File size: 1,707 Bytes
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from fractions import Fraction
import datetime
import av
def timecode_to_seconds(
timecode: str, frame_rate: Union[int, float, Fraction]
) -> Union[float, Fraction]:
"""
Convert non-skip frame timecode into seconds since midnight
"""
# calculate whole frame rate
# 29.97 -> 30, 59.94 -> 60
int_frame_rate = round(frame_rate)
# parse timecode string
h, m, s, f = [int(x) for x in timecode.split(":")]
# calculate frames assuming whole frame rate (i.e. non-drop frame)
frames = (3600 * h + 60 * m + s) * int_frame_rate + f
# convert to seconds
seconds = frames / frame_rate
return seconds
def stream_get_start_datetime(stream: av.stream.Stream) -> datetime.datetime:
"""
Combines creation time and timecode to get high-precision
time for the first frame of a video.
"""
# read metadata
frame_rate = stream.average_rate
tc = stream.metadata["timecode"]
creation_time = stream.metadata["creation_time"]
# get time within the day
seconds_since_midnight = float(
timecode_to_seconds(timecode=tc, frame_rate=frame_rate)
)
delta = datetime.timedelta(seconds=seconds_since_midnight)
# get dates
create_datetime = datetime.datetime.strptime(
creation_time, r"%Y-%m-%dT%H:%M:%S.%fZ"
)
create_datetime = create_datetime.replace(hour=0, minute=0, second=0, microsecond=0)
start_datetime = create_datetime + delta
return start_datetime
def mp4_get_start_datetime(mp4_path: str) -> datetime.datetime:
with av.open(mp4_path) as container:
stream = container.streams.video[0]
return stream_get_start_datetime(stream=stream)
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