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rfm2

Posts: 147
Registered: 13-Dec-2007
Video starting volume level, Neptune
Posted: 5 Dec 21, 00:04
 
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Is there a way to limit the starting volume of a video during playback?
JeffTucker

Posts: 8,158
Registered: 31-Jan-2006
Re: Video starting volume level, Neptune
Posted: 5 Dec 21, 00:27   in response to: rfm2 in response to: rfm2
 
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Not in the skin as it is. I gather there are some Javascript tricks to pulling that off, but incorporating them into the skin would be almost impossible - the lightbox script assembles the video player internally. Terra incognita.

The best you can do is remix the video with some video editing software to reduce the volume. You could do it with ffmpeg, which is installed with jAlbum, but we're talking about doing some command-line finagling here. I'll tinker with it....

ETA: It should be possible to pump the video through the NoPages skin with some custom video settings. I'll get back to you after I've experimented a bit when I'm sober.
JeffTucker

Posts: 8,158
Registered: 31-Jan-2006
Re: Video starting volume level, Neptune
Posted: 5 Dec 21, 03:25   in response to: JeffTucker in response to: JeffTucker
 
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Attachment ss009583.png (13.9 KB)
Turns out to be fairly simple.

Starting from an empty project, choose the NoPages skin, and add the video whose volume you want to tame. On the NoPages > Output tab, uncheck all the boxes (you don't need slide images or thumbnails).

Now head for the jAlbum Settings > Videos tab, and check the Use custom settings box. Edit the custom settings so that there are only three entries - see screenshot.

Make the album, open the output directory, go to the slides folder, and play the MP4 to see how the volume level is. You may have to tinker with the value to get it where you want it. You can now add that MP4 to your real project.
RobM

Posts: 4,171
Registered: 4-Aug-2006
Re: Video starting volume level, Neptune
Posted: 5 Dec 21, 13:01   in response to: JeffTucker in response to: JeffTucker
 
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If you add a setting of -vcodec with a value of copy, it won’t reprocess the video element, preserving quality. See https://jalbum.net/help/en/jAlbum/Settings/Videos#Changing_the_volume
rfm2

Posts: 147
Registered: 13-Dec-2007
Re: Video starting volume level, Neptune
Posted: 5 Dec 21, 20:51   in response to: JeffTucker in response to: JeffTucker
 
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Oops! Finally figured it out.

Edited by: rfm2 on 5 Dec 2021, 21:11
rfm2

Posts: 147
Registered: 13-Dec-2007
Re: Video starting volume level, Neptune
Posted: 5 Dec 21, 22:02   in response to: rfm2 in response to: rfm2
 
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Well, I did finally manage to insert the missing "-filter:a" and control the volume down to the suggested "volume=0.3", but the video output from NoPages was screwed up with a lot of jumping/distortion. I think I'll just use a comment to warn the viewers to adjust the volume on the screen.

Thanks for the help. It was a good learning experience.
RobM

Posts: 4,171
Registered: 4-Aug-2006
Re: Video starting volume level, Neptune
Posted: 5 Dec 21, 22:08   in response to: rfm2 in response to: rfm2
 
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If your original video is an mp4, add the -vcodec switch with a value of copy, see above post by me.

If it isn’t an mp4, process the video with jAlbum first, then adjust the volume with the -vcodec switch, then add the processed video and mark it as do not re-encode.
JeffTucker

Posts: 8,158
Registered: 31-Jan-2006
Re: Video starting volume level, Neptune
Posted: 6 Dec 21, 13:44   in response to: RobM in response to: RobM
 
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RobM wrote:
If your original video is an mp4, add the -vcodec switch with a value of copy, see above post by me.

If it isn’t an mp4, process the video with jAlbum first, then adjust the volume with the -vcodec switch, then add the processed video and mark it as do not re-encode.


Excellent advice - I was thinking pretty much the same thing. First, use jAlbum to get the video into a stable MP4 format. Then hit it one more time to take the volume down, without doing any other reprocessing to it. Finally, add it to the project, marked for no re-encoding.

Either that, or wear ear muffs while viewing the album. ;)
rfm2

Posts: 147
Registered: 13-Dec-2007
Re: Video starting volume level, Neptune
Posted: 6 Dec 21, 19:43   in response to: JeffTucker in response to: JeffTucker
 
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It was an ordeal to get to the desired end point, but for the sake of posterity I’ll describe in detail the steps I went through (some of which may not have been necessary).

The original project had 4 MOV videos ranging in length from 25 seconds to 1 minute. Since processing the original project had converted the MOV videos to MP4, I took one of the converted MP4 files (just to test the process first) from the original project's slides folder and brought it into a new NoPages project. I changed the advanced video settings in the NoPages project to have just the 3 lines (including the 0.3 volume setting) originally suggested. I processed the NoPages project. I then added the line in the video settings about -vcodec copy and made the 1 video NoPages project again. I then had the option of taking the MP4 file from the output slides folder of NoPages and copying it to the output slides folder of the original project (replacing the original), or I could/did (as an experiment) add the MP4 file from the NoPages output slides folder to the original project and mark the video as “Do not re-encode”.

Since that got the desired reduced max volume, I copied the other 3 MP4 output files from the original project to the NoPages project, and then went through the same steps as for the 1 test video. Finally, the original project now has all 4 videos with the reduced max volume.

Since each step of multi-processing those 4 videos is very slow, I think my approach for the next project that has multi, blaring videos will be to add the volume warning comment, or use Jeff’s approach of suggesting ear muffs.

Thanks for all the help from both of you.
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