1/* 2 * Copyright (c) 2010 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 11// Simple Decoder 12// ============== 13// 14// This is an example of a simple decoder loop. It takes an input file 15// containing the compressed data (in IVF format), passes it through the 16// decoder, and writes the decompressed frames to disk. Other decoder 17// examples build upon this one. 18// 19// The details of the IVF format have been elided from this example for 20// simplicity of presentation, as IVF files will not generally be used by 21// your application. In general, an IVF file consists of a file header, 22// followed by a variable number of frames. Each frame consists of a frame 23// header followed by a variable length payload. The length of the payload 24// is specified in the first four bytes of the frame header. The payload is 25// the raw compressed data. 26// 27// Standard Includes 28// ----------------- 29// For decoders, you only have to include `vpx_decoder.h` and then any 30// header files for the specific codecs you use. In this case, we're using 31// vp8. 32// 33// Initializing The Codec 34// ---------------------- 35// The libvpx decoder is initialized by the call to vpx_codec_dec_init(). 36// Determining the codec interface to use is handled by VpxVideoReader and the 37// functions prefixed with vpx_video_reader_. Discussion of those functions is 38// beyond the scope of this example, but the main gist is to open the input file 39// and parse just enough of it to determine if it's a VPx file and which VPx 40// codec is contained within the file. 41// Note the NULL pointer passed to vpx_codec_dec_init(). We do that in this 42// example because we want the algorithm to determine the stream configuration 43// (width/height) and allocate memory automatically. 44// 45// Decoding A Frame 46// ---------------- 47// Once the frame has been read into memory, it is decoded using the 48// `vpx_codec_decode` function. The call takes a pointer to the data 49// (`frame`) and the length of the data (`frame_size`). No application data 50// is associated with the frame in this example, so the `user_priv` 51// parameter is NULL. The `deadline` parameter is left at zero for this 52// example. This parameter is generally only used when doing adaptive post 53// processing. 54// 55// Codecs may produce a variable number of output frames for every call to 56// `vpx_codec_decode`. These frames are retrieved by the 57// `vpx_codec_get_frame` iterator function. The iterator variable `iter` is 58// initialized to NULL each time `vpx_codec_decode` is called. 59// `vpx_codec_get_frame` is called in a loop, returning a pointer to a 60// decoded image or NULL to indicate the end of list. 61// 62// Processing The Decoded Data 63// --------------------------- 64// In this example, we simply write the encoded data to disk. It is 65// important to honor the image's `stride` values. 66// 67// Cleanup 68// ------- 69// The `vpx_codec_destroy` call frees any memory allocated by the codec. 70// 71// Error Handling 72// -------------- 73// This example does not special case any error return codes. If there was 74// an error, a descriptive message is printed and the program exits. With 75// few exceptions, vpx_codec functions return an enumerated error status, 76// with the value `0` indicating success. 77 78#include <stdio.h> 79#include <stdlib.h> 80#include <string.h> 81 82#include "vpx/vpx_decoder.h" 83 84#include "../tools_common.h" 85#include "../video_reader.h" 86#include "./vpx_config.h" 87 88static const char *exec_name; 89 90void usage_exit(void) { 91 fprintf(stderr, "Usage: %s <infile> <outfile>\n", exec_name); 92 exit(EXIT_FAILURE); 93} 94 95int main(int argc, char **argv) { 96 int frame_cnt = 0; 97 FILE *outfile = NULL; 98 vpx_codec_ctx_t codec; 99 VpxVideoReader *reader = NULL; 100 const VpxInterface *decoder = NULL; 101 const VpxVideoInfo *info = NULL; 102 103 exec_name = argv[0]; 104 105 if (argc != 3) die("Invalid number of arguments."); 106 107 reader = vpx_video_reader_open(argv[1]); 108 if (!reader) die("Failed to open %s for reading.", argv[1]); 109 110 if (!(outfile = fopen(argv[2], "wb"))) 111 die("Failed to open %s for writing.", argv[2]); 112 113 info = vpx_video_reader_get_info(reader); 114 115 decoder = get_vpx_decoder_by_fourcc(info->codec_fourcc); 116 if (!decoder) die("Unknown input codec."); 117 118 printf("Using %s\n", vpx_codec_iface_name(decoder->codec_interface())); 119 120 if (vpx_codec_dec_init(&codec, decoder->codec_interface(), NULL, 0)) 121 die_codec(&codec, "Failed to initialize decoder."); 122 123 while (vpx_video_reader_read_frame(reader)) { 124 vpx_codec_iter_t iter = NULL; 125 vpx_image_t *img = NULL; 126 size_t frame_size = 0; 127 const unsigned char *frame = 128 vpx_video_reader_get_frame(reader, &frame_size); 129 if (vpx_codec_decode(&codec, frame, (unsigned int)frame_size, NULL, 0)) 130 die_codec(&codec, "Failed to decode frame."); 131 132 while ((img = vpx_codec_get_frame(&codec, &iter)) != NULL) { 133 vpx_img_write(img, outfile); 134 ++frame_cnt; 135 } 136 } 137 138 printf("Processed %d frames.\n", frame_cnt); 139 if (vpx_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec"); 140 141 printf("Play: ffplay -f rawvideo -pix_fmt yuv420p -s %dx%d %s\n", 142 info->frame_width, info->frame_height, argv[2]); 143 144 vpx_video_reader_close(reader); 145 146 fclose(outfile); 147 148 return EXIT_SUCCESS; 149} 150