text: /*
   *  Copyright (c) 2013 The WebM 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 WEBMDEC_H_
  #define WEBMDEC_H_
  
  #include "./tools_common.h"
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  struct VpxInputContext;
  
  struct WebmInputContext {
    void *reader;
    void *segment;
    uint8_t *buffer;
    const void *cluster;
    const void *block_entry;
    const void *block;
    int block_frame_index;
    int video_track_index;
    uint64_t timestamp_ns;
    int is_key_frame;
    int reached_eos;
  };
  
  // Checks if the input is a WebM file. If so, initializes WebMInputContext so
  // that webm_read_frame can be called to retrieve a video frame.
  // Returns 1 on success and 0 on failure or input is not WebM file.
  // TODO(vigneshv): Refactor this function into two smaller functions specific
  // to their task.
  int file_is_webm(struct WebmInputContext *webm_ctx,
                   struct VpxInputContext *vpx_ctx);
  
  // Reads a WebM Video Frame. Memory for the buffer is created, owned and managed
  // by this function. For the first call, |buffer| should be NULL and
  // |*buffer_size| should be 0. Once all the frames are read and used,
  // webm_free() should be called, otherwise there will be a leak.
  // Parameters:
  //      webm_ctx - WebmInputContext object
  //      buffer - pointer where the frame data will be filled.
  //      buffer_size - pointer to buffer size.
  // Return values:
  //      0 - Success
  //      1 - End of Stream
  //     -1 - Error
  int webm_read_frame(struct WebmInputContext *webm_ctx,
                      uint8_t **buffer,
                      size_t *buffer_size);
  
  int webm_read_frame_alpha(struct WebmInputContext *webm_ctx,
                      uint8_t **buffer,
                      size_t *buffer_size);
  
  void webm_get_cluster_by_time(struct WebmInputContext *webm_ctx, uint64_t time_ns);
  
  int webm_get_chapters(struct WebmInputContext *webm_ctx, const char** names, uint64_t* startTimes, uint64_t* endTimes);
  
  // Guesses the frame rate of the input file based on the container timestamps.
  int webm_guess_framerate(struct WebmInputContext *webm_ctx,
                           struct VpxInputContext *vpx_ctx);
  
  // Resets the WebMInputContext.
  void webm_free(struct WebmInputContext *webm_ctx);
  
  #ifdef __cplusplus
  }  // extern "C"
  #endif
  
  #endif  // WEBMDEC_H_
  