Made FFmpeg executable path configurable

manim/_config/default.cfg

@@ -224,6 +224,8 @@ repr_number = green
 # Uncomment the following line to manually set the loglevel for ffmpeg. See
 # ffmpeg manpage for accepted values
 loglevel = ERROR
+# defaults to the one present in path
+ffmpeg_executable = ffmpeg
 
 [jupyter]
 media_embed =

manim/_config/utils.py

@@ -252,6 +252,7 @@ class MyScene(Scene):
         "dry_run",
         "enable_wireframe",
         "ffmpeg_loglevel",
+        "ffmpeg_executable",
         "format",
         "flush_cache",
         "frame_height",
@@ -633,6 +634,10 @@ def digest_parser(self, parser: configparser.ConfigParser) -> ManimConfig:
         if val:
             self.ffmpeg_loglevel = val
 
+        # TODO: Fix the mess above and below
+        val = parser["ffmpeg"].get("ffmpeg_executable")
+        setattr(self, "ffmpeg_executable", val)
+
         try:
             val = parser["jupyter"].getboolean("media_embed")
         except ValueError:
@@ -967,6 +972,12 @@ def format(self, val: str) -> None:
         doc="Verbosity level of ffmpeg (no flag).",
     )
 
+    ffmpeg_executable = property(
+        lambda self: self._d["ffmpeg_executable"],
+        lambda self, val: self._set_str("ffmpeg_executable", val),
+        doc="Manually specify the path to the ffmpeg executable",
+    )
+
     media_embed = property(
         lambda self: self._d["media_embed"],
         lambda self, val: self._d.__setitem__("media_embed", val),

manim/constants.py

@@ -64,7 +64,6 @@
     "PI",
     "TAU",
     "DEGREES",
-    "FFMPEG_BIN",
     "GIF_FILE_EXTENSION",
     "FFMPEG_VERBOSITY_MAP",
     "VERBOSITY_CHOICES",
@@ -201,9 +200,6 @@
 DEGREES: float = TAU / 360
 """The exchange rate between radians and degrees."""
 
-# ffmpeg stuff
-FFMPEG_BIN: str = "ffmpeg"
-
 # gif stuff
 GIF_FILE_EXTENSION: str = ".gif"
 

manim/scene/scene_file_writer.py

@@ -8,6 +8,7 @@
 import os
 import shutil
 import subprocess
+import sys
 from pathlib import Path
 from typing import Any
 
@@ -20,10 +21,11 @@
 
 from .. import config, logger
 from .._config.logger_utils import set_file_logger
-from ..constants import FFMPEG_BIN, GIF_FILE_EXTENSION
+from ..constants import GIF_FILE_EXTENSION
 from ..utils.file_ops import (
     add_extension_if_not_present,
     add_version_before_extension,
+    ensure_executable,
     guarantee_existence,
     is_gif_format,
     is_png_format,
@@ -79,6 +81,14 @@ def __init__(self, renderer, scene_name, **kwargs):
         self.next_section(
             name="autocreated", type=DefaultSectionType.NORMAL, skip_animations=False
         )
+        # fail fast if ffmpeg is not found
+        if not ensure_executable(Path(config.ffmpeg_executable)):
+            raise RuntimeError(
+                "Manim could not find ffmpeg, which is required for generating video output.\n"
+                "For installing ffmpeg please consult https://docs.manim.community/en/stable/installation.html\n"
+                "Make sure to either add ffmpeg to the PATH environment variable\n"
+                "or set path to the ffmpeg executable under the ffmpeg header in Manim's configuration."
+            )
 
     def init_output_directories(self, scene_name):
         """Initialise output directories.
@@ -464,7 +474,7 @@ def open_movie_pipe(self, file_path=None):
             width = config["pixel_width"]
 
         command = [
-            FFMPEG_BIN,
+            config.ffmpeg_executable,
             "-y",  # overwrite output file if it exists
             "-f",
             "rawvideo",
@@ -547,7 +557,7 @@ def combine_files(
                     pf_path = pf_path.replace("\\", "/")
                 fp.write(f"file 'file:{pf_path}'\n")
         commands = [
-            FFMPEG_BIN,
+            config.ffmpeg_executable,
             "-y",  # overwrite output file if it exists
             "-f",
             "concat",
@@ -614,7 +624,7 @@ def combine_to_movie(self):
             )
             temp_file_path = movie_file_path.replace(extension, f"_temp{extension}")
             commands = [
-                FFMPEG_BIN,
+                config.ffmpeg_executable,
                 "-i",
                 movie_file_path,
                 "-i",

manim/utils/file_ops.py

@@ -15,6 +15,7 @@
     "is_webm_format",
     "is_mov_format",
     "write_to_movie",
+    "ensure_executable",
 ]
 
 import os
@@ -121,6 +122,16 @@ def write_to_movie() -> bool:
     )
 
 
+def ensure_executable(path_to_exe: Path) -> bool:
+    if path_to_exe.parent == Path("."):
+        executable = shutil.which(path_to_exe.stem)
+        if executable is None:
+            return False
+    else:
+        executable = path_to_exe
+    return os.access(executable, os.X_OK)
+
+
 def add_extension_if_not_present(file_name: Path, extension: str) -> Path:
     if file_name.suffix != extension:
         return file_name.with_suffix(extension)