The most difficult pictures to take with the camera have always been screenshots. Screen images are a very important part of BeebMaster and I am very rarely happy with the images produced by the camera. The results are variable in the extreme and some of the pictures I have had to settle for have been downright poor.

I had tried ways of recording the output from the BBC micro, originally onto video recorder, to capture images to use as screenshots. I never got this to work. Using the UHF output on the Beeb produced a very unsatisfactory picture, the composite video output was black-and-white only, and using an RGB-to-SCART lead would not work either. For technical reasons which are beyond me, a video recorder or DVD recorder doesn't seem to be able to pick up the RGB signal produced by the BBC when it's fed in via SCART.

Since November 2006, I have been using my DVD recorder to capture screenshots from BBC micros using the Composite Video output. Although by default it is monochrome, it is very easy to add colour to the Comp Video signal, which has allowed me to produce high quality screenshots using this method.

There's much more on how to turn the monochrome Composite Video into full colour here.

The general procedure is to connect up the Beeb in question to the DVD recorder video the Composite Video. I use the recorder's High Quality Setting, which can fit about an hour of recording on a DVD. I use two re-writable DVDs for doing the recordings, which are erased once I have finished with them.

For each picture I want to capture, I usually record for about five seconds, pause, set up the next picture, and record again. For "live action" activity, such as a utility or game running, I would normally run the sequence two or three times and record it each time to get the best chance of capturing everything I need.

Once the recording is done, I copy the "VOB" files from the DVD onto my PC and then wipe the DVD for re-use.

Before using Ubuntu, I used to have to trawl my way through the video, pressing pause every time I wanted a screenshot, using the save screenshot function, typing in a file name, checking the saved file was the frame I wanted and not the one before or the one after, and then carrying on to the next picture.

Linux has a very handy function called "ffmpeg" which can be used from the command terminal. It is for converting video files between different formats, but also allows a video file to be converted to.jpg, in other words, extracting the frames from the video. It will extract every single frame, which becomes rather unwieldy, but also allows extraction of frames at a specific time interval, so I use it to create frames at intervals of 1.5 seconds, which is ample for what I need.

The end result is a set of images which I can then look through and choose the ones I want to use on my website. From this point on, the method is the same as for making the picture sets from digital camera photographs. The frames are extracted at a size of 768x572 so I leave them at this size. There is no need to crop or rescale them, so I use Phatch to suffix them and take the quality to 70%, and then to make the preview size images.

Sometimes it isn't convenient to connect the DVD recorder to the actual machine I want to capture, for reasons of space. To see what's going on, I have to have a monitor connected to the DVD recorder and there isn't always room to put the recorder and monitor right as close to the machine being captured as the lengths of cable and availability of sockets will allow.

It can also be a bit of a fiddly job to try to fit the little colour composite capacitor to a machine that doesn't have it already, especially if it's one of my machines in a permanent installation and not just a demonstration setup.

Luckily, that's where my Econet comes in, because I can use the *VIEW command to view the station I need to capture on a machine located some distance away with the colour modification applied and enough space to connect everything together and record the VIEWed screen.

Using this method in 2009, I was able to obtain masses of screenshots from my Master Compacts, in colour, even though the Compact doesn't support the colour addition to its composite video signal. I even wrote my own version of *VIEW, which updated in real-time. This was quite a programming achievement for me, because it had to take into account hardware scrolling, mode changes, and logical colour palette definitions!

Although this method works fine for the BBC micro and Master, I have struggled with some earlier and later machines. Some of the later 32-bit Acorns, such as the A5000, do not have a composite video output, and connecting to my DVD recorder with a SCART lead doesn't work. I'm still trying to figure out a way round this. Hopefully I'll crack it one day.

In December 2009, I was able to record my Acorn Atoms using a composite video lead which came with the first of my Atoms. Unfortunately, the picture was extremely unstable on the DVD recorder, constantly rolling vertically around the screen. I had first tried this in September 2009 but had given up after being unable to stabilise the picture. I tried again in December 2009, thinking I might be able to record sufficient material to extract frames at the moment the picture lined up into the correct position. The result was a little bit hit-and-miss but generally it worked. To prevent myself going dizzy whilst doing all this, I also had the Atom connected up to a TV set via the RF output so I could at least see what I was doing!

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