Use Job infrastructure for Debug Replay (#23099)

* use ReplayState enum

* extract shared ffmpeg progress helper

* make start call non-blocking with worker thread

* expose replay state on status endpoint and return 202 from start

* cancel in-flight ffmpeg when stop is called during preparation

* add replay i18n strings for preparing and error states

* show status in replay UI

* navigate immediately on 202 from debug replay menus and dialog

* remove unused

* simplify to use Job infrastructure

* tests

* cleanup and tweaks

* fetch schema

* update api spec

* formatting

* fix e2e test

* mypy

* clean up

* formatting

* fix

* fix test

* don't try to show camera image until status reports ready

* simplify loading logic

* fix race in latest_frame on debug replay shutdown

* remove toast when successfully stopping

it gets hidden almost immediately

frigate/util/ffmpeg.py

@@ -2,8 +2,9 @@
 
 import logging
 import subprocess as sp
-from typing import Any
+from typing import Any, Callable, Optional
 
+from frigate.const import PROCESS_PRIORITY_LOW
 from frigate.log import LogPipe
 
 
@@ -46,3 +47,124 @@ def start_or_restart_ffmpeg(
             start_new_session=True,
         )
     return process
+
+
+logger = logging.getLogger(__name__)
+
+
+def inject_progress_flags(cmd: list[str]) -> list[str]:
+    """Insert `-progress pipe:2 -nostats` immediately before the output path.
+
+    `-progress pipe:2` writes structured key=value lines to stderr;
+    `-nostats` suppresses the noisy default stats output. The output path
+    is conventionally the last token in an FFmpeg argv.
+    """
+    if not cmd:
+        return cmd
+    return cmd[:-1] + ["-progress", "pipe:2", "-nostats", cmd[-1]]
+
+
+def run_ffmpeg_with_progress(
+    cmd: list[str],
+    *,
+    expected_duration_seconds: float,
+    on_progress: Optional[Callable[[float], None]] = None,
+    stdin_payload: Optional[str] = None,
+    process_started: Optional[Callable[[sp.Popen], None]] = None,
+    use_low_priority: bool = True,
+) -> tuple[int, str]:
+    """Run an ffmpeg command, streaming progress via `-progress pipe:2`.
+
+    Args:
+        cmd: ffmpeg argv. Output path must be the last token.
+        expected_duration_seconds: Duration of the expected output clip in
+            seconds. Used to convert ffmpeg's `out_time_us` into a percent.
+        on_progress: Optional callback invoked with a percent in [0, 100].
+            Called once with 0.0 at start, again on each `out_time_us=`
+            stderr line, and once with 100.0 on `progress=end`.
+        stdin_payload: Optional string written to ffmpeg stdin (used by
+            export for concat playlists).
+        process_started: Optional callback invoked with the live `Popen`
+            once spawned — lets callers store the ref for cancellation.
+        use_low_priority: When True, prepend `nice -n PROCESS_PRIORITY_LOW`
+            so concat doesn't starve detection.
+
+    Returns:
+        Tuple of `(returncode, captured_stderr)`. Stdout is left attached
+        to the parent process to avoid buffer-full deadlocks.
+    """
+    full_cmd = inject_progress_flags(cmd)
+    if use_low_priority:
+        full_cmd = ["nice", "-n", str(PROCESS_PRIORITY_LOW)] + full_cmd
+
+    def emit(percent: float) -> None:
+        if on_progress is None:
+            return
+        try:
+            on_progress(max(0.0, min(100.0, percent)))
+        except Exception:
+            logger.exception("FFmpeg progress callback failed")
+
+    emit(0.0)
+
+    proc = sp.Popen(
+        full_cmd,
+        stdin=sp.PIPE if stdin_payload is not None else None,
+        stderr=sp.PIPE,
+        text=True,
+        encoding="ascii",
+        errors="replace",
+    )
+    if process_started is not None:
+        try:
+            process_started(proc)
+        except Exception:
+            logger.exception("FFmpeg process_started callback failed")
+
+    if stdin_payload is not None and proc.stdin is not None:
+        try:
+            proc.stdin.write(stdin_payload)
+        except (BrokenPipeError, OSError):
+            pass
+        finally:
+            try:
+                proc.stdin.close()
+            except (BrokenPipeError, OSError):
+                pass
+
+    captured: list[str] = []
+    if proc.stderr is not None:
+        try:
+            for raw_line in proc.stderr:
+                captured.append(raw_line)
+                line = raw_line.strip()
+                if not line:
+                    continue
+                if line.startswith("out_time_us="):
+                    if expected_duration_seconds <= 0:
+                        continue
+                    try:
+                        out_time_us = int(line.split("=", 1)[1])
+                    except (ValueError, IndexError):
+                        continue
+                    if out_time_us < 0:
+                        continue
+                    out_seconds = out_time_us / 1_000_000.0
+                    emit((out_seconds / expected_duration_seconds) * 100.0)
+                elif line == "progress=end":
+                    emit(100.0)
+                    break
+        except Exception:
+            logger.exception("Failed reading FFmpeg progress stream")
+
+    proc.wait()
+
+    if proc.stderr is not None:
+        try:
+            remaining = proc.stderr.read()
+            if remaining:
+                captured.append(remaining)
+        except Exception:
+            pass
+
+    return proc.returncode or 0, "".join(captured)