diff --git a/server.js b/server.js
index 5f3a3f4..0d2122a 100644
--- a/server.js
+++ b/server.js
@@ -535,6 +535,194 @@ app.post('/api/transcode', async (req, res) => {
     }
 });
 
+app.get('/api/stream', async (req, res) => {
+    const bucket = req.query.bucket;
+    const key = req.query.key;
+    const codec = req.query.codec;
+    const encoder = req.query.encoder;
+
+    if (!bucket) {
+        return res.status(400).json({ error: 'Bucket name is required' });
+    }
+    if (!key) {
+        return res.status(400).json({ error: 'Video key is required' });
+    }
+
+    const safeCodec = codec === 'h265' ? 'h265' : 'h264';
+    const safeEncoder = ['nvidia', 'intel', 'vaapi', 'neon'].includes(encoder) ? encoder : 'software';
+    const codecMap = {
+        software: { h264: 'libx264', h265: 'libx265' },
+        neon: { h264: 'libx264', h265: 'libx265' },
+        nvidia: { h264: 'h264_nvenc', h265: 'hevc_nvenc' },
+        intel: { h264: 'h264_qsv', h265: 'hevc_qsv' },
+        vaapi: { h264: 'h264_vaapi', h265: 'hevc_vaapi' }
+    };
+    const videoCodec = codecMap[safeEncoder][safeCodec];
+
+    const safeKeySegments = key.split('/').map(segment => segment.replace(/[^a-zA-Z0-9_\-]/g, '_'));
+    const progressKey = safeKeySegments.join('/');
+    const safeBucket = bucket.replace(/[^a-zA-Z0-9_\-]/g, '_');
+    const tmpInputPath = path.join(os.tmpdir(), `s3-input-${safeBucket}-${safeKeySegments.join('-')}.tmp`);
+    const cacheExists = fs.existsSync(tmpInputPath);
+
+    const auth = extractS3Credentials(req);
+    const s3Client = createS3Client(auth);
+
+    try {
+        let totalBytes = 0;
+        let downloadedBytes = 0;
+
+        if (!cacheExists) {
+            const command = new GetObjectCommand({ Bucket: bucket, Key: key });
+            const response = await s3Client.send(command);
+            const s3Stream = response.Body;
+            totalBytes = response.ContentLength || 0;
+
+            progressMap[progressKey] = {
+                status: 'downloading',
+                percent: 0,
+                downloadedBytes: 0,
+                totalBytes,
+                details: 'Downloading full source before streaming...',
+                mp4Url: null
+            };
+            broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });
+
+            await new Promise((resolve, reject) => {
+                const writeStream = fs.createWriteStream(tmpInputPath);
+                s3Stream.on('data', (chunk) => {
+                    downloadedBytes += chunk.length;
+                    const percent = totalBytes ? Math.min(100, Math.round(downloadedBytes / totalBytes * 100)) : 0;
+                    const downloadState = {
+                        status: 'downloading',
+                        percent,
+                        downloadedBytes,
+                        totalBytes,
+                        details: totalBytes ? `Downloading source ${percent}%` : 'Downloading source...',
+                        mp4Url: null
+                    };
+                    progressMap[progressKey] = downloadState;
+                    broadcastWs(progressKey, { type: 'progress', key, progress: downloadState });
+                });
+                s3Stream.on('error', reject);
+                writeStream.on('error', reject);
+                writeStream.on('finish', resolve);
+                s3Stream.pipe(writeStream);
+            });
+
+            progressMap[progressKey] = {
+                status: 'downloaded',
+                percent: 100,
+                downloadedBytes,
+                totalBytes,
+                details: 'Source download complete, starting real-time transcode...',
+                mp4Url: null
+            };
+            broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });
+        } else {
+            const stats = fs.statSync(tmpInputPath);
+            totalBytes = stats.size;
+            downloadedBytes = totalBytes;
+            progressMap[progressKey] = {
+                status: 'downloaded',
+                percent: 100,
+                downloadedBytes,
+                totalBytes,
+                details: 'Source already downloaded locally, starting real-time transcode...',
+                mp4Url: null
+            };
+            broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });
+        }
+
+        res.setHeader('Content-Type', 'video/mp4');
+        res.setHeader('Cache-Control', 'no-cache');
+        res.setHeader('Connection', 'keep-alive');
+
+        let ffmpegCommand = null;
+
+        const startStream = (encoderName) => {
+            const streamingOptions = createFfmpegOptions(encoderName).concat(['-movflags', 'frag_keyframe+empty_moov+faststart']);
+            ffmpegCommand = ffmpeg(tmpInputPath)
+                .videoCodec(encoderName)
+                .audioCodec('aac')
+                .outputOptions(streamingOptions)
+                .format('mp4');
+
+            if (/_vaapi$/.test(encoderName)) {
+                ffmpegCommand
+                    .inputOptions(['-vaapi_device', '/dev/dri/renderD128'])
+                    .videoFilters('format=nv12,hwupload');
+            }
+
+            transcodeProcesses.set(progressKey, ffmpegCommand);
+
+            ffmpegCommand
+                .on('progress', (progress) => {
+                    const progressState = {
+                        status: 'transcoding',
+                        percent: Math.min(Math.max(Math.round(progress.percent || 0), 0), 100),
+                        frame: progress.frames || null,
+                        fps: progress.currentFps || null,
+                        bitrate: progress.currentKbps || null,
+                        timemark: progress.timemark || null,
+                        details: `Streaming transcode ${Math.min(Math.max(Math.round(progress.percent || 0), 0), 100)}%`,
+                        mp4Url: null
+                    };
+                    progressMap[progressKey] = progressState;
+                    broadcastWs(progressKey, { type: 'progress', key, progress: progressState });
+                })
+                .on('stderr', (stderrLine) => {
+                    console.log(`ffmpeg stderr: ${stderrLine}`);
+                })
+                .on('end', () => {
+                    transcodeProcesses.delete(progressKey);
+                    progressMap[progressKey] = {
+                        status: 'finished',
+                        percent: 100,
+                        details: 'Streaming transcode complete',
+                        mp4Url: null
+                    };
+                    broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });
+                })
+                .on('error', (err) => {
+                    transcodeProcesses.delete(progressKey);
+                    const failedState = {
+                        status: 'failed',
+                        percent: progressMap[progressKey]?.percent || 0,
+                        details: err.message || 'Streaming transcode failed',
+                        mp4Url: null
+                    };
+                    progressMap[progressKey] = failedState;
+                    broadcastWs(progressKey, { type: 'progress', key, progress: failedState });
+                    if (!res.headersSent) {
+                        res.status(500).json({ error: 'Failed to stream transcoded video', detail: err.message });
+                    } else {
+                        res.destroy(err);
+                    }
+                });
+
+            ffmpegCommand.pipe(res, { end: true });
+        };
+
+        res.on('close', () => {
+            if (ffmpegCommand && typeof ffmpegCommand.kill === 'function') {
+                try {
+                    ffmpegCommand.kill('SIGKILL');
+                } catch (_) {}
+            }
+        });
+
+        startStream(videoCodec);
+    } catch (error) {
+        console.error('Error in stream:', error);
+        if (!res.headersSent) {
+            res.status(500).json({ error: 'Failed to stream video', detail: error.message });
+        } else {
+            res.destroy(error);
+        }
+    }
+});
+
 // Status check for MP4 availability
 app.get('/api/status', (req, res) => {
     const { key } = req.query;