I’ve been processing a collection of product videos which came to me in a huge variety of sizes, aspect ratios, and qualities. I need to re-encode them to work in HTML 5, but, more importantly, I need to make them fit into a common player space on the web page.

It turns out that newer versions of ffmpeg support not only cropping, but also padding, and you can even do both operations at once!

For example, I had a source video that was originally 16:9, but had been letterboxed to 4:3, and then had two different sets of labels added. I needed to crop out the letterboxed portion and the top set of labels, and make the result fit nicely into 16:9. So I used VLC, a screen capture utility, and Photoshop to get the measurements. Then I used ffmpeg to crop the relevant section and pad it out to fit into my space (in this case, I’m left aligning the video in the padded output):


ffmpeg -i original/converted.wmv -vf crop=394:295:6:0,pad=524:295:0:0:0xFFFF00 -sameq converted.mov


That’s cropping a 394 x 295 piece out of the original video (with the origin at 6 pixels from the left, and 0 pixels from the top), and then padding it out to 524 x 295 filling the padded area with bright yellow. The 524 x 295 is really close to 16:9 — and in a later process, it gets resized to the more standard 480 x 272¹.

You can string together the padding and cropping in either order, depending on the effect you’re trying to achieve.

¹I’m sure some educated person out there could tell me why video standards are so confused/confusing, down to the non-square pixels. While a true 16:9 would dictate 480 x 270 pixels, everybody seems to use 480 x 272. Why? The only thing I can figure out is that 272 is evenly divisible by a power of 2, which probably made display hardware cheaper to manufacture. As you can see, my resizing adds a bit of distortion, but at these resolutions, it doesn’t really matter.

Several years ago, we replaced our commodity hardware firewall (a Sonicwall SOHO from ’01) with pfSense running on an unused Dell 4100 desktop from that same year.

pfSense was a little confusing to configure the first time through (doing 1-to-1 NAT with virtual IPs and CARP was initially confusing, but the pfSense forums and The Google came to our rescue). Once in place, though, it did a great job. And when I say a great job, I mean that we could pretty much forget about its existence. It just hummed away in the background, and everything worked. When we needed to check up on our ISP, we discovered that quality of service logging was already supported, as well as pretty graphs of various connection properties. Very nice!

Over the last weekend, the 4100 locked up, and our connection was interrupted. Rebooting gave a firmware error about a bad disk in drive A: — but there was no disk in the drive. Power cycling, opening the machine, wiggling some cables, and blowing out some dust brought it back up, and all was well. Except it wasn’t, really. The machine spontaneously rebooted a number times over the next few days, and occasionally got into the “bad disk in drive A:” boot failure, requiring a hard power cycle. As I watched on the console, I saw the kernel fault out after too many memory checksum errors. The old machine was giving up the ghost.

After commissioning another old desktop (an ’07 vintage Dell, this time), I was able to install pfSense on it. I had to disable some of the extraneous hardware in the BIOS, but after about an hour I had it installed, booting, and ready to go. I was able to simple dump the configuration from the old firewall, load it into the new machine, reassign the LAN and WAN interfaces to the proper devices, and swap the boxes out. voila! Back in business!

With any luck, I won’t have to repeat this process for another five years.

I just received my paper copies.

You can get a copy too!

(I wrote this back in October of last year, never bothered to post it. I probably had a reason for that, but it’s long forgotten by now, so I might as well post what I had.)

So I wasted a great deal of time trying to get my SHA-256 hashes from a .NET application to match up in a PHP application. It seemed really like it should be straightforward: make sure your string has a known character encoding, SHA-256 digest it, and then base64 encode it. How hard could it be?

Well, after a day of ripping my hair out, I concluded it’s harder than it seems. Here’s what the problem is: the application I’m trying to match encodes the strings as UTF-16 before hashing them. Unbeknownst to me, the double-byte strings are big-endian in one case, and little-endian in the other, even though they’re on the same Intel box. Took longer than it should have to track that down.

Oh, but is that the end of it? No, no, no. No, it’s not.

I also had to decrypt some strings. It was encrypted using the ManagedRijndael class, and I had the key and iv string. Those strings also got encoded into wrong-endian UTF-16, which was easily fixed (once I knew what was going on). But I was still getting gibberish. Well, to make a very long story short, the ManagedRijndael class in .NET and the mcrypt_generic function using Rijndael256 algorithm in cipher-block chaining mode in PHP aren’t exactly compatible. The mighty Google finally pointed me to the solution, which is using the Rijndael128 algorithm. The ManagedRijndael class creates actual AES-256, which mcrypt_generic is using Rijndael, which differ in the length of the initialization vector. Switching to the Rijndael128 but still passing the 32-bit key is equivalent to the AES-256.

What’s all this mean, then? This is all stuff that’s probably pretty obvious to anyone who knows anything. I, however, found this bewildering and confuzzling.

Back a few years ago, I posted a quick’n’dirty tool for generating plausible user data. I had a need for some improvements, so I’m posting the new version here.

The new version supports back-references, composite fields, and SQL output. So, for example, you could do:

./user-data-maker.pl -t id:lname:fname:city:state_code:zip:company -f i:ln:fn:c:s:z:/1+^+[Cars,Trucks,Boats,Planes,Motorcycles,Ships,Trains]+^+of+^+/3 -s -m tbl_dealer -n 5

and get the following output:
-- generated data from ./user-data-maker.pl
INSERT INTO tbl_dealer (id,lname,fname,city,state_code,zip,company) VALUES (0,'Nelson','Leslee','Akron','OH',44311,'Nelson Boats of Akron');
INSERT INTO tbl_dealer (id,lname,fname,city,state_code,zip,company) VALUES (1,'Bowen','Beatriz','Miami','FL',33176,'Bowen Trucks of Miami');
INSERT INTO tbl_dealer (id,lname,fname,city,state_code,zip,company) VALUES (2,'Hammond','Raymond','Ninilchik','AK',99639,'Hammond Motorcycles of Ninilchik');
INSERT INTO tbl_dealer (id,lname,fname,city,state_code,zip,company) VALUES (3,'Kim','Arielle','Columbus','MI',48063,'Kim Ships of Columbus');
INSERT INTO tbl_dealer (id,lname,fname,city,state_code,zip,company) VALUES (4,'Estrada','Warner','Iuka','IL',62849,'Estrada Cars of Iuka');

Nothing earth-shattering, but useful to me. Maybe to you too!

Download it here: user-data-maker.pl.gz