diff --git a/scripts/generate_fixtures.sh b/scripts/generate_fixtures.sh
index 34e97b3..86fdd3b 100755
--- a/scripts/generate_fixtures.sh
+++ b/scripts/generate_fixtures.sh
@@ -8,15 +8,45 @@ mkdir -p "$OUT_DIR"
 
 ffmpeg -y -hide_banner -loglevel error -f lavfi -i testsrc=size=128x72:rate=30 -f lavfi -i sine=frequency=1000:sample_rate=44100 -t 1 -c:v libx264 -pix_fmt yuv420p -c:a aac -movflags +faststart "$OUT_DIR/clean.mp4"
 ffmpeg -y -hide_banner -loglevel error -f lavfi -i testsrc=size=128x72:rate=30 -f lavfi -i sine=frequency=1000:sample_rate=44100 -t 1 -c:v libx264 -pix_fmt yuv420p -c:a aac "$OUT_DIR/no_faststart.mp4"
+ffmpeg -y -hide_banner -loglevel error -f lavfi -i testsrc=size=128x72:rate=30 -t 1 -c:v libx264 -pix_fmt yuv420p "$OUT_DIR/video_only.mp4"
+ffmpeg -y -hide_banner -loglevel error -f lavfi -i sine=frequency=1000:sample_rate=44100 -t 1 -c:a aac "$OUT_DIR/audio_only.mp4"
+ffmpeg -y -hide_banner -loglevel error -f lavfi -i testsrc=size=128x72:rate=30 -f lavfi -i sine=frequency=1000:sample_rate=44100 -t 1 -c:v libx264 -pix_fmt yuv420p -c:a aac "$OUT_DIR/clean.mkv"
 
 # Create a truncated file to simulate partial download/corruption
 cp "$OUT_DIR/clean.mp4" "$OUT_DIR/truncated.mp4"
-python3 - <<'PY'
+python3 - <<PY
 import os
-path = "${OUT_DIR}/truncated.mp4"
+path = "$OUT_DIR/truncated.mp4"
 size = os.path.getsize(path)
 with open(path, "r+b") as f:
     f.truncate(max(0, size - 2048))
 PY
 
+# Heavier truncation for more pronounced errors
+cp "$OUT_DIR/clean.mp4" "$OUT_DIR/truncated_hard.mp4"
+python3 - <<PY
+import os
+path = "$OUT_DIR/truncated_hard.mp4"
+size = os.path.getsize(path)
+with open(path, "r+b") as f:
+    f.truncate(max(0, size // 2))
+PY
+
+# Corrupt bytes in the middle of the file
+cp "$OUT_DIR/clean.mp4" "$OUT_DIR/corrupt_mid.mp4"
+python3 - <<PY
+import os
+path = "$OUT_DIR/corrupt_mid.mp4"
+with open(path, "r+b") as f:
+    f.seek(0, os.SEEK_END)
+    size = f.tell()
+    if size > 4096:
+        f.seek(size // 2)
+        chunk = bytearray(f.read(1024))
+        for i in range(len(chunk)):
+            chunk[i] ^= 0xFF
+        f.seek(size // 2)
+        f.write(chunk)
+PY
+
 echo "Fixtures written to $OUT_DIR"