tsvm mov encoder and decoder

assets/disk0/decodemov.js

@@ -0,0 +1,54 @@
+
+let filename = exec_args[1]
+const FBUF_SIZE = 560*448
+
+let status = filesystem.open("A", filename, "R")
+if (status) return status
+
+println("Reading...")
+
+let bytes = filesystem.readAllBytes("A")
+
+con.clear()
+
+let readCount = 0
+
+function readBytes(length) {
+    let ret = new Int8Array(length)
+    for (let k = 0; k < length; k++) {
+        ret[k] = bytes[readCount]
+        readCount += 1
+    }
+    return ret
+}
+
+function readInt() {
+    let b = readBytes(4)
+    return (b[0] & 255) | ((b[1] & 255) << 8) | ((b[2] & 255) << 16) | ((b[3] & 255) << 24)
+}
+
+function readShort() {
+    let b = readBytes(2)
+    return (b[0] & 255) | ((b[1] & 255) << 8)
+}
+
+
+let magic = readBytes(8)
+
+if (String.fromCharCode.apply(null, magic) != '\x1fTSVMMOV') return 1
+
+let width = readShort()
+let height = readShort()
+let fps = readShort()
+let frameCount = readInt() % 16777216
+
+let fbuf = sys.malloc(FBUF_SIZE)
+
+for (let f = 0; f < frameCount; f++) {
+    let payloadLen = readInt()
+    let gzipped = readBytes(payloadLen)
+    gzip.decompTo(gzipped, fbuf)
+    dma.ramToFrame(fbuf, 0, FBUF_SIZE)
+}
+
+sys.free(fbuf)

assets/disk0/encodemov.js

@@ -0,0 +1,64 @@
+
+const FBUF_SIZE = 560*448
+let infile = sys.malloc(120000) // somewhat arbitrary
+let imagearea = sys.malloc(FBUF_SIZE*3)
+let decodearea = sys.malloc(FBUF_SIZE)
+let gzippedImage = sys.malloc(180000) // somewhat arbitrary
+
+let outfilename = exec_args[1]
+
+if (!outfilename) return 1
+
+function appendToOutfile(bytes) {
+    filesystem.open("A", outfilename, "A")
+    filesystem.writeBytes("A", bytes)
+}
+
+function appendToOutfilePtr(ptr, len) {
+    filesystem.open("A", outfilename, "A")
+    dma.ramToCom(ptr, 0, len)
+}
+
+// write header to the file
+let headerBytes = [
+    0x1F, 0x54, 0x53, 0x56, 0x4D, 0x4D, 0x4F, 0x56,
+    0x30, 0x02,
+    0xC0, 0x01,
+    0x1E, 0x00,
+    0x34, 0x00, 0x00, 0x7C
+]
+
+filesystem.open("A", outfilename, "W")
+filesystem.writeBytes("A", headerBytes)
+
+for (let f = 1; f <=52; f++) {
+    let fname = `/movtestimg/${(''+f).padStart(3,'0')}.jpg`
+    filesystem.open("A", fname, "R")
+    let fileLen = filesystem.getFileLen("A")
+    dma.comToRam(0, 0, infile, fileLen)
+
+    graphics.decodeImageTo(infile, fileLen, imagearea)
+
+    print(`Encoding frame ${f}...`)
+
+    graphics.imageToDisplayableFormat(imagearea, decodearea, 560, 448, 3, 1)
+
+    let gzlen = gzip.compFromTo(decodearea, FBUF_SIZE, gzippedImage)
+
+    let frameSize = [
+        (gzlen >>> 0) & 255,
+        (gzlen >>> 8) & 255,
+        (gzlen >>> 16) & 255,
+        (gzlen >>> 24) & 255
+    ]
+
+    appendToOutfile(frameSize)
+    appendToOutfilePtr(gzippedImage, gzlen)
+
+    print(` ${gzlen} bytes\n`)
+}
+
+sys.free(infile)
+sys.free(imagearea)
+sys.free(decodearea)
+sys.free(gzippedImage)

assets/disk0/tvdos/TVDOS.SYS

@@ -141,7 +141,7 @@ filesystem.write = (driveLetter, string) => {
     filesystem._flush(port[0]); filesystem._close(port[0]);
 };
 filesystem.writeBytes = (driveLetter, bytes) => {
-    var string = String.fromCharCode(...bytes);
+    var string = String.fromCharCode.apply(null, bytes); // no spreading: has length limit
     filesystem.write(driveLetter, string);
 };
 filesystem.isDirectory = (driveLetter) => {