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• Python cv2 script that scans a giant image to a video. Raises error : Unknown C++ exception from OpenCV code

  26 avril 2022, par Nolrenea

  I wrote a script that scans a giant image to make a video. Normally I just post my scripts straight to my Code Review account, but this script is ugly, needs to be refactored, implements only horizontal scrolling and contains a bug that I can't get rid of.

  


  It is working but not perfect, I can't get the last line at the bottom of the image, with height of image_height % 1080. If I ignore it, the code is working fine, if I try to fix it, it throws exceptions.

  


  Example :

  


  Original image (Google Drive)

  


  Video Output (Google Drive)

  


  As you can see from the video, everything is working properly except the fact that I can't get the bottom line.

  


  Full working code

  


  ---

  


  import cv2
import numpy as np
import random
import rpack
from fractions import Fraction
from math import prod

def resize_guide(image_size, target_area):
    aspect_ratio = Fraction(*image_size).limit_denominator()
    horizontal = aspect_ratio.numerator
    vertical = aspect_ratio.denominator
    unit_length = (target_area/(horizontal*vertical))**.5
    return (int(horizontal*unit_length), int(vertical*unit_length))

fourcc = cv2.VideoWriter_fourcc(*'h264')
FRAME = np.zeros((1080, 1920, 3), dtype=np.uint8)

def new_frame():
    return np.ndarray.copy(FRAME)

def center(image):
    frame = new_frame()
    h, w = image.shape[:2]
    yoff = round((1080-h)/2)
    xoff = round((1920-w)/2)
    frame[yoff:yoff+h, xoff:xoff+w] = image
    return frame

def image_scanning(file, fps=60, pan_increment=64, horizontal_increment=8, fast_decrement=256):
    image = cv2.imread(file)
    height, width = image.shape[:2]
    assert width*height >= 1920*1080
    video_writer = cv2.VideoWriter(file+'.mp4', fourcc, fps, (1920, 1080))
    fit_height = True
    if height < 1080:
        width = width*1080/height
        image = cv2.resize(image, (width, 1080), interpolation = cv2.INTER_AREA)
    aspect_ratio = width / height
    zooming_needed = False
    if 4/9 <= aspect_ratio <= 16/9:
        new_width = round(width*1080/height)
        fit = cv2.resize(image, (new_width, 1080), interpolation = cv2.INTER_AREA)
        zooming_needed = True
    
    elif 16/9 < aspect_ratio <= 32/9:
        new_height = round(height*1920/width)
        fit = cv2.resize(image, (1920, new_height), interpolation = cv2.INTER_AREA)
        fit_height = False
        zooming_needed = True
    
    centered = center(fit)
    for i in range(fps):
        video_writer.write(centered)
    if fit_height:
        xoff = round((1920 - new_width)/2)
        while xoff:
            if xoff - pan_increment >= 0:
                xoff -= pan_increment
            else:
                xoff = 0
            frame = new_frame()
            frame[0:1080, xoff:xoff+new_width] = fit
            video_writer.write(frame)
    else:
        yoff = round((1080 - new_height)/2)
        while yoff:
            if yoff - pan_increment >= 0:
                yoff -= pan_increment
            else:
                yoff = 0
            frame = new_frame()
            frame[yoff:yoff+new_height, 0:1920] = fit
            video_writer.write(frame)
    
    if zooming_needed:
        if fit_height:
            width_1, height_1 = new_width, 1080
        else:
            width_1, height_1 = 1920, new_height
        new_area = width_1 * height_1
        original_area = width * height
        area_diff = original_area - new_area
        unit_diff = area_diff / fps
        for i in range(1, fps+1):
            zoomed = cv2.resize(image, resize_guide((width_1, height_1), new_area+unit_diff*i), interpolation=cv2.INTER_AREA)
            zheight, zwidth = zoomed.shape[:2]
            zheight = min(zheight, 1080)
            zwidth = min(zwidth, 1920)
            frame = new_frame()
            frame[0:zheight, 0:zwidth] = zoomed[0:zheight, 0:zwidth]
            video_writer.write(frame)
    y, x = 0, 0
    completed = False
    while y != height - 1080:
        x = 0
        while x != width - 1920:
            if x + horizontal_increment + 1920 <= width:
                x += horizontal_increment
                frame = image[y:y+1080, x:x+1920]
                video_writer.write(frame)
            else:
                x = width - 1920
                frame = image[y:y+1080, x:x+1920]
                for i in range(round(fps/3)):
                    video_writer.write(frame)
                if y == height - 1080:
                    completed = True
        while x != 0:
            if x - fast_decrement - 1920 >= 0:
                x -= fast_decrement
            else:
                x = 0
            frame = image[y:y+1080, x:x+1920]
            video_writer.write(frame)
        if y + 2160 <= height:
            y += 1080
        else:
            y = height - 1080
    cv2.destroyAllWindows()
    video_writer.release()
    del video_writer


  


  The above the the code needed to produce the example video. It is working but the bottom line is missing.

  


  Now if I change the last few lines to this :

  


          if y + 2160 <= height:
            y += 1080
        else:
            y = height - 1080
            x = 0
            while x != width - 1920:
                if x + horizontal_increment + 1920 <= width:
                    x += horizontal_increment
                    frame = image[y:y+1080, x:x+1920]
                    video_writer.write(frame)
    cv2.destroyAllWindows()
    video_writer.release()
    del video_writer


  


  I expect it to include the bottom line, but it just throws exceptions instead :

  


  OpenCV: FFMPEG: tag 0x34363268/&#x27;h264&#x27; is not supported with codec id 27 and format &#x27;mp4 / MP4 (MPEG-4 Part 14)&#x27;&#xA;OpenCV: FFMPEG: fallback to use tag 0x31637661/&#x27;avc1&#x27;&#xA;---------------------------------------------------------------------------&#xA;error                                     Traceback (most recent call last)&#xA; in <module>&#xA;----> 1 image_scanning("D:/collages/91f53ebcea2a.png")&#xA;&#xA; in image_scanning(file, fps, pan_increment, horizontal_increment, fast_decrement)&#xA;    122                     x &#x2B;= horizontal_increment&#xA;    123                     frame = image[y:y&#x2B;1080, x:x&#x2B;1920]&#xA;--> 124                     video_writer.write(frame)&#xA;    125     cv2.destroyAllWindows()&#xA;    126     video_writer.release()&#xA;&#xA;error: Unknown C&#x2B;&#x2B; exception from OpenCV code&#xA;</module>

  


  (If you can't get the example code working I can't help you, but I am using Python 3.9.10 x64 on Windows 10, and I have this file : "C :\Windows\System32\openh264-1.8.0-win64.dll", the '.avi' format generates video files with Gibibytes (binary unit, not SI Gigabyte) of size)

  


  How to get rid of the exception ?

  


• Methods For Retaining State

  26 décembre 2011, par Multimedia Mike — General, evernote, organization

  I jump around between projects. A lot. Over the years, I have employed various methods for retaining state or context as I switch to a different project. Here’s a quick survey and a general classification of their effectiveness.

  Good

  • Evernote : This is a cloud-based note-taking service that has a web client, Mac and Windows clients, and clients for just about ever mobile platform out there. I have an account and access it via the web interface as as the Windows, iOS, and Android clients. I really like it.

  
  
  

  Okay

  • Series of text files : I have been doing this for a very long time. I have many little note-filled directories here and there that are consistently migrated to new machines but generally forgotten about. This isn’t a terrible method but can be unwieldy when you work on lots of different machines. I’m still tracking down all these directories and importing them into Evernote.

  Bad

  • Layout of desktop windows : I have a habit of working on one project in a set of windows on one desktop space and another project in a second set of windows in another space, etc. Oh, this makes me shudder just thinking about it, mostly because of living in constant fear of a power failure or some other inadvertent reset (darn you, default config’d Windows Update) that wipes the state clean (sure, all of the work might have been saved, but I was relying on those windows to be set up in just the right manner to remind me of all the things I was working on). These days, I force myself to reboot at least once a week so I can’t get too deep into this habit. When it’s time to change projects, I write up exactly what I was doing and where I left off and stick it in Evernote.
  • Open browser windows : I guess it’s common to have many, many tabs open in one’s web browser in this day and age. Like many, I use open tabs as a stack of items to read. The state problem comes when a few of the open tabs represent TODO items. Then I start living in fear that the browser might crash or be restarted in an unexpected way and I struggle to recall what 3-5 important TODO items were that I had opened in separate tabs (on top of a stack of less important items). Again, I try to shut down the browser frequently in order to break this tendency. TODO items are better filed in Evernote.
  • Unsaved data in a text editor : Okay, this is just sloppy on my part, shoving temporary data into a text editor window thinking it’s supremely ephemeral. The problem comes when it’s linked to one of the many tasks on my desktop that might be bumped down a few priority levels ; when finally returning to the context-free data, I’m at a loss to explain what it’s for. Evernote gets it, once more, with a more thorough description of what was going on.
  • Email inbox : I make an effort to ensure that my email inbox has the fewest number of messages possible. Once things are dealt with, they get filed away elsewhere. This implies that things in my inbox require action. Some things have a habit of hanging around, though. Longer items now get described in better detail and filed away in Evernote.
  • Classic paper : Thanks to Derek in the comments for reminding me of this one. Paper is a reliable standby but it can get unwieldy when Post-It Notes litter your work area. Further, it can be problematic when you have multiple physical work areas.
  • Shell history : Another method I rely on entirely too often. This is when I count on a recipe of command line incantations living on in the history buffer of my Unix shell (generally Bash). What sequence of git commands allowed me to do XYZ ? Let’s check the shell history– I sure hope it’s still in there.

  Conclusion
  I guess what I’m trying to say here is that I really like Evernote. If you have similar troubles with retaining state, try it out. I hear there are many other services similar to it with slightly varying feature sets (people rave about Microsoft OneNote). So there are plenty of options and something out there is surely a fit.

  Evernote has a free tier and a premium tier. For my meager note-taking needs, I don’t come anywhere close to the free tier’s limit but I decided to pay for a premium subscription simply because I feel like I derive so much value from the service.

  One downside, however, is that I seem to be doing a lot less blogging since I got on Evernote earlier this year (though it is where I author most of these posts nowadays ; I especially like that I have a notebook labeled “Posted” whose incrementing count reminds me that I am getting some stuff out there). I originally started this blog as a sort of technical journal in order to organize notes and projects in a central location. It’s strange to think that if Evernote existed in 2005, I might never have had a reason to start this blog.

• GDPR compliance for Matomo’s Premium Features like Heatmaps & Session Recording, Form Analytics, Media Analytics & co

  27 avril 2018, par InnoCraft

  The General Data Protection Regulation (EU) 2016/679, also referred to as RGPD in French, Datenschutz-Grundverordnung, DS-GVO in German, is fast-approaching. It is now less than 30 days until GDPR applies to most businesses around the world on 25th May 2018. If you haven’t heard of this new regulation yet, I recommend you check out our GDPR guide which we continue to expand regularly to get you up to speed with it.

  GDPR compliance in Matomo

  We are currently adding several new features to Matomo to get you GDPR ready. You will have for example the possibility to delete and export data for data subjects, delete and anonymize previously tracked data, anonymize the IP address and location, ask for consent, and more. A beta version with these features is already available. We will release more blog posts and user guides about these features soon and just recently published a post on how to avoid collecting personal information in the first place soon.

  If you are still using Piwik, we highly recommend you update to a recent version of Matomo as all versions of Piwik will NOT be GDPR compliant.

  GDPR compliance for premium features

  InnoCraft, the company of the makers of Matomo, are offering various premium features for your self-hosted Matomo so you can be sure to make the right decisions and continuously grow your business. These features are also available on the cloud-hosted version of Matomo.

  If you are now wondering how GDPR applies to these features, you will be happy to hear that none of them collect any personal information except for possibly Heatmaps & Session Recording and the WooCommerce integration. All of them also support all the new upcoming GDPR features like the possibility to export and delete data. It is important that you update your Matomo Premium Features to the latest version to use these features.

  Making Heatmaps & Session Recording GDPR compliant

  We have added several new features to make it easy for you to be GDPR compliant and in many cases you might not even have to do anything. Some of the changes include :

  • Keystrokes (text entered into form fields) are no longer captured by default.
  • You may enable the capturing of keystrokes, and all keystrokes will be anonymized by default.
  • You may whitelist certain form fields to be recorded in plain text. However, fields that likely contain personal or sensitive information like passwords, phone numbers, addresses, credit card details, names, email addresses, and more will be always anonymized to protect user privacy. (this has always been the case but we have now included many more fields).

  How personal information may still be recorded

  Nevertheless, Heatmaps and Session Recordings may still record personal or sensitive information if you show them as part of the regular website as plain text (and not as part of a form field). The below example shows an email address for a paypal account as well as a name and VAT information as a regular content.

  

  To anonymize such information, simply add a data-matomo-mask attribute to your website :

  <span data-matomo-mask>example@example.com</span>

  You can read more about this in the developer guide “Masking content on your website”.

  WooCommerce Integration

  The WooCommerce integration may record an Order ID when a customer purchases something on your shop. As the Order ID is an identifier which could be linked with your shop to identify an individual, it may be considered as personal information. Matomo now offers an option to automatically anonymize this Order ID so it is no longer considered as personal information. To enable this feature, log in to your Matomo and go to “Administration => Anonymize Data”.

  GDPR compliance for third party plugins on the Matomo Marketplace

  The Matomo Marketplace currently features over 80 free plugins. Over 50 of them are compatible with the latest Matomo 3.X version and most of them should support Matomo’s new GDPR features out of the box. If you are concerned by GDPR and are not sure if a third party plugin stores any personal information, we highly recommend you ask the developer of this plugin about the compliance.

  You can find a link to the plugin’s issue tracker by going to a plugin page and then clicking on “Github” on the bottom right.

  

  If you are a plugin developer, please read our developer guide “GDPR & How do I make my Matomo plugin compliant”.

  The post GDPR compliance for Matomo’s Premium Features like Heatmaps & Session Recording, Form Analytics, Media Analytics & co appeared first on Analytics Platform - Matomo.