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Using a custom profile to render

dlanced
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Using a custom profile to render

Tue May 29, 2018 3:10 pm
I'm having trouble getting my videos to render properly.
In the Render Project tab of the Render dialog I select the Custom profile I created previously. The profile is defined with these parameters:
Code: Select all
ar=44100 s=1280x720 fps=15
When I render the project to a file it creates a video with the correct resolution and sample rate, but at 30 frames/second.
Also, I'm completely confused by purpose of the
Code: Select all
Project | Project Settings
dialog. Does that selection override a custom profile in the Render dialog? Is there any way to create a custom profile in that dialog (I can't see any obvious links)? There's no profile there matching my configuration needs.
I'm using Version 17.12.3 on Ubuntu 18.04.
Thanks.
User avatar bartoloni
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Re: Using a custom profile to render

Thu May 31, 2018 10:25 am
you can modify "customprofiles.xml"

and manually add some customs profiles.... like:

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<profile speeds="preset=slower;preset=medium;preset=faster;preset=ultrafast" category="Custom" name="Quadcopter720 - dominating (H264/AAC) 23 -128 YUV420P" extension="mp4" args="properties=x264-medium f=mp4 vcodec=libx264 acodec=aac g=120 crf=23 ab=128+'k' mlt_image_format=yuv420p"/>


or

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<profile category="Custom" name="MP4 X264 - Quadcopter - 1080 CRF 27 (half size)" extension="mp4" args="properties=x264-medium f=mp4 vcodec=libx264 acodec=aac g=120 crf=27 ab=128+'k'"/>


or just try some custom preset taking infos from FFMPEG forum.. https://trac.ffmpeg.org/wiki/Encode/H.2 ... mumbitrate
or: https://video.stackexchange.com/questio ... n-at-7-fps

you can also change the framerate from the properties of project.. or sources..
https://userbase.kde.org/Kdenlive/Manua ... t_Settings
dlanced
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Thanks. It turns out that Kdenlive had already populated the customprofiles.xml file with the values I'd created in the Render dialog:

<profiles version="1">
<profile args="fps=15 ar=44100 s=1280x720" speeds="preset=slower;preset=medium;preset=faster;preset=ultrafast" category="Custom" extension="mp4" name="myProfile"/>
</profiles>


Do you have any idea why they're not being honored?
humanbeing
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dlanced wrote:
Code: Select all
ar=44100 s=1280x720 fps=15

try r=15 instead of fps=15
dlanced
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humanbeing wrote:
dlanced wrote:
Code: Select all
ar=44100 s=1280x720 fps=15

try r=15 instead of fps=15


That produced a video running at 15 fps, but with the audio at double speed and, obviously, out of sync with the video. Is there a way to control that?
Thanks!
humanbeing
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dlanced wrote:That produced a video running at 15 fps, but with the audio at double speed and, obviously, out of sync with the video. Is there a way to control that?
Thanks!

if i were you, i'd make a copy of the audio, remove the audio from the clip in KDENLiVE, render the video and then remux the resulting video and the original audio again into one file.
dlanced
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humanbeing wrote:
dlanced wrote:That produced a video running at 15 fps, but with the audio at double speed and, obviously, out of sync with the video. Is there a way to control that?
Thanks!

if i were you, i'd make a copy of the audio, remove the audio from the clip in KDENLiVE, render the video and then remux the resulting video and the original audio again into one file.


That's a good idea. Although it creates a rather involved workflow for multiple videos - which is what I usually face.
Thanks,
humanbeing
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just out of curiosity, why do you want to half the frame rate?
dlanced
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Re: Using a custom profile to render

Tue Jun 05, 2018 12:27 pm
humanbeing wrote:just out of curiosity, why do you want to half the frame rate?


The videos I create (https://bootstrap-it.com/index.php/pluralsight-courses/) are made up mostly of slides and low-res screen casts. Since the higher frame rates won't improve quality, why waste space and bandwidth?

When you consider that Pluralsight has more than 6,400 courses and more than 100,000 video clips, the size/bandwidth difference can be a big deal.
humanbeing
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dlanced
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humanbeing wrote:in case you missed it:
https://trac.ffmpeg.org/wiki/EncodingForStreamingSites


I hadn't seen that page. There are some very useful guides there.
Working with ffmpeg directly is a great way to fully control my encoding, but I'm not sure it's the best choice for building a repeatable workflow that involves Kdenlive. And this is all particularly annoying because until I upgraded to Ubuntu 18.04 I was able to render in 15 FPS with no trouble.
Having said that, I should note that Kdenlive is a fantastic tool. It's super stable and I'm able to do some serious work - often encoding multiple videos in parallel - with a cheap workstation I built myself for less than $400. Most of the other authors at Pluralsight are running Camtasia on their high-end $3000 Macs and Windows machines with 64GB of RAM - and they still complain they're crashing regularly.
Gotta be grateful for the Kdenlive developers!
humanbeing
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dlanced wrote:I was able to render in 15 FPS with no trouble

do you encode with x264 or NVEnc?
dlanced wrote:Gotta be grateful for the Kdenlive developers!

absolutely! and i am. the best thing is there's much more to come: https://kdenlive.org/en/2018/05/kdenliv ... gicdomid92

please mark the thread as solved.
dlanced
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humanbeing wrote:
dlanced wrote:I was able to render in 15 FPS with no trouble

do you encode with x264 or NVEnc?


x264.

humanbeing wrote:please mark the thread as solved.


You've been very helpful but, since I still don't have a way to successfully render my video within Kdenlive, I think I'll leave it "unsolved." That way someone else might come along some time and figure out exactly what I've been doing wrong.
humanbeing
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dlanced wrote:x264.

why not NVEnc? my experiments with it showed the transcoding is much faster and quality is the same for static images.

dlanced wrote:You've been very helpful but, since I still don't have a way to successfully render my video within Kdenlive, I think I'll leave it "unsolved." That way someone else might come along some time and figure out exactly what I've been doing wrong.

i don't think it's about right or wrong. i'd say the problem is that KDENLiVE doesn't allow "-c:a copy" or "-c:v copy" from FFMPEG for rendering. you can only "extract a zone" when both video and audio are copied.
dlanced
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humanbeing wrote:
dlanced wrote:x264.

why not NVEnc? my experiments with it showed the transcoding is much faster and quality is the same for static images.

dlanced wrote:You've been very helpful but, since I still don't have a way to successfully render my video within Kdenlive, I think I'll leave it "unsolved." That way someone else might come along some time and figure out exactly what I've been doing wrong.

i don't think it's about right or wrong. i'd say the problem is that KDENLiVE doesn't allow "-c:a copy" or "-c:v copy" from FFMPEG for rendering. you can only "extract a zone" when both video and audio are copied.


There's got to be more. I have hundreds of videos I successfully encoded using 15 FPS on Ubuntu 16.04. So, in principle, it can be done. I just have to figure out what changed with the move to 18.04.

 
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