implement black scene detection

closes #623

README.md

@@ -52,6 +52,7 @@ The main feature is lossless trimming and cutting of video and audio files, whic
 - MKV/MP4 embedded chapters marks editor
 - View subtitles
 - Customizable keyboard hotkeys
+- Black scene detection
 
 ## Example lossless use cases
 

public/menu.js

@@ -278,6 +278,13 @@ module.exports = (app, mainWindow, newVersion) => {
             mainWindow.webContents.send('askSetStartTimeOffset');
           },
         },
+        {
+          label: i18n.t('Detect black scenes'),
+          click() {
+            mainWindow.webContents.send('detectBlackScenes');
+          },
+        },
+        { type: 'separator' },
         { role: 'toggleDevTools', label: i18n.t('Toggle Developer Tools') },
       ],
     },

src/App.jsx

@@ -54,7 +54,7 @@ import {
   getStreamFps, isCuttingStart, isCuttingEnd,
   readFileMeta, getSmarterOutFormat, renderThumbnails as ffmpegRenderThumbnails,
   extractStreams, runStartupCheck, setCustomFfPath as ffmpegSetCustomFfPath,
-  isIphoneHevc, tryMapChaptersToEdl,
+  isIphoneHevc, tryMapChaptersToEdl, blackDetect,
   getDuration, getTimecodeFromStreams, createChaptersFromSegments, extractSubtitleTrack,
 } from './ffmpeg';
 import { shouldCopyStreamByDefault, getAudioStreams, getRealVideoStreams, defaultProcessedCodecTypes, isAudioDefinitelyNotSupported, doesPlayerSupportFile } from './util/streams';
@@ -1736,6 +1736,25 @@ const App = memo(() => {
     }
   }, [customOutDir, filePath, mainStreams, outputDir, setWorking]);
 
+  const detectBlackScenes = useCallback(async () => {
+    if (!filePath) return;
+    if (workingRef.current) return;
+    try {
+      setWorking(i18n.t('Detecting black scenes'));
+      setCutProgress(0);
+
+      const blackSegments = await blackDetect({ filePath, duration, onProgress: setCutProgress });
+      console.log('blackSegments', blackSegments);
+      loadCutSegments(blackSegments.map(({ blackStart, blackEnd }) => ({ start: blackStart, end: blackEnd })));
+    } catch (err) {
+      errorToast(i18n.t('Failed to detect black scenes'));
+      console.error('Failed to detect black scenes', err);
+    } finally {
+      setWorking();
+      setCutProgress();
+    }
+  }, [duration, filePath, setWorking, loadCutSegments]);
+
   const userHtml5ifyCurrentFile = useCallback(async () => {
     if (!filePath) return;
 
@@ -2177,13 +2196,14 @@ const App = memo(() => {
       fixInvalidDuration: tryFixInvalidDuration,
       reorderSegsByStartTime,
       concatCurrentBatch,
+      detectBlackScenes,
       shiftAllSegmentTimes,
     };
 
     const entries = Object.entries(action);
     entries.forEach(([key, value]) => electron.ipcRenderer.on(key, value));
     return () => entries.forEach(([key, value]) => electron.ipcRenderer.removeListener(key, value));
-  }, [apparentCutSegments, askSetStartTimeOffset, checkFileOpened, clearSegments, closeBatch, closeFileWithConfirm, concatCurrentBatch, createFixedDurationSegments, createNumSegments, customOutDir, cutSegments, detectedFps, extractAllStreams, fileFormat, filePath, fillSegmentsGaps, getFrameCount, invertAllSegments, loadCutSegments, loadMedia, openSendReportDialogWithState, reorderSegsByStartTime, setWorking, shiftAllSegmentTimes, shuffleSegments, toggleHelp, toggleSettings, tryFixInvalidDuration, userHtml5ifyCurrentFile, userOpenFiles]);
+  }, [apparentCutSegments, askSetStartTimeOffset, checkFileOpened, clearSegments, closeBatch, closeFileWithConfirm, concatCurrentBatch, createFixedDurationSegments, createNumSegments, customOutDir, cutSegments, detectBlackScenes, detectedFps, extractAllStreams, fileFormat, filePath, fillSegmentsGaps, getFrameCount, invertAllSegments, loadCutSegments, loadMedia, openSendReportDialogWithState, reorderSegsByStartTime, setWorking, shiftAllSegmentTimes, shuffleSegments, toggleHelp, toggleSettings, tryFixInvalidDuration, userHtml5ifyCurrentFile, userOpenFiles]);
 
   const showAddStreamSourceDialog = useCallback(async () => {
     try {

src/ffmpeg.js

@@ -60,7 +60,7 @@ export function runFfmpeg(args) {
 }
 
 
-export function handleProgress(process, cutDuration, onProgress) {
+export function handleProgress(process, cutDuration, onProgress, customMatcher = () => {}) {
   if (!onProgress) return;
   onProgress(0);
 
@@ -72,7 +72,10 @@ export function handleProgress(process, cutDuration, onProgress) {
       let match = line.match(/frame=\s*[^\s]+\s+fps=\s*[^\s]+\s+q=\s*[^\s]+\s+(?:size|Lsize)=\s*[^\s]+\s+time=\s*([^\s]+)\s+/);
       // Audio only looks like this: "line size=  233422kB time=01:45:50.68 bitrate= 301.1kbits/s speed= 353x    "
       if (!match) match = line.match(/(?:size|Lsize)=\s*[^\s]+\s+time=\s*([^\s]+)\s+/);
-      if (!match) return;
+      if (!match) {
+        customMatcher(line);
+        return;
+      }
 
       const str = match[1];
       // console.log(str);
@@ -514,6 +517,26 @@ export async function renderWaveformPng({ filePath, aroundTime, window, color })
   }
 }
 
+export async function blackDetect({ filePath, duration, minInterval = 0.05, onProgress }) {
+  const args = ['-hide_banner', '-i', filePath, '-vf', `blackdetect=d=${minInterval}`, '-an', '-f', 'null', '-'];
+  const process = execa(getFfmpegPath(), args, { encoding: null, buffer: false });
+
+  const blackSegments = [];
+
+  function customMatcher(line) {
+    const match = line.match(/^[blackdetect @ 0x[0-9a-f]+] black_start:([\d\\.]+) black_end:([\d\\.]+) black_duration:[\d\\.]+/);
+    if (!match) return;
+    const blackStart = parseFloat(match[1]);
+    const blackEnd = parseFloat(match[2]);
+    if (Number.isNaN(blackStart) || Number.isNaN(blackEnd)) return;
+    blackSegments.push({ blackStart, blackEnd });
+  }
+  handleProgress(process, duration, onProgress, customMatcher);
+
+  await process;
+  return blackSegments;
+}
+
 export async function extractWaveform({ filePath, outPath }) {
   const numSegs = 10;
   const duration = 60 * 60;