Count VideoToolbox sessions, frames and declined requests in perf.stats (#981)

crates/platform/src/hardware_encode.rs

@@ -133,13 +133,18 @@ pub fn videotoolbox_encoder_factory(
         Ok(c) => c,
         Err(why) => {
             log::info!("hardware {name} encoding declined: {why}");
+            filmcraft_export::note_hw_encode_declined();
             return None;
         }
     };
     match VtEncoder::new(config) {
-        Ok(vt) => Some(Ok(Box::new(HardwareEncoder { vt, y: Vec::new(), u: Vec::new(), v: Vec::new(), decoded: 0 }))),
+        Ok(vt) => {
+            filmcraft_export::note_hw_encode_session();
+            Some(Ok(Box::new(HardwareEncoder { vt, y: Vec::new(), u: Vec::new(), v: Vec::new(), decoded: 0 })))
+        }
         Err(why) => {
             log::info!("hardware {name} encoding declined: {why}");
+            filmcraft_export::note_hw_encode_declined();
             None
         }
     }
@@ -222,6 +227,7 @@ impl VideoEncoder for HardwareEncoder {
         }
         filmcraft_export::timed(filmcraft_export::Stage::Convert, || filmcraft_export::rgba_to_yuv420_8(f.rgba, w, h, &mut self.y, &mut self.u, &mut self.v));
         let packets = self.vt.encode(f.index, &self.y, &self.u, &self.v).map_err(ExportError::Encode)?;
+        filmcraft_export::note_hw_encode_frame();
         // the muxer needs the parameter sets after the first group of pictures
         if f.index == 0 {
             let params = self.vt.parameter_sets().ok_or_else(|| ExportError::Encode("VideoToolbox returned no parameter sets for the first frame".into()))?;

crates/platform/tests/hardware_encode.rs

@@ -9,7 +9,8 @@ use std::panic::AssertUnwindSafe;
 use std::sync::Arc;
 
 use filmcraft_export::{
-    BitrateMode, EncodedPacket, EncoderFrame, ExportSettings, Format, H264Pass, H264Profile, HardwareEncoding, Progress, VideoEncoder, export, rgba_to_yuv420_8,
+    BitrateMode, EncodedPacket, EncoderFrame, ExportSettings, Format, H264Pass, H264Profile, HardwareEncoding, Progress, VideoEncoder, export, hw_encode_stats,
+    rgba_to_yuv420_8,
 };
 use filmcraft_frame::PixelData;
 use filmcraft_isobmff::{CodecConfig, SampleEntry};
@@ -133,6 +134,22 @@ fn factory_only_acts_when_asked() {
     assert!(videotoolbox_encoder_factory(Format::H264, W, H, FPS, &ExportSettings { hardware_encoding: HardwareEncoding::Off, ..s }).is_none());
 }
 
+/// `perf.stats` reads these counters: a declined request, a session and every encoded picture must show.
+/// The counters are process-wide and other tests add to them, so only increases are checked.
+#[test]
+fn hardware_encoder_counters_follow_the_export() {
+    let s = hardware_settings();
+    let before = hw_encode_stats();
+    // an odd picture size is declined before any session is created
+    assert!(videotoolbox_encoder_factory(Format::H264, W + 1, H, FPS, &s).is_none());
+    assert!(hw_encode_stats().declined > before.declined, "a declined request is counted");
+    let Some(mut enc) = hardware(&s, W, H) else { return };
+    let created = hw_encode_stats();
+    assert!(created.sessions > before.sessions, "a created session is counted");
+    encode_all(&mut enc, 3);
+    assert!(hw_encode_stats().frames >= created.frames + 3, "every encoded picture is counted");
+}
+
 #[test]
 fn round_trip_through_our_software_decoder() {
     let s = hardware_settings();