Drawing Class – Week 6

In the sixth class we continued with crosshatching.

Pia set up another bunch of objects for us to draw.


The objects were mostly white. It’s tough to get convincing light grays out of a Sharpie.

Like most of the drawings done during class time, this one is unfinished. The big arch is a piece of corrugated conduit tubing, which would be a much stronger graphical element if I’d had time to shade it, for instance.

However, notice that this is the first drawing we’ve done from observation that isn’t just an outline. So, we must be ready for the final project, right? Pia showed some examples and gave us our final project assignment. Two drawings, connected in content and done from observation using any combination of materials we’ve used in class. Also, an in-class presentation using three or more example drawings to discuss your strengths and weaknesses. Three weeks left.

The homework assignment was to pick four or five objects that vary in shape and scale, make up a composition with a directed light source, showing the ground plane. Then draw it as a value study using crosshatching. Pia wrote “This drawing will take time and patience.” Yup.


Homework 6. Grade: A. Pia’s comment: Very nice! I have a slight problem with the shape of the helmet coming off the edge – somehow doesn’t feel quite the right size & shape for this grouping, but it might just be me!

I didn’t try to use the “Fine” Sharpie for the homework. We were given flexibility to choose just about anything penlike, so I picked a 0.7mm pigment liner pen. I feared one pen might not finish the project, so I bought all five they had at Artist and Craftsman Supply. Good thing, too, because it took four pens to finish this drawing. I like the finer line, though. It’s much more forgiving of small slips while crosshatching.


Drawing Class – Week 5

Week five of drawing class was something of a smorgasbord, as Pia tried valiantly to fit the basics of drawing into a term with only nine class meetings.

Ellipses. What is an ellipse? Pia asked me and got a somewhat-garbled analytic geometry version of the definition, but only because I couldn’t remember the conic section version of the definition off the top of my head. That wasn’t what she wanted, though, so she asked another student, who also turned out to be an engineer, and who gave her an even more mathematical definition. Ha! In the end Pia had to tell us the artist’s definition: an ellipse is a circle seen in perspective.

That’s a little bit surprising, actually. Go ahead, look at some photos of circular things. Better yet, try to sketch some circular things the way you think they ought to look when seen from funny angles. You’ll find that either your drawings look curiously distorted in a way you can’t quite put your finger on, or else all those circles, no matter how funny the viewing angle, end up as perfect ellipses. Cool!

Unfortunately, knowing that doesn’t make drawing the ellipses easy. We filled up a page with freehand ellipses, and they mostly look terrible.


Then we learned to wrap the ellipse in a rectangle. That at least keeps the proportions right and make it pretty easy to put the apexes in the right places. For practice we put circles (ellipses) on the top and bottom of a cube.


Then Pia set out some round bowls, vases, and bottles so we could put a few more ellipses to work. I ended up drawing the Goldschläger bottle I brought in.


Next up, shading. With charcoal we tried to turn a circle into a sphere. We didn’t have an actual sphere to look at, other than Pia’s example of a shaded drawing of a theoretical sphere.


The lighter shadow on the underside of the sphere is supposed to be reflected light from the white tabletop.

I used a lighter palette of tonal ranges than most of the others. This was pretty consistent for the rest of the course.

Now that we’d admitted that shades of gray exist, the next thing was to learn a new way to make grays: by crosshatching. We used a “Fine” point Sharpie marking pen, which isn’t very. We started by creating a set of sample patches of various darknesses, and then tried to shade another sphere, followed by a cube. We didn’t have time to finish this in class, so it ended up being the first part of our homework assignment.


Homework 5, Drawing 1. Grade: Check+. Pia’s comment: Very good.

As you can see, the hatching I used on the sphere ended up having very little to do with the hatching I proposed on the sample patches. Doing the sample patches first meant they were my most naive guess at how to crosshatch.

I tried to use curved strokes to crosshatch the sphere, to emphasize its roundness. Pia was worried it might end up looking like a hairball, but I think I avoided that problem (mostly) by using many lighter strokes. The “Fine” Sharpie wants to make bold black lines, but if you wield it lightly you can get smaller lines with lighter ink coverage. Maybe that’s cheating on a crosshatching assignment.

I probably would have tried to do some light crosshatching on the top surface of the cube, but the assignment said to leave it paper white. The eye fills in the rest of the cube. Or does it?

The other part of the homework assignment went back to the ellipses. We were to set up a nice composition using at least five round vessels of various heights and sizes, including a transparent glass partially filled with water with a knife in it. Contour lines only, no shading yet.


Homework 5, Drawing 2. Grade: A. Pia’s comment: Gorgeous! again!

I learned that not everything is an ellipse, because not everything is a circle. In two places, the varying weight of the glass walls distorts the shape. The top surface of the liquid in the wine glass isn’t round, because of the shape of the wine glass. The base of the wine glass is round, of course, but it’s grossly distorted as seen through the glass walls of the tumbler.


Drawing Class – Week 4

One-point and two-point perspective occupied our full attention for the fourth class session.

Pia set up a cityscape of boxes, all parallel to the tile squares on the floor, and seated us on the floor along the sides of the studio, so we had a view more or less parallel to the streets of the city. That gave us a pretty close approximation of a one-point perspective view of the city. Pia told us to just assume that all vertical edges were vertical, and to frame our drawing so that the eye-level horizon line was within the picture plane.

After lots more measuring and sighting, a vanishing point emerged and guided the rest of the drawing.


Then we moved to the corners of the studio, and drew the city in two-point perspective. The horizon line was still to be within the picture plane, but the vanishing points were beyond the side edges.


The homework assignment was to make one drawing of a deep architectural space. The suggestion was to use parallel (one-point) perspective, or, if using angular (two-point) perspective, to choose an exterior view to keep the vanishing points on the outside. However, it was permitted to try angular perspective for an interior view, for an extra challenge, “but only if you really feel you understand the principles very well”. Several students chose to take on the extra challenge, including me.


Homework 4. Grade: A+. Pia’s comment: Paul – excellent work! Let me just say one more time, ANY of your works that you are willing to donate to my collection (at end of quarter) will find a very appreciative home. But again – no pressure – just if you want.

This was the first homework assignment that really ate up a lot of time. I had been thinking of doing a building exterior, but when the deadline loomed, the day was rainy. I had to work inside, and at home. I almost despaired of finding a suitable deep architectural space at home. These modern homes are full of short walls, funny angles, and curves. In fact, just outside the frame to the right is a diagonal wall that I had to crop out to keep everything rectilinear.

The sketching part of this assignment took a long time. It took several tries to get the scale right and fit everything the way I wanted it. The composition is pretty fragile — it needs the pony wall across the bottom, but it can’t spill over onto the diagonal wall to the right, and so on. It ended up with more blank ceiling than I would have preferred. Left to my own devices I would probably have trimmed off the top, but it seemed like we were supposed to stick with 18×24 inch paper.

Ah, those shutters! They really pull the perspective together in this scene, but look at all those details. I spent a significant fraction of the time just filling all those lines in, even though I made some compromises with reality and omitted some of the more difficult details. As you might imagine, my living room wasn’t really that neat and tidy, either. Now there’s something drawing has over photography: you don’t have to draw the clutter.

It was just luck that the right-hand vanishing point ended up on the paper. That made it much easier to get the shutters right. I constructed them with a straightedge. It would have been impossible (or at least very time-consuming) to get them right freehand. They don’t look too perfect because I did the final charcoal pencil contour lines freehand.

There wasn’t supposed to be any shading in this drawing, but the wording of the assignment didn’t explicitly prohibit it. I couldn’t resist shading the black stone around the fireplace and the black leather recliner and footstool, because the shapes didn’t really parse with just the contour outlines. The three-legged stool ended up shaded too, because its legs are so narrow the lines ran together.

Comparing the drawing to reality in retrospect, the chairs and sofa are too small. There’s a tee-shaped cross bar between the legs of the stool that I completely forgot to draw. Otherwise, ignoring the missing clutter, it looks pretty much like that. The ceiling fan isn’t a small one, but it really does get swallowed up by lots of blank ceiling.

Drawing Class – Week 3

The third session of the beginning drawing class was about sighting and measuring. Both techniques involve holding up a straight reference object like a pencil and using it to capture objective information about the subject as projected onto the picture plane.

Sighting captures an absolute angle on the picture plane. You hold the pencil up so it’s parallel to the feature you want to capture, and also parallel with the picture plane. Then you move it over to the paper and transcribe the angle onto the drawing. Somehow, you’re supposed to be able to hold the pencil at the same angle while moving it to the paper. I found it difficult to make sightings accurate enough to be useful.

Measuring captures a distance, as projected onto the picture plane. You choose a convenient feature of the subject to serve as your reference distance unit. Then, holding the pencil at a constant arm’s length and parallel to the picture plane, you mark that distance with a finger on the side of the pencil. You can then use that as a sort of ruler to count out relative distances elsewhere on the picture plane. In particular, you can measure how many distance units your entire subject spans, horizontally and vertically. With this information, you can first choose a portrait or landscape orientation of the paper, and then compute how large your reference unit should be on the paper in order to fit.

Presbyopia doesn’t make this any easier. I wear eyeglasses with progressive lenses. That means I have to tilt my head to focus at different distances. But when I tilt my head, it screws up the line of sight past the pencil to the subject. To make a measurement this way, I have to choose a compromise focus distance somewhere between arm’s length and the distance to the subject, and just accept that both the pencil and the subject will be a bit blurry.

Because you’re actually measuring and not just eyeballing it, it’s easier to avoid fooling yourself with mistaken assumptions about what the subject ought to look like. And, because you always hold the pencil parallel to the picture plane, you are measuring distances as projected onto the picture plane, not actual distances in space. That means you automatically get foreshortening and perspective for free, to whatever extent your measurements and sightings are accurate.

Our test subjects for measuring and sighting were stacks of three boxes. How very static.


You can see I got the scale about right, but the centering is off. We colored in the top surfaces to help evaluate how well we had reproduced the shapes: not all that well. The extra line on top of the middle box shows where its far edge ought to have been, relative to the top box.

All this measuring and sighting is very time-consuming, especially when you’re new at it. Unusually, I was a little faster at this than some of the other students, so I had time to start a second drawing.


The homework assignment was to do the same thing again: draw a stack of three boxes using measuring and sighting. Fill up the picture plane. Center the biggest box. Shade the top surfaces. Don’t erase the construction lines.


Homework 3. Grade: A. Pia’s comment: Excellent!

I didn’t really intend for the top corner of the top box to kiss the edge of the paper like that. Tolerance buildup. Lesson learned: allow more margin for error.

This is the first time I had to draw straight lines (not counting the blind drawing). These aren’t even freehand lines, they are drawn first in vine charcoal and corrected as necessary, then traced over with charcoal pencil. And the lines are still somewhat wobbly.

The last segment of the class was devoted to a video presentation on one-point and two-point perspective. It treated them as radical innovations discovered by great Renaissance artists. Pia and the video both emphasized that perspective is just one way of representing depth. I can’t deny that other traditions have used other conventions to show depth, but I can still argue that perspective isn’t just another convention. Perspective is how the world actually works. The proof is in every photograph ever taken. I find it difficult to believe that people before the Renaissance couldn’t see that their art wasn’t realistically drawn, or that talented artists were unable to reproduce what was before their eyes.

Drawing Class – Week 2

Tonight was the second session of my beginning drawing class.

We learned about contour drawing. This is a style of line drawing where the you slowly and steadily move your attention along the edge of the subject, while simultaneously moving your pencil across the paper. The idea is that you can accurately reproduce the shape of an object this way. The method forces you to see the actual shape of the object, and not the shape you know or imagine it to have. As an exercise to demonstrate the power of this technique, it’s sometimes done without looking at the paper at all: blind contour drawing. This is not very practical for any but the simplest scene, so we were allowed to peek when necessary to re-establish pencil position or manage overlapping objects: modified blind contour drawing. Once again Pia set out a variety of objects. Shoes, this time, some of which had been brought in by students. We were to pick a view including a few of these shoes and (try to) draw their outer boundaries using modified blind contour drawing.


That big blobby thing in the middle was one of my motorcycle boots. Notice there are multiple erased drawings still visible on the paper. Pia encouraged us to sketch and erase, sketch and erase. So I can’t really show you all the drawings I made, just the last one on each piece of paper.

I guess that wasn’t hard enough, because next Pia set out a bunch of sticks and twigs and we tried our hands at modified blind contour drawing those.


Hmm, that almost looks like sticks.

The other style of drawing we learned about was gesture drawing. Here the idea is to be quick and fluid, recording overall shapes and impressions expressively. We started with the lights out and eyes closed. Pia called out evocative words and we were supposed to make some marks on the paper that expressed them.


This was done rapid-fire, so I can’t remember any of the specific words or which marks were supposed to relate to them. We didn’t critique these or follow up on any of the ideas about marking styles. We were left (throughout the course, for the most part) to use the materials in whatever way seemed right to us.

Oh look, under the barrage of marks you can see one last exercise at blind contour drawing: a profile drawn from a classmate’s face. Not very flattering, alas. When I looked down at the result, it seemed that I had about the right vertical motions but all the horizontal distances were compressed.

Pia posed for us to practice gesture drawing. She held a number of poses for what seemed like several seconds each. We erased each drawing before going on to the next, so most of these are lost.


A student or two also posed for gesture drawing practice.


I really wanted to work longer on that one. It seemed like it had some potential.

The homework assignment was to set up at least three objects from the kitchen drawer. We were to do quick gesture drawings to experiment with composition until we had a good one. Then, erase the gesture drawing and do a modified blind contour drawing with charcoal pencil. I wasn’t satisfied with the first one I completed.


So I did another one to turn in.


Homework 2. Grade: A. Pia’s comment: Very good. Would you be willing to donate to my stash of “samples” for future classes? If you would rather not, that is fine!

Drawing Class – Week 1

Tonight was the first session of my first-ever drawing class, ART 40166 at UCSD Extension. The course title is Drawing: Focus on Perception (Beginning) and the instructor is Pia Stern.

(Actually, I’m writing this after the end of the course, but I chose this journal format to string the narrative together.)

The class was completely full. There were about 22 registered students there, plus several who were not registered. When everybody who had registered actually showed up, Pia sent the standby students home. There just wasn’t enough room in the studio for any more people (with each person at a drawing table). As it was, Pia was worried about how she’d be able to teach such a large group.

Aside from the usual overhead (course mechanics, no credit options, finding out everybody’s name) the main focus was on positive and negative space. We started with white Conte crayon on black construction paper. Pia arranged a number of objects on a central table, and we were to pick a grouping of several objects and fill in white wherever the objects were not.


Each student taped their drawing to the wall and we discussed them, a pattern that would be repeated throughout the course. Pia took this opportunity to start talking about dynamic composition. She set the ground rule that we’d be trying for dynamic compositions in this course, basically because they’re harder. Static compositions come naturally, but the eye for dynamic composition usually has to be trained.

This is familiar terminology, but with a specialized meaning. Dynamic refers to power (originally) or to motion or change (more commonly). Neither meaning is literally applicable here, but either one can be interpreted rather easily as a metaphor. As a semantic opposition, dynamic and static seem to refer to motion and stillness, but here we mean something only indirectly related. That something is not very precisely defined. Asked to give a definition of dynamic composition, one might be tempted to quote Justice Potter Stewart and reply, “I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description; and perhaps I could never succeed in intelligibly doing so. But I know it when I see it….”

We were sent back to the drawing boards (!) to do basically the same exercise again, this time with an eye toward composition.


And once again, this time with charcoal on newsprint.


The class wrapped up early, and the homework assignment was to do two drawings. One white on black, and the other black on white. In each case, we were to fill in the negative spaces, without including any detail in the subject, which was to be “irregular and/or organic”. I chose plants from my backyard landscaping for both drawings.


Homework 1 Drawing 1. Grade: A. Pia’s comment: Nice work!


Homework 1 Drawing 2. Grade: B+. Pia’s comment: A little less dynamic, but still, nice.

Cave Paintings

Trying to catch up on a serious backlog, I was just reading LensWork #24 (Feb-Apr 1999). In that issue is a piece called Letter To A Young Photographer by Michael A. Smith. In it, he says in all apparent seriousness,

Different cultures and centuries provide different experiences of the world. Yet there is a common thread that runs throughout all humanity. It explains why we still thrill to the music of Bach, and why we find the cave paintings so powerfully truthful, even in reproductions in art history textbooks.

He may have a point about Bach, but cave paintings? Powerfully truthful? Please.

Vandenberg Delta launch photographed

Got up this morning to photograph the launch of a Delta II rocket from Vandenberg AFB from the new upper deck at Silver Home. When the light hits the rocket’s trail in the dark, it can be really spectacular. Conditions weren’t right for that phenomenon this morning, but we were still able to see a rocket stage burnout at 6:14am.


Here’s Michelle on the upper concrete pad after the launch had come and gone.


Here’s what we were hoping to get (Michelle’s photo from 2005):


DLNA is not a total loser

I doomed myself by saying that streaming from my Mac Pro to the Sony Playstation 3 was working extremely well. A few days later, it was completely broken. Here’s the story.

The ingredients: two houses with home theater equipment, a collection of movies on DVD, a variety of computers available, an Apple TV, and a PS3. The discs can’t be in both places at once, so I ripped them to hard disk for use in one house, and stored all the discs at the other house for playback there. I am interested in the extras found on many DVDs, not just the feature, so I was careful to rip all the video selections on each disc. I kept them organized with a folder for each product (one disc or multiple). For TV series collections, I’d include an episode number in each filename so they could be retrieved in chronological order. The extras for each product I’d gather together in a folder named Extras and give them sensible filenames. The idea was to bypass the awkward silly menu structure imposed by the DVD authoring and just have access by reasonable names to each significant piece of video.

The resulting collection filled up most of two terabyte external Firewire drives, after re-compression. There was no settop box available with that much storage, at least none at a reasonable price. So, I needed a way to play the video from the external drives. I leave my Mac Pro on all the time, so the obvious solution was to leave the drives mounted on the Mac Pro and stream the video to the living room on demand.

OK, it’s a Mac, and Apple generally does a superb job of getting user interfaces right. So the obvious solution was an Apple TV, streaming from iTunes on the Mac Pro. Total and complete disaster. iTunes was happy to import everything from my complicated directory structure, and to serve it up on demand to the Apple TV. As a flat list. One, single, very long flat list in ASCIIbetical order. That meant that under ‘M’ in the list I had six separate things named “Mission Overview” (yes, I have all the Star Trek series on DVD). Episode 01 of every season of series sorts together in the list, before any of the Episode 02 files. Just a hideous mess.

Waiting through a couple of major revisions in Apple TV software didn’t help. Take Two, then 3.0, still lame. Now, I’m sure this is the right design for some class of user. If you have a few dozen titles and you keep only the main movie from each disc, maybe this is very nice. But it doesn’t match my requirements.

Going down the Apple TV route, I could either keep waiting for Apple to change its design to suit my needs (which seems increasingly unlikely as Apple TV converges on a design that seems more and more oriented toward the iTunes Store), or hack the Apple TV with third-party software. I know there are options available from third parties, and as a reasonably serious computer guy I’m not too intimidated by the prospect of a complicated conversion process. I could make it work, but I never did. For one thing, I wasn’t looking forward to devoting the time it would take to evaluate the various third-party options. For another, I do like the way the Apple TV handles music, and I didn’t want to screw that up. Nonetheless, I was just about ready to dive in, because I needed a way to have convenient access to all that video.

Somewhere in the middle of this drawn-out process, Blu-ray happened, and I bought a Sony Playstation 3 as a Blu-ray player. I was distracted from the DVD archives for a while by newly-purchased Blu-ray movies, and didn’t pay too much attention to the other capabilities of the PS3.

A few weeks ago I happened to upgrade the software in the PS3, just because there was new software available. After installing the upgrade, I again perused the menus to see if there was anything new and cool. I didn’t find anything new of interest, but I did notice again that the PS3 had a way to look for a video server on the network. Hmm! I wondered if it was any less lame than the Apple TV. I didn’t think it was likely, but it might be worth a try.

A quick research session on the Internet taught me that I needed a DLNA server, and that a well-respected one for the Mac was MediaLink from Nullriver. And hey, I already had it licensed and installed on my machine, from some previous experiment with video streaming. I fired it up and pointed it to the two external drives, and went back downstairs to see what it looked like on the PS3.

There it was! The PS3 had already automagically detected the MediaLink server and tagged it Potato, the host name of my Mac Pro. If I just clicked on that, I’d find out just how awful a job the PS3 software would do with my media. Click. It showed me the names of the two drives. Click on one of those, it showed me the top-level directories on that drive. In fact, the whole directory hierarchy I’d painstakingly laid out — and Apple TV promptly flattened — was there to browse. That’s exactly what I wanted. The browsing was even pretty snappy, over my wired Ethernet.

What’s more, the video playback worked, without much annoying delay or any glitches. Even fast forward was smooth and predictable, so I could skip the horrendous theme music when watching episodes of Enterprise. Life was good. And then I made the mistake of saying so, and the very next time I tried to stream video, it failed utterly to work.

Maybe this was a problem introduced by the new PS3 software, and with a little luck Sony had already fixed it. I checked for another new version. Sure enough, there was another update. I let the PS3 update itself and tested again. Still busted.

Maybe this was a known problem with MediaLink — I was running an old version, after all — and Nullriver had already fixed it. I downloaded the latest version of MediaLink, 2.0b1 (a beta release) and installed that, after figuring out that it installs as a preference pane and not as a regular application. Another test, another complete failure.

Oh, the PS3 could still see the MediaLink server. It still showed up tagged Potato. But when I attempted to browse the server, the PS3 claimed “There are no titles” and in the upper right corner, a message box appeared heralding “DLNA Protocol Error 7531”. Wow, what a user-friendly error message. For a translation, I turned again to the Internet, but I didn’t find much in the way of specifics. A lot of people were having random-seeming problems with DLNA protocol errors, including number 7531, but nobody seemed to have much of a clue what exactly it meant or how to fix it.

Well, no problem, right? I can just look up the DNLP specification and find out what that error code is defined to mean. No, I can’t, because the DNLA protocol specification isn’t public. It costs $5000, and I can only imagine what kind of agreements I’d have to sign before I’d even be permitted to pay. In any case, I doubt there’s a lot of precision in the definition of error codes even in the full spec.

With the spec unavailable, I gleaned what I could from various articles discussing DLNA. One particularly useful post was Why do I hate DLNA protocol so much? by Ben Zores, author of GeeXBoX, an open-source Linux-based media center software distribution. From Ben’s rant I learned that at the bottom of multiple layers of directory service and connection management cruft, all that’s really happening is that the server is providing the client with an HTTP URL from which to stream the media.

Armed with that information, I fired up Wireshark to trace the network packets going between Potato and the PS3. Every 60 seconds, I saw a short TCP transaction, a single query and its response. Here’s the query from the PS3 to Potato:

GET /MediaServer/DeviceDescription.xml HTTP/1.1
Date: Sat, 12 Dec 2009 08:20:37 GMT
User-Agent: UPnP/1.0
X-AV-Client-Info: av=5.0; cn="Sony Computer Entertainment Inc."; mn="PLAYSTATION 3"; mv="1.0";

This makes a lot of sense. The PS3 is identifying itself, and asking for something called /MediaServer/DeviceDescription.xml — a generic-sounding name, so it’s probably straight out of the protocol spec. Notice that Potato’s IP address is You can’t see it here, but the PS3’s IP address is, so both are on the same subnet with a netmask of

The response from MediaLink on Potato to the PS3 consisted of a similar header followed by a 55-line XML document. Here’s the header:

HTTP/1.1 200 OK
Content-Type: text/xml; charset="UTF-8"
Content-Length: 2229
Connection: close
Date: Sat, 12 Dec 2009 08:20:36 GMT
Server: Mac OS X/10.x.x, UPnP/1.0, Nullriver HTTP Server/3.0

So far, so good. The Mac OS X server is responding and is going to send a 2229-byte XML response. Here’s the first few lines of the XML:

<?xml version="1.0"?>
<root xmlns="urn:schemas-upnp-org:device-1-0">

Whoa. Look at that IP address given as a hostname in the URLBase tag. It’s That’s not Potato’s IP address, and it’s not even on the same subnet. If MediaLink is telling the PS3 to get its media from that address, it’s no wonder it fails to work!

So, where the heck did that address come from? Googling that particular IP address didn’t reveal anything special. I tried putting that URL from URLBase into my browser, not really expecting to get a response since I knew there was no route to any such subnet on my network. But there was a response, and it was just the kind of terse and somewhat cryptic response you might expect from a server that’s expecting to respond to a specialized client program. I tried trimming off the filename part and submitting just the IP address to the browser, and got the standard Apache web server response for an unconfigured server. Some computer, somewhere on my network, was somehow being reached by this URL and responding!

When you already have Wireshark open, every networking problem looks like a job for packet tracing. So I set up a Wireshark capture filter to log packets to and from the mystery address, and set the trace in motion. Nothing. I repeated the browser access to the mystery server. The access succeeded again, but still no packets were logged by Wireshark. I threw the Wireshark capture filter wide open and tried again. Still, no packets to or from were logged.

OK, that leaves just one thing. When you start a Wireshark trace, you have to specify which physical interface is to be traced. Potato has only one physical network interface active, the first wired Ethernet port en0, so naturally I was tracing on en0. The mystery host must be on some other interface, somehow. The command to list network interfaces is ifconfig, and that’s the next thing I ran.

That told the story: ifconfig showed an interface called vmnet8 that was using the IP address In fact, vmnet8 was listed before en0. I speculated that MediaLink was enumerating the IP addresses of the available ports, and choosing the first one it found.

Another resort to Google quickly revealed that vmnet8 is a virtual networking port installed as a kernel extension (kext) by VMWare Fusion. VMWare doesn’t try to dynamically load it as needed, it just leaves it installed forever to clutter up your kernel. The VMWare Fusion on Potato was a long-expired demo version I didn’t need, so I simply uninstalled it. The vmnet8 port disappeared, without even a reboot. Repeating the trace of packets between the PS3 and Potato, I could see that the URLBase in the XML file had changed to, Potato’s IP address on en0, as expected and desired. (If you’re having this problem and need to keep VMWare Fusion around, I don’t know what to suggest other than to complain to MediaLink for a way to specify which interface or IP address it tries to use.)

I ran downstairs and found that I could again browse the server file hierarchy on the PS3. I declared victory and went straight to bed, it being long past bedtime by then.

The next day when I had a bit of time on my hands, I decided to take advantage of my newly repaired video streaming to watch an episode of Enterprise. It didn’t work. The PS3 couldn’t even see the server. OK, maybe I had left the server shut down in my groggy state the night before. I went upstairs and restarted it. Now the PS3 could see the server and browse the hierarchy again, yay. So I fixed some lunch and sat down to watch. Hit Play and nothing happened for a few seconds. Then the PS3 changed the title of the video I wanted to watch to “Corrupted Data” and returned to the hierarchy browser. Nothing would play. Arrgh. This time the error in the upper right corner was “DLNA Protocol Error 2110” or “DLNA Protocol Error 2101”.

This time Google found me a specific answer when I searched for error 2101. I learned that there was a new problem with the alpha version 2.0a1 and beta version 2.0b1 of MediaLink, having to do with sending thumbnail images to the PS3. It crashes the background program MediaLinkHelper.app, which is the actual DLNA server program, which I confirmed by examining the system log in Console.app. Once the server crashes, of course nothing works. The solution given is to delete the plug-in that tries to handle thumbnail art, /Library/PreferencePanes/MediaLink.prefPane/Contents/Resources/MediaLinkHelper.app/Contents/PlugIns/AlbumArtTranscoder.mltranscoder. I did that and tested again.

My episode started to play, hurray! After the teaser was over and the theme music began to play, I hit fast-forward, as usual. The picture froze and went silent. That’s not how the fast-forward looked and sounded before, and it’s not an improvement. I hit play. I expected to get video, either with or without having skipped ahead by the amount it should have been fast-forwarding. Instead, I continued to hear silence and see a frozen screen, for quite a few more seconds. Before I did anything else, it eventually did start playing, having fast-forwarded ahead about the right amount.

Failing to find anything about this problem with Google, I assumed it was a bug in the beta version of 2.0 that I had “upgraded” to. I foolishly did not save the version 1.54 (I think) that I was originally running. Fortunately, Nullriver makes available version 1.72 for customers who are running Tiger, since the 2.0 versions require Leopard. I downloaded version 1.72 and replaced the beta version with it, and got back the nice, smooth fast-forward behavior I had before.

Once again I have declared victory, and I was able to watch my episode of Enterprise without any additional problems. So far.