libvpx: Pull from upstream

source/libvpx/ivfdec.c

+/*
+ *  Copyright (c) 2013 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.
+ */
+
+#include "./ivfdec.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int file_is_ivf(struct VpxInputContext *input_ctx) {
+  char raw_hdr[32];
+  int is_ivf = 0;
+
+  // TODO(tomfinegan): This can eventually go away, but for now it's required
+  // because the means by which file types are detected differ in vpxdec and
+  // vpxenc.
+  rewind(input_ctx->file);
+
+  if (fread(raw_hdr, 1, 32, input_ctx->file) == 32) {
+    if (raw_hdr[0] == 'D' && raw_hdr[1] == 'K' &&
+        raw_hdr[2] == 'I' && raw_hdr[3] == 'F') {
+      is_ivf = 1;
+
+      if (mem_get_le16(raw_hdr + 4) != 0) {
+        fprintf(stderr, "Error: Unrecognized IVF version! This file may not"
+                " decode properly.");
+      }
+
+      input_ctx->fourcc = mem_get_le32(raw_hdr + 8);
+      input_ctx->width = mem_get_le16(raw_hdr + 12);
+      input_ctx->height = mem_get_le16(raw_hdr + 14);
+      input_ctx->framerate.numerator = mem_get_le32(raw_hdr + 16);
+      input_ctx->framerate.denominator = mem_get_le32(raw_hdr + 20);
+
+      /* Some versions of vpxenc used 1/(2*fps) for the timebase, so
+       * we can guess the framerate using only the timebase in this
+       * case. Other files would require reading ahead to guess the
+       * timebase, like we do for webm.
+       */
+      if (input_ctx->framerate.numerator < 1000) {
+        /* Correct for the factor of 2 applied to the timebase in the
+         * encoder.
+         */
+        if (input_ctx->framerate.numerator & 1)
+          input_ctx->framerate.denominator <<= 1;
+        else
+          input_ctx->framerate.numerator >>= 1;
+      } else {
+        /* Don't know FPS for sure, and don't have readahead code
+         * (yet?), so just default to 30fps.
+         */
+        input_ctx->framerate.numerator = 30;
+        input_ctx->framerate.denominator = 1;
+      }
+    }
+  }
+
+  if (!is_ivf) {
+    rewind(input_ctx->file);
+    input_ctx->detect.buf_read = 0;
+  } else {
+    input_ctx->detect.position = 4;
+  }
+  return is_ivf;
+}
+
+int ivf_read_frame(struct VpxInputContext *input_ctx,
+                   uint8_t **buffer,
+                   size_t *bytes_read,
+                   size_t *buffer_size) {
+  char raw_header[IVF_FRAME_HDR_SZ] = {0};
+  size_t frame_size = 0;
+  FILE *infile = input_ctx->file;
+
+  if (input_ctx->file_type != FILE_TYPE_IVF)
+    return 0;
+
+  if (fread(raw_header, IVF_FRAME_HDR_SZ, 1, infile) != 1) {
+    if (!feof(infile))
+      warn("Failed to read frame size\n");
+  } else {
+    frame_size = mem_get_le32(raw_header);
+
+    if (frame_size > 256 * 1024 * 1024) {
+      warn("Read invalid frame size (%u)\n", (unsigned int)frame_size);
+      frame_size = 0;
+    }
+
+    if (frame_size > *buffer_size) {
+      uint8_t *new_buffer = realloc(*buffer, 2 * frame_size);
+
+      if (new_buffer) {
+        *buffer = new_buffer;
+        *buffer_size = 2 * frame_size;
+      } else {
+        warn("Failed to allocate compressed data buffer\n");
+        frame_size = 0;
+      }
+    }
+  }
+
+  if (!feof(infile)) {
+    if (fread(*buffer, 1, frame_size, infile) != frame_size) {
+      warn("Failed to read full frame\n");
+      return 1;
+    }
+
+    *bytes_read = frame_size;
+    return 0;
+  }
+
+  return 1;
+}