wanghaisheng

Profiling an application in Mac OS X

Finding which process to profile

If your system is running slowly, perhaps a process is using too much CPU time and won't let other processes run smoothly. To find out which processes are taking up a lot of CPU time, you can use Apple's Activity Monitor.

The CPU pane shows how processes are affecting CPU (processor) activity:

wanghaisheng

#!/usr/bin/env python
# encoding: utf-8

from pprint import pformat, pprint
import logging


class PasswordMaskingFilter(logging.Filter):
    """Demonstrate how to filter sensitive data:"""

wanghaisheng

# Requirements:
# - ImageMagick binary
# - Windows.Media.Ocr.Cli binary
# - VideoSubFinder binary
#
# Official GCloud Translate Setup:
# First 500k characters / mo is free: https://cloud.google.com/translate/pricing
# Install Python Module: pip install google-cloud-translate
# Setup Google Cloud account and billing information: https://cloud.google.com/
# Make a new project and enable "Cloud Translation API": https://console.cloud.google.com/apis/dashboard

wanghaisheng

ffmpeg

Converting Audio into Different Formats / Sample Rates

Minimal example: transcode from MP3 to WMA:
ffmpeg -i input.mp3 output.wma

You can get the list of supported formats with:
ffmpeg -formats

You can get the list of installed codecs with:

wanghaisheng

#!/bin/bash
pyinstaller -F -w \
--hidden-import='email.mime.multipart' \
--hidden-import='email.mime.message' \
--hidden-import='email.mime.text' \
--hidden-import='email.mime.image' \
--hidden-import='email.mime.audio' \
--hidden-import='sqlalchemy.sql.default_comparator' \
--hidden-import='jinja2' \
main.py

wanghaisheng

import os
import ffmpeg

def compress_video(video_full_path, size_upper_bound, two_pass=True, filename_suffix='1'):
    """
    Compress video file to max-supported size.
    :param video_full_path: the video you want to compress.
    :param size_upper_bound: Max video size in KB.
    :param two_pass: Set to True to enable two-pass calculation.
    :param filename_suffix: Add a suffix for new video.

wanghaisheng

# Create a new caption file

~~~~~~~~
ffmpeg -i captions.srt captions.ass
~~~~~~~~

# Add subtitles to main video without changing it

~~~~~~~~
ffmpeg -i video.mp4  -vf "subtitles=captions.ass:force_style='OutlineColour=&H80000000,BorderStyle=4,Outline=1,Shadow=0,MarginV=20'" subtitled-video.mp4

wanghaisheng

How to Add a Watermark to Video

FFMPEG filters provide a powerful way to programmatically enhance or alter videos, and it’s fairly simple to add a watermark to a video using the overlay filter. The easiest way to install ffmpeg is to download a pre-built binary for your specific platform. Then you don’t have to worry about including and installing all the right dependencies and codecs you will be using.

Once you have ffmpeg installed, adding a watermark is as easy as passing your existing source through an overlay filter like so:

ffmpeg -i test.mp4 -i watermark.png -filter_complex "overlay=10:10" test1.mp4

Basically, we’re passing in the original video, and an overlay image as inputs, then passing it through the filter, and saving the output as test1.mp4.

wanghaisheng

wanghaisheng

from datetime import datetime
import time

#-------------------------------------------------
# conversions to strings
#-------------------------------------------------
# datetime object to string
dt_obj = datetime(2008, 11, 10, 17, 53, 59)
date_str = dt_obj.strftime("%Y-%m-%d %H:%M:%S")
print date_str