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elan-ev / opencast-studio

Web-based recording studio for Opencast
https://studio.opencast.org
MIT License
50 stars 45 forks source link

Waveform for trimming #648

Open ypatios opened 4 years ago

ypatios commented 4 years ago

It would be helpful to see a waveform of the audio of the recording when trimming.

slampunk commented 4 years ago

I experimented years ago with an offline version of the OC editor, where I generated an svg waveform from a video/arraybuffer to assist in trimming. Check it out here by clicking on the "Use local file" button top right.

Better yet, here's a screenie: image

I could do a PR for this if you're still interested in this feature?

lkiesow commented 4 years ago

Hi Duncan, good to see you yet again. I hope you are doing well.

I've tried your code and it works pretty well, even for lager files. We had a student at UOS look into something like this ~2 years ago but the result was too slow to replace pre-generated waveforms. Your solution on the other hand still seems pretty fast, even when facing a 2h (though only 8kHz) recording. That's cool.

About integrating this into Studio, I'm not sure though. We are trying to keep the tool as simple as possible and you can only trim the beginning and the end of the file for which I'm not entirely sure how helpful the waveform would be. The outcome of our internal discussion was thus the (non-strong) tendency to not include this.

That said, this woulds be an awesome feature for both the new stand-alone video editor and the one embedded in the admin interface where you wouldn't have to pre-generate the image any longer.

slampunk commented 4 years ago

Hey Lars, it's been forever hey :smiley: I am good. I trust you've been well over the intervening years.

I quite like what you have done with this project. I've been told it has been used to good effect down here in Cape Town during the lockdown period for online lectures.

Yes, I agree that simplicity is key for an online recorder, especially in this day and age where face-to-face training is nigh impossible.

I have a soft spot for Opencast; I'd be happy to contribute to a stand-alone video editor, so feel free to reach out once that work starts. In fact, my original intent was to develop an offline editor, and the recorder was simply a mechanism with which to get videos into that editor! However it pans out, it'll answer some (if not all) of the questions I originally had when developing my attempt (questions that still crop up to this day for me).