/* TSVM Interchangeable Picture Format Image is divided into 4x4 blocks and each block is serialised, then the entire file is gzipped # File Structure \x1F T S V M i P F [HEADER] [Blocks.gz] - Header uint16 WIDTH uint16 HEIGHT uint16 HAS ALPHA uint8 0 (IPF CONFIG INDICATOR) byte[9] RESERVED - *.gz uint32 UNCOMPRESSED SIZE * PAYLOAD - Blocks 4x4 pixels are sampled, then divided into YCoCg planes. CoCg planes are "chroma subsampled" by 4:2:0, then quantised to 4 bits (8 bits for CoCg combined) Y plane is quantised to 4 bits By doing so, CoCg planes will reduce to 4 pixels For the description of packing, pixels in Y plane will be numbered as: 0 1 2 3 4 5 6 7 8 9 A B C D E F Bits are packed like so: uint32 SUBSAMPLING MASK (unimplemented; dont write this) uint8 [Co-Top Right | Co-Top Left] uint8 [Co-Bottom Right | Co-Bottom Left] uint8 [Cg-Top Right | Cg-Top Left] uint8 [Cg-Bottom Right | Cg-Bottom Left] uint16 [Y1 | Y0 | Y5 | Y4] uint16 [Y3 | Y2 | Y7 | Y6] uint16 [Y9 | Y8 | YD | YC] uint16 [YB | YA | YF | YE] (total: 12 bytes) If has alpha, append following bytes for alpha values uint16 [a1 | a0 | a5 | a4] uint16 [a3 | a2 | a7 | a6] uint16 [a9 | a8 | aD | aC] uint16 [aB | aA | aF | aE] (total: 20 bytes) Subsampling mask: Least significant byte for top-left, most significant for bottom-right For example, this default pattern 00 00 01 01 00 00 01 01 10 10 11 11 10 10 11 11 turns into: 01010000 -> 0x30 01010000 -> 0x30 11111010 -> 0xFA 11111010 -> 0xFA which packs into: [ 30 | 30 | FA | FA ] (because little endian) - IPF CONFIG INDICATOR: 0 for 4:2:0 Chroma subsampling for both Co and Cg (iPF Type 1) 1 for 4:2:2 Chroma subsampling for Co, but 4:2:0 for Cg (NOT recommended; unused) 2 for 4:2:2 Chroma subsampling for Cg, but 4:2:0 for Co (Recommended over type 1; unused) 3 for 4:2:2 Chroma subsampling for both Co and Cg (iPF Type 2) */ if (!exec_args[2]) { printerrln("Usage: encodeipf input.jpg output.ipf [/noalpha]") return 1 } let configUseAlpha = !(exec_args[3] != undefined && exec_args[3].toLowerCase() == "/noalpha") let pattern = 0 filesystem.open("A", exec_args[1], "R") let status = com.getStatusCode(0) let infile = undefined if (0 != status) return status // read file let fileLen = filesystem.getFileLen("A") infile = sys.malloc(fileLen) dma.comToRam(0, 0, infile, fileLen) // decode const [imgw, imgh, channels, imageData] = graphics.decodeImage(infile, fileLen) // stored as [R | G | B | (A)] sys.free(infile) let hasAlpha = (4 == channels) && configUseAlpha let outBlock = sys.malloc(64) let blockSize = Math.ceil(imgh / 4.0) * Math.ceil(imgw / 4.0) let blockWidth = Math.ceil(imgw / 4.0) println(`Dim: ${imgw}x${imgh}, channels: ${channels}, Has alpha: ${hasAlpha}`) // TODO write output to dedicated ptr and gzip it let writeCount = 0 let writeBuf = sys.malloc(blockSize * ((hasAlpha) ? 20 : 12)) let bayerKernels = [ [ 0,8,2,10, 12,4,14,6, 3,11,1,9, 15,7,13,5, ], [ 8,2,10,0, 4,14,6,12, 11,1,9,3, 7,13,5,15, ], [ 7,13,5,15, 8,2,10,0, 4,14,6,12, 11,1,9,3, ], [ 15,7,13,5, 0,8,2,10, 12,4,14,6, 3,11,1,9, ] ].map(it => it.map(it => (it + 0.5) / 16)) function chromaToFourBits(f) { let r = Math.round(f * 8) + 7 return (r < 0) ? 0 : (r > 15) ? 15 : r } for (let blockY = 0; blockY < Math.ceil(imgh / 4.0); blockY++) { for (let blockX = 0; blockX < Math.ceil(imgw / 4.0); blockX++) { // println(`Encoding block ${1 + blockY * blockWidth + blockX}/${blockSize}`) // print statement is making things slower... let ys = new Uint8Array(16) let as = new Uint8Array(16) let cos = new Float32Array(16) let cgs = new Float32Array(16) for (let py = 0; py < 4; py++) { for (let px = 0; px < 4; px++) { // TODO oob-check let ox = blockX * 4 + px let oy = blockY * 4 + py let t = bayerKernels[pattern % bayerKernels.length][4 * (py % 4) + (px % 4)] let offset = channels * (oy * imgw + ox) let r0 = sys.peek(imageData + offset) / 255.0 let g0 = sys.peek(imageData + offset+1) / 255.0 let b0 = sys.peek(imageData + offset+2) / 255.0 let a0 = (hasAlpha) ? sys.peek(imageData + offset+3) / 255.0 : 1.0 let r = Math.floor((t / 15 + r0) * 15) / 15 let g = Math.floor((t / 15 + g0) * 15) / 15 let b = Math.floor((t / 15 + b0) * 15) / 15 let a = Math.floor((t / 15 + a0) * 15) / 15 let co = r - b // [-1..1] let tmp = b + co / 2.0 let cg = g - tmp // [-1..1] let y = tmp + cg / 2.0 // [0..1] let index = py * 4 + px ys[index] = Math.round(y * 15) as[index] = Math.round(a * 15) cos[index] = co cgs[index] = cg }} // subsample by averaging let cos1 = chromaToFourBits((cos[0]+cos[1]+cos[4]+cos[5]) / 4.0) let cos2 = chromaToFourBits((cos[2]+cos[3]+cos[6]+cos[7]) / 4.0) let cos3 = chromaToFourBits((cos[8]+cos[9]+cos[12]+cos[13]) / 4.0) let cos4 = chromaToFourBits((cos[10]+cos[11]+cos[14]+cos[15]) / 4.0) let cgs1 = chromaToFourBits((cgs[0]+cgs[1]+cgs[4]+cgs[5]) / 4.0) let cgs2 = chromaToFourBits((cgs[2]+cgs[3]+cgs[6]+cgs[7]) / 4.0) let cgs3 = chromaToFourBits((cgs[8]+cgs[9]+cgs[12]+cgs[13]) / 4.0) let cgs4 = chromaToFourBits((cgs[10]+cgs[11]+cgs[14]+cgs[15]) / 4.0) // append encoded blocks to the file let outBlock = writeBuf + writeCount sys.poke(outBlock+ 0, (cos2 << 4) | cos1) sys.poke(outBlock+ 1, (cos4 << 4) | cos3) sys.poke(outBlock+ 2, (cgs2 << 4) | cgs1) sys.poke(outBlock+ 3, (cgs4 << 4) | cgs3) sys.poke(outBlock+ 4, (ys[1] << 4) | ys[0]) sys.poke(outBlock+ 5, (ys[5] << 4) | ys[4]) sys.poke(outBlock+ 6, (ys[3] << 4) | ys[2]) sys.poke(outBlock+ 7, (ys[7] << 4) | ys[6]) sys.poke(outBlock+ 8, (ys[9] << 4) | ys[8]) sys.poke(outBlock+ 9, (ys[13] << 4) | ys[12]) sys.poke(outBlock+10, (ys[11] << 4) | ys[10]) sys.poke(outBlock+11, (ys[15] << 4) | ys[14]) if (hasAlpha) { sys.poke(outBlock+12, (as[1] << 4) | as[0]) sys.poke(outBlock+13, (as[5] << 4) | as[4]) sys.poke(outBlock+14, (as[3] << 4) | as[2]) sys.poke(outBlock+15, (as[7] << 4) | as[6]) sys.poke(outBlock+16, (as[9] << 4) | as[8]) sys.poke(outBlock+17, (as[13] << 4) | as[12]) sys.poke(outBlock+18, (as[11] << 4) | as[10]) sys.poke(outBlock+19, (as[15] << 4) | as[14]) writeCount += 8 } writeCount += 12 }} // write header to the output file let headerBytes = [ 0x1F, 0x54, 0x53, 0x56, 0x4D, 0x69, 0x50, 0x46, // magic imgw & 255, (imgw >>> 8) & 255, // width imgh & 255, (imgh >>> 8) & 255, // height ((hasAlpha) ? 1 : 0), 0x00, // has alpha, iPF type 1 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 // reserved ] filesystem.open("A", exec_args[2], "W") filesystem.writeBytes("A", headerBytes) filesystem.open("A", exec_args[2], "A") dma.ramToCom(writeBuf, 0, writeCount) sys.free(outBlock) sys.free(imageData) sys.free(writeBuf)