Rockbox mail archiveSubject: question to all blind rockboxers
question to all blind rockboxers
From: Paul Erkens <pjealt_at_xs4all.nl>
Date: Fri, 18 May 2007 00:48:58 +0200
Since I got my IAudio x5, I really had a whole bunch of stuff to learn. I
was rather a novice. The information on the net aimed directly at blind
people is there to some degree, and that's wonderful already. But it is not
very extensive up till now.
I'm writing a document right now, from which other blind folks can learn
what I had to learn. I started writing this afternoon, and I'd like to know
from you guys out here, if you think I should do it differently, keep going
this way, or leave it altogether because I'm completely wrong.
If any of you cares to take a look at my first attempts, I am pasting it
below. If the reactions are okay and I can get it finished in the near
future, I'm planning to send it off to the rockbox team, and see if they
find it useful enough to place it on their site for other blind adventurous
souls to use. Rockbox is made by very knowledgeable people, but introductory
docs for the unknowing like myself, I haven't found so far. Would you as a
blind reader find this a useful document? Especially the section describing
the IAudio mp3 player itself.
Comments welcome. It is my first attempt to write it, unfinished nor
polished. I'm not a native English speaker. I just want to know if I'm on
the right track to really make a difference when I get it done. I'd like to
contribute my little bit.
--- Guide for the blind: rockbox on your IAudio x5 mp3 player. Contents ideas: ======== introduction What are we talking about? -walkmans and accessibility -what is mp3 really? Description of the IAudio x5 Hearing the demos on the unit an explanation of firmware what is rockbox for us? How the speech system works About the files to download and what they do Introduction Welcome. This guide is intended for blind folks, wanting to have an accessible mp3 player. I am blind myself, and from the directions on the internet, I finally managed to get rockbox to work on my player. The information I needed was not bundled in one place, and most documents were very brief. Now that I have my own player going and now that I've seen how great rockbox just is for us once it's running, I want to share my knowledge and experience with you, so you don't have to invent the wheel again. In short, if you already know what an mp3 walkman is: with rockbox, you can now navigate almost all menus, configure almost all options and do almost anything a sighted user is capable of, using the display screen on the unit. New functions and possibilities are added constantly, and what you can't do today, may be possible next week. Rockbox makes your mp3 player talk, so you will know what you are doing as you operate its controls. That is what rockbox is all about for blind people. A work in progress, already working on many different mp3 players, talking to you, and improving continuously. This is not a technical document, because I'm not technically inclined myself. I will explain what you are required to do, why you must do it, and in our case without vision: how it should be done. I can only describe the procedure for the IAudio x5 mp3 player. Other players, I don't have any experience with so far. If you have something other than the IAudio x5, this document will provide you with background information so you will understand what's up, but the specific installation details for other players than the IAudio x5 are not covered here. We will begin by providing you with some useful background information. Only read it if you're interested. We will discuss audio compression, and similar background topics. Then, we'll dive into describing the IAudio x5 unit, showing you how to get started with rockbox. In many cases, I will refer to the IAudio x5 rockbox manual on the rockbox site. This document is an addition just to get you started; It's by no means a replacement for anything. If you have any suggestions for this document, please write me at pjealt_at_xs4all.nl. I can't provide support for general rockbox problems, because all I do is write and maintain this document. Please write me only if you think an important concept is missing from this document. What are we talking about? ===================== So, what are we talking about in this document in the first place? Simply put: until rockbox came, we did not have good access to digital walkmans. But now we do. If you buy yourself an x5 walkman from IAudio, this document tells you how to set it up for yourself, so that it talks to you as you operate it. walkmans and accessibility If you like music, talking books, radio plays or other forms of recorded audio, it is great to have a mobile device, on which the audio you want to listen to is stored. When I was young, I used to have one of the first walkman players that could play cassette tapes. It weighed almost two American pounds, which is near to 1 kilo gram in European measurement. It required six pen light batteries, it had head phones attached, the batteries lasted less than two hours, and I was extremely proud to walk around with that brick. But after two months of intensive use, the tape started to slow down, the sound became bad and I did away with it finally. Not only had the player been expensive, but it wore out pretty quickly. These days, walkmans have improved dramatically. The music is no longer stored on cassette tapes but on different media. The modern media are digital in nature. How digital audio works exactly, falls outside the scope of this document. The advantage of using digitally stored audio in your walkman is however, that its sound quality is much better. Besides, it is now much easier to instantly play a song of your liking. You don't have to change tapes and cue back and forth, to find the song you want to hear. Instead, you navigate through your collection using a small display screen on the walkman, to find and play it. And here is our problem. If you can't read the display on the unit, you won't be able to access most of its functions and settings. These devices become more and more menu based, with logical categories in which you can find the option you want to tweak. Absolutely fabulous for sighted people, but by far not for us. You know how computers are made accessible though. The screen is read to us by an electronic voice, and because of that, we can navigate our files, do text processing and many other computer tasks, even including installing windows XP without sighted assistance. If you are determined, that is. Generally, most manufacturers of modern digital equipment don't really adapt their stuff such, that people with disabilities can make good use of them. We can get along some by memorizing key stroke sequences, but modern devices have become way too complex. This meant, that the pleasure of digital walkmans was only available for us if we didn't demand too much. You could buy yourself one, but only 20% or so of its functions that you payed for, will be usable for you. Well: no more. Thanks to the time and effort spent by the rockbox team, we now have the possibility to use these modern walkmans, and not just that. We can also make a well informed choice among the different models on which it runs. Rockbox won't work on all modern walkmans, but more are added over time and what these people have achieved so far, is impressive. Just take a look on the rockbox site, and see which mp3 walkmans are already currently supported. Go to your local dealer and get yourself one from that list. What is mp3 really? Next, we need to understand what mp3 really is. Mp3 is not a walkman, a player, nor a dvd feature. Mp3 is a file format. Let's see what this means. A file on your computer is something you will be familiar with. A file can contain a letter or other text, it could contain a picture, and likewise a file on your computer can also contain audio. If you play an audio file on your computer, you will hear the sound from the file out of your pc speakers. There are a number of different audio file types that are currently used throughout the world. Simply put, there are only two basic types of audio files: compressed, and uncompressed. Let's talk about what this means. On a regular audio cd, audio is stored plainly. The original sound has been encoded into small groups of digits: ones and zeroes, and these are stored on the compact disk. It is possible to have your computer's cd or dvd drive read that digital audio information off the cd, and storing it in regular computer files on your hard drive. This process is called "ripping a cd", i.e. copying the audio data over from the cd on to your computer's hard disk. However, a simple cd contains an enormous amount of data. If we speak in megabytes, a cd contains roughly 800 megabytes worth of audio data. Once you have the contents of your cd inside your computer, you can hook up your digital walkman to it, and then transfer those files. You should be aware however, that the storage capacity of your digital walkman is usually quite limited, if you compare it to the capacity of your computer's hard disk. Audio, in its plain form, is quite big. When digital walkmans first came to market, we had devices that could contain 32 megabytes max. Now if you realise that in plain storage format, an audio file eats up 10 megabytes for every minute of music, you will understand that in these players, there was only room for a song of about 3 minutes in length, and obviously, you want more music in your walkman than just one little song. Two things have been done to overcome this problem. First, a group of clever people invented a method of reducing the size of regular audio files down to a tenth of what they used to be. This is what is now called: audio compression. It essentially just means, bringing down the size of the audio file whilst retaining the maximum possible sound quality. The human ear is not very accurate, compared to a computer. What audio compression does, is throw away those parts of the audio that we are not likely to perceive. The more of the audio you throw away, the smaller the resulting file can be. And now we have something to work with. On a windows machine, a file containing plain audio is called a wave file, usually having a period and the letters w a v at the end of its name. Wave files can be quite big. Usually, they are uncompressed. Plain. On the other hand, the most common way of compressing audio these days, is called mp3. So the word mp3 just refers to the way the audio itself is compressed. Compressed audio files usually have a dot and the letters m p 3 at the end of their name. To summarize: if, for example, you see a file called song.wav on your computer, you know that it usually is an uncompressed audio file, because of the dot wav at the end. If you encounter something like song.mp3 or today.mp3, you know that it is compressed audio, because of the dot m p 3 at the end of the file's name. This is only a rule of thumb, because we did not take into account the fact that even wave files can be compressed, and still be called .wav. But let's not get lost in the details. We mentioned before, that mp3 reduces file sizes by throwing away frequencies in the audio you are not likely to hear. The better compression you want to achieve, the more audio you need to throw away. If you keep going, you will get to a point where the audio damage becomes perceptible. You will hear it. So there's always a tradeoff between filesize and quality. In mp3 jargon, the compression factor that determines both the final file size and also the resulting sound quality, is called the mp3 bitrate. If you are going to create your own mp3 files from cd's you have, then the bitrate is something you can configure. Bitrate and compression factor refers to the same thing, as far as mp3 is concerned. A song in wave format containing 3 minutes worth of cd quality audio, would become 30 megabytes in size on disk. If you make an mp3 out of this, then you will still have a file of reasonable quality if you compress it down to a tenth of its original size. One song in mp3 format could then become 3 megabytes rather than 30, and still sound quite okay. And if you only have 32 megabytes of storage available on your player, that's quite an improvement. You can now store ten songs, rather than just one in uncompressed format. In other words: audio used to be way to large to handle. Mp3 has given us a solution, by drastically cutting down the file size of our digital audio. Old mp3 players were equipped with a memory chip and these devices are still widely used, except that the memory capacity has grown enormously, which is the second improvement over the first digital mp3 players with limited capacity. Mp3 walkmans in the form of a small plastic stick can well contain 4000 megabytes, 4 gig, which is really quite something. And that's not all. Modern mp3 walkmans don't store their audio in a memory chip. Instead, they have a tiny hard disk built in to them. This leads to walkmans with great storage capabilities. 40 to 60 gigabytes (being 40000 to 60000 megabytes) is no exception these days, giving you ample space for thousands of songs. There are many brands to choose from, if you want such a walkman or mp3 player. Before purchasing one, you need to decide for yourself how much you are going to store on it. If a couple of gigabytes is enough, a player with a memory chip will suffice. But if you want 40, 60 or 80 gigabytes worth of music, then you should buy a player that has a hard drive built in. Description of the IAudio x5 ============================ I chose the Cowon x5, which is an mp3 walkman manufactured by a company called IAudio. This player comes in a few flavours. The things that make the difference between the various models are the capacity of the hard disk inside it, and the battery life. If you have an x5l, then the l stands for long battery life. The player is thicker because of the bigger battery. Mine has a normal battery life, it is not the thicker one, and the hard disk can contain up to 60 gigabytes worth of data. The player is as small as a packet of cigarets. It is a metal casing that feels very solid. It has only a few buttons, and a joy stick. You can buy an optional leather protection for it, and even when the player is inside the protection leather, you can operate it well. Let's describe the unit, so you will know what is where. Put the player on a flat surface in front of you. If you feel its roof and all you encounter is four tiny dots, one on each corner, then you now have the unit upside down. The side that is now facing the table, should face the sky. If however, you now feel a very smooth rectangle and a button inside a circle, then the unit is already half way in the correct position. Now, we must make sure that the player is in the same position as I have it here, in order for the side descriptions to match. As you can feel, the roof of the player consists of two distinct levels. A thick and a thin part. Now, the thicker part that feels all smooth, is the visual display screen. Rotate the unit, so the display is at the top of the unit, furthest away from you. The bottom part of your x5 contains this little knob inside a small circle. This is your joy stick, and we will discuss what it does later on. Now, we can describe the four sides of your x5 in succession. The left side contains your head phone connector, and a slit to make the player act as a USB host. The top has a light, the right has power/hold, record, play, microphone and reset hole, while the bottom has the subpack connector. Okay, slowly this time. We'll start with the left side. Sliding your finger from top to bottom, so from the top left towards the bottom left corner, the first thing you encounter is a tiny round hole for your head phones. A little further down is a slit, which is probably a connector you won't be using very often. Sighted people can use it to have the x5 act as a USB host, so they can connect their digital camera to the x5, and transfer the pictures they have in the camera, over to the x5. This way, the camera's internal memory card can be wiped out and the photo shooting can continue again. Rockbox may utilize this connector for other purposes, but to my current knowledge, it is of no use for us right now. The rest of the left side does not contain any extra connectors or controls. The top side, running your finger across, reveals no more than a visual indicator, showing wether the x5 is currently charging. If you're totally blind, this is of no use to you. Then the right side of the player. Again, slide your finger from top to bottom, from upper right to bottom right. First, you will find a switch that you can slide up or down. Initially, it is always in its middle position. This switch has many functions, but to begin with, remember this as your power switch to turn the x5 on and off. Push upwards and let go. Then listen closely if you hear the hard disk spin up. If not, just try again until the device switches itself on. After a few seconds, the hard disk will shut off again, but the device is still awake. Making the hard drive spin, takes power from the battery, so as soon as the x5 is done reading and writing to the disk, it stops to save power. To turn the x5 off again, do the same thing. Push the switch up and let go, until the device switches off. This power switch has yet another function. If you slide it down, it won't flick back to its original position in the middle. After sliding the switch down, it just stays there. In this position, the unit is on hold. This means that none of the other buttons perform any function. Very handy if you want to tuck away the x5 somewhere in a pocket, and you want to be sure the battery won't go flat by accidentally starting playback without head phones, which obviously wastes battery life. Note: you can test wether the device is on or off, by making sure this switch is in the middle so that the x5 accepts key strokes, and then attempting to play, see below. If it playes, then the unit is still on. This is no guarantee that the player is on or off indeed, but is is something to begin with. Further down the right side, just below the power/hold switch, you will find two rectangular buttons. The top one is rec, the bottom one is play. More on these later. Further down, you may feel a couple of teeny weeny holes in the metal strip. The top hole is the internal microphone, and the bottom hole is reset. To reset the unit, you can stick a long, thin object into it, which will touch the hidden reset button. Use it in case your firmware crashes and you want to start over. Finally, the bottom side. In the middle, this side contains a metal slit that almost feels like a slot for an sd memory card, but that is not what it's meant for. This is the connector for the subpack, being a small plastic device that you got together with your x5. One side of the subpack plugs into the x5, and on the other side of the subpack which, when connected, is now the bottom side of the device, you will find a number of connectors. From left to right, the connectors on the subpack are as follows: AC, USB, line in and line out. The last two I am not sure about. They may be line out and then line in. Hearing the demos on the unit ============================= If you are like me, before doing anything else, you will want to hear what your x5 really sounds like. If all goes well, you won't be disappointed. Wear your ear phones and plug the cable into the socket on the top left side of your x5, as described earlier. Then, turn the unit on as described. When the hard disk spins up, wait for it to spin down again and then press play. If you don't hear anything, try play again. I heard music immediately and it sounded just awesome. Not that I love the demo itself, but the quality is pristine. Now, feel your joy stick. This joy stick can be moved in all four directions: east, west, north and south, or three o'clock, nine o'clock, twelve o'clock and six o'clock if you prefer. Place your finger south of the joy stick, six o'clock, and push upward, away from you. The volume will increase. Likewise, place your finger north of the stick and gently pull the stick towards you, down. The volume will decrease. Pushing right will move to the next file on the player. Moving left first goes to the start of the current song or, when done in the first few seconds of the track, moves you to the start of the previous track. You will notice that the demos more or less all sound the same. There's video together with the audio, but just forget about that because it's useless to us. What is firmware? You may wonder, how your mp3 player is capable of playing digital music. Your pc has a micro processor to read from disk, process sound, create video etc. But what about your mp3 player? Well, your x5 is a computer on its own. It too has its own memory, its own hard disk and a micro processor. The operating system is usually stored on the hard disk. In a pc, that is usually windows (sorry linux lovers, just by means of saying), and on mp3 players, the operating system is going to be rockbox. Now to understand what we are actually changing to make the player go rockbox, we need to go over some concepts first. You know that your computer has a processor and that it has memory too. If you turn the pc on, it loads its operating system from hard disk, and then waits for you to do something with it. But let me ask you. How does your pc know that the operating system to load is stored on hard disk? You know that the computer can only do something if it has software that tells it what to do, and the operating system is exactly the piece of software to do that. But, when you first turn on your computer, the operating system still needs to be loaded from hard disk first. So, how can the computer know how to perform its very first steps, if the operating system has not been loaded yet? The computer tests its memory for errors right after you turn it on, but at that time, the hard disk has not even been touched to start loading the operating system. What makes the computer perform its startup tasks? The answer is: the bios. Bios, b i o s, stands for basic input output system. It's a small piece of software, not stored on a hard disk, but on a tiny chip somewhere on your motherboard, deep down inside your pc case. When you turn on your pc, what happens is that the bios first checks to see if all hardware is connected properly, and the bios then takes care of loading the operating system, windows. The bios only knows a few very basic functions to communicate with the hardware, enough to get the computer started. The operating system does the rest. The same goes for your mp3 player, your x5. When you turn it on, the first thing that happens is that the microprocessor starts running the program code, stored in the player's rom memory. After initializing the hardware, this code is responsible for loading the rest of the operating system from the hard disk. Because software is something created by humans, it can always contain errors, called bugs. Every now and then, computer manufacturers release new versions of this code on the internet. But as I said, bios code in a pc is stored on a chip inside the computer, not on the hard disk. Well, it is easy to download a new version of a certain file, on to your computer's hard drive. But how would you reprogram the contents of a special bios chip, deep inside your computer? Luckily, you don't need to worry about it, because the computer has a mechanism to do this for you. If you want to update your computer's bios, for example when USB functions strangely and you read on the manufacturer's site that the latest bios version fixes this, then you can simply download a file containing the new code. You then put this file in a special location, turn your machine off and on, tell it to look for the new bios file, and let it reprogram its own bios chip as you wait a few seconds. Now. Your x5 also has sort of a bios, and an operating system. When you first buy your x5, it's got startup code and an operating system inside it, provided by Iaudio. The code programmed into the rom memory of the player itself, is called the firmware. According to wikipedia, firmware is embedded software, but this can be a confusing and difficult term. Firmware in your x5 is like the bios code in your pc. It runs when you start the player, and makes the player react to your key presses and joy stick movements. However, this initially provided operating system from IAudio is not blind friendly at all. It does not speak, and you'll have a hard time remembering how many times to push your joy stick left, down, right etc, in order to get to a certain function. What rockbox is, is a complete replacement for the player's internal operating system. From the ground up, it has built in support for speech, so that we can use it as well. Part of rockbox must live inside the player's rom memory, and part of rockbox resides on the hard drive. So we need to get rid of the original IAudio operating system and startup code in our x5, and replace it with startup code and the operating system from rockbox. There are two separate processes to carry out. First, we need to put the disk part of rockbox onto the hard drive of our player. Next, we need to replace the boot code, so that the player knows how to load rockbox when we turn it on. A property of this x5 player is, that the original firmware can not continue to exist in the player after rockbox has been installed. On other players, at startup, you can choose to either run the IAudio firmware or the rockbox firmware. On our x5, this is not possible. Once you install rockbox, you loose your original firmware. No problem, because rockbox is better for us than Iaudio's firmware. Which files to get? Everything you need can be downloaded off the internet, from www.rockbox.org. For blind people using screen reading programs to access the information on the computer screen, this site is not easy to work with. If you need to, ask some sighted assistance if you can find someone willing to help you some. It's up to you to know what to get and where to look for it. You don't want to frustrate your helper by leaving it up to them to hunt for something they haven't read or learnt about.Received on 2007-05-18