Efficient insulation

Four years ago I replaced the hot water system in my house with a heat store, which (at the time) was a fairly revolutionary system with some real advantages:

• mains pressure hot water
• high capacity
• enables more efficient boiler usage
• no cold water tank in the loft
• no hot water cylinder in the airing cupboard
• DIY installable

The heat store is essentially a large tank of very hot water, heated indirectly by the boiler. That hot water is then used to instantly heat cold water from the rising main, to provide the hot water for the house. In some ways it operates on similar principles to the hot water part of a combination boiler, except that the heat store is much more powerful (160Kw), allowing it to cope with multiple hot water outlets with ease. It is also potentially more efficient than a combination boiler, as the boiler can run for long efficient burns while charging up the heat store, rather than short on/off burns of the combination boiler while heating water on demand.

In my case, I installed the system in the loft, as it allowed us to reclaim a lot of cupboard space. The system came factory insulated, and it was claimed that it needed no more insulation, even when installed in outbuildings or loft spaces. But I’ve always had a niggling doubt, wondering if I was losing heat to the loft, especially when the weather is cold. But I’ve never been able to prove it to myself one way or the other.

The failure of our central heating boiler this week has given me the opportunity to prove that the heat store is adequately insulated, because while we’re waiting for the new boiler to be installed, I’ve switched the heat store over to electric operation. And electricity usage is very easy to monitor, especially if like me, you happen to have a Currentcost meter.

The heat store has a 3Kw heating element built in, which for the time being I’ve set to run permanently via a thermostat. Whenever the water in the tank drops below 70c, the heating element will cut in and heat the water. Currently the loft drops to about 2c overnight, so if the insulation is inadequate I’d expect to see the heat store lose heat overnight (when we’re not drawing hot water), and for the heating element to cut in, and a 3kw electric load appear on my Currentcost logs.

But it doesn’t. It looks as though the only time I need to top up the heat in the heat store, is when I draw heat off it to produce hot water for the house. Which is good. Incidentally, the regular “blips” of power usage that are particularly noticeable through the night are caused by the freezer, when the compressor cuts in.

Click the image for more detail:

12 hour power usage

First checkup (part iii)

I was called in to see the surgeon this evening, to hear the results of the CT scan. Lots of good news, tinged with some not so good news.

So firstly, and most importantly, there is no sign of any cancer anywhere in my body. As far as the doctors can tell, I am cancer-free, which is excellent news.

They have also identified the likely cause of the pelvic pain that I’ve been struggling with, which has prevented me from stopping my painkillers, which is also excellent news.

Unfortunately that is also the less good news, as it appears to be a small leak from the join in my colon, which has resulted in an abscess forming next to the colon. The surgeon did a sigmoidoscopy, and the hole was clearly visible. Fortunately it looks like a very small leak, but this would explain the general pain, the elevated white blood cell and CRP counts, and (probably) the relatively slow overall progress that I’ve been making.

Options stretch from doing nothing, a course of antibiotics, some minor surgery, to (potentially) having to reinstate my ileostomy again, either temporarily or permanently. Clearly I favour the least invasive approach that produces the right result, as does the surgeon. So, we’re going to start with the antibiotics tomorrow, the surgeon is going to create a new care plan for me, and we’ll meet again in a week or two to determine where we go next. The first part of that plan is likely to involve either an MRI scan or another Gastrografin enema, to provide more detailed images of the actual abscess. The result of that will determine what we need to do next, though it was fairly clear that the surgeon (naturally!) thinks that the surgical approach may give the best result.

So, a slightly mixed result, but right now I’m focusing on “Cancer free” and I’ll worry about the rest tomorrow.

Return to work? (Part ii)

This week my medical certificate expired again, so I needed to discuss with my GP whether I was ready to restart work or not. This is a strange sort of discussion, because although the ultimate decision rests with the GP, he bases that decision on input from me. In turn, I try to give him factual information about my health, pass on any input from the other people who have a stake in this (the IBM Occupational Health people, my management, my surgeon and my DWP caseworker) and not try to influence him with any extraneous emotional input.

Ultimately though, my position is that I want to get back to work as soon as I can practically start, without impacting my recovery. The IBM Occupational Health people seem to have the same concern, tinged by additional issues around Health and Safety, and protecting IBM’s interests in that area. My management feel much the same way, with the additional concern that they don’t want me coming back so soon that I struggle to do my job – because that impacts on IBM’s business. My surgeon doesn’t really care about when (or even if) I go back to work; he’s solely concerned with my recovery. Meanwhile, the poor DWP caseworker seems to hold a rather schizophrenic amalgamation of the interests of all the other stakeholders.

So given all that, I was expecting a fairly detailed discussion with my GP. Whereas in the event he spent about a minute scanning back through my diary where I’ve been detailing my food intake, levels of pain, “bowel habits”, sleep patterns etc, before declaring me to be unready for work still.

So rather frustratingly, I find myself signed off for another month.

If I stand back and review the situation dispassionately I can see why he’s done that, and even agree that it’s probably the right decision. But of course, I’m not standing dispassionately on the sidelines here. This is my life. And I want to be back at work, starting to live it more normally again. And from that perspective, I’ve found this outcome more than a little depressing.

It leaves me wondering just when is this all going to end?

Digitising DVD’s with Linux to stream to PS3

Having posted about converting the format of video files to suit streaming to a PS3, I got an email asking me how I actually convert a DVD into a digital file, and how my network is set up to stream videos to the PS3.

So, a little more explanation. I have a small, very low-power server that runs 24×7 in my house, and is connected to my 100mbps ethernet network. On that server I have quite a lot of disk storage, and run Mediatomb, which is a DNLA-compliant UPnP media server. It serves my collection of video and audio files to any device on my network that wants to access them.

In the case of the video files, that device is my PS3, which is also connected to my ethernet network, and also has an HDMI connection to my LCD TV. With this configuration I can start the PS3, which automatically detects the Mediatomb media server and puts an icon on its GUI interface. I can then select that icon, get a list of the available video files, and by clicking on one, have it played on my TV for me.

The only configuration involved in this solution is of Mediatomb, which involves a couple of documented changes to its configuration file, and specifying where my media files are via its web interface. All very simple.

To create the media files from a DVD, I do the following:

1. Extract the content of the DVD onto my hard drive using a program called vobcopy.
2. Use ffmpeg to convert that content into a more compact form, better suited to streaming over a network.
3. Copy the resulting file to my server where Mediatomb can access it.

Now lets look at the first two steps in more detail:

DVD’s actually store their content as a series of VOB’s; these contain the actual video that you see when you play back a DVD. In general there are separate VOB’s for the main movie, any adverts, trailers, bonus features, etc etc. And just to make life a little more complex, some DVDs store the main movie in more than one VOB, though fortunately vobcopy can hide that from us.

To make things a little more difficult, the movie industry have then encrypted the DVD to make it harder to do what we are about to do. To get around this, you must have installed libdvdcss2, which is a DVD decryption library that is available from the Medibuntu repository.

To find which VOB to extract from the DVD, simply run “vobcopy –info”. This will produce some output like:

richard@t60p:~$ vobcopy –info
Vobcopy 1.1.0 – GPL Copyright (c) 2001 – 2007 robos@muon.de
[Hint] All lines starting with “libdvdread:” are not from vobcopy but from the libdvdread-library

[Info] Path to dvd: /dev/sr0
libdvdread: Using libdvdcss version 1.2.10 for DVD access
[Info] Name of the dvd: STARWARS2UK_D1_2_PAL
[Info] There are 21 titles on this DVD.
[Info] There are 103 chapters on the dvd.
[Info] Most chapters has title 1 with 51 chapters.
[Info] All titles:
[Info] Title 1 has 51 chapters.
[Info] Title 2 has 1 chapter.
[Info] Title 3 has 2 chapters.
[Info] Title 4 has 1 chapter.
[Info] Title 5 has 1 chapter.
[Info] Title 6 has 1 chapter.
[Info] Title 7 has 1 chapter.
[Info] Title 8 has 1 chapter.
[Info] Title 9 has 1 chapter.
[Info] Title 10 has 2 chapters.
[Info] Title 11 has 10 chapters.
[Info] Title 12 has 14 chapters.
[Info] Title 13 has 1 chapter.
[Info] Title 14 has 1 chapter.
[Info] Title 15 has 2 chapters.
[Info] Title 16 has 1 chapter.
[Info] Title 17 has 4 chapters.
[Info] Title 18 has 2 chapters.
[Info] Title 19 has 2 chapters.
[Info] Title 20 has 1 chapter.
[Info] Title 21 has 3 chapters.

[Info] There are 21 angles on this dvd.
[Info] All titles:
[Info] Title 1 has 1 angle.
[Info] Title 2 has 1 angle.
[Info] Title 3 has 1 angle.
[Info] Title 4 has 1 angle.
[Info] Title 5 has 1 angle.
[Info] Title 6 has 1 angle.
[Info] Title 7 has 1 angle.
[Info] Title 8 has 1 angle.
[Info] Title 9 has 1 angle.
[Info] Title 10 has 1 angle.
[Info] Title 11 has 1 angle.
[Info] Title 12 has 1 angle.
[Info] Title 13 has 1 angle.
[Info] Title 14 has 1 angle.
[Info] Title 15 has 1 angle.
[Info] Title 16 has 1 angle.
[Info] Title 17 has 1 angle.
[Info] Title 18 has 1 angle.
[Info] Title 19 has 1 angle.
[Info] Title 20 has 1 angle.
[Info] Title 21 has 1 angle.
[Info] Using Title: 1
[Info] Title has 51 chapters and 1 angles
[Info] Using Chapter: 1
[Info] Using Angle: 1

[Info] DVD-name: STARWARS2UK_D1_2_PAL
[Info] Disk free: 74104.160156 MB
[Info] Vobs size: 5733.919922 MB

It’s highly likely that the VOB with the most chapters is the main movie; in this case title 1. We can check that by running the command “mplayer dvd://[vob_number]“. If we see the main movie playing then we can extract that VOB to our hard disk by running the command “vobcopy –title-number [vob_number]“. vobcopy will then proceed to decrypt and copy that VOB to your hard disk (as STARWARS2UK_D1_2_PAL3-1.vob in this case).

Now we can convert that (very large) file into something smaller and more easy to stream. This uses exactly the same command as the last post; ffmpeg. This time however, we need to make sensible guesses for the bitrates that we want to use for the video and audio streams. Personally I go with 2000k for the video, and 192k for the audio. It’s good enough in terms of quality, and produces a file ~1/3rd the size of the original VOB, which is much more amenable to being streamed over a 100mbps ethernet network. If you’re hoping to do this over wireless, then you’ll probably need to compress even more and sacrifice quality … wireless just doesn’t have the bandwidth to do good quality video streaming.

So, the command to convert that VOB to a .mp4 file is:

ffmpeg -i STARWARS2UK_D1_2_PAL3-1.vob -vcodec libx264 -b 2000k -acodec libfaac -ab 192k STARWARS2UK_D1_2_PAL3-1.mp4

That command will take at least as long to execute as the movie would have taken to play. But once completed, the resulting file can then be copied to my server and be available for instant access in the future.

(Re)encoding video under Linux to stream to a PS3

I’ve recently moved to storing my video collection on my home server as a series of .mp4 files, and streaming them (with Mediatomb) to my PS3, which displays them on my TV. This means I can watch any of my DVD’s without having to find the disc, which is very convenient.

However, I started digitising many years ago, so my collection contains a few older “.avi” files that contain video in early Divx and Xvid formats. Normally these “.avi” files can be streamed directly to the PS3 too, but sometimes the PS3 complains of Unsupported data, error 800288bf, or Corrupted data. I’ve failed to discover exactly what causes these problems, but they’re clearly related to the combination of the codecs used for the audio and video streams and the use of the avi container.

To resolve this, I simply convert (re-encode) these unsupported “.avi” videos into the newer more standards-based .mp4 format. This approach will work equally well for video in the many other formats that the PS3 doesn’t understand. To do this, I use ffmpeg, which is the swiss army knife of video & audio conversion for Linux.

If you intend to replicate this, you need to use a recent and full version of ffmpeg; the version in the standard Ubuntu repositories isn’t sufficient, as it doesn’t include support for patent-encumbered codecs, which you will need. Instead, you can get the version you need from the Medibuntu repository.

First find out what bitrates your existing video is using for it’s video and audio streams. Enter “ffmpeg -i video.avi”. Output will be something like:

richard@t60p:~/Data$ ffmpeg -i video.avi
FFmpeg version SVN-r19352-4:0.5+svn20090706-2ubuntu2, Copyright (c) 2000-2009 Fabrice Bellard, et al.
configuration: –extra-version=4:0.5+svn20090706-2ubuntu2 –prefix=/usr –enable-avfilter –enable-avfilter-lavf –enable-vdpau –enable-bzlib –enable-libgsm –enable-libschroedinger –enable-libspeex –enable-libtheora –enable-libvorbis –enable-pthreads –enable-zlib –disable-stripping –disable-vhook –enable-gpl –enable-postproc –enable-swscale –enable-x11grab –enable-libdc1394 –extra-cflags=-I/build/buildd/ffmpeg-0.5+svn20090706/debian/include –enable-shared –disable-static
libavutil 49.15. 0 / 49.15. 0
libavcodec 52.20. 0 / 52.20. 0
libavformat 52.31. 0 / 52.31. 0
libavdevice 52. 1. 0 / 52. 1. 0
libavfilter 0. 4. 0 / 0. 4. 0
libswscale 0. 7. 1 / 0. 7. 1
libpostproc 51. 2. 0 / 51. 2. 0
built on Oct 13 2009 22:15:16, gcc: 4.4.1
Input #0, avi, from ‘video.avi’:
Duration: 01:24:57.64, start: 0.000000, bitrate: 2281 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 720×304 [PAR 1:1 DAR 45:19], 25 tbr, 25 tbn, 25 tbc
Stream #0.1: Audio: mp3, 44100 Hz, stereo, s16, 192 kb/s
At least one output file must be specified

I’ve highlighted the interesting parts; the average bitrate for the whole file, and the average bitrate of the audio stream. Take one from the other and you have the average bitrate for the video stream.

Now we need to re-encode the video into a format the PS3 likes. We’ll use H.264 video, AAC audio, in an MP4 container, which the PS3 supports well. I’ve just reused the same bitrates as the input file, but in practice you can probably reduce both a little without affecting quality, as H264 and AAC encoding is more efficient than older encoders:

ffmpeg -i video.avi -vcodec libx264 -sameq -b 2089k -acodec libfaac -ab 192k -t “00:05:00″ video.mp4

Notes

• -sameq keeps video quality the same
• -b 2089k specifies the output video bitrate
• -ab 192k specifies the output audio bitrate
• -t “00:05:00″ optionally produces only 5 minutes of output – ideal for testing your settings before you convert a long video
• Encoding time on my dual core laptop is about 1 second for each second of video. So expect a long wait.

First checkup (reprise)

Todays CT scan went pretty much to plan. The basic format was identical to the last time, in that I needed to drink a Barium contrast agent to highlight my upper GI tract, and have an IV contrast agent to highlight my vascular system.

However, this time, knowing what was in store for me, I knew not to eat or drink anything in advance of the scan, which made drinking the Barium contrast agent much easier, if not any more pleasant. The IV contrast agent required that I have a cannular fitted, which was even less fun than normal. In the end it took two nurses, and both arms to get a working connection. Not exactly ideal, given how much I dislike needles.

Still, the CT scanner was absolutely state of the art, and did the actual scans at least an order of magnitude more quickly than the older one that I used last time. The scans couldn’t have taken more than a few seconds each. Very impressive.

Update: I forgot to mention that the IV contrast agent acted very differently this time. The first time I had this done I could very clearly feel the agent being pumped into me, and a hot sensation as it ran around my body. This time I could hardly feel it; there was the barest sensation of warmth, which as before finally settled into my buttocks. However, it was nothing like as peculiar or unpleasant as the first time I had this done. I wonder why not? Different chemical, slower infusion, more tolerance? Who knows. Interesting though.

Sadly, the Barium contrast agent seems to have very badly upset my digestion, so I’ve not had a terribly pleasant time through the late afternoon and early evening. Still, it will all be a small price to pay if the doctors come back with the all-clear. That will probably be a week or two away yet though.

First checkup

Tomorrow I start the transition from the treatment to the monitoring phase of my cancer treatment; I have the first of my (annual?) check-ups to determine if I am still cancer-free. Or not.

I understand that normally this will be done with a combination of a colonoscopy and a full-body CT scan, but in this case I’ve already had a recent colonoscopy as part of my ileostomy reversal, which showed that my colon was completely clear of any polyps. So this time I just get the full-body CT scan, which is looking for any signs of the cancer having spread to other parts of my body.

I’ve had one of these before when I was initially diagnosed and I’m not really looking forward to the procedure, mostly because of the contrast agents that I know they’re going to want to use. I’ll need to drink a litre of gloop (which is horrible) to highlight my upper GI tract, and have a very large cannula inserted in my arm (which I hate) to highlight my vascular system. So my wife is going to come along and support me, hold my hand, and make sure I don’t try to run away!

I keep reminding myself that it will all be worth it, provided the results come back negative. Speaking of which, I suspect I’ll have a week or two waiting on tenterhooks for the results to come back, which will be fun.

Recovery from chemotherapy (week 15)

Sadly, nothing really new to report on this front.

I’m still struggling with my peripheral neuropathy, especially in my feet and toes, which seems to be harder to cope with for some reason. It feels like I’ve got balled-up paper tissues in my shoes; or rather, under my feet, as it feels the same even when I’m not wearing footwear. Most strange, and very irritating. Still, I guess it will either fade, or I’ll eventually get used to it.

I still feel the cold very badly, which given the cold, snowy weather we’ve had recently, has not been much fun. In the end my response was just to turn the heating up, wear a lot more layers, and dream of spring. It wasn’t perfect, but it helped a lot. Of course, I may feel differently about that approach when the gas bill arrives!

This has also persuaded me that in the spring I need to complete the last few major wiring jobs in the loft (some final structured cabling runs, and wiring up an aerial distribution system) so I can get around to finally topping up the loft insulation to the new recommended maximum.

Reversal recovery (part ix)

It’s now approaching 10 weeks since I had my ileostomy taken down, and finally it feels like I’m starting to see some progress. This ties in with a comment from my colleague Harry, who mentioned that it was about 3 months before he started to see real progress too.

Of course, things aren’t perfect yet. A long way from it to be brutally honest, but I’m now seeing a lot more days where I’m mostly in control and able to get on with life to varying extents. I’d like to think that mostly that’s down to my body finally starting to adapt to the changes that my surgeon has made to it, but there’s no doubt that I’ve also got a lot better at fiddling with my medicines and diet (I’ve been keeping a food diary) to reduce the problems too.

Unfortunately when things do go wrong, they really do go wrong quickly, and with a vengeance. At that point all I can do is increase my dose Loperamide and stay within running distance of the toilet. The Loperamide eventually gets things back under control, but usually means that things then swing the other way for the following couple of days, which can be equally unpleasant.

All of which brings me back to the question of when I’m going to be well enough to actually start working again. It’s certainly starting to look like a real possibility; given that IBM intend to restart me on part-time hours initially, and then slowly increase my hours and responsibilities over a two month period, I’d like to think that I ought to be able to start that process reasonably soon.

But that decision is still nearly a fortnight away, and although that gives me time for a bit more improvement, it’s ultimately for my doctors to make, with input from me, rather than the other way around.

Kicking the chemicals (part iii)

My surgeon called the other evening with the results from my urine and blood tests.

The urine test was negative for infections, which in combination with my continuing normal temperature readings pretty much rules out prostatitis in all its forms. Which is good.

My blood tests came back as mostly normal; the Full Blood Count (FBC) showed that my White Cell count was slightly elevated, and the C-Reactive Protein test (CRP) came back a little higher than normal too. However, in both cases these are very non-specific tests, and “normal” is somewhat subjective, especially for the CRP reading. Taken together they probably just indicate that my body is coping with some low level inflammation or infection. Certainly neither were high enough to indicate serious problems such as the return of the tumour or my colon leaking, especially when combined with my continuing normal temperature. Which is very positive.

In the meantime, thanks to the Cocodomal, I’m pretty much rid of that pain so the new plan is to gradually reduce my dose to check if, when and how the pain reoccurs. In parallel, my surgeon will look for any physical reason for the problem in the images that come back from my CT scan on the 25th, and if necessary, get new pelvic MRI & Gastrografin enema tests run (oh joy!), which will give him more detailed images to work from.

I’m pretty sure that he is now convinced that this is purely muscle strain, which makes perfect sense to me too, but he’s keeping an eye on all the other options too, which gives me a lot of confidence. Unfortunately that diagnosis doesn’t give us many options for treatment – because those aren’t muscles that I can exactly rest!