audiobookshelf/server/libs/fluentFfmpeg/options/videosize.js
2022-07-06 17:38:19 -05:00

292 lines
7.6 KiB
JavaScript

/*jshint node:true*/
'use strict';
/*
*! Size helpers
*/
/**
* Return filters to pad video to width*height,
*
* @param {Number} width output width
* @param {Number} height output height
* @param {Number} aspect video aspect ratio (without padding)
* @param {Number} color padding color
* @return scale/pad filters
* @private
*/
function getScalePadFilters(width, height, aspect, color) {
/*
let a be the input aspect ratio, A be the requested aspect ratio
if a > A, padding is done on top and bottom
if a < A, padding is done on left and right
*/
return [
/*
In both cases, we first have to scale the input to match the requested size.
When using computed width/height, we truncate them to multiples of 2
*/
{
filter: 'scale',
options: {
w: 'if(gt(a,' + aspect + '),' + width + ',trunc(' + height + '*a/2)*2)',
h: 'if(lt(a,' + aspect + '),' + height + ',trunc(' + width + '/a/2)*2)'
}
},
/*
Then we pad the scaled input to match the target size
(here iw and ih refer to the padding input, i.e the scaled output)
*/
{
filter: 'pad',
options: {
w: width,
h: height,
x: 'if(gt(a,' + aspect + '),0,(' + width + '-iw)/2)',
y: 'if(lt(a,' + aspect + '),0,(' + height + '-ih)/2)',
color: color
}
}
];
}
/**
* Recompute size filters
*
* @param {Object} output
* @param {String} key newly-added parameter name ('size', 'aspect' or 'pad')
* @param {String} value newly-added parameter value
* @return filter string array
* @private
*/
function createSizeFilters(output, key, value) {
// Store parameters
var data = output.sizeData = output.sizeData || {};
data[key] = value;
if (!('size' in data)) {
// No size requested, keep original size
return [];
}
// Try to match the different size string formats
var fixedSize = data.size.match(/([0-9]+)x([0-9]+)/);
var fixedWidth = data.size.match(/([0-9]+)x\?/);
var fixedHeight = data.size.match(/\?x([0-9]+)/);
var percentRatio = data.size.match(/\b([0-9]{1,3})%/);
var width, height, aspect;
if (percentRatio) {
var ratio = Number(percentRatio[1]) / 100;
return [{
filter: 'scale',
options: {
w: 'trunc(iw*' + ratio + '/2)*2',
h: 'trunc(ih*' + ratio + '/2)*2'
}
}];
} else if (fixedSize) {
// Round target size to multiples of 2
width = Math.round(Number(fixedSize[1]) / 2) * 2;
height = Math.round(Number(fixedSize[2]) / 2) * 2;
aspect = width / height;
if (data.pad) {
return getScalePadFilters(width, height, aspect, data.pad);
} else {
// No autopad requested, rescale to target size
return [{ filter: 'scale', options: { w: width, h: height }}];
}
} else if (fixedWidth || fixedHeight) {
if ('aspect' in data) {
// Specified aspect ratio
width = fixedWidth ? fixedWidth[1] : Math.round(Number(fixedHeight[1]) * data.aspect);
height = fixedHeight ? fixedHeight[1] : Math.round(Number(fixedWidth[1]) / data.aspect);
// Round to multiples of 2
width = Math.round(width / 2) * 2;
height = Math.round(height / 2) * 2;
if (data.pad) {
return getScalePadFilters(width, height, data.aspect, data.pad);
} else {
// No autopad requested, rescale to target size
return [{ filter: 'scale', options: { w: width, h: height }}];
}
} else {
// Keep input aspect ratio
if (fixedWidth) {
return [{
filter: 'scale',
options: {
w: Math.round(Number(fixedWidth[1]) / 2) * 2,
h: 'trunc(ow/a/2)*2'
}
}];
} else {
return [{
filter: 'scale',
options: {
w: 'trunc(oh*a/2)*2',
h: Math.round(Number(fixedHeight[1]) / 2) * 2
}
}];
}
}
} else {
throw new Error('Invalid size specified: ' + data.size);
}
}
/*
*! Video size-related methods
*/
module.exports = function(proto) {
/**
* Keep display aspect ratio
*
* This method is useful when converting an input with non-square pixels to an output format
* that does not support non-square pixels. It rescales the input so that the display aspect
* ratio is the same.
*
* @method FfmpegCommand#keepDAR
* @category Video size
* @aliases keepPixelAspect,keepDisplayAspect,keepDisplayAspectRatio
*
* @return FfmpegCommand
*/
proto.keepPixelAspect = // Only for compatibility, this is not about keeping _pixel_ aspect ratio
proto.keepDisplayAspect =
proto.keepDisplayAspectRatio =
proto.keepDAR = function() {
return this.videoFilters([
{
filter: 'scale',
options: {
w: 'if(gt(sar,1),iw*sar,iw)',
h: 'if(lt(sar,1),ih/sar,ih)'
}
},
{
filter: 'setsar',
options: '1'
}
]);
};
/**
* Set output size
*
* The 'size' parameter can have one of 4 forms:
* - 'X%': rescale to xx % of the original size
* - 'WxH': specify width and height
* - 'Wx?': specify width and compute height from input aspect ratio
* - '?xH': specify height and compute width from input aspect ratio
*
* Note: both dimensions will be truncated to multiples of 2.
*
* @method FfmpegCommand#size
* @category Video size
* @aliases withSize,setSize
*
* @param {String} size size string, eg. '33%', '320x240', '320x?', '?x240'
* @return FfmpegCommand
*/
proto.withSize =
proto.setSize =
proto.size = function(size) {
var filters = createSizeFilters(this._currentOutput, 'size', size);
this._currentOutput.sizeFilters.clear();
this._currentOutput.sizeFilters(filters);
return this;
};
/**
* Set output aspect ratio
*
* @method FfmpegCommand#aspect
* @category Video size
* @aliases withAspect,withAspectRatio,setAspect,setAspectRatio,aspectRatio
*
* @param {String|Number} aspect aspect ratio (number or 'X:Y' string)
* @return FfmpegCommand
*/
proto.withAspect =
proto.withAspectRatio =
proto.setAspect =
proto.setAspectRatio =
proto.aspect =
proto.aspectRatio = function(aspect) {
var a = Number(aspect);
if (isNaN(a)) {
var match = aspect.match(/^(\d+):(\d+)$/);
if (match) {
a = Number(match[1]) / Number(match[2]);
} else {
throw new Error('Invalid aspect ratio: ' + aspect);
}
}
var filters = createSizeFilters(this._currentOutput, 'aspect', a);
this._currentOutput.sizeFilters.clear();
this._currentOutput.sizeFilters(filters);
return this;
};
/**
* Enable auto-padding the output
*
* @method FfmpegCommand#autopad
* @category Video size
* @aliases applyAutopadding,applyAutoPadding,applyAutopad,applyAutoPad,withAutopadding,withAutoPadding,withAutopad,withAutoPad,autoPad
*
* @param {Boolean} [pad=true] enable/disable auto-padding
* @param {String} [color='black'] pad color
*/
proto.applyAutopadding =
proto.applyAutoPadding =
proto.applyAutopad =
proto.applyAutoPad =
proto.withAutopadding =
proto.withAutoPadding =
proto.withAutopad =
proto.withAutoPad =
proto.autoPad =
proto.autopad = function(pad, color) {
// Allow autopad(color)
if (typeof pad === 'string') {
color = pad;
pad = true;
}
// Allow autopad() and autopad(undefined, color)
if (typeof pad === 'undefined') {
pad = true;
}
var filters = createSizeFilters(this._currentOutput, 'pad', pad ? color || 'black' : false);
this._currentOutput.sizeFilters.clear();
this._currentOutput.sizeFilters(filters);
return this;
};
};