idct: Split off Xvid IDCT

The Xvid IDCT is only required to decode some Xvid-encoded MPEG-4 files,
so there is no point in having it as an unconditional part of idctdsp.

1 files changed, 36 insertions, 0 deletions

diff --git a/libavcodec/xvididct.c b/libavcodec/xvididct.c
new file mode 100644
index 0000000000..1453e51700
--- /dev/null
+++ b/libavcodec/xvididct.c
@@ -0,0 +1,36 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "config.h"
+#include "libavutil/attributes.h"
+#include "avcodec.h"
+#include "idctdsp.h"
+#include "xvididct.h"
+
+av_cold void ff_xvididct_init(IDCTDSPContext *c, AVCodecContext *avctx)
+{
+    const unsigned high_bit_depth = avctx->bits_per_raw_sample > 8;
+
+    if (high_bit_depth ||
+        !(avctx->idct_algo == FF_IDCT_AUTO ||
+          avctx->idct_algo == FF_IDCT_XVIDMMX))
+        return;
+
+    if (ARCH_X86)
+        ff_xvididct_init_x86(c);
+}