Author Archives: Multimedia Mike

Ramping Up On JavaScript

I didn’t think I would ever have sufficient motivation to learn JavaScript, but here I am. I worked a little more on that new FATE index page based on Google’s Visualization API. To that end, I constructed the following plan:

Part 1: Create A JSON Data Source
Create a JSON data source, now that I figured out how to do that correctly. JSON data really is just a JavaScript data structure. It can be crazy to look at since it necessitates packing dictionaries inside of arrays inside of dictionaries inside of arrays. (Check the examples– observe that the data structure ends with “}]}]}});”.) But in the end, the Google visualization knows what to do with it.

Done.

Part 2: Connect the JSON Data Source
Hook the JSON data source up to the newest revision of the FATE front page, rolled out a little while ago.

Done.

Part 3: Save The User’s Most Recent Sort Criteria
The problem is that the page resets the sort criteria on a refresh. There needs to be a way to refresh the page while maintaining that criteria. This leads me to think that I should have some “refresh” button embedded in the page which asks the server for updated data using a facility I have heard of named XMLHttpRequest. I found a simple tutorial on the matter but was put off by the passage “Because of variations among the Web browsers, creating this object is more complicated than it need be.”

Backup idea: Cookies. Using this tutorial as a guide, set a cookie whenever the user changes either the sort column or the sort order.

Done, though I may want to revisit the XHR idea one day.

Part 4: Make It Look Good
Finally, figure out how the div tag works to make the layout a little cleaner.

Done. Sort of. There are 2 div tags on the page now, one for the header and one for the table. I suppose I will soon have to learn CSS to really drag this page out of 1997.

Bonus: Caching the JSON Data
Ideally, the web browser makes the JSON data request using the If-Modified-Since HTTP header. Use a sniffer to verify this. If this is true, add a table to the FATE MySQL table which contains a single column specifying the timestamp when the web config cache table was last updated. If this time is earlier than the time in the request header, respond with a 304 (not modified) HTTP code.

Not done. It seems that these requests don’t set the appropriate HTTP header, at least not in Firefox.

I hope to put this page into service soon, just as soon as I can dump the rest of the existing index.php script into this new one. As usual, not elegant, but it works.

Renoise XRNS

A little piece of me died today when I read of the existence of XRNS, a music tracker format that uses XML. A music tracker format that uses XML! Can you imagine? If you can’t, Google for “filetype:xrns” to find plenty of samples.

[xml]
< ?xml version="1.0" encoding="UTF-8"?>


4
1
false
4
96
123
3
true

36
68
67
47

Untitled
By Somebody
…

…

[/xml]
And on it goes. It’s difficult to articulate why this feels so heretical. It’s like those old MOD/tracker formats were designed to be so pure, so efficient. This completely destroys that. Now your playback engine has to carry the baggage of a full XML parsing library.

There are elements of the FFmpeg development team that would enjoy seeing the program grow to be able to handle all the various tracker-type formats (myself included, obviously). It’s not going to be pretty when XRNS collides with FFmpeg.

Addendum: Share the love over on the Renoise forums.

The Murder FILM

Do you have any idea who killed Jennifer Shefield?
How well did you know Jennifer Shefield?
What can you tell me about Jennifer Shefield?

Call me cold, but I just can’t bring myself to care about the above questions more than I care about what multimedia format is being used in an old Amiga shareware game simply entitled Murder, the demo of which can be downloaded in 11 .lha files from Aminet. LHA… does that ever take me back to the BBS days. That and ARJ.

Back to the format, though, it’s definitely not related to Sega’s FILM format (one of my all-time favorite formats). I think this may just be a series of Amiga IFF files with a header on them. This is because I see markers such as “8SVX”.

The files also contain curious advice about playback. Apart from a string that specifically stipulates “Motorola 68000 family”, there’s also this tidbit in the header: “Amiga Hint LIST subtype FILM requires that all CAT chunks are exactly the same size, start at long word boundaries (pad with filler chunks) and come one after the other right to the end of the LIST. Write to agmsmith at 71330.3173@CompuServe.com for more info.” I would email that address for the sake of due diligence but — darn — bad timing! CompuServe finally died just last week. The files were apparently made by a piece of software named AGMSMakeFilm which also seems to be available at the Aminet.

MultimediaWiki page and samples, naturally.

Google Visualizing FATE

I guess that Cloud Computing stuff doesn’t only apply to data storage. There are also things like Google’s Visualization API for manipulating and presenting data. In this paradigm, the data is under my control but the code to manipulate it lives on Google’s servers.

Good or bad? That’s up for debate, but the table visualization definitely caught my eye. Look at the experimental results when I put FATE data into the table. Notice how easy it is to sort by columns (the default sort is such that the failed builds float to the top). I may be a little too close to the situation, but I think it’s a little better than my last attempt. Again, no more up-to-15-minute delay with this system; new build data is available for presentation as soon as it is submitted to the database.

Let me know what you think. Personally, I think we may have a winner here. Maybe Google’s other visualizations (assorted graphs and such) could be just the thing we have been searching for in order to plot trends like performance and code size.

I just wish I could understand the data source wire protocol. As it stands, the index-v3.php script generates JavaScript on the fly to populate the table. It would be a bit more elegant if the data were provided by a separate script. But, hey, this works.