In a recent project I came across this problem: I have some screencasting raw video footage that is H.264 material (in .mp4 container) from an HDMI recorder. I'm basically recording hand-written technical illustrations as they evolve. I'm later adding separately recorded voice-over to the project. In consequence, I usually need to cut the raw footage into segments, interspersed with stills ... whenever the voice-over explaning something needs more time than the corresponding drawing. Also, I need to edit out my interaction with the whiteboard UI, so the source video gets cut down considerably.

In all my previous projects I've extracted the stills as PNG images from the source H.264 simply using Kdenlive. So while I'm building up the storyline in the timeline I see where stills are needed and extract them from the clip monitor as needed. So far I never noticed any color differences between video footage and PNG stills. Today I rendered the project using Kdenlive 15.12.0 and a recent MLT and only later noticed that in the final videos colors differ between parts from live raw footage versus still images. I have no effects on either video or still image clips. I extracted the stills from the source video clips. I originally started the project in Kdenlive 15.08 and also extracted all stills using 15.08.

I'm using Kdenlive directly compiled from git source, together with MLT and ffmpeg also directly compiled from their respective git repos.

The color mismatch is especially visible for green and cyan ... as my video uses technical illustrations and thus clearly distinctive colors, such differences in the "same" color become very visible and annoying.

The render output format again is H.264 in a .mp4 container.

Any suggestion on what went wrong or what I did wrong?

This seems to have been an intermediant bug in Kdenlive, probably 15.08.x around the time when I was extracting the stills from the video clips in Kdenlive. I've gone through my project and reextracted all stills again from the adjacent video clips ... and now the colors keep consistent. Strange, but luckily Kdenlive seems to work again for extracting frames as it should.

Thanks for sharing and updating!

I experienced png green-ness years ago but I noticed it only that one time really:
https://www.youtube.com/watch?v=vq2gj6EMaEU

You can see at second 7 how it becomes less green all the sudden.

I think a possible workaround in old versions (and maybe in the future if it happens again ) would be to use the Motion/Freeze effect.

qubodup wrote:I think a possible workaround in old versions (and maybe in the future if it happens again ) would be to use the Motion/Freeze effect.

Unfortunately, the freeze effect, as its cousin the speed effect, exhibit all kind of problems with H.264 source footage. In one project I went the route to transcode from H.264 to DNxHD which blew video footage out of any dimension: from a 30MB to 1GB. My source footage is neatly compressed H.264 grabbed from HDMI.

So after that many bad experiences I'm now going for extracting frames and using ffmpeg for sped-up footage. I won't touch speed and freeze anytime soon, as they caused me problems every time I used them over the course of the past several years.