Using Pulse Density Modulation for 8-bit PCM

[antrykot]

Wasn't it experimentally established that 1/14 duty cycle works better than 1/16?

 

To get 1/14 duty cycle timer period has to be 7 cycles. The following should get you what you want:

        mva #3 skctl
        mva #$7e audctl

        ldx #2
        lda #0
        sta audf2
        sta audf4
        sta audf1
        stx audf3
        sta stimer
        sta audf3

Edited July 1, 2018 by antrykot

[mono]

@antrykot: Thanks for reminder. I fixed previous car images (didn't recalculate checksums):

- lower_16 - channel 1 controlled by 3,

- upper_16 - channel 2 controlled by 4

and created new for 1/14 PDM:

- lower_14 - channel 1 controlled by 3,

- upper_14 - channel 2 controlled by 4.

Edited July 1, 2018 by mono

[phaeron]

 

Wasn't it experimentally established that 1/14 duty cycle works better than 1/16?

 

To get 1/14 duty cycle timer period has to be 7 cycles.

 

 

1/7 vs. 1/8, not 1/14 vs. 1/16. The output channel is in toggle mode but with the high pass there is only a pulse at each transition; there is no divide by two effect.

 

There is not a big difference between 7 cycles and 8 cycles. It looks a little cleaner on the scope, but that could either be due to noise or a slightly uneven duty cycle. In practice I can't hear a difference between the two.

[antrykot]

But I wasn't talking about divide by two. The pulse is half a cycle wide, 0.5/7 is 1/14.

[Matej]

Can some kind of PCMtracker be done???

[emkay]

Can some kind of PCMtracker be done???

As you have to divide the CPU speed by every used channel, it possibly will not be funny to listen to all the side noise.

IF every channel could use a separate sampling rate, directly depending on the played frequency, the side noise may act as a character sound type of the played instrument. Just like the sampling noise of many MODs on the Amiga have this. It is disturbing the listening fun in some cases, but it doesn't interfere with the music.

 

I'm still pondering about a PCF Version of anything for the Atari.

OK PFC is just a term created by me. It means Pulse Code Forming, wich would be using the "3.4MHz" feature of POKEY, for forming resulting waves at that speed, using the generators, not only the volume. The possibilities had to be checked, then a program for pre-calculating the needed data on the PC had to be written. Then throw the data at that row to the POKEY registers for playback.

You know, POKEY can do a lot of wave forms, up and down, forward and backward sawtooth... using that at a high sampling frequency, the resulting waves would be not the same, but very close .

Edited July 5, 2018 by emkay

[Poison]

is possible to add into FUjiconverter Batch conversion ?

[+skr]

Playing back on the!cart

 

...having trouble uploading the video, will try again tomorrow.

Edited July 27, 2018 by skr

[+skr]

Heres the video.

1D5400E2-E076-49EE-8EC9-4A65090C28BC.MOV

[Rybags]

Can't tell what it is, way too much background noise.

[+skr]

Can't tell what it is, way too much background noise.

That´s the downside of a meeting with like 60 Atarians.

[Mclaneinc]

Does that video prove or disprove the flat earth theory?

 

Or SKR's house is on a slant?

[Mathy]

Hello Paul

 

The video was shot at the Fujiama 2018 in Lengenfeld, Germany.

 

But you guys are lucky. When you listen to the sound from the video, you only hear the noise IN the video. Those of us at the Fujiama not only hear the noise from the video, but also the noise around us. That's twice the noise you hear!

 

 

Sincerely

 

Mathy

[+skr]

Does that video prove or disprove the flat earth theory?

 

Or SKR's house is on a slant?

It simply proves, that the!cart also plays fujiconverted files on real hardware. Not more, not less. And my house is a few hundred kilometers away from where the video was shot.

[Mclaneinc]

Ha ha...Oh well at least the usual dislike of on the side non widescreen video's has not hit here yet..

 

I'm so used to seeing people being chewed on for not having adjusted the video or used a phone on the side to film groups etc, refreshing...Hence the er joke...that died...very quickly......(quicker than that Norwegian Blue parrot I use so often in my humour)

 

Cue FJC........

[Mclaneinc]

Hello Paul

 

The video was shot at the Fujiama 2018 in Lengenfeld, Germany.

 

But you guys are lucky. When you listen to the sound from the video, you only hear the noise IN the video. Those of us at the Fujiama not only hear the noise from the video, but also the noise around us. That's twice the noise you hear!

 

 

Sincerely

 

Mathy

 

Sounds like there's a baying pack of people there, too much beer?

[Mathy]

Hello Paul

 

No. Just having fun. Some drink beer, some drink water, some drink soft drinks.

 

Sincerely

 

Mathy (who just posted some bad quality pictures (it's fairly dark inside, with lots of monitors putting out lots of light) in the Fujiama 2018 thread.)

[Mathy]

Hello guys

 

Most of the people are outside for the BBQ, so I toke advantage of the situation to shoot this video:

 

IMG_1127.MOV

 

I'm using the Ultimate Cartridge, so I can only make 15 second files, but with stereo sound. Sound quality can vary, depending on the song/mp3 you convert (don't know why) but this one is very good.

 

Sincerely

 

Mathy

Edited July 28, 2018 by Mathy

[flashjazzcat]

Oh well at least the usual dislike of on the side non widescreen video's has not hit here yet..

It's here... just not vocalised. It's known as Vertical Video Syndrome. It seems that portrait mode video is acknowledged as a "thing" now, and watching - on a 16:9 display - 9:16 portrait mode footage of another 16:9 monitor seems in no way awkward or contrived.

[Mclaneinc]

Good god, it has a name...Jeebs...

 

What is wrong with people...

 

Sure I like a WS film on my WS TV but on a phone I'm not expecting Steven Bloody Spielberg to organise the photography...

 

My rules for a photo: I can tell what it is I'm looking at....end of..

 

Oh, 2, and its not of me

[+CharlieChaplin]

Hello guys

 

Most of the people are outside for the BBQ, so I toke advantage of the situation to shoot this video:

 

IMG_1127.MOV

 

I'm using the Ultimate Cartridge, so I can only make 15 second files, but with stereo sound. Sound quality can vary, depending on the song/mp3 you convert (don't know why) but this one is very good.

 

Sincerely

 

Mathy

 

What makes me wonder, the 1MB cart images do sound really good and have low or no (white) noise, whereas all of my WAV and MP3 conversions for the PDM player do have medium or high (white) noise. Songs that are quite silent (or soft) have a lot of noise, songs that are quite loud have less noise. So I tried to turn up the volume in the original MP3 or WAV and did convert with volume increase of 1.5 or 2.0, alas it did not help and the noise is still very high.

 

Even more strange is that some of the 1MB cart images play soft/silent music and still do not have any noise, while e.g. "My immortal" by Evanescence (which is mostly soft/silent) when converted is so full of noise, it is almost unrecognizable. Last not least, the PDM player plays in mono only, but listening to 22khz (converted to stereo, but played back in mono) and 44khz (mono) conversions seems to me as if there is no difference (amount of noise seems to be the same, file length in megabytes/kilobytes/bytes is absolutely the same, etc.)... shouldn't there be a difference between mono and stereo 44khz vs. 22khz (regarding noise or file length) ?!? Or am I doing / configuring something wrong in the Fuji converter ?!?

 

My usual setup for Fuji Convert is this: playback method: PCM 4+4, Channels: mono (44khz) or stereo (22khz), region: PAL, frequency: 44khz or 22khz (adjusts automatically to 44khz for mono and 22khz for stereo), Gain: 1.5 (or 2.0), Offset: 0, Duration: -1, Dither unmarked/not tagged, output Media: IDE player (FJC), max size 32M;

Edited July 28, 2018 by CharlieChaplin

[flashjazzcat]

Sure I like a WS film on my WS TV but on a phone I'm not expecting Steven Bloody Spielberg to organise the photography...

I'm not sure what kind of handset requires the assistance of a blockbuster Hollywood director to rotate through 90 degrees in the user's hands. Slight exaggeration there. But no matter: you broached the subject, and now you have a response.

[Mclaneinc]

Pah, Mr Logic strikes again...

 

Sure you were not up for the role of Spock

[+CharlieChaplin]

Here is a video of M.I. by E. converted with Fuji Convert by me into a (alas, extremely noisy) PDM file, intentionally shortened, so the record companies cannot complain. Is the amount of noise normal for a PDM (PCM 4+4) file ?!? Or did I choose wrong settings in Fuji Convert ?

 

M_I_as_PDM_file.zip

 

video container: AVI with MPEG4 / XVID

 

 

[Xuel]

Here is a video of M.I. by E. converted with Fuji Convert by me into a (alas, extremely noisy) PDM file, intentionally shortened, so the record companies cannot complain. Is the amount of noise normal for a PDM (PCM 4+4) file ?!? Or did I choose wrong settings in Fuji Convert ?

 

M_I_as_PDM_file.zip

 

video container: AVI with MPEG4 / XVID

I suspect two things are happening for soft clear tones like this: 1) 8-bits is not enough dynamic range and 2) The imperfections of PDM are accentuated.

 

Even Covox has some noise. Compare these stereo conversions:

 

imm-trim pcm4+4 stereo 31200Hz atarimax pal.zip

imm-trim covox stereo 31200Hz atarimax pal.zip