Category Archives: howto’s

Create PDF files from any document type for free

2008 notice: now that OpenOffice can create PDFs natively just by pressing a button, this guide is really useful to create PDF in other applications: everywhere you have access to a “print” function, you can use this procedure to create a PDF.

Yes, there is indeed a way to create a PDF out of every kind of printable document, paying nothing to Adobe, and without any legal infringement. It is called “GhostScript”; it is a freeware tool ported from UNIX environment, distributed under the GNU license, and is capable of coverting any Postscript document to PDF format. What do you need? First, the document , then a fake printer driver, which you will use to create a Postscript file from the data to print, and finally the tool itself, Ghostscript.

There are different kinds of Postscript printers among the ones you can choose in the drivers list which come with Windows, but we’ll take the HP Color Laserjet PS; just do this: [Start > Settings > Printers > Add Printer], then choose “Local Printer”; now, depending from your OS, the screens will appear in a different order, but you just need to select “FILE:” as the printing port:

Here is an example of the dialogue you’ll be facing

and select the previously told model, HP Color Laserjet PS, in the Printers list:

The printer, selected and ready to be installed.

If you already have a real printer, I obviously suggest you NOT to set this one as the default printer .

First step completed. When you’ll want to create a PDF, just go in the “Print…” menu of the application (usually [File > Print…]) and select this printer as the output. You will then be asked for the name and the location where you want to put the .PRN file.

Second: you now need the tool to convert from PRN to PDF. Just get Ghostscript from the Downloads/Tools section (you need to get also Ghostview, a preview tool to see how the document will look — you can get both of them also on the official page).

Installed the two tools, start Ghostview, and open from there the PRN file you created; you can now see the screen preview:

This image has been intentionally compressed to reduce its size, don’t worry about the quality of the conversion, it is very good.

Do [File > Convert], select PDFwrite as peripheral, and leave the quality to 600dpi; after this, choose where to put the PDF file.

Done!

Fix and repair those divx that freeze during playback

That’s a tough work, but someone has to do it, right? I learned by myself, by errors after errors.

I’ll make you laugh: at first, when I discovered what great tool was VirtualDub, I used it to delete the stuck frames and then recompress the whole movie losing quality. This took dam long, I assure you. Then I discovered I could delete frames, and save the file without recompressing, kewl! But right after that I also discovered (the first movie which could take advantage of this has been Pulp Fiction) that Premiere could actually read those frames… so I just cutted them, pasted in a new clip, recompress them to make them compliant with the normal codec, and then re-past the recompressed, working clips into the stream. Woo that WAS kewl, I could keep all the movie, in better quality than I had by recompressing the whole video, and all this in half the time!

 

…until I read Doom9’s (www.doom9.net or doom9.go.to) guide to fix DivX, and I discovered the existence of some nice tools which did it for free, and really fast, that is AVIDeFreezer and DivFix.

All the tools explained in this article can be found in the Downloads/AudioVideo section of this website.

Follows a guide to AVIDeFreezer which you can find also in the ZIP in HTML format (this is just a copy/paste, with minimal adaptations, the intellectual property of this guide is of the software’s author.

1. First open VirtualDub and click "Open Video File" in the File menu.

2. When you have opened the file, use the slider to get near the place with the bad frames, then click play. When the program gets to the bad frame it will give you an error like below.

Example of how corrupted frames are shown in VirtualDub

 

3. Now click previous keyframe, and make a note of the frame number, this number should be entered as the start frame in the AVIDeFreezer.

4. Now click next keyframe untill you get to a working frame, normally this should be the first keyframe, but sometimes when a movie is really messed up they can be more. Make a note of this frame number too, this will be used as the end frame in the AVIDeFreezer.

5. If the movie has more than one segment with bad frames return to 2 and do this for every corrupted sequence.

6. When you have found all bad frames start AVIDeFreezer.

7. First open the original file and choose a location for the new file, don’t try to overwrite the original file, since that will cause problems. Also be sure that the destination folder has enough space to contain a file about the same size of the original movie.

8. Now enter the start and end frame for all the corrupted segments you found using VirtualDub (this example is a version of Wild Things, this movie had 5 bad frames).

How AVIDeFreezer appears with all the frames intervals inserted

 

9. When you have entered all the intervals click DeFreeze and the program will start working, the first part where it fixes all the bad frames is pretty fast, but when it gets to "Writing Streams To New File" it will work for a while depending on the size of the movie and the speed of your harddisk, this is because it is copying the original file to the new file, except for the bad frames which are now fixed.

10. When the program has finished writing the new file it will crash and close itself, but don’t worry the new file is ok and working.

11. When you watch the movie the frames that where bad before may have some small errors (see below), but they won’t freeze anymore, and you didn’t need to cut them out.

An example of artefact you may get after fixing a corrupted movie.

 

But not every tool is prefect. So, when some DivX’s won’t get fixed with VirtualDub/AVIDeFreezer (and this can happen if the movies are encoded in VKI – Variable Keyframe Interval, or if the movies you downloaded are incomplete, since the server closed, and you got noone else to resume from, VirtualDub will begin to "guess" frames till the end of the file, unless it finds a corrupted one, which will mean you won’t be able to go past that frame with VirtualDub, and the movie will seem definitely lost.

But you have a last hope, and this is DivFix, which worked with every movie I tried it on, showing its flexibility as a great tool, unless you want to edit the "corrected" movies so obtained with VirtualDub, since it won’t be possible. This is because DivX have an "index" at the very end of the file, which is used by players to gather info about the file and reproduce it correctly. If the download is uncomplete (so missing the index), a player won’t be able to read that movie, but VirtualDub can guess te frames as I said, until a corrupted frame occurs, and VDub stops searching for other frames (too bad) truncating the movie at the first corruption. DivFix creates this index, working on the existing frames, apparently no matter how many of them are corrupt, so allowing every player to play the movie with no freezes from the first to the last downloaded frame, with obviously some reproduction artefacts in the video stream, as snow, weird colour wakes, and so on, in the corrupted frames. But this newly-created index is not recognized as valid by VDub (I really don’t know why), which will try to guess frames from the beginning, getting stuck at the first corrupted frame as I said.

Make a backup copy of the AVI just in case, then open it inside DivFix and press the Rebuild Index button, that’s all.

An example of DivFix at work

 

A tip for habitual users of DivFix: under Win2k/XP you can add DivFix in the contextual menu "Open With >" for AVI files (just for DivFix 1.06; right click on the file in Windows Explorer), so you won’t need to start manually the program: right-click on the AVI you want to fix, in "Open With >", click on "Choose Program…" and browse to your DivFix location, then double click on the divfix.exe file, being sure that "Always use the selected program…" is disabled. DivFix will open, fix the file, and close; from now on, you’ll be able to choose DivFix from "Open With >" everytime you have an AVI to fix.

 

This is all I know about the matter. Actually not everything, but you can easily guess the details I omitted .

Last update: I noticed (and while I am adding these very words, I had the confirmation elsewhere) that using the DivX4 codec (nothing in relation with DivX3.11, but the name, and the backward compatibility; dowload it from Downloads/AudioVideo) to playback also DivX3.11 movies, freezes will be simply ignored, and you will be able to continue the playback normally (getting anyway those artefacts we talked about before). Even in this case anyway, if the index at the end of the files is missing, you’ll still need DivFix to re-create it. ThePlaya, the DivX player included with the full bundle of DivX4, and which you’ll find also here, is capable of playing index-less DivX 3.11/4 files, yet it never worked fine for me, since the playback was choppy, and then again even worse than choppy.

There’s nothing in here such "How to fix your corrupted movies by redownloading only the corrupted segments", which is still an important part of the official guides to fixing DivX’s. This is because it often (c’mon, let’s say "always") happens that you do NOT have the opportunity to ask the guy running the server to install the utility-they-need-to-check-the-CRC and please-run-it-for-me-cuz-otherwise-my-movie-won’t-play-well-pretty-please. Only two people did it for me, and they were my friends . Anyway, if you still want to try and compassionate someone into helping you this much, you can find the utilities I am talking about in the Downloads/Internet section, they are named Rsync and Zidrav (stick to the second if you want my opinion).

Build your own cycleradio™ to listen to music on your bycicle without batteries

2008 notice: this article is way outdated now that lithium MP3 players are sold for a few bucks, still you can feel like a nerd and build this contraption out of sheer fun.

I made the whole thing myself, during a summer vacation, some years ago, when I was really, really, REALLY bored, so I came up with this weird idea. The system’s gonna be disassembled from my mountain bike shortly (still works OK after years of dust on the bicycle), just because lately (another summer vacation), I’ve had the occasion to make some long and rough rides, which I’ll repeat through all the holidays, and the walkman, which was going anyway to be trashed if I didn’t recycle it this way, doesn’t appreciate the frequent 1.5G shocks (my a$$ neither, but it’s another story…); plus the dynamo doesn’t fit well with the rear tyre at HIGH speeds.

Anyway, if you use your bicycle for city rides, not so fast as well, the CycleRadio™ will be your faithful bike-audio system for very, very long.

I’ll pass throught the graphic explanation of the manual steps, to come directly to explain HOW the whole thing is done and works.

Why? Only because if you are really unable to figure how to technically assemble all this, I can do nothing but recommend you to a good physiotherapist. And, not less notably, also because I don’t have a webcam to paste here the pics of how I did it on my bike.

Let’s proceed.

Find a dynamo. Used, new, stolen from your neighbor’s ’60 bike, or from your mom’s ’80, but broken, one (as in my case). You should be able to get a 6V one, since it’ll give more reliability to the system.

Hey, are you sure it is 6V?
This is the prize for your quest, brave knight. Pssssst noone’s around, get a screwdriver!

 

Now you have to find a suitable place to fix it to the frame of your proud mountain bike. I chose the rear bracket which is normally used to attach the rear lamp (there are some nice holes where you need only a bolt to stick the dynamo). In the best of cases, you’ll need your brute strenght (better if helped by a solid pair of vanadium pliers) to fold the arm of the dynamo to make it rotate perfectly against the tyre (be careful here, placing the rotating part too tight may spoil the rubber, as placing it too near to the carvings of the tread will hurt often on the dynamo itself, causing it to be displaced very soon); also, you may need some steel wire to stabilize the structure to the frame).

Next, you’ll need someting to convert the AC of the dynamo to the DC which uses a walkman. And you may need to buy some electric pieces, if you can’t manage to remove them from an old TV, radio, or whatever.

This is what you need:

4 diodes:

Anyone of'em is ok. If you know how to use them :-P
A diode is represented as –>|– where the point of the arrow is the positive pole. The side of the diode with the black or coloured ring is the positive pole.

 

1 capacitor:

Do not pull those wires!
These are two examples of what you need. Better get a capacitor of some Volts higher of the dynamo’s, lilke 10-12-16V, and at least of 2000uF, or your walkman playback, during fast rides, will simply suck.

 

solderer (needed only to make a "clean" work; I didn’t use one)

 

And this is how you need to assemble them:

Admire the artistic talent...
Clear eh? Now, don’t cry and use your fantasy, it’s clear indeed. I put in here ALL of the components, so you’ll use this image as reference. Make sure the positive pole of the diode-square and the positive pole of the capacitor match. The same for the negative poles.

 

A good place to stick this small rectifier, which is the sum of the 4 diodes plus the capacitor (and which you’ll have packed in some Scotch tape, or better insulating tape, to make it waterproof, after you made sure there are no short circuits – just use insulating tape also on the bare contacts) is right about here:

Don't ever try this at home kids!
Place the scotch-packeted rectifier circuit right in the place marked with the bright-yellow dot. Place instead the scotch-packeted battery-pack in the place marked with the bright-green dot.

 

Now you have in place the dynamo and the rectifier circuit. Mmmmm what next… why! Just wire them! You don’t need to connect specific poles, just one pole of the dynamo with one pole of the rectifier (not the ones connected to the capacitor, but the free ones) and then the other pole of the dynamo with the free pole of the rectifier (Important Notice Only For True L4m3r5: a dynamo has two poles, not only the one you can see at the bottom of it. The second pole is — try to guess — the bracket used to fix it to the bike frame!).

 

Let’s come to the batteries. Not the battieries you usually put inside a walkman, but every kind of rechargeable battery, the bigger the better, which has a Voltage of 6~9V (so, even the one of dad’s old cellular phone, if you know how to use its poles, or, as the ones I used, the rechargeable batteries of a broken portable vacuum cleaner…). You’ll attach the battery-pack somewhere else on the frame (see the previous pic).

In this case the positive output pole of the rectifier (the one on the side of the capacitor) must match with the positive pole of the battery, same for the negative poles.

 

One step to the victory!

Now, just wire togheter the positive pole of the battery with the positive pole of the walkman, same for the negative. You’ll need to open the walkman so to pull out the wires which actually reach the electrodes, and connect these wires with the wires coming from the battery (didn’t I tell you? The walkman will be lost, since, after that, you won’t be able to put batteries in it; so, better use an old walkman… you know the huge crappy one your grandma bought you for birthday, not knowing you already had an untraslim-single battery one? )

I suggest you to place the walkman on the handle-bar, right in the middle, where every mountain-bike has a short straight metal tube going from the handle-bar itself to its axis. Just fix here a small transparent zip-bag (like the ones used to put makeup accessories – here the mom will be useful again…) with a small table of plywood on the bottom, so to create a solid surface. Done.

You don’t need me to tell you how to pull cables from one piece to another do you?