Re-Add support for PNG or PNM as watermark images, which was broken

since the move to image2 API
Patch by Victor Paesa <wzrlpy@arsystel.com>
Original thread:
Date: Aug 13, 2006 9:18 AM
Subject: [Ffmpeg-devel] [PATCH] Attempt image2 in watermark vhook

Originally committed as revision 6129 to svn://svn.ffmpeg.org/ffmpeg/trunk

vhook/watermark.c

@@ -420,6 +420,10 @@ int get_watermark_picture(ContextInfo *ci, int cleanup)
             }
                ci->p_ext = &(ci->filename[ci->i]);
             ci->file_iformat = av_find_input_format (ci->p_ext);
+            if (0 == ci->file_iformat) {
+                av_log(NULL, AV_LOG_INFO, "get_watermark_picture() attempt to use image2 for [%s]\n", ci->p_ext);
+                ci->file_iformat = av_find_input_format ("image2");
+            }
             if (0 == ci->file_iformat) {
                 av_log(NULL, AV_LOG_ERROR, "get_watermark_picture() Really failed to find iformat [%s]\n", ci->p_ext);
                 return -1;