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| 1 | +import ffprobe from '@ffprobe-installer/ffprobe'; |
| 2 | +import { exec } from 'child_process'; |
| 3 | +import fs from 'fs'; |
| 4 | +import path from 'path'; |
| 5 | +import { visit } from 'unist-util-visit'; |
| 6 | +import { promisify } from 'util'; |
| 7 | + |
| 8 | +const execAsync = promisify(exec); |
| 9 | + |
| 10 | +/** |
| 11 | + * Rehype plugin to add aspect ratio preservation to video tags |
| 12 | + */ |
| 13 | +export default function rehypeVideoAspectRatio({ staticDir }) { |
| 14 | + return async (tree, file) => { |
| 15 | + const promises = []; |
| 16 | + |
| 17 | + visit(tree, 'mdxJsxFlowElement', (node) => { |
| 18 | + if (node.name === 'video') { |
| 19 | + // Find video source - check src attribute or source children |
| 20 | + let videoSrc = null; |
| 21 | + |
| 22 | + // Look for src in attributes |
| 23 | + if (node.attributes) { |
| 24 | + const srcAttr = node.attributes.find( |
| 25 | + (attr) => attr.type === 'mdxJsxAttribute' && attr.name === 'src' |
| 26 | + ); |
| 27 | + |
| 28 | + if (srcAttr) { |
| 29 | + videoSrc = srcAttr.value; |
| 30 | + } |
| 31 | + } |
| 32 | + |
| 33 | + // If no src attribute, look for source children |
| 34 | + if (!videoSrc && node.children) { |
| 35 | + const sourceNode = node.children.find( |
| 36 | + (child) => |
| 37 | + child.type === 'mdxJsxFlowElement' && child.name === 'source' |
| 38 | + ); |
| 39 | + |
| 40 | + if (sourceNode?.attributes) { |
| 41 | + const srcAttr = sourceNode.attributes.find( |
| 42 | + (attr) => attr.type === 'mdxJsxAttribute' && attr.name === 'src' |
| 43 | + ); |
| 44 | + |
| 45 | + if (srcAttr) { |
| 46 | + videoSrc = srcAttr.value; |
| 47 | + } |
| 48 | + } |
| 49 | + } |
| 50 | + |
| 51 | + const isLocalFile = |
| 52 | + videoSrc && |
| 53 | + !videoSrc.startsWith('http://') && |
| 54 | + !videoSrc.startsWith('https://') && |
| 55 | + !videoSrc.startsWith('//'); |
| 56 | + |
| 57 | + if (isLocalFile) { |
| 58 | + const videoPath = path.join( |
| 59 | + videoSrc.startsWith('/') ? file.cwd : file.dirname, |
| 60 | + staticDir, |
| 61 | + videoSrc |
| 62 | + ); |
| 63 | + |
| 64 | + if (fs.existsSync(videoPath)) { |
| 65 | + const promise = getVideoDimensions(videoPath).then((dimensions) => { |
| 66 | + if (dimensions.width && dimensions.height) { |
| 67 | + applyAspectRatio(node, dimensions.width, dimensions.height); |
| 68 | + } |
| 69 | + }); |
| 70 | + |
| 71 | + promises.push(promise); |
| 72 | + } else { |
| 73 | + throw new Error(`Video file does not exist (got ${videoPath})`); |
| 74 | + } |
| 75 | + } |
| 76 | + } |
| 77 | + }); |
| 78 | + |
| 79 | + await Promise.all(promises); |
| 80 | + }; |
| 81 | +} |
| 82 | + |
| 83 | +/** |
| 84 | + * Apply aspect ratio styles to a video node |
| 85 | + */ |
| 86 | +function applyAspectRatio(node, width, height) { |
| 87 | + const data = { |
| 88 | + estree: { |
| 89 | + type: 'Program', |
| 90 | + body: [ |
| 91 | + { |
| 92 | + type: 'ExpressionStatement', |
| 93 | + expression: { |
| 94 | + type: 'ObjectExpression', |
| 95 | + properties: [ |
| 96 | + { |
| 97 | + type: 'Property', |
| 98 | + key: { type: 'Identifier', name: 'aspectRatio' }, |
| 99 | + value: { type: 'Literal', value: width / height }, |
| 100 | + kind: 'init', |
| 101 | + }, |
| 102 | + ], |
| 103 | + }, |
| 104 | + }, |
| 105 | + ], |
| 106 | + }, |
| 107 | + }; |
| 108 | + |
| 109 | + node.attributes = node.attributes || []; |
| 110 | + |
| 111 | + let styleAttr = node.attributes?.find( |
| 112 | + (attr) => attr.type === 'mdxJsxAttribute' && attr.name === 'style' |
| 113 | + ); |
| 114 | + |
| 115 | + if (styleAttr) { |
| 116 | + const properties = |
| 117 | + styleAttr.value?.data?.estree?.body?.[0]?.expression?.properties ?? []; |
| 118 | + |
| 119 | + data.estree.body[0].expression.properties.push(...properties); |
| 120 | + } |
| 121 | + |
| 122 | + styleAttr = { |
| 123 | + type: 'mdxJsxAttribute', |
| 124 | + name: 'style', |
| 125 | + value: { |
| 126 | + type: 'mdxJsxAttributeValueExpression', |
| 127 | + data, |
| 128 | + }, |
| 129 | + }; |
| 130 | + |
| 131 | + const existingIndex = node.attributes.findIndex( |
| 132 | + (attr) => attr.type === 'mdxJsxAttribute' && attr.name === 'style' |
| 133 | + ); |
| 134 | + |
| 135 | + if (existingIndex !== -1) { |
| 136 | + node.attributes[existingIndex] = styleAttr; |
| 137 | + } else { |
| 138 | + node.attributes.push(styleAttr); |
| 139 | + } |
| 140 | +} |
| 141 | + |
| 142 | +/** |
| 143 | + * Get video dimensions using ffprobe |
| 144 | + */ |
| 145 | +async function getVideoDimensions(filePath) { |
| 146 | + const { stdout } = await execAsync( |
| 147 | + `${ffprobe.path} -v error -of flat=s=_ -select_streams v:0 -show_entries stream=height,width "${filePath}"` |
| 148 | + ); |
| 149 | + |
| 150 | + const lines = stdout.trim().split('\n'); |
| 151 | + const dimensions = {}; |
| 152 | + |
| 153 | + for (const line of lines) { |
| 154 | + if (line.includes('width')) { |
| 155 | + const width = Number(line.split('=')[1]); |
| 156 | + |
| 157 | + if (Number.isFinite(width) && width > 0) { |
| 158 | + dimensions.width = width; |
| 159 | + } |
| 160 | + } else if (line.includes('height')) { |
| 161 | + const height = Number(line.split('=')[1]); |
| 162 | + |
| 163 | + if (Number.isFinite(height) && height > 0) { |
| 164 | + dimensions.height = height; |
| 165 | + } |
| 166 | + } |
| 167 | + } |
| 168 | + |
| 169 | + return dimensions; |
| 170 | +} |
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