLC 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_file_buffer.h"
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#include "packager/base/strings/stringprintf.h"
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#include "packager/media/base/text_sample.h"
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#include "packager/media/formats/webvtt/webvtt_utils.h"
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namespace shaka {
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namespace media {
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namespace {
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const char* kHeader = "WEBVTT\n";
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const int kTsTimescale = 90000;
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} // namespace
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WebVttFileBuffer::WebVttFileBuffer(
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uint32_t transport_stream_timestamp_offset_ms,
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const std::string& style_region_config)
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: transport_stream_timestamp_offset_(transport_stream_timestamp_offset_ms *
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kTsTimescale / 1000),
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style_region_config_(style_region_config) {
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// Make sure we start with the same state that we would end up with if
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// the caller reset our state.
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Reset();
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}
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void WebVttFileBuffer::Reset() {
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sample_count_ = 0;
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buffer_.clear();
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buffer_.append(kHeader);
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if (transport_stream_timestamp_offset_ > 0) {
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// https://tools.ietf.org/html/rfc8216#section-3.5 WebVTT.
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base::StringAppendF(&buffer_,
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"X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:%d\n",
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transport_stream_timestamp_offset_);
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}
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buffer_.append("\n"); // end of header.
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if (!style_region_config_.empty()) {
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buffer_.append(style_region_config_);
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buffer_.append("\n\n");
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}
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}
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void WebVttFileBuffer::Append(const TextSample& sample) {
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DCHECK_GT(buffer_.size(), 0u) << "The buffer should at least have a header";
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sample_count_++;
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// Ids are optional
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if (sample.id().length()) {
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buffer_.append(sample.id());
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buffer_.append("\n"); // end of id
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}
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// Write the times that the sample elapses.
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buffer_.append(MsToWebVttTimestamp(sample.start_time()));
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buffer_.append(" --> ");
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buffer_.append(MsToWebVttTimestamp(sample.EndTime()));
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const std::string settings = WebVttSettingsToString(sample.settings());
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if (!settings.empty()) {
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buffer_.append(" ");
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buffer_.append(settings);
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}
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buffer_.append("\n"); // end of time & settings
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buffer_.append(WebVttFragmentToString(sample.body()));
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buffer_.append("\n"); // end of payload
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buffer_.append("\n"); // end of sample
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}
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bool WebVttFileBuffer::WriteTo(File* file, uint64_t* size) {
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DCHECK(file);
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DCHECK_GT(buffer_.size(), 0u) << "The buffer should at least have a header";
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if (size)
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*size = buffer_.size();
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const int written = file->Write(buffer_.c_str(), buffer_.size());
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if (written < 0) {
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return false;
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}
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return static_cast<size_t>(written) == buffer_.size();
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}
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} // namespace media
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} // namespace shaka
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