python
Using FFmpeg to programmatically slice and splice video
My wife has a research project in which she needs to analyze brief (8-second) segments of hundreds of much longer videos. My goal was to take the videos (~30 minutes each) and cut out only the relevant sections and splice them together, including a static marker between each segment. This should allow her and her colleagues to analyze the videos quickly and using precise time-points (instead of using a slider in a video player to locate and estimate time-points). I’ve posted my notes from this process below for my own reference, and in case it should prove useful to anyone else.
To my knowledge, the best tool for the job is FFmpeg, an open source video tool. › Continue reading
Twitter Status IDs and Direct Message IDs
I recently created a Magic Eight Ball twitter-bot as a demo. Written in Python using the python-twitter API wrapper, it runs every 2 minutes and polls twitter for new replies (status updates containing @osric8ball) and direct messages (DMs) to osric8ball. If there are any, it replies with a random 8-Ball response.
Every status update and DM has an associated numeric ID. Initially, I stored the highest ID in a log file and used that when I polled twitter (i.e. “retrieve all replies and DMs with ID > highest ID”). However, I discovered that status updates and DMs apparently are stored in separate tables on twitter’s backend, as they have a separate set of IDs. Since the highest status ID was an order of magnitude larger than the highest DM ID, my bot completely ignored all DMs. This was not entirely obvious at first, as the IDs looked very similar, other than an extra digit: 2950029179 and 273876291.
My fix for this was to store both the highest status update ID and the highest DM ID is separate log files.
Another interesting twist: you have to be a follower of a user in order to send that user a DM. › Continue reading
Pages
Archives
- April 2012
- March 2012
- January 2012
- December 2011
- November 2011
- September 2011
- August 2011
- July 2011
- June 2011
- May 2011
- March 2011
- February 2011
- January 2011
- November 2010
- May 2010
- March 2010
- January 2010
- December 2009
- October 2009
- September 2009
- August 2009
- July 2009
- May 2009
- April 2009
- March 2009
- February 2009
- January 2009
- December 2008
- November 2008
- October 2008
- September 2008
- August 2008
- July 2008
- June 2008
- May 2008
- April 2008
- March 2008