Fix AVAssetReader unwraps and add session notes

Author: richiemcilroy

crates/editor/PLAYBACK-FINDINGS.md

@@ -324,6 +324,37 @@ The CPU RGBA→NV12 conversion was taking 15-25ms per frame for 3024x1964 resolu
 
 ---
 
+### Session 2026-02-15 (Performance Check + AVAssetReader Fix)
+
+**Goal**: Run playback benchmarks, fix panics in decoder fallback path
+
+**What was done**:
+1. Ran full playback validation on MP4 and fragmented recordings
+2. Identified AVAssetReader panicking with `unwrap()` on directory paths (fragmented recordings)
+3. Fixed by replacing `unwrap()` with proper error propagation
+
+**Changes Made**:
+- `crates/video-decode/src/avassetreader.rs`: Replaced `ffmpeg::format::input(&path).unwrap()` and `.ok_or(...).unwrap()` with `map_err()?` and `ok_or_else()?` for clean error propagation instead of panics
+
+**Results** (MP4 Mode):
+- ✅ Decoder: AVAssetReader (hardware), display init=114-123ms, camera init=25-33ms
+- ✅ Playback: 637-640 fps effective, avg=1.6ms, p95=5.0ms, p99=6.3ms
+- ✅ Camera sync: 0ms drift (perfect)
+- ✅ Mic sync: 88-100ms (borderline on this run, normally 77-88ms)
+- 🟡 System audio: 193-205ms (known issue, inherited from recording)
+
+**Results** (Fragmented Mode):
+- ✅ Decoder: FFmpeg (hardware) with VideoToolbox, display init=100-110ms, camera init=7ms
+- ✅ Playback: 153-173 fps effective, avg=5.8-6.5ms, p95=9.0-12.4ms
+- ✅ Camera sync: 0ms drift (perfect)
+- ✅ Mic sync: 10-23ms (excellent)
+- ✅ AVAssetReader now cleanly falls back to FFmpeg without panicking
+- 🟡 System audio: 85-116ms (borderline, known issue)
+
+**Stopping point**: All playback metrics healthy. AVAssetReader panic fixed. No further action needed.
+
+---
+
 ## References
 
 - `PLAYBACK-BENCHMARKS.md` - Raw performance test data (auto-updated by test runner)

crates/recording/FINDINGS.md

@@ -415,6 +415,32 @@ System Audio ────┘                       ├─► MP4 (macos.rs) ─
 
 ---
 
+### Session 2026-02-15 (Performance Check + AVAssetReader Fix)
+
+**Goal**: Run recording and playback benchmarks, fix any issues
+
+**What was done**:
+1. Ran MP4 baseline benchmarks (cold + warm runs)
+2. Ran fragmented baseline benchmark
+3. Ran playback benchmark on resulting recordings
+4. Fixed AVAssetReader panic on directory paths (fragmented recordings)
+
+**Changes Made**:
+- `crates/video-decode/src/avassetreader.rs`: Replaced two `unwrap()` calls with proper error propagation via `?` and `map_err`. Previously panicked when given a directory path (fragmented recordings); now returns clean error that triggers graceful FFmpeg fallback.
+
+**Results**:
+- ✅ MP4: 29.2fps, 10.4-10.7ms jitter, 2.7% dropped, 0ms A/V sync, 81-94ms mic timing
+- ✅ Fragmented: 29.5-29.6fps, 4.6-5.9ms jitter, 1.3% dropped, 0ms A/V sync, 1-4ms mic timing
+- ✅ Playback MP4: 637fps effective, 1.6ms avg, 5.0ms p95, 0ms camera drift
+- ✅ Playback Fragmented: 153fps effective, 6.5ms avg, 12.4ms p95, 0ms camera drift
+- ✅ AVAssetReader no longer panics on directory paths
+- 🟡 System audio: 120-246ms (known lower-priority issue)
+- 🟡 MP4 dropped frames at 2.7% (single 160ms spike from encoder warmup, not actionable)
+
+**Stopping point**: All major metrics pass. AVAssetReader panic fixed. System audio timing remains as documented known issue.
+
+---
+
 ## References
 
 - `BENCHMARKS.md` - Raw performance test data (auto-updated by test runner)

crates/video-decode/src/avassetreader.rs

@@ -237,13 +237,13 @@ impl AVAssetReaderDecoder {
         keyframe_index: Option<Arc<KeyframeIndex>>,
     ) -> Result<Self, String> {
         let (pixel_format, width, height) = {
-            let input = ffmpeg::format::input(&path).unwrap();
+            let input = ffmpeg::format::input(&path)
+                .map_err(|e| format!("Failed to open video input '{}': {e}", path.display()))?;
 
             let input_stream = input
                 .streams()
                 .best(ffmpeg::media::Type::Video)
-                .ok_or("Could not find a video stream")
-                .unwrap();
+                .ok_or_else(|| format!("No video stream in '{}'", path.display()))?;
 
             let decoder = avcodec::Context::from_parameters(input_stream.parameters())
                 .map_err(|e| format!("decoder context / {e}"))?
@@ -338,7 +338,11 @@ impl AVAssetReaderDecoder {
         height: u32,
     ) -> Result<(R<av::AssetReaderTrackOutput>, R<av::AssetReader>), String> {
         let asset = av::UrlAsset::with_url(
-            &ns::Url::with_fs_path_str(path.to_str().unwrap(), false),
+            &ns::Url::with_fs_path_str(
+                path.to_str()
+                    .ok_or_else(|| format!("Invalid UTF-8 in path: {path:?}"))?,
+                false,
+            ),
             None,
         )
         .ok_or_else(|| format!("UrlAsset::with_url{{{path:?}}}"))?;