some changes

cht/stream/ffmpeg.py

@@ -1,17 +1,13 @@
 """
 Thin wrapper around ffmpeg-python for building and running ffmpeg pipelines.
 
-All ffmpeg command construction goes through this module so manager.py
-and other consumers never build raw CLI arg lists.
-
+All ffmpeg command construction goes through this module.
 Uses ffmpeg-python's own run/run_async for subprocess management.
 """
 
 import logging
-import os
 import signal
 import subprocess
-from pathlib import Path
 
 import ffmpeg
 
@@ -20,84 +16,37 @@ log = logging.getLogger(__name__)
 GLOBAL_ARGS = ("-hide_banner", "-loglevel", "warning")
 
 
-def receive_to_pipe(stream_url, segment_dir=None, segment_duration=60):
-    """Receive mpegts stream and pipe to stdout for mpv.
+def receive_and_record(stream_url, output_path):
+    """Receive mpegts stream and write to a single growing file.
 
-    If segment_dir is provided, also saves segments to disk.
-    Uses pipe (not fifo) so OS kernel buffers prevent blocking.
+    mpv reads this file for DVR-style playback.
+    ffmpeg scene detection runs on this file for frame extraction.
+    Audio is preserved in the recording (muxed mpegts).
     """
     stream = ffmpeg.input(stream_url, fflags="nobuffer", flags="low_delay")
-
-    out_pipe = ffmpeg.output(stream, "pipe:", c="copy", f="mpegts")
-
-    if segment_dir:
-        out_segments = ffmpeg.output(
-            stream,
-            str(segment_dir / "segment_%04d.ts"),
-            c="copy",
-            f="segment",
-            segment_time=segment_duration,
-            reset_timestamps=1,
-        )
-        return ffmpeg.merge_outputs(out_pipe, out_segments).global_args(*GLOBAL_ARGS)
-
-    return out_pipe.global_args(*GLOBAL_ARGS)
-
-
-def receive_and_segment(stream_url, segment_dir, segment_duration=60):
-    """Receive mpegts stream and save as segmented .ts files."""
-    stream = ffmpeg.input(stream_url, fflags="nobuffer", flags="low_delay")
     return (
-        ffmpeg.output(
-            stream,
-            str(segment_dir / "segment_%04d.ts"),
-            c="copy",
-            f="segment",
-            segment_time=segment_duration,
-            reset_timestamps=1,
-        )
+        ffmpeg.output(stream, str(output_path), c="copy", f="mpegts")
         .global_args(*GLOBAL_ARGS)
     )
 
 
-def receive_and_segment_with_monitor(stream_url, segment_dir, fifo_path, segment_duration=60):
-    """Receive stream, save segments AND tee to a named pipe for monitoring."""
-    if not fifo_path.exists():
-        os.mkfifo(str(fifo_path))
-
-    stream = ffmpeg.input(stream_url, fflags="nobuffer", flags="low_delay")
-
-    out_segments = ffmpeg.output(
-        stream,
-        str(segment_dir / "segment_%04d.ts"),
-        c="copy",
-        f="segment",
-        segment_time=segment_duration,
-        reset_timestamps=1,
-    )
-
-    out_monitor = ffmpeg.output(
-        stream,
-        str(fifo_path),
-        c="copy",
-        f="mpegts",
-    )
-
-    return ffmpeg.merge_outputs(out_segments, out_monitor).global_args(*GLOBAL_ARGS)
-
-
 def extract_scene_frames(input_path, output_dir, scene_threshold=0.3,
-                         max_interval=30, start_number=1):
+                         max_interval=30, start_number=1, start_time=0.0):
     """Extract frames from a file on scene change.
 
     Uses ffmpeg select filter with scene detection and a max-interval fallback.
-    Returns (stdout bytes, stderr bytes) for timestamp parsing.
+    start_time: skip to this position before processing (avoids re-scanning).
+    Returns (stdout, stderr) as decoded strings for timestamp parsing.
     """
     select_expr = (
         f"gt(scene,{scene_threshold})"
         f"+gte(t-prev_selected_t,{max_interval})"
     )
-    stream = ffmpeg.input(str(input_path))
+    input_opts = {}
+    if start_time > 0:
+        input_opts["ss"] = str(start_time)
+
+    stream = ffmpeg.input(str(input_path), **input_opts)
     stream = stream.filter("select", select_expr).filter("showinfo")
 
     output = (
@@ -116,23 +65,6 @@ def extract_scene_frames(input_path, output_dir, scene_threshold=0.3,
     return stdout.decode("utf-8", errors="replace"), stderr.decode("utf-8", errors="replace")
 
 
-def extract_audio_pcm(input_path):
-    """Extract audio as 16kHz mono PCM wav, returning an output node for piping."""
-    stream = ffmpeg.input(str(input_path))
-    return (
-        ffmpeg.output(
-            stream.audio,
-            "pipe:",
-            vn=None,
-            acodec="pcm_s16le",
-            ar=16000,
-            ac=1,
-            f="wav",
-        )
-        .global_args(*GLOBAL_ARGS)
-    )
-
-
 def run_async(output_node, pipe_stdout=False, pipe_stderr=False):
     """Start an ffmpeg pipeline asynchronously via ffmpeg-python's run_async."""
     log.info("run_async: %s", " ".join(output_node.compile()))