Hi,
I am somewhat new to kdenlive and dealing with video in general. I am having a really hard time establishing a consistent work-flow.

I am making a series of instructional videos and a few lectures intended for web based distribution.

My camera: Sony HDR-AX2000 set to shoot in 1080/60i and produces m2ts AVCHD files.
My computer is a core i5 running Ubuntu 11.04.

I have found that my computer is not powerful enough to edit AVCHD directly so I first transcode to DNxHD using ffmpeg and these parameters:
-s 1280x720 -deinterlace -r 30 -b 60000k -threads 8 -vcodec dnxhd -acodec pcm_s16le -ar 48000 -ac 2 %1.mov

Although very time consuming to transcode, the resulting DNxHD files seam to be easy to edit. However, when I render my final project (usually HDV NTSC 720p 2-pass) into I get audio sync issues every time.

Basically, what am I doing wrong? Is there a problem from shooting at 1080/60i and transcoding to 720p? Am I using the right parameters for ffmpeg for NTSC HDV? What work-flows are other people using with AVCHD on slower machines?

Thanks

Have you tried using proxy clips? This generates low quality versions of high res video, such as AVCHD, to edit in the timeline. When it comes to render, it uses the original clips, rather than the proxy.

Must admit, I had a few sync issues with DNxHD, never got to the bottom of it, just been using proxy clips since then

I just finished transcoding a one-hour clip of 1080/60i AVCHD footage to DNxHD using the kdenlive project tree menu. The resulting HDxHD starts fine but the audio slowly goes out of sync. About 20min in it is totally unwatchable.

Thanks for the advice about proxy clips, I have used them before. I worry that if I can't transcode the footage to begin with, and I make a whole project with proxys, will I be able to render it?

Also, I seem to have to tweak levels and contrast a lot. Why is it that when I pause video in the clip or project viewer and wait a second it looks great but when I click play it gets all washed out.

Thanks

bump

First a comment about your transcoding params:

I am a bit surprised by the "-threads 8" option. Usually you set the threads value to the number of processors, and I don't think you have an 8 core PC if it's not fast enough for AVCHD.

Does the audio sync problem on transcoded files only happen in Kdenlive / MLT or can you also see it using ffplay? You can test it with:

ffplay myvideo.mov

and do some fast and back forwarding with left / right arrows.

You didn't say which version of Kdenlive you are using? You might want to give a try to the svn version using sunab's experimental PPA that contains the latest Kdenlive / MLT versions

https://launchpad.net/~sunab/+archive/kdenlive-svn

OK i fixed the treads problem in my ffmpeg command, but I still have audio sync issues. I tried the ffplay but I get this error:

[mov,mp4,m4a,3gp,3g2,mj2 @ 0x1ce0aa0]moov atom not found
20110616190017.m2ts.mov: Operation not permitted

I have played the mov (with audio sync problem) in vlc and mplayer so it's a problem with transcode of the file.

I added the SVN PPA but I cannot update to the SVN version because Synaptic reports the kdenlive package is broken. I am currently using 0.8.0-0ubuntu0~sunab~natty1.

I'm starting to get really frustrated.

Thanks

might want to try a full remove an re-install of kdenlive

apt-get autoremove kdenlive

apt-get update

apt-get install kdenlive

make sure the PPA is added before doing this