🐛 fix(av1-transfer): use bash exec -a instead of executable= to rename ffmpeg process

subprocess.Popen with executable= fails on linuxbrew due to symlink/execve
incompatibility. Use bash exec -a so ffmpeg is resolved via PATH instead.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

av1-transfer/main.py

@@ -20,7 +20,7 @@ import argparse
 import ctypes
 import ctypes.util
 import queue
-import shutil
+import shlex
 import subprocess
 import sys
 from concurrent.futures import ThreadPoolExecutor, as_completed
@@ -130,22 +130,19 @@ def transcode_one_file(file_info, overall_bar, slot_bars, slot_queue, process_na
         ]
 
         if process_name:
-            # 用 executable 指定真实路径，argv[0] 设为别名
-            # 等效于 shell 的: exec -a <process_name> ffmpeg ...
-            ffmpeg_exe = shutil.which("ffmpeg")
-            if not ffmpeg_exe:
-                raise RuntimeError("找不到 ffmpeg 可执行文件")
-            cmd = [process_name] + ffmpeg_args
+            # 用 bash 的 exec -a 重命名 ffmpeg 进程的 argv[0]
+            # ffmpeg 通过 PATH 查找，避免 execve 直接调用 symlink 的兼容问题
+            shell_args = " ".join(shlex.quote(str(a)) for a in ffmpeg_args)
             proc = subprocess.Popen(
-                cmd,
-                executable=ffmpeg_exe,
+                f"exec -a {shlex.quote(process_name)} ffmpeg {shell_args}",
+                shell=True,
+                executable="/bin/bash",
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE,
             )
         else:
-            cmd = ["ffmpeg"] + ffmpeg_args
             proc = subprocess.Popen(
-                cmd,
+                ["ffmpeg"] + ffmpeg_args,
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE,
             )