create mpeg_encode parameter file on the fly

tutorial/t8.geo

-/********************************************************************* 
+/*********************************************************************
  *
  *  Gmsh tutorial 8
- * 
+ *
  *  Post-processing, scripting, animations, options
  *
  *********************************************************************/
@@ -15,7 +15,7 @@ Include "view4.pos";
 
 // We then set some general options:
 
-General.Trackball = 0; 
+General.Trackball = 0;
 General.RotationX = 0; General.RotationY = 0; General.RotationZ = 0;
 General.Color.Background = White; General.Color.Foreground = Black;
 General.Color.Text = Black;
@@ -53,15 +53,14 @@ View[v2].Height = 130;
 
 View[v3].Visible = 0;
 
-// We then loop from 1 to 255 with a step of 1. (To use a different
+// We then loop from 1 to 3 with a step of 1. (To use a different
 // step, just add a third argument in the list. For example, `For num
 // In {0.5:1.5:0.1}' would increment num from 0.5 to 1.5 with a step
 // of 0.1.)
 
 t = 0;
 
-//For num In {1:1}
-For num In {1:255}
+For num In {1:3}
 
   View[v0].TimeStep = t;
   View[v1].TimeStep = t;
@@ -69,30 +68,35 @@ For num In {1:255}
   View[v3].TimeStep = t;
 
   t = (View[v0].TimeStep < View[v0].NbTimeStep-1) ? t+1 : 0;
-  
+
   View[v0].RaiseZ += 0.01/View[v0].Max * t;
 
   If (num == 3)
-    // We want to create 320x240 frames when num == 3:
-    General.GraphicsWidth = 320; 
-    General.GraphicsHeight = 240;
+    // We want to create 640x480 frames when num == 3:
+    General.GraphicsWidth = General.MenuWidth + 640;
+    General.GraphicsHeight = 480;
   EndIf
 
+  frames = 50;
+
   // It is possible to nest loops:
-  For num2 In {1:50}
+  For num2 In {1:frames}
 
     General.RotationX += 10;
     General.RotationY = General.RotationX / 3;
     General.RotationZ += 0.1;
- 
+
     Sleep 0.01; // sleep for 0.01 second
     Draw; // draw the scene
 
     If (num == 3)
       // The `Print' command saves the graphical window; the `Sprintf'
       // function permits to create the file names on the fly:
+      /*
       Print Sprintf("t8-%02g.gif", num2);
+      Print Sprintf("t8-%02g.ppm", num2);
       Print Sprintf("t8-%02g.jpg", num2);
+      */
     EndIf
 
   EndFor
@@ -101,25 +105,48 @@ For num In {1:255}
     // Here we could make a system call to generate a movie. For example,
 
     // with whirlgif:
-    //
-    // System "whirlgif -minimize -loop -o t8.gif t8-*.gif";
-
-    // with mpeg_encode:
-    //
-    // System "mpeg_encode t8.par";
+    /*
+    System "whirlgif -minimize -loop -o t8.gif t8-*.gif";
+    */
+
+    // with mpeg_encode (create parameter file first, then run encoder):
+    /*
+    Printf("PATTERN I") > "t8.par";
+    Printf("BASE_FILE_FORMAT PPM") >> "t8.par";
+    Printf("GOP_SIZE 1") >> "t8.par";
+    Printf("SLICES_PER_FRAME 1") >> "t8.par";
+    Printf("PIXEL HALF") >> "t8.par";
+    Printf("RANGE 10") >> "t8.par";
+    Printf("PSEARCH_ALG EXHAUSTIVE") >> "t8.par";
+    Printf("BSEARCH_ALG CROSS2") >> "t8.par";
+    Printf("IQSCALE 1") >> "t8.par";
+    Printf("PQSCALE 1") >> "t8.par";
+    Printf("BQSCALE 25") >> "t8.par";
+    Printf("REFERENCE_FRAME DECODED") >> "t8.par";
+    Printf("OUTPUT t8.mpg") >> "t8.par";
+    Printf("INPUT_CONVERT *") >> "t8.par";
+    Printf("INPUT_DIR .") >> "t8.par";
+    Printf("INPUT") >> "t8.par";
+    tmp = Sprintf("t8-*.ppm [01-%02g]", frames);
+    Printf(tmp) >> "t8.par";
+    Printf("END_INPUT") >> "t8.par";
+    System "mpeg_encode t8.par";
+    */
 
     // with mencoder:
-    //
-    // System "mencoder 'mf://*.jpg' -mf fps=5 -o t8.mpg -ovc lavc
-    //         -lavcopts vcodec=mpeg1video:vhq";
-    // System "mencoder 'mf://*.jpg' -mf fps=5 -o t8.mpg -ovc lavc
-    //         -lavcopts vcodec=mpeg4:vhq";
+    /*
+    System "mencoder 'mf://*.jpg' -mf fps=5 -o t8.mpg -ovc lavc
+            -lavcopts vcodec=mpeg1video:vhq";
+    System "mencoder 'mf://*.jpg' -mf fps=5 -o t8.mpg -ovc lavc
+           -lavcopts vcodec=mpeg4:vhq";
+    */
 
     // with ffmpeg:
-    //
-    // System "ffmpeg -hq -r 5 -b 800 -vcodec mpeg1video
-    //         -i t8-%02d.jpg t8.mpg"
-    // System "ffmpeg -hq -r 5 -b 800 -i t8-%02d.jpg t8.asf"
+    /*
+    System "ffmpeg -hq -r 5 -b 800 -vcodec mpeg1video
+            -i t8-%02d.jpg t8.mpg"
+    System "ffmpeg -hq -r 5 -b 800 -i t8-%02d.jpg t8.asf"
+    */
   EndIf
 
 EndFor

tutorial/t8.par

-#
-# parameter file for mpeg_encode 
-#
-
-PATTERN          I
-# PATTERN          IB
-# PATTERN          IBBBP
-# PATTERN          IBBPBBPBBPBBPBB
-
-BASE_FILE_FORMAT JPEG
-# BASE_FILE_FORMAT PPM
-# BASE_FILE_FORMAT YUV
-# YUV_SIZE         320x240
-
-GOP_SIZE         1
-# GOP_SIZE         30
-
-SLICES_PER_FRAME 1
-
-PIXEL            HALF
-
-RANGE            10
-
-PSEARCH_ALG      TWOLEVEL
-# PSEARCH_ALG      LOGARITHMIC
-
-BSEARCH_ALG      CROSS2
-
-IQSCALE          1
-# IQSCALE          8
-
-PQSCALE          10
-
-BQSCALE          25
-
-REFERENCE_FRAME  DECODED
-# REFERENCE_FRAME  ORIGINAL
-
-OUTPUT           t8.mpg
-
-INPUT_CONVERT   *
-
-INPUT_DIR       .
-
-INPUT
-t8-*.jpg [01-50]
-# t8-*.ppm [01-50]
-# t8-*.yuv [01-50]
-END_INPUT
-