diff --git a/app.py b/app.py
index 97fca89..8d180e4 100644
--- a/app.py
+++ b/app.py
@@ -62,10 +62,20 @@ VIDEO_EXTENSIONS = {
 
 
 def get_video_info(filepath: str) -> dict | None:
+    """
+    Use ffprobe to get duration, total bitrate, codec, and dimensions.
+
+    Bitrate resolution strategy (handles HEVC/MKV where stream-level
+    bit_rate is absent):
+      1. Stream-level bit_rate  — present for H.264/MP4, often missing for HEVC
+      2. Format-level bit_rate  — reliable for all containers
+      3. Derived from size/duration — final fallback
+    """
     cmd = [
         'ffprobe', '-v', 'error',
         '-select_streams', 'v:0',
-        '-show_entries', 'format=duration,bit_rate,size:stream=codec_name,width,height',
+        '-show_entries',
+        'format=duration,bit_rate,size:stream=codec_name,width,height,bit_rate',
         '-of', 'json',
         filepath,
     ]
@@ -78,15 +88,26 @@ def get_video_info(filepath: str) -> dict | None:
         stream = (data.get('streams') or [{}])[0]
 
         duration   = float(fmt.get('duration', 0))
-        bit_rate   = int(fmt.get('bit_rate', 0))
         size_bytes = int(fmt.get('size', 0))
         codec      = stream.get('codec_name', 'unknown')
         width      = stream.get('width', 0)
         height     = stream.get('height', 0)
 
-        if bit_rate == 0 and duration > 0:
+        # Prefer stream-level bitrate, fall back to format-level, then derive
+        stream_br = int(stream.get('bit_rate') or 0)
+        format_br = int(fmt.get('bit_rate') or 0)
+        if stream_br > 0:
+            bit_rate = stream_br
+        elif format_br > 0:
+            bit_rate = format_br
+        elif duration > 0:
             bit_rate = int((size_bytes * 8) / duration)
+        else:
+            bit_rate = 0
 
+        # Target ≈ 1/3 of the total bitrate, reserving 128 kbps for audio.
+        # For HEVC sources the format bitrate already includes audio, so the
+        # same formula applies regardless of codec.
         audio_bps        = 128_000
         video_bps        = bit_rate - audio_bps if bit_rate > audio_bps else bit_rate
         target_video_bps = max(int(video_bps / 3), 200_000)
@@ -345,13 +366,21 @@ def run_compression_job(job_id: str) -> None:
 
         src_path       = file_info['path']
         target_bitrate = file_info.get('target_bit_rate_bps', 1_000_000)
+        src_codec      = file_info.get('codec', 'unknown').lower()
         p              = Path(src_path)
         out_path       = str(p.parent / (p.stem + suffix + p.suffix))
 
+        # Choose encoder to match the source codec.
+        # hevc / h265 / x265  → libx265
+        # everything else     → libx264  (safe, universally supported)
+        is_hevc = src_codec in ('hevc', 'h265', 'x265')
+        encoder = 'libx265' if is_hevc else 'libx264'
+
         push_event(job, {
             'type': 'file_start', 'index': idx, 'total': total,
             'filename': p.name, 'output': out_path,
-            'message': f'Compressing ({idx + 1}/{total}): {p.name}',
+            'encoder': encoder,
+            'message': f'Compressing ({idx + 1}/{total}): {p.name} [{encoder}]',
         })
 
         try:
@@ -365,12 +394,34 @@ def run_compression_job(job_id: str) -> None:
             duration_secs = 0
 
         video_k = max(int(target_bitrate / 1000), 200)
+
+        # Build the encoder-specific part of the ffmpeg command.
+        #
+        # libx264 uses -maxrate / -bufsize for VBV (Video Buffering Verifier).
+        # libx265 passes those same constraints via -x265-params because its
+        # CLI option names differ from the generic ffmpeg flags.
+        # Both use AAC audio at 128 kbps.
+        # -movflags +faststart is only meaningful for MP4 containers; it is
+        # harmless (silently ignored) for MKV/MOV/etc.
+        if is_hevc:
+            vbv_maxrate = int(video_k * 1.5)
+            vbv_bufsize = video_k * 2
+            encoder_opts = [
+                '-c:v', 'libx265',
+                '-b:v', f'{video_k}k',
+                '-x265-params', f'vbv-maxrate={vbv_maxrate}:vbv-bufsize={vbv_bufsize}',
+            ]
+        else:
+            encoder_opts = [
+                '-c:v', 'libx264',
+                '-b:v', f'{video_k}k',
+                '-maxrate', f'{int(video_k * 1.5)}k',
+                '-bufsize', f'{video_k * 2}k',
+            ]
+
         cmd = [
             'ffmpeg', '-y', '-i', src_path,
-            '-c:v', 'libx264',
-            '-b:v', f'{video_k}k',
-            '-maxrate', f'{int(video_k * 1.5)}k',
-            '-bufsize', f'{video_k * 2}k',
+            *encoder_opts,
             '-c:a', 'aac', '-b:a', '128k',
             '-movflags', '+faststart',
             '-progress', 'pipe:1', '-nostats',
diff --git a/static/css/main.css b/static/css/main.css
index 75fc31b..c23a460 100644
--- a/static/css/main.css
+++ b/static/css/main.css
@@ -767,6 +767,35 @@ body {
   color: var(--text-muted);
   text-transform: uppercase;
   letter-spacing: 0.04em;
+  padding: 2px 7px;
+  border-radius: var(--radius-pill);
+  border: 1px solid var(--border-base);
+  background: var(--bg-card2);
+  white-space: nowrap;
+}
+
+/* H.265 / HEVC — amber tint to flag it uses libx265 */
+.codec-tag.hevc {
+  background: rgba(180, 100, 0, 0.10);
+  border-color: rgba(180, 100, 0, 0.35);
+  color: #7a4500;
+}
+[data-theme="dark"] .codec-tag.hevc {
+  background: rgba(251, 191, 36, 0.12);
+  border-color: rgba(251, 191, 36, 0.30);
+  color: #fbbf24;
+}
+
+/* H.264 / AVC — subtle blue tint */
+.codec-tag.h264 {
+  background: rgba(26, 86, 219, 0.07);
+  border-color: rgba(26, 86, 219, 0.25);
+  color: #1e40af;
+}
+[data-theme="dark"] .codec-tag.h264 {
+  background: rgba(147, 197, 253, 0.10);
+  border-color: rgba(147, 197, 253, 0.25);
+  color: #93c5fd;
 }
 
 /* Checkbox styling */
diff --git a/static/js/app.js b/static/js/app.js
index 7c29f4e..d9602c2 100644
--- a/static/js/app.js
+++ b/static/js/app.js
@@ -272,11 +272,19 @@ function showScanStatus(msg, type) {
 function renderFileTable(files) {
   let html = '';
   files.forEach((f, idx) => {
-    const sizeFmt   = f.size_gb.toFixed(3);
+    const sizeFmt    = f.size_gb.toFixed(3);
     const curBitrate = f.bit_rate_mbps ? `${f.bit_rate_mbps} Mbps` : 'Unknown';
     const tgtBitrate = f.target_bit_rate_mbps ? `${f.target_bit_rate_mbps} Mbps` : '—';
-    const codec = f.codec || 'unknown';
-    const pathDir = f.path.replace(f.name, '');
+    const codec      = (f.codec || 'unknown').toLowerCase();
+    const pathDir    = f.path.replace(f.name, '');
+
+    // Normalise codec label and pick a CSS modifier for the badge colour
+    const isHevc    = ['hevc', 'h265', 'x265'].includes(codec);
+    const isH264    = ['h264', 'avc', 'x264'].includes(codec);
+    const codecLabel = isHevc ? 'H.265 / HEVC'
+                     : isH264 ? 'H.264 / AVC'
+                     : codec.toUpperCase();
+    const codecMod  = isHevc ? 'hevc' : isH264 ? 'h264' : '';
 
     html += `
       <tr id="row-${idx}" data-path="${escHtml(f.path)}">
@@ -305,7 +313,7 @@ function renderFileTable(files) {
           <span class="bitrate-badge target">${escHtml(tgtBitrate)}</span>
         </td>
         <td class="col-codec">
-          <span class="codec-tag">${escHtml(codec)}</span>
+          <span class="codec-tag ${codecMod}" title="Encoder: ${isHevc ? 'libx265' : 'libx264'}">${escHtml(codecLabel)}</span>
         </td>
       </tr>`;
   });
@@ -370,6 +378,7 @@ els.compressBtn.addEventListener('click', async () => {
       path: f.path,
       size_bytes: f.size_bytes,
       target_bit_rate_bps: f.target_bit_rate_bps || 1000000,
+      codec: f.codec || 'unknown',
     })),
     suffix,
   };