How to Download WebM Videos

// Check WebM file extension
function isWebM(filename) {
  return /\.webm$/i.test(filename);
}

// Check WebM MIME type
function isWebMMimeType(mimeType) {
  return /^(video|audio)\/webm$/i.test(mimeType);
}

// Browser support check
function supportsWebM() {
  const video = document.createElement('video');
  return !!(video.canPlayType && video.canPlayType('video/webm').replace(/no/, ''));
}

// Monitor for WebM requests
const webmDetector = {
  detectedFiles: new Set(),
  
  init() {
    // Override fetch
    const originalFetch = window.fetch;
    window.fetch = function(...args) {
      const url = args[0];
      
      if (typeof url === 'string' && isWebM(url)) {
        webmDetector.detectedFiles.add(url);
        console.log('WebM detected via fetch:', url);
      }
      
      return originalFetch.apply(this, args).then(response => {
        const contentType = response.headers.get('content-type');
        if (contentType && isWebMMimeType(contentType)) {
          webmDetector.detectedFiles.add(url);
          console.log('WebM detected via content-type:', url);
        }
        return response;
      });
    };
    
    // Monitor video elements
    this.observeVideoElements();
  },
  
  observeVideoElements() {
    const observer = new MutationObserver((mutations) => {
      mutations.forEach((mutation) => {
        mutation.addedNodes.forEach((node) => {
          if (node.nodeType === 1) { // Element node
            this.scanElement(node);
          }
        });
      });
    });
    
    observer.observe(document.body, {
      childList: true,
      subtree: true
    });
    
    // Scan existing elements
    this.scanElement(document.body);
  },
  
  scanElement(element) {
    // Check video elements
    const videos = element.querySelectorAll ? 
      element.querySelectorAll('video') : 
      (element.tagName === 'VIDEO' ? [element] : []);
    
    videos.forEach(video => {
      if (video.src && isWebM(video.src)) {
        this.detectedFiles.add(video.src);
        console.log('WebM video element detected:', video.src);
      }
      
      // Check source children
      video.querySelectorAll('source').forEach(source => {
        if (source.src && isWebM(source.src)) {
          this.detectedFiles.add(source.src);
          console.log('WebM source element detected:', source.src);
        }
      });
    });
  }
};

// Initialize detector
webmDetector.init();

// Detect WebM by file signature
function detectWebMHeader(arrayBuffer) {
  const view = new DataView(arrayBuffer);
  
  // WebM uses EBML (Extensible Binary Meta Language)
  // Check for EBML header: 0x1A45DFA3
  const ebmlHeader = view.getUint32(0, false);
  
  if (ebmlHeader === 0x1A45DFA3) {
    // Look for WebM doctype
    const bytes = new Uint8Array(arrayBuffer.slice(0, 100));
    const str = Array.from(bytes).map(b => String.fromCharCode(b)).join('');
    
    return str.includes('webm');
  }
  
  return false;
}

// Check if URL serves WebM content
async function isWebMContent(url) {
  try {
    const response = await fetch(url, { 
      method: 'HEAD',
      headers: { 'Range': 'bytes=0-99' }
    });
    
    // Check content-type header
    const contentType = response.headers.get('content-type');
    if (contentType && isWebMMimeType(contentType)) {
      return true;
    }
    
    // Check binary header if partial content supported
    if (response.status === 206) {
      const buffer = await response.arrayBuffer();
      return detectWebMHeader(buffer);
    }
    
    return false;
  } catch (error) {
    console.warn('Failed to check WebM content:', error);
    return false;
  }
}

# Simple wget download
wget "https://example.com/video.webm"

# With custom headers
wget --header="Referer: https://example.com/" \
     --header="User-Agent: Mozilla/5.0..." \
     "https://example.com/video.webm"

# Resume partial download
wget -c "https://example.com/video.webm"

# Basic download with progress
curl --progress-bar -o video.webm "https://example.com/video.webm"

# With headers for protected content
curl -H "Referer: https://example.com/" \
     -H "Origin: https://example.com/" \
     -o video.webm \
     "https://example.com/video.webm"

# Resume interrupted download
curl -C - -o video.webm "https://example.com/video.webm"

# Extract and download WebM from web pages
yt-dlp -f "webm" "https://example.com/page-with-video"

# Prefer WebM format
yt-dlp -f "best[ext=webm]" "https://example.com/page-with-video"

# Download all WebM qualities
yt-dlp -f "webm/best" "https://example.com/page-with-video"

# Force WebM output format
yt-dlp --merge-output-format webm "https://example.com/page-with-video"

// Download WebM from browser with progress
async function downloadWebM(url, filename, onProgress) {
  try {
    const response = await fetch(url);
    const contentLength = response.headers.get('content-length');
    const totalBytes = contentLength ? parseInt(contentLength, 10) : 0;
    
    const reader = response.body.getReader();
    const chunks = [];
    let receivedBytes = 0;
    
    while (true) {
      const { done, value } = await reader.read();
      
      if (done) break;
      
      chunks.push(value);
      receivedBytes += value.length;
      
      if (onProgress && totalBytes > 0) {
        const progress = (receivedBytes / totalBytes) * 100;
        onProgress(progress, receivedBytes, totalBytes);
      }
    }
    
    // Create blob and download
    const blob = new Blob(chunks, { type: 'video/webm' });
    const downloadUrl = URL.createObjectURL(blob);
    
    const a = document.createElement('a');
    a.href = downloadUrl;
    a.download = filename;
    a.click();
    
    // Cleanup
    URL.revokeObjectURL(downloadUrl);
    
    return blob;
  } catch (error) {
    console.error('WebM download failed:', error);
    throw error;
  }
}

// Usage with progress callback
downloadWebM('https://example.com/video.webm', 'downloaded.webm', 
  (progress, received, total) => {
    console.log(`Download progress: ${progress.toFixed(1)}% (${received}/${total} bytes)`);
  }
);

const fs = require('fs');
const https = require('https');
const path = require('path');

function downloadWebMStream(url, outputPath, options = {}) {
  return new Promise((resolve, reject) => {
    const file = fs.createWriteStream(outputPath);
    
    const requestOptions = {
      headers: {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36',
        ...options.headers
      }
    };
    
    const request = https.get(url, requestOptions, (response) => {
      if (response.statusCode !== 200) {
        reject(new Error(`HTTP ${response.statusCode}: ${response.statusMessage}`));
        return;
      }
      
      const totalBytes = parseInt(response.headers['content-length'] || '0', 10);
      let downloadedBytes = 0;
      
      response.on('data', (chunk) => {
        downloadedBytes += chunk.length;
        
        if (options.onProgress && totalBytes > 0) {
          const progress = (downloadedBytes / totalBytes) * 100;
          options.onProgress(progress, downloadedBytes, totalBytes);
        }
      });
      
      response.pipe(file);
      
      file.on('finish', () => {
        file.close();
        console.log(`WebM download completed: ${outputPath}`);
        resolve({ 
          success: true, 
          file: outputPath,
          size: downloadedBytes 
        });
      });
      
      file.on('error', (err) => {
        fs.unlink(outputPath, () => {}); // Delete partial file
        reject(err);
      });
    });
    
    request.on('error', reject);
    request.setTimeout(30000, () => {
      request.abort();
      reject(new Error('Download timeout'));
    });
  });
}

// Usage
downloadWebMStream('https://example.com/video.webm', './downloads/video.webm', {
  onProgress: (progress, downloaded, total) => {
    process.stdout.write(`\rDownload progress: ${progress.toFixed(1)}% (${downloaded}/${total} bytes)`);
  }
});

// Extract WebM metadata using File API
async function extractWebMMetadata(file) {
  const buffer = await file.arrayBuffer();
  const view = new DataView(buffer);
  
  const metadata = {
    format: 'WebM',
    size: buffer.byteLength,
    elements: []
  };
  
  let offset = 0;
  
  // Parse EBML elements
  while (offset < Math.min(buffer.byteLength, 1024)) { // Parse first 1KB
    try {
      const element = parseEBMLElement(view, offset);
      if (!element) break;
      
      metadata.elements.push(element);
      offset += element.totalSize;
    } catch (e) {
      break;
    }
  }
  
  return metadata;
}

function parseEBMLElement(view, offset) {
  if (offset >= view.byteLength - 4) return null;
  
  const id = view.getUint32(offset, false);
  let size = 0;
  let sizeLength = 1;
  
  // Parse EBML variable-length size
  const firstByte = view.getUint8(offset + 4);
  if (firstByte & 0x80) {
    size = firstByte & 0x7F;
  } else if (firstByte & 0x40) {
    size = ((firstByte & 0x3F) << 8) | view.getUint8(offset + 5);
    sizeLength = 2;
  }
  // ... more size parsing logic
  
  return {
    id: id.toString(16),
    size,
    totalSize: 4 + sizeLength + size
  };
}

# Extract comprehensive WebM metadata
ffprobe -v quiet -print_format json -show_format -show_streams video.webm

# Get video codec information
ffprobe -v quiet -select_streams v:0 -show_entries stream=codec_name,width,height,r_frame_rate -of csv="p=0" video.webm

# Get audio codec information  
ffprobe -v quiet -select_streams a:0 -show_entries stream=codec_name,sample_rate,channels -of csv="p=0" video.webm

# Check for VP9 codec
ffprobe -v quiet -select_streams v:0 -show_entries stream=codec_name -of csv="p=0" video.webm | grep vp9

# Convert WebM to MP4 (re-encode)
ffmpeg -i input.webm -c:v libx264 -c:a aac output.mp4

# Fast conversion (copy streams if compatible)
ffmpeg -i input.webm -c:v copy -c:a aac -strict experimental output.mp4

# High quality conversion
ffmpeg -i input.webm \
       -c:v libx264 -preset slow -crf 18 \
       -c:a aac -b:a 128k \
       output.mp4

# Batch conversion
for file in *.webm; do
  ffmpeg -i "$file" -c:v libx264 -c:a aac "${file%.webm}.mp4"
done

// YouTube uses WebM for many video qualities
const youtubeWebMFormats = {
  // VP9 video with Opus audio
  '298': { codec: 'vp9+opus', quality: '720p60', container: 'webm' },
  '299': { codec: 'vp9+opus', quality: '1080p60', container: 'webm' },
  
  // VP8 video with Vorbis audio
  '43': { codec: 'vp8+vorbis', quality: '360p', container: 'webm' },
  '44': { codec: 'vp8+vorbis', quality: '480p', container: 'webm' }
};

// Download YouTube WebM
// yt-dlp -f "299" "https://www.youtube.com/watch?v=VIDEO_ID"

// Discord converts many uploads to WebM
function detectDiscordWebM() {
  const discordAttachments = [];
  
  document.querySelectorAll('a[href*="cdn.discordapp.com"], a[href*="media.discordapp.net"]').forEach(link => {
    if (link.href.includes('.webm')) {
      discordAttachments.push({
        url: link.href,
        filename: link.href.split('/').pop(),
        type: 'discord_attachment'
      });
    }
  });
  
  return discordAttachments;
}

// Detect WebM from browser screen recording
function setupScreenRecordingDetection() {
  const originalGetDisplayMedia = navigator.mediaDevices.getDisplayMedia;
  
  navigator.mediaDevices.getDisplayMedia = function(constraints) {
    return originalGetDisplayMedia.call(this, constraints).then(stream => {
      console.log('Screen recording started, likely producing WebM');
      
      // Monitor MediaRecorder usage
      const originalMediaRecorder = window.MediaRecorder;
      window.MediaRecorder = function(stream, options) {
        const recorder = new originalMediaRecorder(stream, options);
        
        recorder.addEventListener('dataavailable', (event) => {
          if (event.data && event.data.type === 'video/webm') {
            console.log('WebM blob created from screen recording:', event.data);
          }
        });
        
        return recorder;
      };
      
      return stream;
    });
  };
}

// Download large WebM files in chunks
async function downloadWebMChunks(url, chunkSize = 1024 * 1024) { // 1MB chunks
  const response = await fetch(url, { method: 'HEAD' });
  const totalSize = parseInt(response.headers.get('content-length'));
  
  if (!totalSize) {
    throw new Error('Content-Length header missing');
  }
  
  const chunks = [];
  let downloaded = 0;
  
  while (downloaded < totalSize) {
    const start = downloaded;
    const end = Math.min(downloaded + chunkSize - 1, totalSize - 1);
    
    const chunkResponse = await fetch(url, {
      headers: { 'Range': `bytes=${start}-${end}` }
    });
    
    if (chunkResponse.status !== 206) {
      throw new Error('Server does not support range requests');
    }
    
    const chunk = await chunkResponse.arrayBuffer();
    chunks.push(chunk);
    downloaded = end + 1;
    
    console.log(`Downloaded chunk: ${downloaded}/${totalSize} bytes`);
  }
  
  // Combine chunks
  const totalBuffer = new Uint8Array(totalSize);
  let offset = 0;
  
  chunks.forEach(chunk => {
    totalBuffer.set(new Uint8Array(chunk), offset);
    offset += chunk.byteLength;
  });
  
  return new Blob([totalBuffer], { type: 'video/webm' });
}

// Extract segments from WebM streams
function extractWebMSegments(webmBlob) {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();
    
    reader.onload = function(e) {
      const buffer = e.target.result;
      const segments = parseWebMClusters(buffer);
      resolve(segments);
    };
    
    reader.onerror = reject;
    reader.readAsArrayBuffer(webmBlob);
  });
}

function parseWebMClusters(buffer) {
  const view = new DataView(buffer);
  const segments = [];
  
  // This is a simplified parser - real WebM parsing is much more complex
  let offset = 0;
  
  while (offset < buffer.byteLength - 8) {
    // Look for Cluster elements (0x1F43B675)
    const id = view.getUint32(offset, false);
    
    if (id === 0x1F43B675) {
      const size = parseVarInt(view, offset + 4);
      segments.push({
        offset,
        size: size.value,
        type: 'cluster'
      });
      offset += 4 + size.length + size.value;
    } else {
      offset++;
    }
  }
  
  return segments;
}

// Capture WebM streams in real-time
class WebMStreamCapture {
  constructor() {
    this.capturedStreams = new Map();
    this.setupInterception();
  }
  
  setupInterception() {
    // Intercept MediaRecorder API
    const originalMediaRecorder = window.MediaRecorder;
    
    window.MediaRecorder = function(stream, options) {
      const recorder = new originalMediaRecorder(stream, options);
      const streamId = Date.now().toString();
      
      const captureData = {
        id: streamId,
        chunks: [],
        startTime: Date.now(),
        options
      };
      
      recorder.addEventListener('dataavailable', (event) => {
        if (event.data && event.data.size > 0) {
          captureData.chunks.push(event.data);
          console.log(`WebM chunk captured: ${event.data.size} bytes`);
        }
      });
      
      recorder.addEventListener('stop', () => {
        const finalBlob = new Blob(captureData.chunks, { type: 'video/webm' });
        captureData.finalBlob = finalBlob;
        console.log(`WebM recording completed: ${finalBlob.size} bytes`);
      });
      
      this.capturedStreams.set(streamId, captureData);
      return recorder;
    }.bind(this);
  }
  
  downloadAllCapturedStreams() {
    this.capturedStreams.forEach((capture, id) => {
      if (capture.finalBlob) {
        const url = URL.createObjectURL(capture.finalBlob);
        const a = document.createElement('a');
        a.href = url;
        a.download = `captured_${id}.webm`;
        a.click();
        URL.revokeObjectURL(url);
      }
    });
  }
}

// Initialize capture system
const webmCapture = new WebMStreamCapture();

// Check WebM codec support
function checkWebMSupport() {
  const video = document.createElement('video');
  
  const support = {
    webm: !!video.canPlayType('video/webm').replace(/no/, ''),
    vp8: !!video.canPlayType('video/webm; codecs="vp8"').replace(/no/, ''),
    vp9: !!video.canPlayType('video/webm; codecs="vp9"').replace(/no/, ''),
    opus: !!video.canPlayType('audio/webm; codecs="opus"').replace(/no/, ''),
    vorbis: !!video.canPlayType('audio/webm; codecs="vorbis"').replace(/no/, '')
  };
  
  return support;
}

// Provide fallback for unsupported browsers
function provideWebMFallback(videoElement) {
  const support = checkWebMSupport();
  
  if (!support.webm) {
    // Replace WebM source with MP4 alternative
    const sources = videoElement.querySelectorAll('source[type="video/webm"]');
    sources.forEach(source => {
      const mp4Src = source.src.replace('.webm', '.mp4');
      source.src = mp4Src;
      source.type = 'video/mp4';
    });
  }
}

// Stream large WebM files efficiently
async function streamLargeWebM(url, onChunk) {
  const response = await fetch(url);
  const reader = response.body.getReader();
  
  try {
    while (true) {
      const { done, value } = await reader.read();
      
      if (done) break;
      
      // Process chunk immediately instead of storing
      if (onChunk) {
        await onChunk(value);
      }
    }
  } finally {
    reader.releaseLock();
  }
}

// Usage: process WebM data in chunks
streamLargeWebM('https://example.com/large-video.webm', async (chunk) => {
  // Process chunk (e.g., save to IndexedDB, analyze, etc.)
  console.log('Processing chunk:', chunk.length, 'bytes');
});

# Analyze WebM quality and bitrate
ffprobe -v quiet -select_streams v:0 \
        -show_entries stream=width,height,bit_rate,codec_name \
        -of json video.webm

# Compare WebM vs MP4 quality
ffprobe -v quiet -show_entries format=bit_rate,duration,size \
        -of json video.webm