Video recording quality (resolution)

[Michael]

Hey guys.

I`ve got a question, how to rise quality of video recording (desktop sharing)? We use HTML5 client. Everything goes well. But we got a request to rise a video resolution in recordings. It`s far from original. Is it any options how to configure the system?

Regards, M

[Chad Pilkey]

I don't think we have any configuration options for this. Do you know what browser and OS (with versions) they were using? I think some browsers do automatic downscaling of the stream if the computer's CPU or bandwidth are deemed to be insufficient. I'm not sure if that's affecting things in this case though. Do you have any example screenshots or video samples?

[Paulo R. Lanzarin]

A video example comparing the meeting experience and the final recording is very important, as Chad suggested.
The recording should be source quality since there's no regulation when dumping the source stream into a file.
If source and recording are significantly different, there's something wrong we need to investigate.

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[Michael]

hey

here is some samples. Comparing to 'active presenteer' software. Chrome browser. BBB record for fullscreen ("Loading (6).webm" file) or window RDP ("BBB-1_app.webm" file from 3:10)

https://drive.google.com/file/d/1sQxCz9sqrPDbIn9DQO_SRimZqiSqGs-J/view?usp=sharing

very strange if we don`t have any config for extend video quality o_O

[Michael]

Hey!

Is there any update for this situation?

[Michael]

Hey

maybe I can provide some more info on this? rebuilding record can increase it`s quality?

~Regards, M

[Chad Pilkey]

You could compare the video in the raw folder against the final screen share video and see if there's a noticeable quality difference. The screen share video is sent through this script for processing, https://github.com/bigbluebutton/bigbluebutton/blob/dce2e6c86094a9fab1cd15aa01ef95f73b9d7c1c/record-and-playback/core/lib/recordandplayback/generators/video.rb#L83-L137. The recording scripts are one of the parts that I've touched the least so it's mostly a black box for me.

As for the difference in quality between applications. The first video was created by ActivePresenter which is a native application that stores and the writes the information to a local file. I would basically always expect that a native application that doesn't care about sending it over a network would be the best quality. They can choose whatever codec they like and the only limiter is the hardware on the local machine. The next best quality was the Windows RDP and that also is a native application that sends the stream to one destination. They can do whatever they like with codecs, but they do have to cut some quality because it has to be sent to another computer. The worst case was BigBlueButton and it's also the most restricted because it lives in the browser and is designed to be sent to a classroom of people. Being in the browser means that we're limited to whatever codecs they want to support (H264 and/or VP8) and we have no visibility of the host or receiver computers' capabilities. If we set the quality to the highest available we'd run into issues with medium to lower-end computers and most residential bandwidth speeds. The reason I bring all of this up is because even if we set the frame rate and resolution to the highest we could we'd most likely run into other issues. If the desire is to have a very high quality capture of the screen then it's probably best to look elsewhere.

[Michael]

Chad, greetings

Pls just help me to configure quality of video capture on our system. Can it be done by config modification or it`s system hardcoded parameters that cannot be changed?

Thx

вторник, 16 апреля 2019 г., 20:55:50 UTC+3 пользователь Chad Pilkey написал:

[Michael]

I`ve checked raw files. They have much better quality then final video in the browser.

here is that samples: https://drive.google.com/open?id=10R4V17Ayin9GvtT22mJ-iPpOcCDAmqm9

[Chad Pilkey]

Did some more digging. It looks like there is configuration options for the resolution of the screen share video and they're currently set to 1280x720 (720p). https://github.com/bigbluebutton/bigbluebutton/blob/dce2e6c86094a9fab1cd15aa01ef95f73b9d7c1c/record-and-playback/presentation/scripts/presentation.yml#L5-L6. That file should be in /usr/local/bigbluebutton/core/scripts/presentation.yml. Any changes might get overwritten on an update to the recording scripts so make sure to make a backup. After you've made a change you should be able to rebuild the recording and apply the new values I think.

[Michael]

Chad, big thx! Will try and will report for result.

[Michael]

Looks like it works.

Big thx for for help!