Thanks! I hate it!

Ingredients

• Raspberry Pi
• USB floppy drive
• Audio Cable / Headphones
• USB Battery

WHY?!?!

As I discussed yesterday, it's possible to fit half an hour of speech on a single floppy disk. The best band in the world are The Beatles, and their shortest album is A Hard Day's Night - at 30 minutes, 45 seconds. Beatles audio was designed to be played over crappy AM radio in mono, so is well suited to being compressed using the latest audio codecs.

OK, I also got sent a USB floppy drive to review and wanted to do something interesting with it!

Compress your audio

A floppy disk can hold a maximum of 1,457,664 Bytes.

Using the Opus Audio Codec, you can squish audio to miniscule file sizes.

I got a single WAV of the album, and ran this command - which is about the best quality within the target filesize:

opusenc hdn.wav --downmix-mono --bitrate 6.7 --framesize 60 --discard-comments --discard-pictures --cvbr hdn.opus

That got it down to a trim 1,429,105 bytes. Enough space left over for some low-resolution cover art!

You can shrink the audio by a few more bytes by using removing the default metadata from .opus files.

How does it sound?

The copyright for Hard Day's Night should have expired in 2014. Sadly, the law was changed in the UK in 2013. So it doesn't expire for another 14 years. Here are some samples which I am using for non-commercial research purposes. This, I hope, falls under the fair dealing exception.

(I've re-encoded it to MP3 in order for it to play in the browser.)

Building It

Sadly, the Pi Zero doesn't have an an audio out jack. But the USB floppy drive is pretty big, so we don't lose much space by going for a full-sized Pi. The Pi has a weird combined video / audio jack. I powered it using a USB Battery.

All held together with rubber-bands. Classy!

Here's a high tech block diagram:

🔋---→💻---→ 🎧 
      ↑
      |
      💾

Run these magic commands

I used Raspberry Pi OS Lite which doesn't have a desktop manager, and fits on a 4GB microSD card.

Set the audio output to go via the headphone jack:

sudo raspi-config

Then choose: Option 7 (Advanced Options), then A4 (Audio), then 1 (Headphones).

Set the headphone volume to 100% (or whatever you fancy):

amixer sset "Headphone" 100%

Make sure you have the Opus tools and codecs installed:

sudo apt install opus-tools

Make sure that the floppy disk has been detected:

dmesg

It will probably show us as sda - mount it with

sudo mount /dev/sda /mnt

Go to the directory with your audio in it:

cd /mnt

Decode the file and pass it through to aplay - this should start playing music straight through your headphones.

opusdec --force-wav --quiet hdn.opus - | aplay

ENJOY!

Notes

Depending on the speed of your drive, and the framesize of your audio, you may experience buffer-underruns. This will cause the audio to skip. Just like jogging with a CD Walkman!

I printed the album cover on a Bluetooth Thermal Printer.

ToDo

• Build a circuit to let me press buttons to play, pause, and skip tracks.
• Make it auto-play when the disk is inserted.
• Use the Rockband Moggs to make acapella / vocal only disks. Should be better quality without the backing music.
• 3D print a case so I can go jogging with it while wearing a shell suit.
• Register a patent on the blockchain so people have to pay me a trillionth of a EdentCoin every time they play music using my brilliant invention.

Put your ideas in the comment box.

Thanks

Huge thanks to Alistair for sending me a bunch of old floppies to play with.

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1. File transfer speeds are always going to be slower that I can be bothered to wait
2. My ears aren't going to get any better at hearing

For years, I ripped all of my music as FLAC. I collected ridiculously high-resolution audio files. I devoured disk drive space for surround sound soundtracks.

"One day," I thought, "I'll have an amazing audio system to play these back on."

The reality is that I spend most of my time listening to music on £40 bluetooth headphones. I have a nice 5.1 surround sound system - but it isn't exactly THX certified. And, thanks to the construction of British houses, I can't turn it up to 11 without my neighbours complaining.

Yesterday, as I was waiting for a couple of GB of new music to fly through the aether to my phone, I was struck by a realisation...

I am not an archivist.

I don't need to preserve all my commercially-bought music in the highest resolution possible. It isn't my job to faithfully preserve every ultrasonic decibel. And I am never going to own a set of speakers which will super-charge my old ears.

It's OK to bounce my music down to a more convenient file format.

Enter Opus

I've written before about the Opus file format. It's the modern and open successor to MP3. It isn't lossless - but I've compared the quality, and I can't hear a damned difference.

Turns out, everyone agrees with me. Even at extremely low bitrates it is superior to every other format.

Opus plays back natively on Android, it supports all the normal music metadata / IDv3 tags, and works perfectly with surround sound. The codec and tools are Open Source and Linux friendly.

And, best of all, it's small! Even when I encode at the maximum possible bitrate (I'm not a total savage!) an hour of 5.1 audio is about 20% of the size of FLAC.

I know I could buy a bigger disk. But while home storage is relatively cheap, mobile storage is still expensive. Yes, WiFi 6 will make everything better - but I don't need to fling gigabytes through the air to my tin ears.

So, from now on, everything is getting run through: opusenc --bitrate 1536 in.flac out.opus

I've always wanted to say to people "just so you know, I am also recording this call." Well, now I can.

A little back story...

Around 4 years ago, I experimented with recording phone calls. It was quite a clunky process, involving conference calling in another line.

Of course, Android has theoretically supported native call recording since its inception. However, Google have ignored all the requests to actually enable it.

Android has a number of call recording apps. On most phones, the call recording works by putting the phone on speaker mode and using the microphone to record both sides of the conversation. That has obviously disadvantages for call quality - not to mention that you don't always want to have your conversations on speakerphone!

Luckily the enterprising chaps at GrinZone have found a way round this limitations on some phones.

With InCall Recorder on my Galaxy Note II, I can finally record line quality audio on my phone calls.

Take a listen:

One of the great things about InCall Recorder is that it automatically upload the recorded MP3s up to DropBox - so your calls are instantly available to you and anyone else with whom you choose to share the folder. In the UK, it is perfectly legal for an individual to record their calls - and there is no need to inform the other party nor obtain consent. Individuals are exempt from having to comply with the data protection act. Interestingly, so are journalists...

In other countries, check your local laws :-)

Of course, it's polite to inform someone that you're recording them. More than that, for some people it really improves their attitude and their service. At the moment, I'm going through the tedious process of buying a house - I've found that with some individuals, it's very handy not only to record the call and play it back for reference, but to let the other party know that's what I'm doing.

Listening back to some of my favourite calls over the last year has been very interesting and quite emotional - I can certainly see why our security services enjoy listening in so much!

Amazon's mp3 store on mobile

Music is a huge seller in the mobile marketplace.  Why carry a walkman or a discman when your phone can deliver high quality music to your £3.99 headphones?  Hear a song you like on the radio, in a concert, from a busker singing - a few clicks and it's on your phone ready to play.

At the moment, MNOs* rule the roost in terms of mobile music sales.  Customers don't want to type in their credit card number on a phone's keypad.  They're also wary of risky premium rate, reverse billed SMS.  They want ensured compatibility. That's why MNO portals do so well - the charge goes straight on the customer's bill.  If there's a problem, they know who to ring and complain.

Amazon, I think, changes that preconception.  A customer probably already has a relationship with Amazon and trusts them.  A customer can go straight to Amazon's Mobile Site, log in and then purchase using the infamous 1-Click.  A little up front complication (the logging in) is off-set by Amazon's wishlisting, giftlisting, customer reviews, recommendations and silky-smooth interface.

Could Amazon change the mobile purchase marketplace in the same way that they revolutionised book-selling?  MNO portals are traditionally locked gardens (only MNO customers get access; as opposed to walled gardens where customers can't get out).  Will competition from Amazon - and their inevitable imitators - radically alter the market?  We've already seen DRM dropped from mobile music, a range of new subscription plans, and complex bundles - what next?

But, for now, potential Amazon customers simply see "This mobile site does not currently support the purchase of this item."  For how long, I wonder...?

*Yes, I work for one. No, I don't speak on their behalf.

The Spec

Mello Branded Cyprus CompactFlash MP3 player (v11) + 128MB Compact Flash card (a 128MB CF card gives you 124MB (130658304bytes) which is just about enough for 2 hours of 128Kb music. If you go down to FM quality (64kb) you'll get 4 hours worth of music.).

Manufactured by http://www.themindfactory.com/Products/Mello_MP3/mello_mp3.html

Purchased from http://e2thepower.com for £99.99

• Acts as a true Plug&Play USB mass storage device.
• Takes CF type 1 cards from 8MB up to 2GB!
• 110x80x20mm
• 75g w/o 2*AA batteries
• SNR >82dB
• THD=N (0dB) <-80dB
• Transfer rate 560KB/sec
• Compatible with Windows 98/2000/ME/XP
• Battery life 17+ hours.

The Player

The Mello is very light and surprisingly large. It's about the same size as a Sony UltraSlim cassette walkman. The controls are well fairly well arranged (Vol+ Vol- FF RW Stop Play/Pause EQ/Mode). It would have been nice to get a jog dial, but as 128MB really only holds ~42 3 minute songs it's not too much of a hardship. Having said that, the Mello doesn't support directories (you can have sub-directories, but all the songs show in the order they were transferred to the card) and on start up you are presented with

Radioh~1.mp3
Radioh~2.mp3
Blur-s~1.mp3
Blur-T~1.mp3

Yup - no support for ID3 on start up - once it starts to play you get shown the ID3 tag. Although it only stays on screen for 30 sec, so you have to press a button to see what you are listening to! The volume on the Mello goes quite loud (from 0 - 31) but doesn't remember your last preference (it defaults to 6 which is a little too quiet for my liking). The equaliser (which works remarkably well) also doesn't remember its settings.

Because the Mello acts like a USB hard-drive you can download any sort of file to it and upload from it to any computer. The Mello has a DIR function to let you see its directory, but that too only presents short filenames.

It does feel slightly too.... it's hard to describe... hollow. It's light, fairly sizable and make of cheapish plastic. The unit isn't very rugged and came with a sizable scratch on its back. The Mello comes with a carry-case with storage pouches that allow you to hold extra CF cards. Because the buttons are on the face of the Mello, it's quite hard to press them if the unit is in your pocket. There is a hold switch to prevent accidental button presses.

How it performed

Tested on WinXP Pro, K6/2-500, 578MB RAM, Quantum Fireball 20GB drive, MoBo GA-5AX.

WinXP detected the device as soon as it was plugged in without any problems. Sound quality is good, even with the supplied headphone; I detected no hiss. The headphones have a resistance based volume control on them. The equaliser works surprisingly well. The Mello had no problems playing MP3s from 56kb - 192kb, it might play more but I didn't have any to test with.

The Mello doesn't remember the last track that was being played, so if you stop the unit in the middle of an album, you'll have to trawl through the tracks to find it again. The unit shuts itself off if not being used, which helps conserve battery life.

The Mello doesn't handle seamless MP3 changes particularly well. If you have an album like "Sgt Pepper" or "The Wall" there is a brief but noticeable gap between tracks.

Problems

The manual states that it can be formatted as FAT16 or FAT32. Formatting as FAT32 didn't work in XP but reformatting as FAT did. It only reads ID3v1 tags - you'll have to make sure you synchronise your tags if you use ID3v2. The screen isn't backlit, it has two LEDs at the side which give off a gloomy glow that is just enough to see the screen - the buttons don't light up at all. The buttons could do with being slightly larger, better shaped and sized but they are perfectly sufficient. The USB cable is about 1 metre long, which is just about sufficient. But it has a weird miniature 4-pin end plug which can be a little difficult to plug into the Mello, especially if you're in a rush. I think the cable is proprietary (i.e. non standard) so make sure you look after it.

Transfer Speeds

Radiohead's Amnesiac (39 mins 40 sec / 40.2 MB) took 100 seconds (about 400KB/s). This is slower than the 560KB/s claimed, but it's still very fast, you could fill the whole card in around 5 minutes.

Overall Verdict

This is a great bargain. 128MB MP3 player and removable storage all in one for £99.99. But, it is cheap; it looks plasticky and feels like it wouldn't survive too many accidental drops. The User-Interface is annoying.

7/10. It works, it's cheap, very upgradeable, but has enough usability flaws which stop it being great.