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• How to add subtitles to PowerPoint presentation

  5 septembre 2018, par ppdlx

  Okay, to clear things up I will say that I’m posting here because I found the answer and want to help people in future who come upon the same problem. Since PowerPoint is not the right tool to title an presentation I will tell you my way of doing this. If you can do it in PowerPoint alone, super for you but I could not do it in PowerPoint alone, therefore this way. So what I did is the following, I simply recorded the presentation and made subtitles for it and in the final I hardcoded the subtitles into the video. Here is how I did it.

  How to add subtitles to your PowerPoint presentation

  First, I downloaded the latest SnagIt software from their official website. You can have a free trial there. Click here to download SnagIt. Then using SnagIt I recorded my whole screen and played the presentation. I made a video file of the presentation. Let’s call it presentation.mp4.

  Then I downloaded my subtitle making software, an awesome open source program called Subtitle Edit from it’s official website. It’s really simple to use it and it is awesome and user friendly. It doesn’t take too long to subtitle a three minute presentation. When you are satisfied with the subtitles save them as .srt and call them whatever you like. Now we have a video file and corresponding subtitles for it.

  Now we need to hardcode the subtitles into the video file, in other words to burn the subtitles to the video. I did this using another awesome open source software called ffmpeg. See the website and download it from official ffmpeg website. Extract it somewhere and for convinience put subtitle and video file to it’s bin directory. You can put it elsewhere if you like it that way. The first command I used is to transform .srt to .ass.

  ffmpeg -i subtitles.srt subtitles.ass

  Afterwards it’s easy to make a subtitled video file with the following command :

  ffmpeg -i presentation.mp4 -vf ass=subtitles.ass presentation_subtitled.mp4

  I am not sure for the command and can’t get now to see the correct command but if it fails you can seek help on this page.

  Now that we have our presentation_subtitled.mp4 we can now trim the video to our likings.

  ffmpeg -i presentation_subtitled.mp4 -ss 00:01:00 -to 00:02:00 -c copy presentation_final.mp4

  Of course, edit the -ss and -to option, it’s the start time and the end time of your video.

  That’s it ! Now you have your presentation_final.mp4 video file where you have your presentation with subtitles. Ffmpeg is awesome because you can convert it to any format you like.

  You have some help with hardcoding subtitles on Subtitle Edit web page, but one software gave me a virus, one software didn’t work, and after trial and error this is the way that worked for me and it’s really convinied due to great open source software - Subtitle Edit and ffmpeg.

• Improving accuracy of Google Cloud Speech API

  17 août 2018, par Shaikat Haque

  I am currently recording audio from a web page on my Mac OS computer and running it through the cloud speech api to produce a transcript. However, the results aren’t that accurate and there are chunks of missing words in the results.

  Are there any steps that would help me yield more accurate results ?

  Here are the steps I am taking to convert audio to text :

  1. Use Soundflower to channel audio output from my soundcard to mic in.
  2. Play audio from website
  3. Use quickTime player to record audio which is saved as a .m4a file.
  4. Use the command line tool ffmpeg to convert the .m4a file to a
     .flac, and also combine 2 audio channels (stereo) to 1 audio channel (mono).
  5. Upload the .flac file to Google Cloud Storage. The file has a sample rate of 44100Hz and has 24 bits per sample.
  6. Use the longRunningRecognize api via the node.js client library,
     pointing to the file in Google cloud storage.

• mpegts proxy allowing multiple concurrent views of same source feed

  5 juillet 2018, par Yass T

  I am having trouble finding a (preferably non-commercial) linux compatible project that would allow to "restream" one particular MPEGTS live source feed to multiple clients, without requesting it more than once from the source.

  Imagine an mpegts live source feed coming from http://my_mpegts_provider (imagine we have the direct link, no m3u style playlist), I would like a program to be able to grab that source and proxy it to one AND more client devices (let’s say VLC players) when they are requesting it, even if not requested at the same time.

  In other words, can we proxy the MPEGTS stream so only our proxy will be seen as the "client" (from the source provider point of view) when multiple devices (on the same network) connect to the SAME source on this side ?

  I tried the node-ffmpeg-mpegts-proxy but it clearly showed two separate connections to the source when asking for the same "channel" with two different VLC clients (confirmed with netstat).

  Thanks, and sorry in advance if my post is out of stackoverflow rules, I can’t think of a better place to gather some good opinions