webmdec.h

   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 };
  33
  34 // Checks if the input is a WebM file. If so, initializes WebMInputContext so
  35 // that webm_read_frame can be called to retrieve a video frame.
  36 // Returns 1 on success and 0 on failure or input is not WebM file.
  37 // TODO(vigneshv): Refactor this function into two smaller functions specific
  38 // to their task.
  39 int file_is_webm(struct WebmInputContext *webm_ctx,
  40                  struct VpxInputContext *vpx_ctx);
  41
  42 // Reads a WebM Video Frame. Memory for the buffer is created, owned and managed
  43 // by this function. For the first call, |buffer| should be NULL and
  44 // |*bytes_in_buffer| should be 0. Once all the frames are read and used,
  45 // webm_free() should be called, otherwise there will be a leak.
  46 // Parameters:
  47 //      webm_ctx - WebmInputContext object
  48 //      buffer - pointer where the frame data will be filled.
  49 //      bytes_in_buffer - pointer to buffer size.
  50 //      buffer_size - unused TODO(vigneshv): remove this
  51 // Return values:
  52 //      0 - Success
  53 //      1 - End of Stream
  54 //     -1 - Error
  55 // TODO(vigneshv): Make the return values consistent across all functions in
  56 // this file.
  57 int webm_read_frame(struct WebmInputContext *webm_ctx,
  58                     uint8_t **buffer,
  59                     size_t *bytes_in_buffer,
  60                     size_t *buffer_size);
  61
  62 // Guesses the frame rate of the input file based on the container timestamps.
  63 int webm_guess_framerate(struct WebmInputContext *webm_ctx,
  64                          struct VpxInputContext *vpx_ctx);
  65
  66 // Resets the WebMInputContext.
  67 void webm_free(struct WebmInputContext *webm_ctx);
  68
  69 #ifdef __cplusplus
  70 }  // extern "C"
  71 #endif
  72
  73 #endif  // WEBMDEC_H_