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Kdenlive and 1440x1080 50i - profiles/rendering/resizing

praet0ri4n
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Hi everybody,

I would like to ask you for help. My camcorder captures hdv video of the size 1440x1080 50i and stores them as .MTS files.
I want to edit these files, compose a movie in Kdenlive on Ubuntu 12.04 and render the final work. This works generally but the final output is not ideal.

These are the problems I came across
> when I add those MTS files to a new kdenlive project, Kdenlive complains that the project has to be changed to 1440x1080 50fps, but there is no such profile
> Kdenlive recognizes those files as 50fps, but mediainfo and rightclick on video file > properies > audio/video state that it is 25fps.
> rendering with x264/aac and resizing to 720x540 leads to a result where I see the videos playing back choppy. The choppiness was not obvious at the first look, but after I played back the original MTS and a rendered video there is deffinitely a difference in playback.

After upgrading to the latest kdenlive 0.9.8 and melt 0.9.0 I had success only with one particular configuration:
> project setting: 1440x1080 25pfs (Kdenlive still complains)
> rendering profile: x264/aac, no resizing OR the profile HDV > PAL 1080 50i
The final product plays back almost as smooth as the original MTS. I wonder if the output is interlaced now or not. Anyway mediainfo says it is not.
> changing the rendering profile from "Auto" to "Force Progressive" leads to choppy video
> with Scan type back to "Auto" and resizing to the halfth, 720x540 it is again choppy
> any other MPEG2/4,etc. rendering profile leads either to choppy video or to video with interlaced-like effect but in bigger scale

I understand, that every kind of deinterlacing leads to quality loss and I read somewhere, that deinterlacing causes the fps to be halfth of the original. But maybe there is some way to get away with smooth playback and a reduced size. I dont mind to leave the output without resizing, but I plan to upload some of videos on the internet and reducing the size and bitrate will be needed.

How shall I setup Kdenlive for editing those files?
Can I have both? Smooth playback and a resized (progressive?) smallsize video?
Can somebody suggest a rendering profile I should use? One that would properly deinterlace and preserve as much information as possible..

NOTE: The choppiness not very obvious, but it is disturbing.

If somebody is interrested I can upload a pair of MTS and rendered video files somewhere to compare. I am ready to paste mediainfo outputs and other output as well, just tell me what you need.
Thank you!
User avatar TheDiveO
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What do you exactly mean with "choppiness"? How can it be disturbing if it's not obvious? Do you see deinterlacing artefacts? And what do you use as your playback device? On a sidenote: smooth playback doesn't equal smooth image content. Especially with deinterlacing you easily end up with material that plays back smoothly, fps-wise, but looks terrible, image-wise. And what do you intent the rendered output format to be? Anamorphic HDTV 1440x1080 50i? This way you would leave proper deinterlacing and stretching into 16:9 with square pixels up to the playback device. Or is your audience 1080p 25fps?


TheDiveO on YouTube: diving videos and aerial (quadcopter) videos, all made with Kdenlive.
TheDiveO Blog: know-how about Protune-grading in Kdenlive, GoPro HD Hero 3, DJI Phantom Quadcopter, full face mask diving, and some more...
praet0ri4n
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Hello TheDiveO,

thanks for your answer and your hint about fps-wise <> picture-wise. That pointed me to google for another keywords. I have found out, that the choppiness I referred to could be absolutely normal. When comparing the same scene with e.g. fast moving objects, the interlaced one seems more fluid whereas the progressive is more movie-like.

The difference is exactly the same as in this youtube video:
http://www.youtube.com/watch?v=LV8UDBsf45Q

When rendering in Kdenlive the final output is interlaced only when I don't resize it. Makes sense. Once Kdenlive identifies that a resize should be done it deinterlaces the input first, since interlaced video can not be resized as is. I am right? And that was the source of my confusion..

But what about the Kdenlive complaint, that I should change the profile? What is the sense of the project profiles anyway? To me it seems that profiles are needed only to determine fps, pixel proportions, etc. at render time, where those values can not be edited by hand.
What happens when I choose e.g. DVD Widescreen/PAL for my files?

Audience is my family watching the movies I make on a LCD TV. I tend to stick with interlaced unresized output for now because it looks nicer :)
User avatar TheDiveO
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I'm not sure whether Kdenlive always deinterlaces when it the project profile settings would call for resize. Instead, my (albeit limited) understanding is that the project profile settings specify whether deinterlacing is required. Part of these settings is not only frame size but also pixel aspect ratio. Interlace or progressive is another profile property.

As for DVD ... I'm avoiding this like hell, too many unclear fudge parameters involved for my taste. I rather prefer to stick with HD progressive video, which still has enough pitfalls to offer. Since I shot only raw HD footage in progressive mode, 25fps, and with the usual 16:9 frame aspect ratio post production gets easier. It's already enough color grading work to get satisfyingly graded footage from GoPro HD Hero Protune footage and from a Canon HF G30 videocam. I'm solely rendering to 1080p/25fps final footage.

This way I don't have to fiddle with anamorphic DVD widescreen scaling and other bitstream-reduction tricks. While modern LCD TVs are really good at image processing and interpolation, I still prefer to have real 1920x1080 instead of widened 1440x1080 footage. As I'm solely streaming via network or from a memory stick, I'm not limited to the low DVD bitrates. Instead, I render 8MByte/s H.264 and that's more than enough for my purposes. DVD has such a long history and too many false compromise to my liking.

As for pan and move ... instead of going with 50fps interlaced I'm rather going with 25fps and shutter control. This way I can control to some extend how much motion blur gets into the footage. Often, 50fps progressive looks rather strobe-like. That's one of the reasons I went for a Canon HF G30 as this one of the rare consumer videocams that allows almost full manual control. And I've learnt that this is actually necessary to get at least halfway decent raw footage.


TheDiveO on YouTube: diving videos and aerial (quadcopter) videos, all made with Kdenlive.
TheDiveO Blog: know-how about Protune-grading in Kdenlive, GoPro HD Hero 3, DJI Phantom Quadcopter, full face mask diving, and some more...

 
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