X-Git-Url: https://granicus.if.org/sourcecode?a=blobdiff_plain;f=ivfdec.c;h=6dcd66f734d575ceb48474cf332bc1dde693133c;hb=f441a652b7f646edfd32a3bb327ae6cda3e2f412;hp=4a0816ff0aeee1a6a66fe00aece1df777669b565;hpb=a944deae974e09a4f90e77c7772729346fcbf524;p=libvpx

diff --git a/ivfdec.c b/ivfdec.c
index 4a0816ff0..6dcd66f73 100644
--- a/ivfdec.c
+++ b/ivfdec.c
@@ -8,23 +8,41 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "./ivfdec.h"
-
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+
+#include "vpx_ports/mem_ops.h"
+
+#include "./ivfdec.h"
+
+static const char *IVF_SIGNATURE = "DKIF";
+
+static void fix_framerate(int *num, int *den) {
+  // 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 (*num < 1000) {
+    // Correct for the factor of 2 applied to the timebase in the encoder.
+    if (*num & 1)
+      *den *= 2;
+    else
+      *num /= 2;
+  } else {
+    // Don't know FPS for sure, and don't have readahead code
+    // (yet?), so just default to 30fps.
+    *num = 30;
+    *den = 1;
+  }
+}
 
 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') {
+    if (memcmp(IVF_SIGNATURE, raw_hdr, 4) == 0) {
       is_ivf = 1;
 
       if (mem_get_le16(raw_hdr + 4) != 0) {
@@ -37,27 +55,8 @@ int file_is_ivf(struct VpxInputContext *input_ctx) {
       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;
-      }
+      fix_framerate(&input_ctx->framerate.numerator,
+                    &input_ctx->framerate.denominator);
     }
   }
 
@@ -70,16 +69,10 @@ int file_is_ivf(struct VpxInputContext *input_ctx) {
   return is_ivf;
 }
 
-int ivf_read_frame(struct VpxInputContext *input_ctx,
-                   uint8_t **buffer,
-                   size_t *bytes_read,
-                   size_t *buffer_size) {
+int ivf_read_frame(FILE *infile, 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))