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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;
+}