shaka-packager/packager/media/formats/webvtt/text_padder.cc

61 lines
2.0 KiB
C++

// Copyright 2018 Google LLC. 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/formats/webvtt/text_padder.h>
#include <algorithm>
#include <packager/status/status_macros.h>
namespace shaka {
namespace media {
namespace {
const uint64_t kStreamIndex = 0;
} // namespace
TextPadder::TextPadder(int64_t zero_start_bias_ms)
: zero_start_bias_ms_(zero_start_bias_ms) {}
Status TextPadder::InitializeInternal() {
return Status::OK;
}
Status TextPadder::Process(std::unique_ptr<StreamData> data) {
DCHECK_EQ(data->stream_index, kStreamIndex);
const bool is_text_sample =
data->stream_data_type == StreamDataType::kTextSample;
return is_text_sample ? OnTextSample(std::move(data))
: Dispatch(std::move(data));
}
Status TextPadder::OnTextSample(std::unique_ptr<StreamData> data) {
const TextSample& sample = *data->text_sample;
// If this is the first sample we have seen, we need to check if we should
// start at time zero.
if (max_end_time_ms_ < 0) {
max_end_time_ms_ =
sample.start_time() > zero_start_bias_ms_ ? sample.start_time() : 0;
}
// Check if there will be a gap between samples if we just dispatch this
// sample right away. If there will be one, create an empty sample that will
// fill in that gap.
if (sample.start_time() > max_end_time_ms_) {
const std::string kNoId = "";
auto filler = std::make_shared<TextSample>(kNoId, max_end_time_ms_,
sample.start_time(),
TextSettings{}, TextFragment{});
RETURN_IF_ERROR(
MediaHandler::DispatchTextSample(kStreamIndex, std::move(filler)));
}
max_end_time_ms_ = std::max(max_end_time_ms_, sample.EndTime());
return Dispatch(std::move(data));
}
} // namespace media
} // namespace shaka