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

49 lines
1.7 KiB
C++

// Copyright 2018 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
#ifndef PACKAGER_MEDIA_FORMATS_WEBVTT_TEXT_PADDER_H_
#define PACKAGER_MEDIA_FORMATS_WEBVTT_TEXT_PADDER_H_
#include "packager/media/base/media_handler.h"
namespace shaka {
namespace media {
/// A media handler that will inject empty text samples to fill any gaps
/// that may appear in the text stream.
class TextPadder : public MediaHandler {
public:
/// Create a new text padder.
///
/// |zero_start_bias_ms| is the threshold used to determine if we should
/// assume that the stream actually starts at time zero. If the first sample
/// comes before the |zero_start_bias_ms|, then the start will be padded as
/// the stream is assumed to start at zero. If the first sample comes after
/// |zero_start_bias_ms| then the start of the stream will not be padded as
/// we cannot assume the start time of the stream.
explicit TextPadder(int64_t zero_start_bias_ms);
~TextPadder() override = default;
private:
TextPadder(const TextPadder&) = delete;
TextPadder& operator=(const TextPadder&) = delete;
Status InitializeInternal() override;
Status Process(std::unique_ptr<StreamData> data) override;
Status OnTextSample(std::unique_ptr<StreamData> data);
const int64_t zero_start_bias_ms_;
// Will be set once we see our first sample. Using -1 to signal that we have
// not seen the first sample yet.
int64_t max_end_time_ms_ = -1;
};
} // namespace media
} // namespace shaka
#endif // MEDIA_FORMATS_WEBVTT_TEXT_PADDER_H_