libvpx: Pull from upstream

source/libvpx/examples/simple_decoder.c

+/*
+ *  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. The `VPX_CODEC_DISABLE_COMPAT` macro can be defined to ensure
+// strict compliance with the latest SDK by disabling some backwards
+// compatibility features. Defining this macro is encouraged.
+//
+// Initializing The Codec
+// ----------------------
+// The decoder is initialized by the following code. This is an example for
+// the VP8 decoder, but the code is analogous for all algorithms. Replace
+// `vpx_codec_vp8_dx()` with a pointer to the interface exposed by the
+// algorithm you want to use. The `cfg` argument is left as NULL in this
+// example, because we want the algorithm to determine the stream
+// configuration (width/height) and allocate memory automatically. This
+// parameter is generally only used if you need to preallocate memory,
+// particularly in External Memory Allocation mode.
+//
+// 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_sz`). 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
+// postprocessing.
+//
+// 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 exeptions, vpx_codec functions return an enumerated error status,
+// with the value `0` indicating success.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define VPX_CODEC_DISABLE_COMPAT 1
+
+#include "vpx/vp8dx.h"
+#include "vpx/vpx_decoder.h"
+
+#include "./ivfdec.h"
+#include "./tools_common.h"
+#include "./vpx_config.h"
+
+static const char *exec_name;
+
+void usage_exit() {
+  fprintf(stderr, "Usage: %s <infile> <outfile>\n", exec_name);
+  exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv) {
+  FILE *infile, *outfile;
+  vpx_codec_ctx_t codec;
+  vpx_codec_iface_t *iface;
+  int flags = 0, frame_cnt = 0;
+  vpx_video_t *video;
+
+  exec_name = argv[0];
+
+  if (argc != 3)
+    die("Invalid number of arguments");
+
+  if (!(infile = fopen(argv[1], "rb")))
+    die("Failed to open %s for reading", argv[1]);
+
+  if (!(outfile = fopen(argv[2], "wb")))
+    die("Failed to open %s for writing", argv[2]);
+
+  video = vpx_video_open_file(infile);
+  if (!video)
+    die("%s is not an IVF file.", argv[1]);
+
+  iface = get_codec_interface(vpx_video_get_fourcc(video));
+  if (!iface)
+    die("Unknown FOURCC code.");
+
+  printf("Using %s\n", vpx_codec_iface_name(iface));
+
+  if (vpx_codec_dec_init(&codec, iface, NULL, flags))
+    die_codec(&codec, "Failed to initialize decoder");
+
+  while (vpx_video_read_frame(video)) {
+    vpx_codec_iter_t iter = NULL;
+    vpx_image_t *img = NULL;
+    size_t frame_size = 0;
+    const unsigned char *frame = vpx_video_get_frame(video, &frame_size);
+    if (vpx_codec_decode(&codec, frame, 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",
+         vpx_video_get_width(video), vpx_video_get_height(video), argv[2]);
+
+  vpx_video_close(video);
+
+  fclose(outfile);
+  fclose(infile);
+
+  return EXIT_SUCCESS;
+}