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import json
import re
import codecs
import logging
from subprocess import Popen, PIPE, DEVNULL
import shlex
utf8reader = codecs.getreader('utf-8')
def LoggedPopen(command, *args, **kwargs):
logging.info("Popen(command={} args={}) with kwargs={}".format(
" ".join(map(repr, command)),
" ".join(map(repr, args)),
" ".join(map(repr, kwargs))))
return Popen(command, *args, **kwargs)
def ffprobe_data(ospath):
logging.info('ffprobe %s', ospath)
process = LoggedPopen(['ffprobe', '-v', 'quiet', '-print_format', 'json',
'-show_format', '-show_streams', ospath], stdout=PIPE, stderr=DEVNULL)
data = json.load(utf8reader(process.stdout))
assert process.wait() == 0, "ffprobe failed"
process.stdout.close()
return data
def stream(ospath, ss, t):
logging.info('start ffmpeg stream h264 480p on path=%s ss=%s t=%s', ospath, ss, t)
t_2 = t + 2.0
cutter = LoggedPopen(
shlex.split("ffmpeg -ss {ss:.6f} -async 1 -i ".format(**locals())) +
[ospath] +
shlex.split("-c:a aac -strict experimental -ac 2 -b:a 44k"
""
" -c:v libx264 -pix_fmt yuv420p -profile:v high -level 4.0 -preset ultrafast -trellis 0"
" -crf 31 -vf scale=w=trunc(oh*a/2)*2:h=360"
""
" -f mpegts -output_ts_offset {ss:.6f} -t {t:.6f} pipe:%d.ts".format(**locals())),
stdout=PIPE, stderr=DEVNULL)
return cutter
def find_next_keyframe(ospath, start, max_offset):
"""
:param: start: start search pts as float '123.123'
:param: max_offset: max offset after start as float
:return: PTS of next iframe but not search longer than max_offset
"""
logging.info("start ffprobe to find next i-frame from {}".format(start))
if start == 0.0:
return 0.0
process = LoggedPopen(
shlex.split("ffprobe -read_intervals {start:.6f}%+{max_offset:.6f} -show_frames "
"-select_streams v -print_format flat".format(**locals())) + [ospath],
stdout=PIPE, stderr=DEVNULL)
data = {'frame': None}
try:
line = process.stdout.readline()
while line:
frame, name, value = re.match('frames\\.frame\\.(\d+)\\.([^=]*)=(.*)', line.decode('ascii')).groups()
if data['frame'] != frame:
data.clear()
data['frame'] = frame
data[name] = value
if 'key_frame' in data and data['key_frame'] == '1':
if 'pkt_pts_time' in data and data['pkt_pts_time'][1:-1] != 'N/A' and float(
data['pkt_pts_time'][1:-1]) > start:
logging.info("Found pkt_pts_time={}".format(data['pkt_pts_time']))
return float(data['pkt_pts_time'][1:-1])
elif 'pkt_dts_time' in data and data['pkt_dts_time'][1:-1] != 'N/A' and float(
data['pkt_dts_time'][1:-1]) > start:
logging.info("Found pkt_dts_time={}".format(data['pkt_dts_time']))
return float(data['pkt_dts_time'][1:-1])
line = process.stdout.readline()
raise Exception("Failed to find next i-frame in {} .. {} of {}".format(start, max_offset, ospath))
finally:
process.stdout.close()
process.terminate()
logging.info("finished ffprobe to find next i-frame from {}".format(start))
def calculate_splittimes(ospath, chunk_duration):
"""
:param ospath: path to media file
:return: list of PTS times to split the media, in the form of
((start1, duration1), (start2, duration2), ...)
(('24.949000', '19.500000'), ('44.449000', ...), ...)
Note: - start2 is equal to start1 + duration1
- sum(durationX) is equal to media duration
"""
def calculate_points(media_duration):
pos = 10
while pos < media_duration:
yield pos
pos += chunk_duration
duration = float(ffprobe_data(ospath)['format']['duration'])
points = list(calculate_points(duration))
adj_points = points
# for point in points:
# adj_points += [find_next_iframe(ospath, point, chunk_duration / 2.0)]
#
for (point, nextPoint) in zip([0.0] + adj_points, adj_points + [duration]):
yield ("{:0.6f}".format(point), "{:0.6f}".format(nextPoint - point))
def thumbnail_png(path, size):
logging.debug("thumbnail %s", path)
process = LoggedPopen(['ffmpegthumbnailer', '-i', path,
'-o', '-', '-s', str(size), '-c', 'png'],
stdout=PIPE, stderr=DEVNULL)
return process
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