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kdenlive renders full timeline with lots of blank video

jerems
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I'm using Kdenlive 19.04.1 on windows 10 and I have set up my zone for rendering using the I and O method and it shows up blue on the preview monitor. When I try and render the clip, it renders fine but if the movie is 4 mins long and the timeline in the app is 18 mins long total the output movie is 4 mins of my movie and 14 mins of a black screen.

Is there something I'm doing wrong? I've tried rending using full project and selected zone with only the 4 mins selected with no luck. I tried it on two projects and both same outcomes except the other one had a 21 min timeline so the output was 4 mins of the movie and 17 mins of a black screen.

Is there a way to shrink the timeline after editing to only be as long as the movie?
Merlimau
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If you enable in the render dialog „selected zone” it should render the zone determined in the timeline only.

Which render format do you use (mp4?).
jerems
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Hi,

Yes I tried selecting the selection zone with the correct portions of the timeline selected and it still rendered the whole thing. I'm rendering in MPEG-2 as MP4 only renders sound when I render the movie...no video is rendered...which is another issue but MPEG-2 works fine except the excess blank screen at the end.
jerems
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I think I figured out the issue to both problems, I found on another thread for the video issue this document:

https://bugsfiles.kde.org/attachment.cgi?id=108162

I downloaded the latest MP4 codecs and installed as per the document, I think my main issue was that the environment was set up incorrectly. All the files were referencing old locations that didn't exist anymore.

I got those all changed and now it works properly and even MP4 works correctly.

Thanks for your help.
User avatar pappl
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I get the same problem with Kdenlive on Linux. :'(
My Video is ~3mins long but the rendered video is 20 minutes like the whole timeline.
Already set in and out-points and rendering only selected zone, but still 17 minutes additional black screen in the end.
How can i get rid of this, i'm rendiering with the default mp4/h264 1080p profile?

Please help,
pappl
zakazak
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pappl wrote:I get the same problem with Kdenlive on Linux. :'(
My Video is ~3mins long but the rendered video is 20 minutes like the whole timeline.
Already set in and out-points and rendering only selected zone, but still 17 minutes additional black screen in the end.
How can i get rid of this, i'm rendiering with the default mp4/h264 1080p profile?

Please help,
pappl


+1 ... exactly the same problem on Linux.
User avatar pappl
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zakazak wrote:
pappl wrote:I get the same problem with Kdenlive on Linux. :'(
My Video is ~3mins long but the rendered video is 20 minutes like the whole timeline.
Already set in and out-points and rendering only selected zone, but still 17 minutes additional black screen in the end.
How can i get rid of this, i'm rendiering with the default mp4/h264 1080p profile?

Please help,
pappl


+1 ... exactly the same problem on Linux.



Strange there is no way to trim the timeline length after last clip. This would solve the problem as a workaround.
User avatar pappl
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Here is a workaround to trim the last minutes of the rendered video without reencoding in 1 second.

Open terminal and type:

Code: Select all
ffmpeg -ss 00:00:00 -t 00:05:33 -i "PATH TO LONG VIDEO.mp4" -acodec copy -vcodec copy -movflags faststart "PATH TO NEW TRIMMED VIDEO.mp4"


Edit the time after -t to your need (HH:MM:SS), in this case 5min 33sec

Last edited by pappl on Mon Jun 17, 2019 10:17 pm, edited 2 times in total.
User avatar a@pavel.bz
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Just wanted to point that I've discovered what causing it.
There is an option "Use GPU processing (Movit library)" in the Playback section of settings. It it's checked - you'll have those issues with rendering tens of minutes of empty screen even when trying to render only selected zone.

https://invent.kde.org/kde/kdenlive/issues/221
User avatar pappl
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a@pavel.bz wrote:Just wanted to point that I've discovered what causing it.
There is an option "Use GPU processing (Movit library)" in the Playback section of settings. It it's checked - you'll have those issues with rendering tens of minutes of empty screen even when trying to render only selected zone.

https://invent.kde.org/kde/kdenlive/issues/221


I will not disable GPU acceleration since this is a standard feature of every video editing software since decades.

I'll use quick ffmpeg trimming after rendering in terminal until a fix is released. This will save 30 minutes for every video GPU rendered.
I added faststart to the trimming code to make videos youtube and streaming compatible:

Code: Select all
ffmpeg -ss 00:00:00 -t 00:07:44 -i "PATH TO LONG VIDEO.mp4" -acodec copy -vcodec copy -movflags faststart "PATH TO NEW TRIMMED VIDEO.mp4"


Will trim at 7min 44sec and leave start at 00h00min00secs.

pappl

Edit: Changed code to avoid video curruption.

Last edited by pappl on Mon Jun 17, 2019 10:16 pm, edited 1 time in total.
jbm
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Thanks for your report. This was in fact an issue in MLT that was fixed a few days ago. I will upload a new 19.04.2d AppImage in a few hours with the fix.
kdevelopfan
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jbm wrote:Thanks for your report. This was in fact an issue in MLT that was fixed a few days ago. I will upload a new 19.04.2d AppImage in a few hours with the fix.


But the appimage does not allow enabling GPU playback so how do we verify ?
Any hopes of getting the fix in the native package via the ppa repo and/or the flatpak ?
kdevelopfan
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Seems like I found a workaround...

1. I upgraded the recently released Shotcut 19.06.
2. In kdenlive, instead of using "render to file", use "Generate script".
3. Run that script from command line. eg: /home/user1/software/Shotcut/Shotcut.app/melt -progress ./kdenlive-renderqueue/renderscript.mlt

No more huge blank video in the end !
Finally have GPU playback+effects as well as GPU accelerated rendering.
Seeing 100%GPU usage. CPU usage has dropped to half its previous value !

 
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