diff --git a/server.js b/server.js
index 139e1a8..54e2ff7 100644
--- a/server.js
+++ b/server.js
@@ -2,6 +2,7 @@ const express = require('express');
 const cors = require('cors');
 const dotenv = require('dotenv');
 const fs = require('fs');
+const os = require('os');
 const path = require('path');
 const http = require('http');
 const WebSocket = require('ws');
@@ -174,10 +175,23 @@ app.post('/api/transcode', async (req, res) => {
         const response = await s3Client.send(command);
         const s3Stream = response.Body;
 
+        const tmpInputPath = path.join(os.tmpdir(), `s3-input-${Date.now()}-${Math.random().toString(16).slice(2)}.tmp`);
+        await new Promise((resolve, reject) => {
+            const writeStream = fs.createWriteStream(tmpInputPath);
+            s3Stream.pipe(writeStream);
+            s3Stream.on('error', reject);
+            writeStream.on('error', reject);
+            writeStream.on('finish', resolve);
+        });
+
         // Triggers fluent-ffmpeg to transcode to MP4
         console.log(`Starting transcoding for ${key} with codec ${videoCodec}`);
 
-        ffmpeg(s3Stream)
+        const cleanupTmpInput = () => {
+            fs.unlink(tmpInputPath, () => {});
+        };
+
+        ffmpeg(tmpInputPath)
             .videoCodec(videoCodec)
             .audioCodec('aac')
             .outputOptions([
@@ -204,6 +218,7 @@ app.post('/api/transcode', async (req, res) => {
                 console.log(`ffmpeg stderr: ${stderrLine}`);
             })
             .on('end', () => {
+                cleanupTmpInput();
                 console.log(`Finished transcoding ${key} to MP4`);
                 let progressState;
                 try {
@@ -223,6 +238,7 @@ app.post('/api/transcode', async (req, res) => {
                 }
             })
             .on('error', (err) => {
+                cleanupTmpInput();
                 console.error(`Error transcoding ${key}:`, err);
                 const failedState = { status: 'failed', percent: progressMap[progressKey]?.percent || 0, details: err.message || 'Transcoding failed', mp4Url };
                 progressMap[progressKey] = failedState;