Using Amazon Transcribe to get 2020 Presidential Debate #1 Speaker Segments

TLDR: I used Amazon Transcribe to transcribe the first presidential debate audio that included timestamps for each word, to create the following speaker timeline visualization (created using a Plotly timeline chart). Click image to view full size visualization.

After watching the US 2020 Presidential Debate #1  I was curious to see if there was an automated way to identify when a debater was interrupted while speaking during their 2 minutes allotted time.

I envisioned a timestamped transcription that could be used to create a timeline of each speaker talking and identifying overlaps where one speaker was talking first and second speaker starts during that talk ‘segment’.

Unfortunately Amazon Transcribe purposefully shifts all of the transcribed words’ start times to eliminate overlapping word time periods. Therefore, it wasn’t possible to get the data I wanted to satisfy my curiousity using Amazon Transcribe.

It may be possible to infer overlapping speaker talking and interruptions with multiple small interleaving speaker segments but that would be hard to distinguish from two people having a conversation with the Amazon Transcribe results. Might investigate alternative automated transcription methods and make new post. TBD.

Here is link to Github repository containing code.

Getting Debate Audio

I used youtube-dl to download the debate audio from a CSPAN video recording of the debate which was on YouTube. I used Libav to trim off the beginning ~30 minute portion of the audio which was recorded debate stage prep before the debate actually started.

Using Amazon Transcribe

I used Amazon Transcribe to create a transcription of the debate audio.

The transcription contains “segments” for each identified speaker in the audio. These segments identify the speaker and have start and end times. Amazon Transcribe seemed to be pretty good at identifying the speakers in the audio. The transcription itself was not perfect.

Amazon Transcribe requires an audio file in an S3 bucket. The audio was an mp3 file.

Uploading the file and running the Amazon Transcribe job were done using Python and AWS Boto3 SDK.

The transcription process produces a JSON file that is saved in the S3 bucket. The JSON file contains the following content and high-level structure:

    • jobName – job name specified for transcription.
    • accountId – Amazon account or IAM account?
    • results– contains elements below:
      • transcripts – complete text of audio transcription.
      • speaker_labels – contains elements below:
        • speakers – the number of speakers specified for transcription.
        • segments – one or more time based segments by speaker. Has start and end time, and speaker label.
          • items – segments have one or more time based items. Has start and end time, and speaker label. Does not include word.
      • items – separate section with more than one item, one for each word or inferred punctuation. Includes word along with alternatives with confidence value for each word. Has start and end time, but does not have speaker label.
    • status – of transcription job eg in-process, failed or completed.

Processing Transcription

The JSON file read into a Pandas dataframe that was processed and used as data source for a Plotly timeline chart.

The timeline chart data was created from the [‘results’][‘speaker_labels’][‘segment’] elements which identified the speaker and had segment start and end times.

A Plotly timeline chart requires datetimes for period start and end and x-axis values. However the transcription has start and end times that are elapsed seconds since audio starts.

So “fake” start and end dates were created by adding arbitrary date (1970-01-01) to a “HH:mm:ss” value created from the seconds values.

AWS Textract – WHO “Draft landscape of COVID-19 candidate vaccines” – convert PDF to csv

TLDR: I extracted text from the WHO’s vaccine candidate PDF file using AWS Textract and made text into a set of interactive web pages . View the AWS Textract PDF extract output csv files in this Github repository and view and interact with the web pages here.

The World Health Organization (WHO) maintains a regularly updated PDF document named Draft landscape of COVID-19 candidate vaccines which contains all COVID-19 vaccine candidates and treatments currently being developed and their status.

The main content in this PDF document is a tabular format with one vaccine or treatment per row. There is also some non-tabular text content including introduction text and footer notes.

I wanted a machine readable format version of this PDF document’s table data so I could do some analysis. This meant I needed to do PDF text extraction. There are lots of solutions. I ended up using Amazon Textract to extract the PDF into csv file format.

“Amazon Textract is a service that automatically detects and extracts text and data from scanned documents. It goes beyond simple optical character recognition (OCR) to also identify the contents of fields in forms and information stored in tables”

Using Textract

You need an AWS account to use Textract and it does cost to use the service (see costs for this analysis at bottom of post).

The Textract service has UI that you can use to upload and process documents manually eg not using code. However, it is also included in the AWS Boto3 SDK so you can code or use command line automation with Textract too.

I used the manual UI for this one time processing of the PDF. However, if I was to automate this to regularly extract data from the PDF I would use Python and Boto3 SDK. The Boto3 SDK Textract documentation and example code are here.

Use this link to go directly to the AWS Textract UI once you are logged into your AWS console.

The Textract UI is quite intuitive and easy to use. You manually upload your PDF file, it processes the file and shows you the interpreted content which is described in “blocks” of text, tables, images, and then you can select which to extract from document.

During this process the the manual Textract process asks permission to create a new S3 folder in your account where it uploads the PDF before processing it. This is because Textract will only accept documents from S3.

Screenshot of Textract UI

The Textract PDF extract output is a zip file contained bunch of files that is automatically downloaded to your computer. The zip file contained the files listed below.

These 3 files appear to be standard information for any AWS Textract job.

    • apiResponse.json
    • keyValues.csv
    • rawText.txt

The rest of the AWS Textract output will vary depending on your document. In this case it returned a file for each table in the document.

    • table-1.csv
    • table-2.csv
    • table-3.csv
    • table-4.csv
    • table-5.csv
    • table-6.csv
    • table-7.csv
    • table-8.csv
    • table-9.csv

To process the AWS Textract table csv files , I imported them into a Pandas dataframe. The Python code used is in Github.

There was some minor clean-up of OCR/interpreted tabular data which included stripping trailing white spaces from all text and removing a few blank table rows. In addition the PDF tables had two header rows that were removed and manually replaced with single header row. Also there were some minor OCR mistakes for example some zeros were rendered as capital letter ‘O’ and some words were missing last letter.

The table columns in the *WHO Draft landscape of COVID-19 candidate vaccines* PDF document tables are shown below. Textract did a good job of capturing these columns.

Vaccine columns:

    • COVID-19 Vaccine developer or manufacturer
    • Vaccine platform
    • Type of candidate vaccine
    • Number of doses
    • Timing of doses
    • Route of administration
    • Stage – Phase 1
    • Stage – Phase 1/2
    • Stage – Phase 2
    • Stage – Phase 3

Treatment columns:

    • Platform
    • Type of candidate vaccine
    • Developer
    • Coronavirus target
    • Current stage of clinical evaluation/regulatory -Coronavirus candidate
    • Same platform for non-Coronavirus candidates

Cost for procesing 9 page PDF file 3 times:

I copied the costs from AWS Billing below to give readers some idea of what Textract costs.

Amazon Textract USE1-AsyncFormsPagesProcessed $1.35

AsyncPagesProcessed: 0-1M pages of AnalyzeDocument Forms, $50 USD per 1000 pages 27.000 pages $1.35

Amazon Textract USE1-AsyncTablespages Processed $0.41
Asyncpages Processed: 0-1M pages of AnalyzeDocument Tables, $15 USD per 1000 pages 27.000 pages $0.41

Amazon Textract USE1-SyncFormspages Processed $0.30
Syncpages Processed: 0-1M pages of AnalyzeDocument Forms, $50 USD per 1000 pages 6.000 pages $0.30

Amazon Textract USE1-SyncTablespages Processed $0.09
Syncpages Processed: 0-1M pages of AnalyzeDocument Tables, $15 USD per 1000 pages 6.000 pages $0.09

HTML tabular presentation of Textract output data

View it here.


Scraping public health web page to get data

During the 2020 COVID-19 pandemic in Canada I wanted to get COVID-19 confirmed cases counts data for the city of Montreal.

The data I wanted was made freely available by the Quebec Government’s Health Montreal website in a tabular format that was updated regularly.

I wanted to be able to use this data for this Leaflet choropleth map visualization. If interested, read more details on this visualization in another blog post.

There are many ways to get data from web pages. First I did it manually by copy and paste into Excel. This is ok for a one time analysis. You can even use Excel Power Query web feature to automate this a bit more. However, if you want to fully automate getting data from a web page you should use web scraping techniques.

Note that the code described below is available in this Github repository

Initial data retrieval and transformation done using Excel
To get the web page data, at first, I simply manually copied and pasted into an Excel workbook. This was quite easy to do as the tabular format copies and pastes nicely into an Excel grid.

To automate this a bit more and do some more complex data transformations I switched to using Excel Power Query’s web query feature and Power Query to transform the data for the choropleth map visualization.

Full automation and scheduling using Python, cron job and AWS S3
However, this was intended to be an ongoing analysis so it needed to fully automated and the data retrieval and transformation process to be run on a scheduled basis.

In addition to scraping the data from the web page, the data had to be made available somewhere on the internet where the choropleth map visualization could freely access it by a url.

As the choropleth map visualization is hosted on I could have used Git on the web server to do an automated, scheduled push of new data from web server to the Github repository. I decided to give this a pass and try it some other time.

Instead, I choose to upload the data to public AWS S3 bucket that the choropleth map visualization could access with a simple url for each data file.

Everything from scraping the website to uploading data to AWS S3 was done in Python. The Python code is run on scheduled basis using a cron job on a web server. The cron job runs a few times each evening when the data is usually updated on the website.

Python, BeautifulSoup4, Requests and Pandas to retrieve and transform the web page data and create a JSON file that could be uploaded to AWS S3 bucket and made available to the choropleth map visualization.

Python module Boto was used to upload the data from web server to an AWS S3 bucket.

Let go through the code.

BeautifulSoup4 was used to get web page and find the specific table that holds the tabular data as below. The table with the counts by neighbourhood was the 4th table in the web page:

# get health montreal webpage html
 url = ''
 page = requests.get(url)
 soup = BeautifulSoup(page.content, 'html.parser')
 # get all tables on webpage
 tables = soup.find_all('table')
 # select 4th table in list of tables on webpage
 table = tables[3]

Then Pandas is used to read that table into a dataframe and then add more readable consistent column headers as below:

  # read table into pandas dataframe
    df_table_data_all_cols = pd.read_html(str(table))[0]
    # rename columns 
    df_table_data_all_cols.columns = ['region_name', 'case_count','case_percent','case_per_100k','mort_count', 'mort_per_100k']
    df_table_data = df_table_data_all_cols[['region_name','case_count','case_percent','case_per_100k','mort_count', 'mort_per_100k']]

The web page table dataframe was merged with the “lookup” dataframe. This merging is basically equivalent to a SQL JOIN::

   # join lookup table to scrape data to get geojson_name field to use on map
    df_table_data_w_lookup = pd.merge(df_montreal_regions_lookup, df_table_data, left_on='website_name', right_on='region_name', how='left')
    df_table_data_final = df_table_data_w_lookup[['website_name', 'region_name', 'geojson_name', 'case_count','case_percent','case_per_100k','mort_count', 'mort_per_100k']]

The lookup table has one row per Montreal neighbourhood with 2 columns: one for the Health Montreal website neighbourhood name and a second for the Leaflet map’s geoJSON geographical region boundary names. This is required because the Health Montreal website neighbourhood names were not identical to the map’s geographical region boundary names.

Of course, I could have modified the map’s geographical region boundary names to reflect Health Canada naming convention but creating a “lookup” table was easier and provided flexibility in case Health Montreal table’s names changed (which they did, in fact several times!).

The Python code does a check to see if current data on the web page is same as previously retrieved. I only wanted to upload new data to AWS S3 if it was necessary. This check is done by comparing the total case count on web page to previous case count:

   # if new is diff from prev, update files and upload to aws
    if str_total_case_prev == str_total_case_new:
        scrape_result = 'no change, case total is still same as prev case total: ' + str_total_case_prev
        # create scrape result string to print to cron log
        scrape_result = 'new cases found: ' + str_total_case_new + ' prev case total: ' + str_total_case_prev
        # transform pandas dataframe into dictionary to write as json
        json_table = df_table_data_final.to_dict('records')
        # write new montreal covid_data to json file for map to use
        with open('uploads/montreal_covid_data.json', 'w') as f:
            f.write('var covid_data = \n')
            json.dump(json_table, f, ensure_ascii=True)
            # write today's date to use in index page as last updated date
        with open('uploads/last_update_date.json', 'w') as f:
            f.write('var last_update_date = \n')
            json.dump(todays_date, f)

If the counts are the same then code stops. If the new count is different than the previous count the code create new data that is uploaded to the AWS S3 bucket.

A scrape_results string is also created that is written to the cron log.

Uploading to an AWS S3 bucket is conceptually quite straightforward. The Python module Boto makes it easy to create the connection and bucket definitions:

  ## create aws S3 connection
    conn = S3Connection(canada_covid_aws_keys['AWS_KEY'], canada_covid_aws_keys['AWS_SECRET'])
    bucket = conn.get_bucket('canada-covid-data')

The bucket itself has a Public Policy so anyone can read the data files. Each bucket file has a public url so the map visualization can simply reference these to get the data.

However, authentication is required in order transfer the data from the web server to the S3 bucket. So there is some behind the scenes setup work to do on the AWS side. First, to create and configure the bucket and second to create and configure the IAM objects to do authentication.

An IAM User Policy was created to allow that User to write, read and delete on that bucket. The User has an AWS key and secret that are provided as part of the Boto connection to do the S3 authentication. Of course the key and secret should not be exposed and are imported into the Python code from another non-public location on the web server.

Once connection is made, then the Python code deletes the existing files on S3 before uploading new files:

    # identify files to be uploaded to aws
    upload_files = [f for f in listdir(upload_path) if isfile(join(upload_path, f))]

    # delete existing files from bucket
    for key in bucket.list():

    # write new files to bucket 
    for file in upload_files:
        k = Key(bucket)
        k.key = file
        k.set_contents_from_filename(upload_path + file)

The Leaflet map visualization will then show the new updated data next time it is viewed or browser page refreshed.

AWS S3 csv file as D3 report data source

This is an example of how to read a csv file retrieved from an AWS S3 bucket as a data source for a D3 javascript visualization.

The D3 visualization would be an HTML document hosted on a web server. 

You will use the AWS SDK to get the csv file from the S3 bucket and so you need to have an AWS S3 bucket key and secret but I won’t cover that in this post.

The key point of this post is to highlight that the bucket.getObject function data is read into D3 using  d3.csv.parse(data.Body.toString());  

Another note is that d3.csv.parse is for D3 version 3. Older versions use d3.csvParse. 

Once implemented, whenever the webpage is refreshed it retrieves latest csv file from the S3 bucket and the D3 visualization is updated.

<script src=""></script>

<script type="text/javascript">

// aws key and secret (note these should be retrieved from server not put as plain text into html code)
AWS.config.accessKeyId = 'xxxxxxxxxxxxxxxxxxxxxxx';
AWS.config.secretAccessKey = 'xxxxxxxxxxxxxxxxxxxxxxx';
AWS.config.region = 'us-east-1';

// create the AWS.Request object
var bucket = new AWS.S3();

// use AWS SDK getobject to retrieve csv file
    Bucket: 'my-S3-bucket', 
    Key: 'myfile.csv'

// function to use the data retrieve 
function awsDataFile(error, data) {
    if (error) {
        return console.log(error);

        // this where magic happens using d3.csv.parse to read myCSVdata.Body.toString()
    myCSVdata = d3.csv.parse(data.Body.toString()); 

        // now loop through data and get fields desired for visualization 
    var counter = 0;
    myCSVdata.forEach(function(d) {
            d.field1= +d.field1;
            d.field2= +d.field2;
            countLoop = counter++;

        // now you can create rest of D3 vizualization here 
        // for example like this example

        my D3 vizualization code here

// this closes bucket.getObject 




AWS RDS Postgres database external secure connection

Require an SSL Connection to a PostgreSQL DB Instance? Here are some notes from my investigations.

Not great examples on that but take a look at this other documentation for secure connection to Redshift database which has working examples

Go to EC2 Security Groups, and modify the Inbound PostgreSQL rule from the VPS server eg something like “sg-c2a232b8” to either your current IP or to Anywhere eg

Setting it to Anywhere means both you and your EC2 application can connect to the database, but so can the rest of the world. Setting it to just your current IP means only you and anyone else on that IP (if it is a work or university IP) can connect to the database. Of course, they will need the key, username and password so reasonably secure.