ultrawidify/js/modules/ArDetect.js

252 lines
8.1 KiB
JavaScript

if(Debug.debug)
console.log("Loading: ArDetect");
// global-ish variables
var _ard_oldAr;
var _arSetup = function(){
var vid = document.getElementsByTagName("video")[0];
if(vid === undefined){
setTimeout(_arSetup, 1000);
return;
}
var canvas = document.createElement("canvas");
canvas.style.position = "absolute";
//todo: change those values to push canvas off-screen
canvas.style.top = "1080px";
canvas.style.zIndex = 10000;
// var test = document.getElementsByClassName("content style-scope ytd-video-secondary-info-renderer")[0]
var test = document.getElementsByTagName("body")[0];
test.appendChild(canvas);
console.log("test: ", test, "vid: ", vid, "canvas: ", canvas);
// vid.append(canvas);
var context = canvas.getContext("2d");
// do setup once
// tho we could do it for every frame
var canvasScaleFactor = 1280 / vid.videoWidth;
var canvasWidth = vid.videoWidth * canvasScaleFactor;
var canvasHeight = vid.videoHeight * canvasScaleFactor;
canvas.width = canvasWidth;
canvas.height = canvasHeight;
// init oldAr to physical <video> aspect ratio
_ard_oldAr = vid.videoWidth / vid.videoHeight;
_ard_vdraw(vid, context, canvasWidth, canvasHeight, false);
};
var _ard_processAr = function(video, width, height, edge_h, edge_w){
// width, height —> canvas/sample
//edge_w -—> null/undefined, because we don't autocorrect pillarbox yet
var actualAr = video.videoWidth / video.videoHeight;
var sampleAr = width / height;
// normalize width/height
var letterbox = 2 * edge_h;
var trueHeight = height - letterbox;
var trueAr = width / trueHeight;
if(Debug.debug){
console.log("ArDetect::_ard_last_ar() -> physical ar of video is", actualAr, "but true aspect ratio is", trueAr);
}
// poglejmo, če se je razmerje stranic spremenilo
// check if aspect ratio is changed:
var arDiff = trueAr - _ard_oldAr;
if (arDiff < 0)
arDiff = -arDiff;
// ali je sprememba v mejah dovoljenega? Če da -> fertik
// is ar variance within acceptable levels? If yes -> we done
if (arDiff < trueAr * Settings.arDetect.allowedVariance)
return;
// če je sprememba več od dovoljenega, spremeni razmerje stranic. Stvari se razlikujejo glede na to, ali smo v fullscreen ali ne
// if change is greater than allowed, change the aspect ratio. Whether we do that depends on whether we're in fullscreen.
if( FullScreenDetect.isFullScreen() ){
if(Debug.debug)
console.log("[ArDetect::_ard_processAr] attempting to fix aspect ratio.");
// _ard_oldAr = trueAr;
Resizer.setAr_fs(trueAr);
}
}
var _ard_vdraw = function (vid, context, w, h, conf){
var blackbar_tresh = 10; // how non-black can the bar be
var how_far_treshold = 8; // how much can the edge pixel vary (*4)
var msec_pause = 333; // how long is the pause between two executions — 33ms ~ 30fps
if(vid === undefined || vid.paused || vid.ended){
// we slow down if paused, no detection
setTimeout(_ard_vdraw, 3000, vid, context, w, h);
return false;
}
context.drawImage(vid, 0,0, w, h);
// "random" columns — todo: randomly pick about 10 of those
var rc = [ 4, 9, 42, 69 ];
var cimg = [];
var cols = [];
for(var i = 0; i < rc.length; i++){
//where-x, where-y, how wide, how tall
//random col, first y, 1 pix wide, all pixels tall
cols[i] = context.getImageData(rc[i], 0, 1, h).data;
}
// fast test to see if video is full screen
isLetter=true;
for(var i in cols){
// if any of those points fails this check, we aren't letterboxed
isLetter &= (cols[i][4] <= blackbar_tresh && cols[i][5] <= blackbar_tresh && cols[i][6] <= blackbar_tresh);
// should also check bottom
}
console.log("letterbox " + (isLetter?"potentially detected, making further tests":"not detected (there's pixels on upper edge!)"));
if(!isLetter){
setTimeout(_ard_vdraw, msec_pause, vid, context, w, h); //no letterbox, no problem
return;
}
// let's do a quick test to see if we're on a black frame
// let's also pick all points in advance (assuming canvas will always be 1280x720)
var blackPoints = 0;
var blackPointsMax = cols.length * 8; // 8 we sample each col at 8 different places
for(var i in cols){ // 360
if( cols[i][0] < blackbar_tresh && cols[i][2] < blackbar_tresh && cols[i][1] < blackbar_tresh )
blackPoints++;
if( cols[i][360] < blackbar_tresh && cols[i][361] < blackbar_tresh && cols[i][362] < blackbar_tresh )
blackPoints++;
if( cols[i][720] < blackbar_tresh && cols[i][721] < blackbar_tresh && cols[i][722] < blackbar_tresh )
blackPoints++;
if( cols[i][1080] < blackbar_tresh && cols[i][1081] < blackbar_tresh && cols[i][1082] < blackbar_tresh )
blackPoints++;
if( cols[i][1440] < blackbar_tresh && cols[i][1441] < blackbar_tresh && cols[i][1442] < blackbar_tresh )
blackPoints++;
if( cols[i][1800] < blackbar_tresh && cols[i][1801] < blackbar_tresh && cols[i][1802] < blackbar_tresh )
blackPoints++;
if( cols[i][2160] < blackbar_tresh && cols[i][2162] < blackbar_tresh && cols[i][2163] < blackbar_tresh )
blackPoints++;
if( cols[i][2876] < blackbar_tresh && cols[i][2877] < blackbar_tresh && cols[i][2878] < blackbar_tresh )
blackPoints++;
}
if(blackPoints > (blackPointsMax >> 1) ){
// if more than half of those points are black, we consider the entire frame black (or too dark to get anything useful
// out of it, anyway)
console.log("ArDetect::_vdraw() -> black frame detected", blackPoints, "/", blackPointsMax, "black points (", (blackPointsMax>>1), "allowed)" );
setTimeout(_ard_vdraw, msec_pause, vid, context, w, h); //no letterbox, no problem
return;
}
// let's see where black bars end
var endPixelTop = []; // where the black bar ends.
var endPixelBottom = [];
var bottomLimit = 0;
for(var i in cols){
bottomLimit = cols[i].length - 1;
// define default value for both
endPixelTop[i] = -1;
endPixelBottom[i] = -1;
// check the top pixel
var cls = cols[i].length - 4;
var cls_quarter = cls >> 2;
for(var j = 0; j < cls_quarter - 4; j += 4){
if(cols[i][j] > blackbar_tresh && cols[i][j+1] > blackbar_tresh && cols[i][j+2] > blackbar_tresh){
endPixelTop[i] = j >> 2; // equal to division by 4
break;
}
}
if(endPixelTop[i] == -1) // this means we must have a really exotic apect ratio, or the entire column is black
continue; // we'll go with a black column.
// check for bottom pixel
// cls_quarter = bottomLimit - cls_quarter;
// NOTE: this sometimes causes browser to crash, keep commented. We'll assume some basic competence by the video
// makers and assume letterbox is always vertically centered.
// for(bottomLimit -= 5; bottomLimit => cls_quarter; bottomLimit -= 4){
// if(cols[i][bottomLimit] > blackbar_tresh && cols[i][bottomLimit+1] > blackbar_tresh && cols[i][bottomLimit+2] > blackbar_tresh ){
// endPixelBottom[i] = j >> 2;
// break;
// }
// }
}
// check if black borders match; if the line isn't horizontal we could be looking at an object in
// the actual video that shouldn't be cropped out.
// TODO: disregard values with -1 in case of pillarbox
isLetter = true;
sampleLength = endPixelTop.length - 1;
letterboxThickness = endPixelTop[i]; // todo: better letterbox calculation
for(var i = 0; i < sampleLength; i++){
isLetter &= endPixelTop[i] == endPixelTop[i+1];
// isLetter &= endPixelBottom[i] == endPixelBottom[i+1];
}
if(Debug.debug || Debug.debugArDetect )
console.log("letterbox " + (isLetter?("detected — upper bar width: " + endPixelTop[0] + "px"):"cannot be confirmed — uneven edge (do nothing)"));
if(isLetter)
_ard_processAr(vid, w, h, letterboxThickness);
setTimeout(_ard_vdraw, msec_pause, vid, context, w, h);
}
var ArDetect = {
arSetup: _arSetup,
vdraw: _ard_vdraw,
arChangedCallback: function() {}
}