def extract_frames(video_path: str, output_frames_dir: str, notification_path: Optional[str]=None, quality: int=0) -> None:
"""Use ffmpeg to read a video file and extract the frames.
Requires 'ffmpeg' to be on the command line.
The resulting JPEG frames will be named in the format '%06d.jpg'.
Uses notification_path to indicate whether the extraction completed;
this will be named video_path'/.finished-extraction' if None.
Will warn and write over the output dir if it exists but no file at notification_path exists.
Quality must be between 0 and 31, where 0 is the highest.
"""
if notification_path is None: notification_path = pjoin(dirname(video_path), ".finished-extraction")
if pexists(notification_path) and pexists(output_frames_dir):
logger.info("Frames directory {} is already complete; skipping.".format(output_frames_dir))
else:
if pexists(output_frames_dir):
logger.warn("Frames directory {} already exists but is incomplete. Extracting frames...".format(output_frames_dir))
else:
logger.info("Extracting frames into {}".format(output_frames_dir))
if not pexists(video_path):
raise ValueError('Cannot extract frames: video.avi does not exist')
wrap_cmd_call([
'ffmpeg',
'-i', video_path,
'-q:v', quality,
pjoin(output_frames_dir, '%06d.jpg')
])
with open(notification_path, 'w'): print('') # all done
def gen_video(video_path: str,
input_frames_dir: str,
video_frame_rate: str,
input_image_extension: str = '.jpg',
encoding: str = 'libx265',
crf: int = 0) -> None:
"""Use ffmpeg to read generate a video from frames.
Requires 'ffmpeg' to be on the command line.
The resulting JPEG frames will be named in the format '%06d.jpg'.
"""
input_format_str = pjoin(input_frames_dir,
"%06d{}".format(input_image_extension))
wrap_cmd_call([
'ffmpeg',
'-f',
'concat', # I don't remember why!
'-r',
video_frame_rate, # we don't know this because we just have frames
'-safe',
'0', # just allow any filename
'-i',
input_format_str,
'-vf',
'scale=trunc(iw/2)*2:trunc(ih/2)*2', # compatibility with some players, including QuickTime
'-c:v',
encoding,
'-crf',
crf,
'-pix_fmt',
'yuv420p',
'-y',
video_path
])
def fix_path(path: str) -> str:
# ffmpeg won't recognize './' and will simply not write images!
# and Python doesn't recognize ~
if '%' in path:
raise ValueError(
'For technical limitations (regarding ffmpeg), local paths cannot contain a percent sign (%), but "{}" does'
.format(path))
if path == '~': return os.environ['HOME'] # prevent out of bounds
if path.startswith('~'):
path = pjoin(os.environ['HOME'], path[2:])
return path.replace('./', '')
def fix_path_platform_dependent(path: str) -> str:
"""Modifies path strings to work with Python and external tools.
Replaces a beginning '~' with the HOME environment variable.
Also accepts either / or \ (but not both) as a path separator in windows.
"""
path = fix_path(path)
# if windows, allow either / or \, but not both
if platform.system() == 'Windows':
bits = re.split('[/\\\\]', path)
return pjoin(*bits).replace(":", ":\\")
else:
return path
def pjoin_sanitized_rel(*pieces: Iterable[any]) -> str:
"""Builds a path from a hierarchy, sanitizing the path by replacing /, :, <, >, ", ', \, |, ?, *, <DEL>, and control characters 0–32 with a hyphen-minus (-).
Each input to pjoin_sanitized must refer only to a single directory or file (cannot contain a path separator).
This means that you cannot have an absolute path (it would begin with os.path (probably /); use pjoin_sanitized_abs for this.
"""
return pjoin(*[_sanitize_bit(str(bit)) for bit in pieces])
def pjoin_sanitized_abs(*pieces: Iterable[any]) -> str:
"""Same as pjoin_sanitized_rel but starts with os.sep (the root directory)."""
return pjoin(os.sep, pjoin_sanitized_rel(*pieces))