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/* | |
* Copyright (c) 2010 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. | |
*/ | |
// Simple Decoder | |
// ============== | |
// | |
// This is an example of a simple decoder loop. It takes an input file | |
// containing the compressed data (in IVF format), passes it through the | |
// decoder, and writes the decompressed frames to disk. Other decoder | |
// examples build upon this one. | |
// | |
// The details of the IVF format have been elided from this example for | |
// simplicity of presentation, as IVF files will not generally be used by | |
// your application. In general, an IVF file consists of a file header, | |
// followed by a variable number of frames. Each frame consists of a frame | |
// header followed by a variable length payload. The length of the payload | |
// is specified in the first four bytes of the frame header. The payload is | |
// the raw compressed data. | |
// | |
// Standard Includes | |
// ----------------- | |
// For decoders, you only have to include `vpx_decoder.h` and then any | |
// header files for the specific codecs you use. In this case, we're using | |
// vp8. | |
// | |
// Initializing The Codec | |
// ---------------------- | |
// The libvpx decoder is initialized by the call to vpx_codec_dec_init(). | |
// Determining the codec interface to use is handled by VpxVideoReader and the | |
// functions prefixed with vpx_video_reader_. Discussion of those functions is | |
// beyond the scope of this example, but the main gist is to open the input file | |
// and parse just enough of it to determine if it's a VPx file and which VPx | |
// codec is contained within the file. | |
// Note the NULL pointer passed to vpx_codec_dec_init(). We do that in this | |
// example because we want the algorithm to determine the stream configuration | |
// (width/height) and allocate memory automatically. | |
// | |
// Decoding A Frame | |
// ---------------- | |
// Once the frame has been read into memory, it is decoded using the | |
// `vpx_codec_decode` function. The call takes a pointer to the data | |
// (`frame`) and the length of the data (`frame_size`). No application data | |
// is associated with the frame in this example, so the `user_priv` | |
// parameter is NULL. The `deadline` parameter is left at zero for this | |
// example. This parameter is generally only used when doing adaptive post | |
// processing. | |
// | |
// Codecs may produce a variable number of output frames for every call to | |
// `vpx_codec_decode`. These frames are retrieved by the | |
// `vpx_codec_get_frame` iterator function. The iterator variable `iter` is | |
// initialized to NULL each time `vpx_codec_decode` is called. | |
// `vpx_codec_get_frame` is called in a loop, returning a pointer to a | |
// decoded image or NULL to indicate the end of list. | |
// | |
// Processing The Decoded Data | |
// --------------------------- | |
// In this example, we simply write the encoded data to disk. It is | |
// important to honor the image's `stride` values. | |
// | |
// Cleanup | |
// ------- | |
// The `vpx_codec_destroy` call frees any memory allocated by the codec. | |
// | |
// Error Handling | |
// -------------- | |
// This example does not special case any error return codes. If there was | |
// an error, a descriptive message is printed and the program exits. With | |
// few exceptions, vpx_codec functions return an enumerated error status, | |
// with the value `0` indicating success. | |
#include <stdio.h> | |
#include <stdlib.h> | |
#include <string.h> | |
#include "vpx/vpx_decoder.h" | |
#include "../tools_common.h" | |
#include "../video_reader.h" | |
#include "./vpx_config.h" | |
static const char *exec_name; | |
void usage_exit(void) { | |
fprintf(stderr, "Usage: %s <infile> <outfile>\n", exec_name); | |
exit(EXIT_FAILURE); | |
} | |
int main(int argc, char **argv) { | |
int frame_cnt = 0; | |
FILE *outfile = NULL; | |
vpx_codec_ctx_t codec; | |
VpxVideoReader *reader = NULL; | |
const VpxInterface *decoder = NULL; | |
const VpxVideoInfo *info = NULL; | |
exec_name = argv[0]; | |
if (argc != 3) die("Invalid number of arguments."); | |
reader = vpx_video_reader_open(argv[1]); | |
if (!reader) die("Failed to open %s for reading.", argv[1]); | |
if (!(outfile = fopen(argv[2], "wb"))) | |
die("Failed to open %s for writing.", argv[2]); | |
info = vpx_video_reader_get_info(reader); | |
decoder = get_vpx_decoder_by_fourcc(info->codec_fourcc); | |
if (!decoder) die("Unknown input codec."); | |
printf("Using %s\n", vpx_codec_iface_name(decoder->codec_interface())); | |
if (vpx_codec_dec_init(&codec, decoder->codec_interface(), NULL, 0)) | |
die("Failed to initialize decoder."); | |
while (vpx_video_reader_read_frame(reader)) { | |
vpx_codec_iter_t iter = NULL; | |
vpx_image_t *img = NULL; | |
size_t frame_size = 0; | |
const unsigned char *frame = | |
vpx_video_reader_get_frame(reader, &frame_size); | |
if (vpx_codec_decode(&codec, frame, (unsigned int)frame_size, NULL, 0)) | |
die_codec(&codec, "Failed to decode frame."); | |
while ((img = vpx_codec_get_frame(&codec, &iter)) != NULL) { | |
vpx_img_write(img, outfile); | |
++frame_cnt; | |
} | |
} | |
printf("Processed %d frames.\n", frame_cnt); | |
if (vpx_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec"); | |
printf("Play: ffplay -f rawvideo -pix_fmt yuv420p -s %dx%d %s\n", | |
info->frame_width, info->frame_height, argv[2]); | |
vpx_video_reader_close(reader); | |
fclose(outfile); | |
return EXIT_SUCCESS; | |
} |