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May 8, 2018 23:01
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Fun with Python subprocess! Works on Python 2.7.x.
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import json | |
import logging | |
import os | |
import subprocess | |
logger = logging.getLogger(os.path.splitext(os.path.basename(__file__))[0]) | |
# If you have ever used jq and tried to use it in Python but ran into | |
# issues with building a new jq instance rather than using the system- | |
# available jq binary then this may be beneficial to you! | |
# Please note that this has been tested on rather large JSON documents | |
# but it can be quite easy to overrun the buffers and cause the | |
# operation to fail but this is a good start. | |
def execute_jq_cmd(data_str, jq_query): | |
proc = subprocess.Popen( | |
'jq \'{}\' -'.format(jq_query), | |
shell=True, | |
stdin=subprocess.PIPE, | |
stdout=subprocess.PIPE, | |
stderr=subprocess.PIPE | |
) | |
proc.stdin.write(data_str) | |
proc_comm = proc.communicate() | |
proc_stdout = proc_comm[0].strip() | |
proc_stderr = proc_comm[1].strip() | |
if proc_stdout: | |
try: | |
return json.loads(proc_stdout) | |
except Exception as err: | |
logger.exception(err) | |
return [] | |
elif proc_stderr: | |
raise Exception(proc_stdout) | |
# This assumes that you already have ffmpeg/ffprobe installed. | |
def ffprobe_json(file_path): | |
"""Execute ffprobe and return a dictionary object containing media medata. | |
:param file_path: Path of the file to analyze. | |
:type file_path: str | |
:return: Dictionary structure containing media metadata. | |
:rtype: dict | |
""" | |
file_path = os.path.abspath(file_path) | |
FFPROBE_CMD = [ | |
'ffprobe', | |
# '/usr/local/bin/ffprobe', | |
'-v quiet', | |
'-show_format', | |
'-show_streams', | |
'-show_programs', | |
'-show_chapters', | |
'-show_private_data', | |
'-show_pixel_formats', | |
'-show_error', | |
'-print_format json', | |
'-i "{}"'.format(file_path) | |
] | |
p = subprocess.Popen( | |
' '.join(FFPROBE_CMD), | |
shell=True, | |
stdout=subprocess.PIPE, | |
stderr=subprocess.PIPE | |
) | |
# Better handling of large quanitties of data without overloading buffers. | |
draineddata = [] | |
drainerthread = threading.Thread(target=draineddata.extend, args=(p.stdout,)) | |
drainerthread.daemon = True | |
drainerthread.start() | |
p.wait() | |
drainerthread.join() | |
out = ''.join(draineddata) | |
data_dict = {} | |
if out: | |
data_dict.update(json.loads(out)) | |
return data_dict |
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