In my last post, I wrote about my experiences with Podcast Producer 2: the good, the bad and the downright ugly. Well, I had a bit of a breakthrough today in getting Podcast Producer 2 to “play nice with Windows,” so I’m posting my “new and improved” workaround.
As I described earlier, the main problem is the way PP2 posts videos to user blogs maintained by Wiki Server (which is a core part of Snow Leopard server). The primary culprits are the width and height tags that are included in the IMG tag that is written to the blog entry. If the video files were of a small resolution, PP2 would typically write out height tags that were empty, which breaks Internet Explorer on Windows, since IE assumes an empty height tag means a height of zero. But even if the video files were at a larger resolution, PP2 would write out width tags that were narrower than the actual width of the video file, presumably to make the thumbnail smaller than the video. That breaks any browser on Windows, since the Quicktime plugin for Windows doesn’t seem to be able to scale videos to fit within the dimensions defined by smaller-than-actual width and height tags. It works fine on a Mac, since it appears that the Quicktime plugin for Mac can shrink videos to fit into whatever dimensions are defined in a web browser.
My workaround was to manually edit these entries, removing the width and height tags. This would make the thumbnails full size, the same size as the associated video files denoted in the ALT attribute of the IMG file (a rather non-standard use of the ALT attribute, but that’s another issue). This workaround was a lot of work: manually editing the HTML of each and every video file produced by my server had become a daily chore. In the last month, I had edited over 1,000 blog entries. But at least the videos would play on Windows.
I had originally thought I should be able to fix this by changing the code found in the “_podcast.html” file found in the WikiTemplates folder in Library->Application Support->Apple->WikiServer. After all, this file looks like the exact template used by PP2 when it posts to WikiServer. But even though I removed the width and height attributes from this template file, it had no effect on the blog entries posted by PP2. I have since found that these templates are not used by PP2; they are used by WikiServer itself. That is, when you go to a user blog, click the plus sign to manually add a blog entry, and select the option to add podcast content, the resulting code is drawn from the _podcast.html file in the WikiTemplates folder. So PP2 must be getting the code from somewhere else.
Today I found out where: in a line of code in /usr/lib/podcastproducer/actions/wikiserver.rb. Near the top of this file is the following line…
MOVIE_ERB_TEMPLATE = "<%= h($properties[\"Description\"]) %> <br> <br> <img src=\"<%= poster_image_url %>\" alt=\"<%= published_url %>\" width=\"<%= width %>\" height=\"<%= height %>\" class=\"aligncenter posterimg\" />"
Bingo. I just took out the width and height tags from this line and restarted the server. Now PP2 doesn’t write out the width and height tags when it posts video podcasts. And I no longer have to manually edit the posts produced by PP2 to enable them to work on Windows. Hallelujah.
While studying this file, I think I discovered what may be the reason why PP2 is mucking up the dimension attributes. Further in this file are these lines of code…
if width > 480
height = PcastQT.info(input_published_path, "height").to_i * 480 / width
width = 480.0
end
So if I understand this correctly, what this does is check if a video is wider than 480, and if so, force it to stay at a width of 480 and adjust the height downward proportionally. That is, if a video has standard “VGA” dimension of 640 wide by 480 high, this bit of code forces it to be 480 wide by 360 high (the original height 480 multiplied by 0.75, or 480/640). And again, this scaling of the thumbnail downward is what seems to be breaking the Quicktime plugin on Windows.
I’m still not sure why videos that are smaller that 480 wide are being posted by PP2 with an empty height attribute, but I have a theory. I notice that in this section of code that the width is explicitly defined by this line of code:
width = PcastQT.info(input_published_path, "width").to_i
But height is not explicitly defined UNLESS the “if width > 480″ is evaluated true. This could be why I’ve discovered that for smaller submitted videos (say at a resolution of 320 by 240) the code being posted by PP2 has an empty height attribute (specifically, height=””). But whether or not this theory is correct, I’m happy that I’ve discovered a fix. By removing the width and height attributes completely from the MOVIE_ERB_TEMPLATE line of code, I’ve effectively addressed both the empty height attribute problem and the scaled-down width attribute problem.
Of course, Apple is likely to rewrite this file with a software update. Here’s hoping they correct this problem, so that I don’t have to hack the same file in the future. But just in case, I’ve documented my fix here for my reference, and potentially for the benefit of others frustrated trying to get Podcast Producer 2 to play nice with Windows.
UPDATE: I think I’ve discovered where the code lives that swaps out the video file for the thumbnail when you click on it. It appears to be in the javascript file wiki.js at /usr/share/collaboration/javascript/wiki.js. Near the bottom of this file is an “expandMedia” function that’s part of the QTMediaExpander class. The “objectHTML” variable appears to contain the code that embeds the Quicktime object…
var objectHTML = '<object classid="clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B" width="'+img.width+'" height="'+(img.height+(extendHeight?16:0))+'" codebase="http://www.apple.com/qtactivex/qtplugin.cab"><param name="SRC" value="/collaboration/fake.qti"><param name="QTSRC" value="'+fullSrc+'?sessionID='+server().sessionID+'"><param name="TYPE" value="video/quicktime"><param name="SCALE" value="aspect"><param name="AUTOPLAY" value="true"><param name="CONTROLLER" value="true"><param name="TARGET" value="myself"><param name="BGCOLOR" value="'+backgroundColor+'"></object>'
I don’t think I should try to hack something here now, not with a PP2 server filled with 1200 videos and counting. But perhaps between semesters or over the summer break I’ll poke around here to see if I can’t get a prettier javascript Quicktime player instead of the plain vanilla Quicktime interface provided by the Quicktime plugin. Many people have requested a player that displays the elapsed time of the video, something I know is possible since Apple has such players on their own website (including here, for example).