Hello all

I've got the movie with around 63 clips and on most of them, I have applied a Speed effect to slow the scenes down.
Movie length is around 13 and half minutes.

I can't render it at one go, it always crashes with the long error message. I have read at some other thread here in the forums, that this happens inside of the Speed effect.

I have tried to render only 1 minute long part around that particular guide placementt where it crashes and that works OK. I was able to render it. Time when it crashes is about 10min.

So, I have added Guide into the middle of the movie (at 6:30) position and render from the beginning to this guide and render from guide to the end.

I have merged these two XVid avi movies with avimerge tool and watched the final movie.

The problem is that there is a obvious glitch in the sound at the guide position.

I have analyzed spectrum in the audacity and on the graph it looks like there is no signal for 0.4sec around that guide placement.

Does anyone have any experience with this? Is it a problem of the guide feature or merging?

Avimerge gives me better result then merging with ffmpeg, that's why I have used it.

Thanks in advance.

Martin

Hi there,

I'm not sure if it might help, but my first guess is - the Problem must have something to do with your SourceClip.

In your case, try to convert your clip with kdenlive first, before you start working.
For best results in a losless encoded clip.
You might have to setup an own Transcoding Preset, but thats very easy.

I'm using DNxHD, and I've got no Problems with speed Effect. (somtimes h.264 lossless but I try to avoid)
But I always obey to render those clips first, lossless to there final destinate speed to avoid slowing down my Workflow.

kind greetings,
yours-truly.de

Hi yt

Thanks for your comment. I have tried to replace that particular clip with simple black title clip, but the crash has appeared somewhere else, so I wasn't able to render the whole movie either.

I don't mind to have one or more guides and render movie part by part, which might even speed up the things, if I change just one small thing somewhere and render just that "sub-movie" and eventually merge the stuff which is quick anyway.

Yes, my source is H.264.

By your sentence

"But I always obey to render those clips first, lossless to there final destinate speed to avoid slowing down my Workflow"

you mean that you simple render to files all the clips, one by one, with all effects applied and then use those when making the movie itself?

Cheers,

Martin

Hi yt again

just coming back to your comment.

So, you do two things right?

1. you transcode every single clip into DNxHD
2. you render every single clip with all effect applied?

and then, you do the assembly with transitions?

Bug Report?

As temporary work around can you render the video only without sound or does it still crash? If it doesn't crash would it be worth exporting the audio separately, rendering just the video part then multiplexing them after with ffmpeg or Avidemux?

Sorry for my late answer.

1. Yes - First I bring my clips in a Format that fits most for my project. At Full HD I use DNxHD, for smaller and simple Projects I use ffvhuff(another lossless codec), mpg4 or h.264.
h.264 is also possible but, same as mpg4, you should transcode to iFrames only / lossless. That is important for workflow and quality if you have more than one rendering to do. Specialy h.264 with a strong compression might bring you trouble, if you use videoeffects because of the Bidirectional thing ...

2. The preview might slow down awful if you have to much effects. Speddchanges are one of the greatest performance killer in my projects.
To convert my clips I'm often using mencoder or ffmpeg through a small batchscript. This is a great possibility to use effects eg unsharp (to sharpen pictures)

example batchskript
ls /home/input_conversion/*.mts | while read file; do
echo $file
mencoder -idx "$file" -vf-add unsharp=l:5x5:1.15:c:5x5:1.15,dsize=854:-2,cropdetect,scale=854:480 -aspect 16:9 -sws 9 -ovc lavc -lavcopts vcodec=ffvhuff -ofps 25 -o "$file"_neu\.avi

(thats a very heavy sharpen for an older presentation beamer)

Regards
yt

! - Interesting Point from Yellow. My clips are usually without sound, because I'm using a separate soundtrack.

Hi there

thanks for the suggestions and comments.

I have realized that it's not probably a good idea to start doing movies in a way I did. Initially, I didn't do any conversions and used separate MP3 soundtrack.

Problem is that I am new to this area and my intention was basically to "do something". Until the moment when I
got into the troubles I have described.

So, my last question to conclude this thread would be:

Is there any good tutorial for start? I am interested in tips and tricks how to prepare all the assets (video, music). My source is usually MP3 for the music (I always mute original music from the clips...) and h264 for the video (Sony HDR-CX11E). Many thanks.

Every creative start is a good start :D ...

I suggest, you have - same as I do have, just a "home computer". Nothing special for Video editing in HD with several Tracks to edit.
You really need high performance, or really expensive Software or better - both - expensive Hard n Software. but even that would not help you, if you don't have a clue, what you are doing.
But a lot of things could be easily done with a small try n error.

So here same small hints - because I don't know a good tutorial to start with:

mp3 is ok. HD = Harddisk
mp3 - not the best choice - costs a little cpu power but only a very few HD performance
wav - not the best choice - costs just a very few cpu power, but more HD performance

mpg is ok too, but with high CPU costs, low HD
DNxHD is low CPU high HD

With those little things in mind, you'll get a clue, on how to work with less trouble.

For a good Performance - you should have at least two separate HDs on separate IDE/SATA ports. One for video, one for Sound. The one which is less busy is used to render the final result.
Partition isn't useful, but try to work with an nearly empty HD for each project, or if you could spend some money, try to setup a raid configuration. Which has nearly the same result like a dualcore. If one is busy, the other one could help...

the cheapest setup should have two HDs and a dualcore with some gigs RAM for Linux.
Windows has an advantage on some setups, because a lot of commercial Software uses the Grafic Card CPU (GPU) for acceleration.
This is not yet implemented in a free Linux Software as far as I know. :(

But therefore, a very useful community :)

Best Regards,
yt

(hope my english isn't that bad at all)

Danke schoen Meister :)