Make video thumbnail position work properly for webms, and make it configurable with new option videoThumbPercentage

configs/main.js.example

@@ -118,6 +118,9 @@ module.exports = {
 	//max thumb dimensions (square) in px. images smaller than this are not thumbnailed
 	thumbSize: 250,
 
+	//0-100 percent through a video to try taking video thumbnails from, to remedy black first frames or fade-ins
+	videoThumbPercentage: 5,
+
 	/* extra mime types for files to be uploaded as attachments (no thumbnails) e.g. text files/archives
 		NOTE: appropriate extensions will need to be added to nginx configuration, and uncommend the provided
 		"other files" section which includes an example configuration for .txt files to match this default config.

helpers/files/videothumbnail.js

@@ -2,7 +2,7 @@ const ffmpeg = require('fluent-ffmpeg')
 	, { thumbSize } = require(__dirname+'/../../configs/main.js')
 	, uploadDirectory = require(__dirname+'/uploadDirectory.js');
 
-module.exports = (file, geometry, frames) => {
+module.exports = (file, geometry, timestamp) => {
 
 	return new Promise((resolve, reject) => {
 		ffmpeg(`${uploadDirectory}/file/${file.filename}`)
@@ -13,7 +13,7 @@ module.exports = (file, geometry, frames) => {
 			return reject(err);
 		})
 		.screenshots({
-			timestamps: [(frames === 'N/A' ? 0 : '1%')],//1% should remedy black first frames or fade-ins
+			timestamps: [timestamp],
 			count: 1,
 			filename: `thumb-${file.hash}${file.thumbextension}`,
 			folder: `${uploadDirectory}/file/`,

models/forms/makepost.js

@@ -3,7 +3,7 @@
 const path = require('path')
 	, { createHash, randomBytes } = require('crypto')
 	, randomBytesAsync = require('util').promisify(randomBytes)
-	, { remove, pathExists } = require('fs-extra')
+	, { remove, pathExists, stat: fsStat } = require('fs-extra')
 	, uploadDirectory = require(__dirname+'/../../helpers/files/uploadDirectory.js')
 	, Mongo = require(__dirname+'/../../db/db.js')
 	, Socketio = require(__dirname+'/../../socketio.js')
@@ -24,7 +24,8 @@ const path = require('path')
 	, timeUtils = require(__dirname+'/../../helpers/timeutils.js')
 	, deletePosts = require(__dirname+'/deletepost.js')
 	, spamCheck = require(__dirname+'/../../helpers/checks/spamcheck.js')
-	, { checkRealMimeTypes, thumbSize, thumbExtension, postPasswordSecret, strictFiltering } = require(__dirname+'/../../configs/main.js')
+	, { checkRealMimeTypes, thumbSize, thumbExtension, videoThumbPercentage,
+		postPasswordSecret, strictFiltering } = require(__dirname+'/../../configs/main.js')
 	, buildQueue = require(__dirname+'/../../queue.js')
 	, dynamicResponse = require(__dirname+'/../../helpers/dynamic.js')
 	, { buildThread } = require(__dirname+'/../../helpers/tasks.js');
@@ -274,7 +275,19 @@ module.exports = async (req, res, next) => {
 							await moveUpload(file, processedFile.filename, 'file');
 						}
 						if (!existsThumb) {
-							await videoThumbnail(processedFile, processedFile.geometry, videoData.streams[0].nb_frames);
+							const numFrames = videoData.streams[0].nb_frames;
+							if (numFrames === 'N/A' && subtype === 'webm') {
+								await videoThumbnail(processedFile, processedFile.geometry, videoThumbPercentage+'%');
+								let videoThumbStat = null;
+								try {
+									videoThumbStat = await fsStat(`${uploadDirectory}/file/thumb-${processedFile.hash}${processedFile.thumbextension}`);
+								} catch (err) { /*ENOENT, the thumb failed to create. No need to handle this.*/	}
+								if (!videoThumbStat || videoThumbStat.size === 0) {
+									await videoThumbnail(processedFile, processedFile.geometry, 0);
+								}
+							} else {
+								await videoThumbnail(processedFile, processedFile.geometry, ((numFrames === 'N/A' || numFrames <= 1) ? 0 : videoThumbPercentage+'%'));
+							}
 						}
 						break;
 					}