Makefile

@@ -34,27 +34,12 @@ never-gonna-give-you-up.wav : never-gonna-give-you-up.mp4
 	  -ar 15704 \
 	  -y $@
 
-rickroll-17s.wav.s : rickroll-17s.wav pack-vocoder.js
-	node pack-vocoder.js $< $@
-
-rickroll-17s.wav : rickroll-17s.mp4
-	ffmpeg -i "rickroll-17s.mp4" \
-	  -vn \
-	  -t 2.0 \
-	  -acodec pcm_u8 \
-	  -ac 1 \
-	  -ar 15000 \
-	  -y $@
-
 %.o : %.s
 	ca65 -v -t atari -o $@ $<
 
-rickroll.xex : rickroll.o dither4.o never-gonna-give-you-up.wav.o atari-asm-xex.cfg
+%.xex : %.o dither4.o never-gonna-give-you-up.wav.o atari-asm-xex.cfg
 	ld65 -v -C ./atari-asm-xex.cfg -o $@ dither4.o never-gonna-give-you-up.wav.o $<
 
-vocoder.xex : rickroll.o vocoder.o rickroll-17s.wav.o atari-asm-xex.cfg
-	ld65 -v -C ./atari-asm-xex.cfg -o $@ vocoder.o rickroll-17s.wav.o $<
-
 clean :
 	rm -f *.o
 	rm -f *.s.png

dither-image.js

@@ -79,19 +79,8 @@ class RGB {
         let lm = val & 15;
         let crlv = cr ? 50 : 0;
 
-        let phase = ((cr - 1) * 25 - 33) * (2 * Math.PI / 360);
-
-        let y = 255 * (lm + 1) / 16;
-        let i = crlv * Math.cos(phase);
-        let q = crlv * Math.sin(phase);
-
-        let r = y + 0.956 * i + 0.621 * q;
-        let g = y - 0.272 * i - 0.647 * q;
-        let b = y - 1.107 * i + 1.704 * q;
-
         /*
-        // PAL
+        let phase = ((cr - 1) * 25 - 58) * (2 * Math.PI / 360);
-        let phase = ((cr - 1) * 25.7 - 15) * (2 * Math.PI / 360);
 
         let y = 255 * (lm + 1) / 16;
         let i = crlv * Math.cos(phase);
@@ -102,7 +91,18 @@ class RGB {
         let b = y - 1.107 * i + 1.704 * q;
         */
 
-        return new RGB(r, g, b).clamp().fromNTSC();
+        // PAL
+        let phase = ((cr - 1) * 25.7 - 15) * (2 * Math.PI / 360);
+
+        let y = 255 * (lm + 1) / 16;
+        let i = crlv * Math.cos(phase);
+        let q = crlv * Math.sin(phase);
+
+        let r = y + 0.956 * i + 0.621 * q;
+        let g = y - 0.272 * i - 0.647 * q;
+        let b = y - 1.107 * i + 1.704 * q;
+
+        return new RGB(r, g, b).clamp().fromSRGB();
     }
 
     map(callback) {
@@ -1004,9 +1004,11 @@ ${byte2byte(odd(frame.palette3))}
 .align 1024
 displaylist:
     ; 24 lines overscan
-    .repeat 3
+    .repeat 2
         .byte $70 ; 8 blank lines
     .endrep
+    ; include a DLI to mark us as frame 0
+    .byte $f0 ; 8 blank lines
 
     ; ${height} lines graphics
     ; ANTIC mode e (160px 2bpp, 1 scan line per line)

dither4.s

@@ -27,6 +27,7 @@ sample_ptrh = $85
 sample_ptr = sample_ptrl
 scanline = $86
 audiotemp = $87
+frame_counter = $89
 
 ;height = 160
 height = 192
@@ -65,7 +66,6 @@ audio_high_byte:
         byteseq $3
         byteseq $4
         byteseq $5
-        byteseq $6
         byteseq $7
         byteseq $8
         byteseq $9
@@ -102,6 +102,12 @@ audio_high_byte:
     lda #.hibyte(displaylist)
     sta DLISTH
 
+    ; Set up the DLI handler
+    lda #.lobyte(dli_handler)
+    sta VDSLSTL
+    lda #.hibyte(dli_handler)
+    sta VDSLSTH
+
     ; Disable VBI but allow Reset and DLI
     lda #$a0
     sta NMIEN
@@ -152,24 +158,25 @@ wait_loop:
         sta AUDC1          ; 4 cyc
     .endmacro
 
-    .macro audio_prep ; 8-9 cycles
+    .macro audio_prep
         ; Y is VCOUNT at entry
         lda (sample_ptr),y ; 5/6 cyc
         sta audiotemp      ; 3 cyc
     .endmacro
 
-    .macro audio_play_lo ; 8 cycles
+    ; call with A pre-loaded to audiotemp
-        ; A is loaded with packed audio byte at entry
+    .macro audio_play_lo
-        and #$0f       ; 2 cyc
+        ;lda audiotemp ; 3 cyc
-        ora #$10       ; 2 cyc
+        and #$0f ; 2 cyc
-        sta AUDC1      ; 4 cyc
+        ora #$10 ; 2 cyc
+        sta AUDC1 ; 4 cyc
     .endmacro
 
     ; clobbers Y
     .macro audio_play_hi ; 12 cycles
-        ldy audiotemp         ; 3 cyc
+        ldy audiotemp ; 3 cyc
         lda audio_high_byte,y ; 5 cyc
-        sta AUDC1             ; 4 cyc
+        sta AUDC1 ; 4 cyc
     .endmacro
 
     .macro audio_inc
@@ -184,12 +191,17 @@ wait_loop:
         cmp #.hibyte(audio_samples_end) ; 2 cyc
         bmi audio_cont                  ; 2 cyc
 
+        sta WSYNC
+
         ; 10 cycles, optional
         lda #.lobyte(audio_samples)     ; 2
         sta sample_ptrl                 ; 3
         lda #.hibyte(audio_samples)     ; 2
         sta sample_ptrh                 ; 3
 
+        sta WSYNC
+        ldy VCOUNT             ; 4 cycles
+
         audio_cont:
     .endmacro
 
@@ -203,22 +215,26 @@ wait_loop:
         sty scanline ; 3 cycles
         inner_scanline frame_offset, 0 ; 23-26 cycles before break, 12 cycles after
 
-        ldy scanline  ; 3 cycles
+        ldy scanline ; 3 cycles
-        audio_prep    ; 8-9 cycles
+        audio_prep
-        audio_play_lo ; 8 cycles
+        audio_play_lo
 
         ldy scanline   ; 3 cycles
         inner_scanline frame_offset, 128 ; 23-26 cycles before break, 12 cycles after
 
-        audio_play_hi  ; 12 cycles
+        audio_play_hi
 
+        ; pair cleanup: 6 cycles
         ldy VCOUNT             ; 4 cycles
         bne each_scanline_pair ; 2 cycles
 
-        ; Do bookkeeping during vblank!
         audio_inc      ; 22-32 cycles
-        ;ldy VCOUNT             ; 4 cycles
 
+        ; frame cleanup: 11 cycles
+        lda frame_counter ; 3 cycles
+        eor #1            ; 2 cycles
+        sta frame_counter ; 3 cycles
+        ;jmp wait_start    ; 3 cycles
         jmp each_frame    ; 3 cycles
     .endscope
     .endmacro
@@ -228,3 +244,10 @@ run_frame1:
     run_frame 0
 
 .endproc
+
+
+.proc dli_handler
+    lda #0
+    sta frame_counter
+    rti
+.endproc

pack-vocoder.js

@@ -1,102 +0,0 @@
-import wavefile from 'wavefile';
-let WaveFile = wavefile.WaveFile;
-
-import {default as dct} from 'dct';
-
-const sampleRate = 15000;
-let frameRate = 60;
-let samplesPerFrame = sampleRate / frameRate;
-
-import {
-    readFileSync,
-    writeFileSync
-} from 'fs';
-
-function audio2voices(samples) {
-    let voices = [];
-
-    let floatSamples = samples.map((byte) => ((byte / 256) - 0.5) * 2);
-    let transformed = dct(floatSamples);
-    console.log('audio2voices');
-    console.log(floatSamples);
-    console.log(transformed);
-    //throw new Error('xxxxx');
-
-    let freqs = transformed.map((_f, i) => i * frameRate);
-
-    let bands = new Float64Array(256);
-    for (let i = 0; i < transformed.length; i++) {
-        let amplitude = transformed[i];
-        let freq = freqs[i];
-        if (freq == 0) {
-            continue;
-        }
-        let divisor = Math.floor(sampleRate / freq) - 1;
-        if (divisor > 255) {
-            continue;
-        }
-        bands[divisor] += amplitude;
-    }
-    console.log(bands);
-
-    for (let i = 0; i < 4; i++) {
-        let divisor = 0;
-        let max = 0;
-        for (let j = 0; j < bands.length; j++) {
-            if (bands[j] > max) {
-                divisor = j;
-                max = bands[j];
-            }
-        }
-        let amplitude16 = Math.floor(max * 7) + 8;
-        voices.push(divisor, amplitude16);
-    }
-    return voices;
-}
-
-function byte2byte(arr) {
-    let lines = [];
-    for (let i=0; i < arr.length; i++) {
-        lines.push(`.byte ${arr[i]}`);
-    }
-    return lines.join('\n');
-}
-
-function output2assembly(output) {
-    return `
-.segment "AUDIO"
-
-    .export audio_samples
-    .export audio_samples_end
-
-audio_samples:
-    ${byte2byte(output)}
-audio_samples_end:
-    .byte 24
-
-`;
-}
-
-function wav2assembly(buffer) {
-    let wav = new WaveFile(buffer);
-    let samples = wav.getSamples();
-    let seconds = samples.length / sampleRate;
-    let frames = Math.floor(seconds * frameRate);
-
-    let output = [];
-    for (let i = 0; i < frames * samplesPerFrame; i += samplesPerFrame) {
-        let voices = audio2voices(samples.slice(i, i + samplesPerFrame));
-        output.push(...voices);
-    }
-
-    console.log(output);
-    return output2assembly(output);
-}
-
-let infile = process.argv[2];
-let outfile = process.argv[3];
-
-let buffer = readFileSync(infile);
-let asm = wav2assembly(buffer);
-writeFileSync(outfile, asm, 'utf-8');
-

pack-wav.js

@@ -20,7 +20,7 @@ class Dither {
     }
 
     to4bit(val8) {
-        let val = (val8 / 255) + this.err;
+        let val = (val8 / 255) - this.err;
         if (val < 0) {
             val = 0;
         }
@@ -29,7 +29,7 @@ class Dither {
         }
         let val4 = Math.round(val * 15);
         let dithered = (val4 / 15);
-        this.err = (val - dithered);
+        this.err = (dithered - val);
         return val4;
     }
 }

package-lock.json

@@ -10,7 +10,6 @@
         "wavefile": "^11.0.0"
       },
       "devDependencies": {
-        "dct": "^0.1.0",
         "eslint": "^8.36.0"
       }
     },
@@ -815,16 +814,6 @@
         "node": ">= 8"
       }
     },
-    "node_modules/dct": {
-      "version": "0.1.0",
-      "resolved": "https://registry.npmjs.org/dct/-/dct-0.1.0.tgz",
-      "integrity": "sha512-/uUtEniuMq1aUxvLAoDtAduyl12oM1zhA/le2f83UFN/9+4KDHXFB6znEfoj5SDDLiTpUTr26NpxC7t8IFOYhQ==",
-      "dev": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">=0.12.0"
-      }
-    },
     "node_modules/debug": {
       "version": "4.3.4",
       "resolved": "https://registry.npmjs.org/debug/-/debug-4.3.4.tgz",
@@ -2614,12 +2603,6 @@
         "which": "^2.0.1"
       }
     },
-    "dct": {
-      "version": "0.1.0",
-      "resolved": "https://registry.npmjs.org/dct/-/dct-0.1.0.tgz",
-      "integrity": "sha512-/uUtEniuMq1aUxvLAoDtAduyl12oM1zhA/le2f83UFN/9+4KDHXFB6znEfoj5SDDLiTpUTr26NpxC7t8IFOYhQ==",
-      "dev": true
-    },
     "debug": {
       "version": "4.3.4",
       "resolved": "https://registry.npmjs.org/debug/-/debug-4.3.4.tgz",

package.json

@@ -6,7 +6,6 @@
     "wavefile": "^11.0.0"
   },
   "devDependencies": {
-    "dct": "^0.1.0",
     "eslint": "^8.36.0"
   }
 }

vocoder.s

@@ -1,230 +0,0 @@
-SAVMSC = $58
-VDSLST = $200
-VDSLSTL = $200
-VDSLSTH = $201
-COLPF0 = $D016
-COLPF1 = $D017
-COLPF2 = $D018
-COLPF3 = $D019
-COLBK = $D01A
-
-AUDC1 = $D201
-DMACTL = $D400
-DLISTL = $D402
-DLISTH = $D403
-WSYNC = $D40A
-VCOUNT = $D40B
-NMIEN = $D40E
-
-temp1l = $80
-temp1h = $81
-temp1 = temp1l
-temp2l = $82
-temp2h = $83
-temp2 = temp2l
-sample_ptrl = $84
-sample_ptrh = $85
-sample_ptr = sample_ptrl
-scanline = $86
-audiotemp = $87
-
-;height = 160
-height = 192
-bytes_per_line = 40
-pages_per_frame = 32
-lines_per_frame = 262
-;scanline_offset = 31 + (40 - 24) / 2
-scanline_offset = 30
-scanline_max = (lines_per_frame - scanline_offset) / 2
-
-.data
-
-.import audio_samples
-.import audio_samples_end
-
-.import frame1_top
-.import frame1_bottom
-.import frame1_palette1_even
-.import frame1_palette1_odd
-.import frame1_palette2_even
-.import frame1_palette2_odd
-.import frame1_palette3_even
-.import frame1_palette3_odd
-.import displaylist
-
-audio_high_byte:
-    .scope
-        .macro byteseq val
-            .repeat 16
-                .byte val | $10
-            .endrep
-        .endmacro
-        byteseq $0
-        byteseq $1
-        byteseq $2
-        byteseq $3
-        byteseq $4
-        byteseq $5
-        byteseq $6
-        byteseq $7
-        byteseq $8
-        byteseq $9
-        byteseq $a
-        byteseq $b
-        byteseq $c
-        byteseq $d
-        byteseq $e
-        byteseq $f
-    .endscope
-
-.code
-
-.export start
-
-.proc start
-    ; Set up the audio sample buffer
-    lda #.lobyte(audio_samples)
-    sta sample_ptrl
-    lda #.hibyte(audio_samples)
-    sta sample_ptrh
-
-    ; Disable display DMA
-    lda #$00
-    sta DMACTL
-
-    ; Disable VBI and DLI but allow Reset
-    lda #$20
-    sta NMIEN
-
-    ; Set up the display list
-    lda #.lobyte(displaylist)
-    sta DLISTL
-    lda #.hibyte(displaylist)
-    sta DLISTH
-
-    ; Disable VBI but allow Reset and DLI
-    lda #$a0
-    sta NMIEN
-
-    ; Manually wait for first scan line
-wait_vblank:
-    sta WSYNC
-    lda VCOUNT
-    bne wait_vblank
-
-    ; Re-enable display DMA
-    lda #$22
-    sta DMACTL
-
-wait_start:
-    ; Wait for the vblank
-    ; Resynchronize the scanline counter
-wait_loop:
-    ldy VCOUNT    ; 4 cycles
-    bne wait_loop ; 2 cycles
-
-    .macro inner_scanline frame_offset, line_offset
-        ; Y should be VCOUNT at entry
-        ; it'll fire on unused lines, but harmlessly
-
-        ; 23-26 cycles before break
-        ; Leisurely memory fetches
-        lda frame1_palette1_even + frame_offset + line_offset - scanline_offset / 2,y ; 4/5 @FIXME alternate
-        pha                                                                           ; 3
-        ldx frame1_palette2_even + frame_offset + line_offset - scanline_offset / 2,y ; 4/5
-        lda frame1_palette3_even + frame_offset + line_offset - scanline_offset / 2,y ; 4/5
-        tay                                                                           ; 2
-        pla                                                                           ; 3
-
-        ; Wait for horizontal blank
-        sta WSYNC                                                                     ; 4
-
-        ; 12 cycles after break
-        ; Update color registers as fast as possible
-        sta COLPF0 ; 4
-        stx COLPF1 ; 4
-        sty COLPF2 ; 4
-    .endmacro
-
-    .macro audio_play_raw
-        ;ldy VCOUNT ; set on entry
-        lda (sample_ptr),y ; 5/6 cyc
-        sta AUDC1          ; 4 cyc
-    .endmacro
-
-    .macro audio_prep ; 8-9 cycles
-        ; Y is VCOUNT at entry
-        lda (sample_ptr),y ; 5/6 cyc
-        sta audiotemp      ; 3 cyc
-    .endmacro
-
-    .macro audio_play_lo ; 8 cycles
-        ; A is loaded with packed audio byte at entry
-        and #$0f       ; 2 cyc
-        ora #$10       ; 2 cyc
-        sta AUDC1      ; 4 cyc
-    .endmacro
-
-    ; clobbers Y
-    .macro audio_play_hi ; 12 cycles
-        ldy audiotemp         ; 3 cyc
-        lda audio_high_byte,y ; 5 cyc
-        sta AUDC1             ; 4 cyc
-    .endmacro
-
-    .macro audio_inc
-        ; 22 cycles
-        lda sample_ptrl ; 3 cyc
-        clc             ; 2 cyc
-        adc #131        ; 2 cyc
-        sta sample_ptrl ; 3 cyc
-        lda sample_ptrh ; 3 cyc
-        adc #0          ; 2 cyc
-        sta sample_ptrh ; 3 cyc
-        cmp #.hibyte(audio_samples_end) ; 2 cyc
-        bmi audio_cont                  ; 2 cyc
-
-        ; 10 cycles, optional
-        lda #.lobyte(audio_samples)     ; 2
-        sta sample_ptrl                 ; 3
-        lda #.hibyte(audio_samples)     ; 2
-        sta sample_ptrh                 ; 3
-
-        audio_cont:
-    .endmacro
-
-    .macro run_frame frame_offset
-    .scope
-        ; each scanline is 228 color clocks
-        ; that's 114 CPU cycles
-        ; minus 41-43 for DMA leaves 71-73 clock cycles per line
-
-    each_scanline_pair:
-        sty scanline ; 3 cycles
-        inner_scanline frame_offset, 0 ; 23-26 cycles before break, 12 cycles after
-
-        ldy scanline  ; 3 cycles
-        audio_prep    ; 8-9 cycles
-        audio_play_lo ; 8 cycles
-
-        ldy scanline   ; 3 cycles
-        inner_scanline frame_offset, 128 ; 23-26 cycles before break, 12 cycles after
-
-        audio_play_hi  ; 12 cycles
-
-        ldy VCOUNT             ; 4 cycles
-        bne each_scanline_pair ; 2 cycles
-
-        ; Do bookkeeping during vblank!
-        audio_inc      ; 22-32 cycles
-        ;ldy VCOUNT             ; 4 cycles
-
-        jmp each_frame    ; 3 cycles
-    .endscope
-    .endmacro
-
-each_frame:
-run_frame1:
-    run_frame 0
-
-.endproc