ivf_file_reader.h - mozsearch

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/*

 *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

*/

#ifndef MODULES_VIDEO_CODING_UTILITY_IVF_FILE_READER_H_

#define MODULES_VIDEO_CODING_UTILITY_IVF_FILE_READER_H_

#include <memory>

#include <optional>

#include <utility>

#include "api/video/encoded_image.h"

#include "api/video_codecs/video_codec.h"

#include "rtc_base/system/file_wrapper.h"

namespace webrtc {

class IvfFileReader {

 public:

  // Creates IvfFileReader. Returns nullptr if error acquired.

  static std::unique_ptr<IvfFileReader> Create(FileWrapper file);

  ~IvfFileReader();

  IvfFileReader(const IvfFileReader&) = delete;

  IvfFileReader& operator=(const IvfFileReader&) = delete;

  // Reinitializes reader. Returns false if any error acquired.

  bool Reset();

  // Returns codec type which was used to create this IVF file and which should

  // be used to decode EncodedImages from this file.

  VideoCodecType GetVideoCodecType() const { return codec_type_; }

  // Returns count of frames in this file.

  size_t GetFramesCount() const { return num_frames_; }

  // Returns next frame or std::nullopt if any error acquired. Always returns

  // std::nullopt after first error was spotted.

  std::optional<EncodedImage> NextFrame();

  bool HasMoreFrames() const { return num_read_frames_ < num_frames_; }

  bool HasError() const { return has_error_; }

  uint16_t GetFrameWidth() const { return width_; }

  uint16_t GetFrameHeight() const { return height_; }

  bool Close();

 private:

  struct FrameHeader {

    size_t frame_size;

    int64_t timestamp;

};

  explicit IvfFileReader(FileWrapper file) : file_(std::move(file)) {}

  // Parses codec type from specified position of the buffer. Codec type

  // contains kCodecTypeBytesCount bytes and caller has to ensure that buffer

  // won't overflow.

  std::optional<VideoCodecType> ParseCodecType(uint8_t* buffer,

                                               size_t start_pos);

  std::optional<FrameHeader> ReadNextFrameHeader();

  VideoCodecType codec_type_;

  size_t num_frames_;

  size_t num_read_frames_;

  uint16_t width_;

  uint16_t height_;

  uint32_t time_scale_;

  FileWrapper file_;

  std::optional<FrameHeader> next_frame_header_;

  bool has_error_;

};

}  // namespace webrtc

#endif  // MODULES_VIDEO_CODING_UTILITY_IVF_FILE_READER_H_