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diff --git a/harvesting.md b/harvesting.md index 846f2847..40077112 100644 --- a/harvesting.md +++ b/harvesting.md @@ -7,47 +7,6 @@ that were not available as pre-recorded videos. It's a great way to help speakers get stuff out of their heads and into a form we can all learn from. Here's a process for doing so. -# Skim the transcript and the videos to see if anything needs to be removed, and which video to use - -BigBlueButton gives us the webcams and audio as one video -(`--bbb-webcams.webm`) and the screenshare (if any) as another video -(`--bbb-deskshare.webm`). If the speaker shared their screen, we can -focus on that instead of their webcam. The following ffmpeg command -combines the audio from the webcams (which has been previously -extracted into a separate file, `--bbb-webcams.opus`) with the video -from the screenshare. - - ffmpeg -i example--bbb-webcams.opus -i example--bbb-deskshare.webm -c copy example--answers.webm - -We also want to check if people accidentally shared sensitive -information on their screen, or if anyone said something that they -might not have said if they remembered that thethe Q&A videos will be -shared after the talk. Sometimes there's some time before we get -around to closing the meeting at the end of the Q&A. Usually, a quick -read of the transcript will show anything that needs to be trimmed. -Here's how to stop the recording at a specified time: - - ffmpeg -i input.webm -to hh:mm:ss -c copy output.webm - -Cutting out stuff from the middle of a recording is slightly more -complicated. It might be easier to use a nonlinear video editor such -as kdenlive to edit the video. If you want to use ffmpeg, using -filters to select the frames and reencode the video will probably work -out better than splitting the file into multiple parts and then -concatenating them without reencoding, as the latter tends to need to -be split on keyframes. Here's a sample command based on this -[StackOverflow](https://stackoverflow.com/questions/64866231/remove-a-section-from-the-middle-of-a-video-without-concat) answer that removes the section between 15 seconds and -45 seconds: - - ffmpeg -i input.webm \ - -vf "select='not(between(t,15,45))', setpts=N/FRAME_RATE/TB" \ - -af "aselect='not(between(t,15,45))', asetpts=N/SR/TB" \ - output.webm - -Alternatively, you can let us know what parts needs to be trimmed, and -we can figure that part out. - - # Add chapter markers Chapter markers make it easier for people to jump to the part of the |