File size: 2,289 Bytes
e37c13d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | """ffmpeg encoders for the published video streams.
RGB / tactile -> H.264 yuv444p CRF18 (visually lossless, seekable)
depth -> FFV1 gray16le (mathematically lossless, millimetres)
"""
from __future__ import annotations
import subprocess
from pathlib import Path
import numpy as np
from .config import CRF, FPS, H, W
class VideoWriter:
"""Streaming ffmpeg writer. Use as a context manager and `write()` blocks."""
def __init__(self, path: Path, pix_fmt="bgr24", codec="libx264",
width=W, height=H, fps=FPS):
self.path = Path(path)
self.path.parent.mkdir(parents=True, exist_ok=True)
self._cmd = self._build(pix_fmt, codec, width, height, fps)
self._proc = None
def _build(self, pix_fmt, codec, width, height, fps):
cmd = ["ffmpeg", "-y", "-hide_banner", "-loglevel", "error",
"-f", "rawvideo", "-pix_fmt", pix_fmt,
"-s", f"{width}x{height}", "-r", str(fps), "-i", "-"]
if codec == "libx264":
cmd += ["-c:v", "libx264", "-profile:v", "high444", "-preset", "medium",
"-crf", CRF, "-pix_fmt", "yuv444p", "-movflags", "+faststart"]
elif codec == "ffv1":
cmd += ["-c:v", "ffv1", "-level", "3", "-pix_fmt", "gray16le"]
else:
raise ValueError(f"unknown codec {codec!r}")
return cmd + ["-an", str(self.path)]
def __enter__(self):
self._proc = subprocess.Popen(self._cmd, stdin=subprocess.PIPE)
return self
def write(self, block: np.ndarray) -> None:
self._proc.stdin.write(np.ascontiguousarray(block).tobytes())
def __exit__(self, exc_type, exc, tb):
if self._proc.stdin:
self._proc.stdin.close()
rc = self._proc.wait()
if rc != 0 and exc_type is None:
raise RuntimeError(f"ffmpeg failed ({rc}) writing {self.path}")
return False
def rgb_writer(path: Path) -> VideoWriter:
"""8-bit colour stream. Feed BGR blocks (ffmpeg's native order)."""
return VideoWriter(path, pix_fmt="bgr24", codec="libx264")
def depth_writer(path: Path) -> VideoWriter:
"""16-bit depth stream, lossless. Feed uint16 millimetre blocks."""
return VideoWriter(path, pix_fmt="gray16le", codec="ffv1")
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