From 07a027ef87333662b3709215025838646ee3d6be Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben@decadent.org.uk>
Date: Sun, 15 Oct 2006 00:57:16 +0000
Subject: [PATCH] Added more standard headers that are strictly required. Added
 explicit input frame rate to ffmpeg command line since the assumed default is
 25 fps and *not* the output frame rate. Changed menu duration to 12 frames
 regardless of frame rate since this *should* be legal at 29.97 fps and it
 seems to avoid some problematic rounding errors.

---
 generate_dvd.cpp | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/generate_dvd.cpp b/generate_dvd.cpp
index 398fdd1..64079d2 100644
--- a/generate_dvd.cpp
+++ b/generate_dvd.cpp
@@ -1,8 +1,12 @@
 // Copyright 2005-6 Ben Hutchings <ben@decadent.org.uk>.
 // See the file "COPYING" for licence details.
 
+#include <cerrno>
+#include <cstring>
 #include <fstream>
+#include <iomanip>
 #include <iostream>
+#include <ostream>
 #include <sstream>
 #include <stdexcept>
 
@@ -76,11 +80,16 @@ namespace
     // We would like to use just a single frame for the menu but this
     // seems not to be legal or compatible.  The minimum length of a
     // cell is 0.4 seconds but I've seen a static menu using 12 frames
-    // on a "PAL" disc so let's say 0.5 seconds rounded down.
-    const char menu_duration_string[] = "0.5";
+    // on a commercial "PAL" disc so let's use 12 frames regardless.
     unsigned menu_duration_frames(const video::frame_params & params)
     {
-	return params.rate_numer / params.rate_denom / 2;
+	return 12;
+    }
+    double menu_duration_seconds(const video::frame_params & params)
+    {
+	return double(menu_duration_frames(params))
+	    * double(params.rate_numer)
+	    / double(params.rate_denom);
     }
 }
 
@@ -212,7 +221,10 @@ void dvd_generator::generate_menu_vob(unsigned index,
 		    std::string("symlink: ").append(std::strerror(errno)));
 	}
 	command_stream <<
-	    "ffmpeg -f image2 -vcodec png -i " << background_name << "-%02d"
+	    "ffmpeg -f image2 -vcodec png"
+	    " -r " << frame_params_.rate_numer <<
+	    "/" << frame_params_.rate_denom <<
+	    " -i " << background_name << "-%02d"
 	    " -target " << frame_params_.common_name <<  "-dvd"
 	    " -vcodec mpeg2video -aspect 4:3 -an -y /dev/stdout";
     }
@@ -373,7 +385,9 @@ void dvd_generator::generate(const std::string & output_dir) const
 	    // Define a cell covering the whole menu and set a still
 	    // time at the end of that, since it seems all players
 	    // support that but some ignore a still time set on a PGC.
-	    "          <cell start='0' end='" << menu_duration_string << "'"
+	    "          <cell start='0' end='"
+	     << std::fixed << std::setprecision(4)
+	     << menu_duration_seconds(frame_params_) << "'"
 	    " chapter='yes' pause='inf'/>\n"
 	    "        </vob>\n";
 
-- 
2.39.5