fix: Windows环境下进度条因stdout阻塞迟迟未能显示

顺便重构一下`hevc_encode`，这样就“轻”多了。

cmps_hevc_crf18.py

@@ -46,70 +46,79 @@ def get_duration(file_path: Path):
         raise
 
 
-def read_progress(ostream_line, dur, pbar):
-    if not ostream_line.startswith("out_time_ms="):
+def set_progress(line: str, dur, pbar):
+    if not line.startswith("out_time_ms="):
         return
     try:
-        us = int(ostream_line.split('=')[1])
+        us = int(line.split('=')[1])
         if us < 0:
             return
-        secs = us / 1_000_000
-        if secs > dur * 1.1:  # Allow 10% overshoot
-            pbar.n = dur
-        else:
-            pbar.n = secs
+        current_sec = us / 1_000_000
+        pbar.n = min(current_sec, dur)
         pbar.refresh()
-    except (ValueError, OverflowError):
-        pass
+    except (ValueError, IndexError, OverflowError):
+        return
+
+
+def start_ffmpeg(infile: Path, outfile: Path):
+    cmd = [
+        "ffmpeg", "-y", "-i", str(infile),
+        "-progress", "pipe:1", "-nostats", "-loglevel", "error",
+        *COMPRESS_OPTIONS, str(outfile)
+    ]
+    return subprocess.Popen(
+        cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT,
+        bufsize=1,
+        text=True,
+        encoding='utf-8')
+
+
+def clean_on_failure(proc: subprocess.Popen, outfile: Path):
+    if proc.poll() is None:
+        proc.kill()
+        proc.wait()
+    if outfile.exists():
+        try:
+            outfile.unlink()
+        except OSError:
+            pass
 
 
 def hevc_encode(infile: Path, outfile: Path, progress: bool = True):
-    # too heavy bro.
     dur = get_duration(infile)
-    cmd = [
-        "ffmpeg", "-y", "-i", str(infile),
-        "-progress", "pipe:1", "-nostats",
-        *COMPRESS_OPTIONS, str(outfile)
-    ]
     logger.debug(f"Duration: {dur:.2f} seconds")
-    logger.debug(f"Command: {' '.join(cmd)}")
-    proc = subprocess.Popen(
-        cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
-        text=True, encoding='utf-8', bufsize=1)
-    progress = progress and is_tty()
-    pbar = None if not progress else get_progress_bar(
+    proc = start_ffmpeg(infile, outfile)
+    logger.debug(f"Command: {proc.args}")
+
+    pbar = get_progress_bar(
         total=dur, unit='s',
-        bar_format='{l_bar}{bar}| {n:.2f}/{total:.2f}({unit})')
+        bar_format='{l_bar}{bar}| {n:.2f}/{total:.2f}({unit})'
+    ) if progress and is_tty() else None
+
     try:
-        while True:
-            line = proc.stdout.readline()
-            if not line and proc.poll() is not None:
+        for line in iter(proc.stdout.readline, ''):
+            set_progress(line.strip(), dur, pbar)
+            if proc.poll() is not None:
                 break
-            if not pbar:
-                continue
-            read_progress(line.strip(), dur, pbar)
+
         proc.wait()
         if proc.returncode != 0:
-            raise subprocess.CalledProcessError(proc.returncode, cmd)
+            raise subprocess.CalledProcessError(proc.returncode, "ffmpeg")
     except (
         KeyboardInterrupt,
         subprocess.CalledProcessError
     ) as e:
-        if proc.poll() is None:
-            proc.kill()
-            proc.wait()
         logger.error(
             f"Encoding failed with code {proc.returncode}:"
             f" {e.__class__.__name__}")
-        if outfile.exists():
-            try:
-                outfile.unlink()
-            except OSError:
-                pass
+        clean_on_failure(proc, outfile)
         raise
     finally:
         if pbar:
             pbar.close()
+        proc.stdout.close()
 
 
 def build_file_list(srcdir, extensions):