vd_ffmpeg: set thread count to number of cores on machine by default

Make "-lavdopts threads=0" mean an autodetected number of threads, and
make that the default value of the option. Also increase the upper
limit of the option from 8 to 16. Add new file osdep/numcores.c which
tries to determine the number of cores available on the machine.

numcores.c is based (heavily modified) on public domain numcpus.c by
Philip Willoughby <pgw99@doc.ic.ac.uk>, downloaded from
http://csgsoft.doc.ic.ac.uk/numcpus/

2 files changed, 67 insertions, 0 deletions

diff --git a/osdep/numcores.c b/osdep/numcores.c
new file mode 100644
index 0000000000..86a327e041
--- /dev/null
+++ b/osdep/numcores.c
@@ -0,0 +1,66 @@
+/*
+ * This file is part of MPlayer.
+ *
+ * MPlayer is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * MPlayer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with MPlayer; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include "numcores.h"
+
+#ifdef _SC_NPROCESSORS_ONLN
+#define SCNAME _SC_NPROCESSORS_ONLN
+#elif defined _SC_NPROC_ONLN
+#define SCNAME _SC_NPROC_ONLN
+#elif defined _SC_CRAY_NCPU
+#define SCNAME _SC_CRAY_NCPU
+#endif
+
+#ifdef _WIN32
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+int default_thread_count(void)
+{
+    SYSTEM_INFO info;
+    GetSystemInfo(&info);
+    int count = info.dwNumberOfProcessors;
+    if (count > 0)
+        return count;
+    return -1;
+}
+
+#elif defined SCNAME
+
+int default_thread_count(void)
+{
+    long nprocs = sysconf(SCNAME);
+    if (nprocs < 1)
+        return -1;
+    return nprocs;
+}
+
+#else
+
+int default_thread_count(void)
+{
+    return -2;
+}
+
+#endif
diff --git a/osdep/numcores.h b/osdep/numcores.h
new file mode 100644
index 0000000000..b999d9e275
--- /dev/null
+++ b/osdep/numcores.h
@@ -0,0 +1 @@
+int default_thread_count(void);