framereader: eliminate tempfile usage (#30289)

tools/lib/framereader.py

@@ -3,7 +3,6 @@ import os
 import pickle
 import struct
 import subprocess
-import tempfile
 import threading
 from enum import IntEnum
 from functools import wraps
@@ -168,31 +167,21 @@ def rgb24tonv12(rgb):
 
 
 def decompress_video_data(rawdat, vid_fmt, w, h, pix_fmt):
-  # using a tempfile is much faster than proc.communicate for some reason
-
-  with tempfile.TemporaryFile() as tmpf:
-    tmpf.write(rawdat)
-    tmpf.seek(0)
-
   threads = os.getenv("FFMPEG_THREADS", "0")
   cuda = os.getenv("FFMPEG_CUDA", "0") == "1"
-    args = ["ffmpeg",
+  args = ["ffmpeg", "-v", "quiet",
           "-threads", threads,
           "-hwaccel", "none" if not cuda else "cuda",
           "-c:v", "hevc",
           "-vsync", "0",
           "-f", vid_fmt,
           "-flags2", "showall",
-            "-i", "pipe:0",
+          "-i", "-",
           "-threads", threads,
           "-f", "rawvideo",
           "-pix_fmt", pix_fmt,
-            "pipe:1"]
-    with subprocess.Popen(args, stdin=tmpf, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL) as proc:
-      # dat = proc.communicate()[0]
-      dat = proc.stdout.read()
-      if proc.wait() != 0:
-        raise DataUnreadableError("ffmpeg failed")
+          "-"]
+  dat = subprocess.check_output(args, input=rawdat)
 
   if pix_fmt == "rgb24":
     ret = np.frombuffer(dat, dtype=np.uint8).reshape(-1, h, w, 3)