Hi!

I am rather new to kdenlive, and to H.264 video, so this might be confused and uninformed (have previously worked a lot with Kino and a cam, recording in raw dv format). However, I have tried to read all I can in these fora and on the internet, and still cannot really figure this out.

The situation: I have a Panasonic cam, that produces AVCHD in the format of 1080i, 50 fps. I cannot work with them on my computer (I can play them in kdenlive, but not scroll, so basically not editable) so I transcode them to DNxHD 1920x1080 50i 220 Mb/s, and work with these clips. (although when looking at clip properties after transcode, it says 25 fps...??)

My LCD TV is 720i. Computer screen 1920 x 1200, graphics card nVidia GeForce 9500 GT.

My issue now is that I wish to choose an export format that preserves as much of the quality as possible. I have been experimenting with the various mpeg2, mpeg4, xvid and dvd (vob) options in kdenlive, and experience the following:

mpeg2 most often produces film that plays well on my PC, but that is jumpy on the TV.
vob (dvd) produces film in the format 720 x 576, plays well on TV but less clear image - the impression is that quality is lost.
mpeg4, with bitrates up to around 10000 k plays mostly well, sometimes (like when there is water surface with a lot of rapidly shifting reflections) jumpy, sharper than vob but sometimes "granular" (squares are visible). Plays well on PC, but clearly granular in full screen mode.
xvid and theora: crashes, produces no film.

All exported film shows some vertical striping, mostly when things are moving. This is more pronounced when watching in reduced windows, as compared to viewing in full screen mode. Something to do with the scale of the video? Should I experiment with de-interlace / force progressive?

Any advice on how to move further is much appreciated. Resources on the internet to study closer, or things to try.


Best,


Magnus

50i = 25fps. The i means interlaced. The 50 means 50 Hz, but interlace means there are 2 fields per frame. So, the 50 Hz means 50 fields per second, which means effectively 25 frames per second.

Re: "mpeg2 most often produces film that plays well on my PC, but that is jumpy on the TV." MPEG-2 should be good if bandwidth is not a concern. However, it is not clear how you are playing your MPEG-2 or MPEG-4 to the TV. Are you using a home theater PC? If so, what connection - VGA, DVI, TV-Out? It sounds like you want one output that works good on both TV and computer. Is that correct?

Magnus wrote to me:

Hi!

I saw your answer to my post about choosing export format. However, when I tried to answer, I was asked to complete a captcha, that was not visible in my Firefox browser, ad when chaning to google chrome, I was notified that my post triggered a spam filter, and would not be accepted.....

So here is what I tried to post:

Ok, thanks for clarifying about the fps.

The TV I play on (LCD) is directly connected to a computer via DVI/HDMI-cable. I play film on this computer with MPlayer, VLC, and Mythtv. And you are right, I would want something that plays well both on the TV and my regular desktop computer, but, since there seems to be somewhat conflicting capacities, I'd rather say: optimal performance on the TV, as priority number one.

I'm a bit surprised about the bad performance or my exported mpeg2's, and as you say, my belief was that they SHOULD play well. Bandwith should not be a problem, as the film plays from the harddisk of the computer and the TV is directly connected via DVI/HDMI (or are there limits to this connection that could cause problems?).

Do you have any suggestions about what to try? I keep experimenting with the variety of export options.... many different configurations to try... :)

Magnus

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In that case, your TV setup is basically the same as computer playback, and I can not offer any reason why the mpeg2 playback is not fine. Also, it is not clear to me what "jumpy" means. Maybe it is simply motion judder that is more noticeable on the TV because you are viewing it on a larger screen from a greater distance than when viewing on a computer.
http://broadcastengineering.com/hdtv/solutions-judder-problem/