From 8724e3e2dd3c74cab4320e81ed0b71f03a0ab142 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Wed, 20 May 2015 23:07:47 +0200
Subject: [PATCH] vo_xv: make number of buffers configurable

---
 DOCS/man/vo.rst   |  6 ++++++
 video/out/vo_xv.c | 11 ++++++++---
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/DOCS/man/vo.rst b/DOCS/man/vo.rst
index 915ef960b1..b6a6baf91d 100644
--- a/DOCS/man/vo.rst
+++ b/DOCS/man/vo.rst
@@ -69,6 +69,12 @@ Available video output drivers are:
     ``no-colorkey``
         Disables color-keying.
 
+    ``buffers=<number>``
+        Number of image buffers to use for the internal ringbuffer (default: 2).
+        Increasing this will use more memory, but might help with the X server
+        not responding quickly enough if video FPS is close to or higher than
+        the display refresh rate.
+
 ``x11`` (X11 only)
     Shared memory video output driver without hardware acceleration that works
     whenever X11 is present.
diff --git a/video/out/vo_xv.c b/video/out/vo_xv.c
index e6578b1460..0d2c632cc8 100644
--- a/video/out/vo_xv.c
+++ b/video/out/vo_xv.c
@@ -63,6 +63,8 @@
 #define CK_SRC_SET           1 // use and set specified / default colorkey
 #define CK_SRC_CUR           2 // use current colorkey (get it from xv)
 
+#define MAX_BUFFERS 10
+
 struct xvctx {
     struct xv_ck_info_s {
         int method; // CK_METHOD_* constants
@@ -72,13 +74,14 @@ struct xvctx {
     unsigned long xv_colorkey;
     int xv_port;
     int cfg_xv_adaptor;
+    int cfg_buffers;
     XvAdaptorInfo *ai;
     XvImageFormatValues *fo;
     unsigned int formats, adaptors, xv_format;
     int current_buf;
     int current_ip_buf;
     int num_buffers;
-    XvImage *xvimage[2];
+    XvImage *xvimage[MAX_BUFFERS];
     struct mp_image *original_image;
     uint32_t image_width;
     uint32_t image_height;
@@ -89,7 +92,7 @@ struct xvctx {
     uint32_t max_width, max_height; // zero means: not set
     int Shmem_Flag;
 #if HAVE_SHM && HAVE_XEXT
-    XShmSegmentInfo Shminfo[2];
+    XShmSegmentInfo Shminfo[MAX_BUFFERS];
     int Shm_Warned_Slow;
 #endif
 };
@@ -463,7 +466,7 @@ static int reconfig(struct vo *vo, struct mp_image_params *params, int flags)
     for (i = 0; i < ctx->num_buffers; i++)
         deallocate_xvimage(vo, i);
 
-    ctx->num_buffers = 2;
+    ctx->num_buffers = ctx->cfg_buffers;
 
     for (i = 0; i < ctx->num_buffers; i++) {
         if (!allocate_xvimage(vo, i)) {
@@ -848,6 +851,7 @@ const struct vo_driver video_out_xv = {
         .xv_ck_info = {CK_METHOD_MANUALFILL, CK_SRC_CUR},
         .colorkey = 0x0000ff00, // default colorkey is green
                     // (0xff000000 means that colorkey has been disabled)
+        .cfg_buffers = 2,
     },
     .options = (const struct m_option[]) {
         OPT_INT("port", xv_port, M_OPT_MIN, .min = 0),
@@ -862,6 +866,7 @@ const struct vo_driver video_out_xv = {
                     {"auto", CK_METHOD_AUTOPAINT})),
         OPT_INT("colorkey", colorkey, 0),
         OPT_FLAG_STORE("no-colorkey", colorkey, 0, 0x1000000),
+        OPT_INTRANGE("buffers", cfg_buffers, 0, 1, MAX_BUFFERS),
         {0}
     },
 };