[MPlayer-dev-eng] [PATCH] Interlaced vo_png support

[tracy at amphibious.org]

Here's a short patch to libvo/vo_png.c to add writing out interlaced fields as 
individual PNGs instead of merged progressive frames.

Usage:
  mplayer -vo png:interlaced foo.mpg

This is my first contribution to mplayer so please let me know if this
is not the correct procedure.  This patch is against current CVS.

-------------- next part --------------
Index: libvo/vo_png.c
===================================================================
RCS file: /cvsroot/mplayer/main/libvo/vo_png.c,v
retrieving revision 1.29
diff -u -p -r1.29 vo_png.c
--- libvo/vo_png.c	24 Apr 2006 04:23:53 -0000	1.29
+++ libvo/vo_png.c	1 May 2006 22:57:59 -0000
@@ -32,7 +32,10 @@ static vo_info_t info = 
 
 LIBVO_EXTERN (png)
 
+static uint32_t write_field(mp_image_t* mpi, uint32_t starting_line, uint32_t line_increment);
+
 int z_compression = Z_NO_COMPRESSION;
+int interlaced = 0;
 static int framenum = 0;
 
 struct pngdata {
@@ -149,8 +152,17 @@ static uint8_t destroy_png(struct pngdat
 }
 
 static uint32_t draw_image(mp_image_t* mpi){
+    if(interlaced == 0){
+        write_field(mpi, 0, 1);
+    } else {
+	write_field(mpi, 0, 2);
+	write_field(mpi, 1, 2);
+    }
+}
+
+static uint32_t write_field(mp_image_t* mpi, uint32_t starting_line, uint32_t line_increment){
     char buf[100];
-    int k;
+    int j, k;
     struct pngdata png;
     png_byte *row_pointers[mpi->h];
 
@@ -159,7 +171,7 @@ static uint32_t draw_image(mp_image_t* m
     
     snprintf (buf, 100, "%08d.png", ++framenum);
 
-    png = create_png(buf, mpi->w, mpi->h, mpi->flags&MP_IMGFLAG_SWAPPED);
+    png = create_png(buf, mpi->w, mpi->h/line_increment, mpi->flags&MP_IMGFLAG_SWAPPED);
 
     if(png.status){
  	    mp_msg(MSGT_VO,MSGL_WARN, MSGTR_LIBVO_PNG_ErrorInCreatePng);
@@ -168,8 +180,9 @@ static uint32_t draw_image(mp_image_t* m
 
     if( mp_msg_test(MSGT_VO,MSGL_DBG2) ) {
         mp_msg(MSGT_VO,MSGL_DBG2, "PNG Creating Row Pointers\n"); }
-    for ( k = 0; k < mpi->h; k++ )
-	row_pointers[k] = mpi->planes[0]+mpi->stride[0]*k;
+
+    for ( j = 0, k = starting_line; k < mpi->h; k += line_increment, j++ )
+	row_pointers[j] = mpi->planes[0]+mpi->stride[0]*k;
 
     //png_write_flush(png.png_ptr);
     //png_set_flush(png.png_ptr, nrows);
@@ -220,13 +233,15 @@ static int int_zero_to_nine(int *sh)
 }
 
 static opt_t subopts[] = {
-    {"z",   OPT_ARG_INT, &z_compression, (opt_test_f)int_zero_to_nine},
+    {"z",             OPT_ARG_INT, &z_compression, (opt_test_f)int_zero_to_nine},
+    {"interlaced",    OPT_ARG_BOOL, &interlaced,    NULL},
     {NULL}
 };
 
 static int preinit(const char *arg)
 {
     z_compression = 0;
+    interlaced = 0;
     if (subopt_parse(arg, subopts) != 0) {
         return -1;
     }