[kdenlive] Preview rendering is rendering ... wait ... every other second...?

[Jean-Baptiste Mardelle]

On Saturday, June 25, 2016 6:58:41 PM CEST, Harald Albrecht wrote:
> Dear Kdenlivers,
>
> two questions, somehow related:
>
> ====
> 1. With the most recent git master preview rendering now does 
> something strangely funny: it renders every other second only. 
> The problem appears only when I use a self-made preview profile 
> ("MPEG-2 1080p 25fps", picked up somewhere in the Kdenlive 
> forum), which looks as follows:
>
> -s 1920x1080 -r 25 -vcodec mjpeg -qscale 1 -acodec pcm_s16le

> In the past, this profile worked without flaws. What am I doing 
> wrong? The stock MJPEG profile works correctly.

The timeline preview profile must be in the form:
s=1920x1080 vcodec=mjpeg qscale=1 r=25

There should be no audio setting in the preview rendering profile, since 
audio is taken from the real source clips.

>
> The project itself uses the stock "HD 1080p 25 fps" profile.
> ====
>
> ====
> 2. The stock MJPEG profile results in a rather "blocky" 
> display, kind of 2D Minecraft-y rendering. It's defined as 
> "f=avi vcodec=mjpeg progressive=1". How can I trade in my disk 
> space for better display that doesn't look like being rendered 
> in Minecraft or using my childhood LEGO bricks?
> ====

Adding qscale=1 to the default profile should improve the result, I just 
changed the default in git.

Hope it helps,

jb