Amiga questions you've always been too embarrassed to ask

[van_dammesque]

Originally Posted by Weasel Fierce

Another question:
What is the hardware spec to reasonably play MP3 files on an Amiga?
I tried on my 030 some years back and it was pretty awful From memory, you needed a pretty beefed up 486 on PC.

My 040 @ 25 MHz played mp3s but the bitrate was very low, something like 32-48kbps.

[Jope]

None of them really play mp3 very reasonably without offloading it to a hardware decoder.

It works well enough to listen to what is inside an mp3 file you came across, but the CPU usage is so heavy that doing stuff at the same time starts suffering.

If you want to leave more CPU cycles free, you can of course crank the quality settings way down, but then it doesn't sound very nice, why not play a protracker module instead? ;-)

[jizmo]

Solution: convert and play the music as 22khz IFF/WAV files instead; less CPU usage, less buffering and same or better quality while letting you to do other things while playing. Converters are aplenty and there's plenty of storage space these days available so the somewhat bigger footprint audio size will not be an issue.

[Jope]

Surely an external mp3 cd player connected to your speakers would be a more reasonable solution in this case? No breaks in the music when your Amiga crashes either. :-)

[Daedalus]

Originally Posted by NLS

AFAIK 68000/68010 have 24 bit address bus.
(also has some 32 bit registers which makes it more like a hybrid 16/24/32 bit CPU)

Just for clarity, when I was talking about the bus width, I meant the data bus, not the address bus. The address bus width doesn't impact performance, only addressable space. But the 68000 and 68010 have a 16-bit data bus, which means each 32-bit transfer requires two memory cycles, whereas on a 68020 and above where you have a 32-bit data bus (even if the address bus is 24-bit), such a transfer happens in a single cycle.

[Daedalus]

Converting to 22kHz will improve playability, and won't dramatically impact the output quality either if you're playing through Paula on a standard screenmode. But under certain conditions Paula can play up to ~56kHz, which means cutting 44.1kHz audio to 22kHz to play is going to cause issues.

For full quality decoding, the minimum requirement is a 68060. That will let you decode full samplerate, full resolution audio up to about 192 or 256kbit/s, and that will take a sizeable chunk of your CPU time. To get that full quality out you'll really need a soundcard, but that's how I played much of my music in the late '90s and early '00s. The Pentium PC I had beside the Amiga at the time could also play them (and on paper should have made easier work of it), but the Amiga could actually do more without causing the audio to stutter, so it stayed on as my main music machine. It helped that I had SCSI, lots of RAM, graphics and sound cards in there too so the CPU requirements from other support operations were minimised.

[TCD]

Originally Posted by Daedalus

That will let you decode full samplerate, full resolution audio up to about 192 or 256kHz, and that will take a sizeable chunk of your CPU time.

Do you mean kHz or kbit/s?

[Weasel Fierce]

Originally Posted by Jope

Surely an external mp3 cd player connected to your speakers would be a more reasonable solution in this case? No breaks in the music when your Amiga crashes either. :-)

This was purely idle musing, since I realized I had a random MP3 on the hard drive and tried playing it

[jizmo]

Originally Posted by Jope

Surely an external mp3 cd player connected to your speakers would be a more reasonable solution in this case? No breaks in the music when your Amiga crashes either. :-)

Would be the most viable solution, yes

Most people who want to play MP3s on Amiga do so to demonstrate themselves or others that it can be done, but really – there's much better solutions for listening to music, or using your Amiga for what it does the best.

[Weasel Fierce]

Anyone with a Checkmate case:

What dimensions of power supply will fit in there? I have an old one that Amigakit sold which was meant for a tower case but I have no idea what type it is. Its 9 cm tall though.

[Daedalus]

Originally Posted by TCD

Do you mean kHz or kbit/s?

The 192 or 256 is kbit/s, sorry. Updated.

[TCD]

No worries. This thred that was posted yesterday shows that you can even play 320 kbit/s MP3s on a 030 equipped Amiga with Prelude. Quite impressive

[khph_re]

Meynaf rewrote Mpega.lib for better playback on 030 and above.
Never tested it myself as my A1200 has no sound :-(

http://meynaf.free.fr/pr/mpega030.lzx

Thread here:
https://eab.abime.net/showthread.php?t=102628

I use to convert songs to ADPCM with compression - played back great, and size was comparable to MP3.

[meynaf]

Originally Posted by khph_re

Meynaf rewrote Mpega.lib for better playback on 030 and above.

With it i could play 320kbps on my A1200 030/50.
But, of course, with half frequency and mono...

[khph_re]

Originally Posted by meynaf

With it i could play 320kbps on my A1200 030/50.
But, of course, with half frequency and mono...

That is very impressive! Did you ever get the mythical source code in the end?

[meynaf]

Originally Posted by khph_re

That is very impressive! Did you ever get the mythical source code in the end?

Yes. But i did not do much with it.

[mfilos]

Silly question.
I set a variable that I use on a script. How on earth I can concatenate it with text WITHOUT space...

Simple example:
Set test 100
Echo $test MHz (will give me 100 MHz with space)
Echo $testMHz (will give me $testMhz which is logical as variable is not set)
Echo "$test"MHz(will still give me 100 MHz with space)

How on earth I can ommit the space in order to have 100MHz?

[TCD]

In a script this works:

set test 100;
echo "$test" noline;
echo Mhz

[mfilos]

Yeah I was aware of the noline option but as I wanna assign the concatenated output to a variable as well...

[TCD]

This works with echo, but I can't figure out how to assign it to a variable then:

set test 100
echo $test$$Mhz

Edit: Duh! This works:

set test 100
set test2 $test$$Mhz