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      1 /*
      2  *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 #ifndef WEBMDEC_H_
     11 #define WEBMDEC_H_
     12 
     13 #include "./tools_common.h"
     14 
     15 #ifdef __cplusplus
     16 extern "C" {
     17 #endif
     18 
     19 struct VpxInputContext;
     20 
     21 struct WebmInputContext {
     22   void *reader;
     23   void *segment;
     24   uint8_t *buffer;
     25   const void *cluster;
     26   const void *block_entry;
     27   const void *block;
     28   int block_frame_index;
     29   int video_track_index;
     30   uint64_t timestamp_ns;
     31   int is_key_frame;
     32   int reached_eos;
     33 };
     34 
     35 // Checks if the input is a WebM file. If so, initializes WebMInputContext so
     36 // that webm_read_frame can be called to retrieve a video frame.
     37 // Returns 1 on success and 0 on failure or input is not WebM file.
     38 // TODO(vigneshv): Refactor this function into two smaller functions specific
     39 // to their task.
     40 int file_is_webm(struct WebmInputContext *webm_ctx,
     41                  struct VpxInputContext *vpx_ctx);
     42 
     43 // Reads a WebM Video Frame. Memory for the buffer is created, owned and managed
     44 // by this function. For the first call, |buffer| should be NULL and
     45 // |*buffer_size| should be 0. Once all the frames are read and used,
     46 // webm_free() should be called, otherwise there will be a leak.
     47 // Parameters:
     48 //      webm_ctx - WebmInputContext object
     49 //      buffer - pointer where the frame data will be filled.
     50 //      buffer_size - pointer to buffer size.
     51 // Return values:
     52 //      0 - Success
     53 //      1 - End of Stream
     54 //     -1 - Error
     55 int webm_read_frame(struct WebmInputContext *webm_ctx, uint8_t **buffer,
     56                     size_t *buffer_size);
     57 
     58 // Guesses the frame rate of the input file based on the container timestamps.
     59 int webm_guess_framerate(struct WebmInputContext *webm_ctx,
     60                          struct VpxInputContext *vpx_ctx);
     61 
     62 // Resets the WebMInputContext.
     63 void webm_free(struct WebmInputContext *webm_ctx);
     64 
     65 #ifdef __cplusplus
     66 }  // extern "C"
     67 #endif
     68 
     69 #endif  // WEBMDEC_H_
     70