[Kdenlive-devel] Problem: Brightness changing when using still frames

[Steve Guilford]

Are you referring to this problem?

> However the problem persists. Could you check my project
> (http://overbeck-it.de/tmp/kdenlive-test.tgz)? The error is easily
> reproduced:
> Open 00038_53.MTS in the clip monitor.
> 1. Extract some frame from the middle to a PNG and add this to the project.
> 2. Add the png to the timeline (track1)
> 2. Add 00038_53.MTS to the timeline (track2)
> The change in brightness can be easily seen on the switch from track 1
> to track 2
>
> The same goes for overlapping 00038_53.MTS with a frozen version of
> 00038_53.MTS.

 From Dan's answer it sounds as if the fix was applied to MLT.  Do you 
know if that was the case?

On 09/17/2014 05:48 AM, Claus R. F. Overbeck wrote:
> Hi List,
>
> Dan fixed the problem mentioned below for me in the beginning of the
> year. Now I have a new computer, I got Ubuntu 14.04 on it and installed
> the recent kdenlive version from the ppa. And now the initial problem
> returned. Didn't the fix make it into the new kdenlive version?
>
> Any help on how to fix the blinking is appreciated.
>
> Thanks
> Claus
>
> On 20.02.2014 09:05, Dan Dennedy wrote:
>> On Wed, Feb 19, 2014 at 10:30 PM, Dan Dennedy <dan at dennedy.org> wrote:
>>> On Wed, Feb 19, 2014 at 12:05 PM, Claus R. F. Overbeck
>>> <claus.overbeck at abovo-it.com> wrote:
>>>> On 19.02.2014 19:12, Dan Dennedy wrote:
>>>>> Here is today's 32-bit version. I do not recall if it runs on Debian
>>>>> stable. I think it might depend on a newer glibc such that it will
>>>>> work on Debian testing or unstable tho. Well, you can try:
>>>>>
>>>>> http://builds.meltytech.com/kdenlive/kdenlive-ubuntu12.04-x86-20140219.tar.bz2
>>>>>
>>>>>> Does that build include MLT?
>>>>> Yes, and x264, lame, frei0r, and FFmpeg. :o) You do not need to
>>>>> install this. You simply extract it anywhere you like and run the
>>>>> start-kdenlive script. You must use this launch script and not try to
>>>>> run the binary in bin/ directly!
>>>> Hi Dan,
>>>>
>>>> thanks for the build. It runs on my debian (which has some packets from
>>>> testing and unstable).
>>>>
>>>> However the problem persists. Could you check my project
>>>> (http://overbeck-it.de/tmp/kdenlive-test.tgz)? The error is easily
>>>> reproduced:
>>>> Open 00038_53.MTS in the clip monitor.
>>>> 1. Extract some frame from the middle to a PNG and add this to the project.
>>>> 2. Add the png to the timeline (track1)
>>>> 2. Add 00038_53.MTS to the timeline (track2)
>>>> The change in brightness can be easily seen on the switch from track 1
>>>> to track 2
>>>>
>>>> The same goes for overlapping 00038_53.MTS with a frozen version of
>>>> 00038_53.MTS.
>>>>
>>> Claus, I started looking into this. I do not have a fix yet, but it
>>> looks like a workaround (with the build I provided) is to make the
>>> project use the ITU-R 601 colorspace. You will need to create a custom
>>> project profile under Settings, switch the project to it using Project
>>>> Project Settings, and save (Save As?) the project. I recommend you
>>> restart Kdenlive after that and load the new project. Hope that helps
>>> for now.
>> OK, I found and fixed the bug. When the project called for an ITU 709
>> YCbCr colorspace, MLT also requested that colorspace for the RGB side
>> of a YCbCr-to-RGB conversion. But, libswscale in FFmpeg needed the
>> default 601-based coefficients.
>>
>> Now, I want to warn you about an unresolved problem using the freeze
>> effect in Kdenlive preview. You see, Kdenlive via MLT uses SDL for
>> video playback. Normally, during playback, it is using YCbCr, but when
>> paused it switches to RGB mode. When you switch back and forth between
>> paused scrubbing/stepping over the freeze and playing through it
>> several times, it causes the "frozen" frame within the effect to
>> render between RGB and YCbCr respectively. There are slight
>> inaccuracies in the YCbCr<->RGB conversions that will accumulate on
>> the frozen frame's image each time you do this. This is not a problem
>> when you Render as it makes one pass through the freeze effect using
>> the same image format throughout, but it will manifest in the preview
>> depending upon how often you review the effect in different modes.
>>
>> By mid-day Thursday, you can get a new build:
>>
>> http://builds.meltytech.com/kdenlive/kdenlive-ubuntu12.04-x86-20140220.tar.bz2
>>
>

-- 
Steve Guilford
http://www.dbplugins.com