render a mp4 to 640x360 is blurred, recording kdenlive with recordmydesktop is pin sharp[solved]

Hi everybody,

why does kdenlive render mp4 to burred mp4?

Using xubuntu 12.04, kdenlive 4.8.5. I want to render a mp4 file, a video sequence taken in a room where I am sitting at a table and explaining something. I insert the pin sharp mp4-file 640x360, h264 to a kdenlive project, I render it with kdenlive to same: h264, 640x360. I changed "video" 12000 to 600, 400, 800 , .. I tried a lot. Every rendering results in bad blurred result. Taking 600 the result of a 30 sec video is 2,2MB of size, using recordmydesktop and recording from kdenlive monitor-preview (!!!!) the result is pin sharp again!!! I converted the recordmydesktop-ogv file to mp4 with handbrake. And I can't belive it: the pin sharp recordmydesktop-mp4 is of size of only 1,2 MB!!! Nearly the half of size of the blurred result of rendering with kdelive. My suggestion to all kdenlive users: take kdenlive to cut videos only, rendering doesn't work, take recordmydestop and record the video from kdenlive-monitor. Incredible ... !!

Where could be the fault?

The script:
#! /bin/sh
PARAMETERS="-pid:20908 $MELT atsc_720p_2398 avformat - $SOURCE $TARGET f=mp4 hq=1 acodec=aac ab=128k ar=48000 pix_fmt=yuv420p vcodec=libx264 minrate=0 vb=600k \
g=250 bf=3 b_strategy=1 subcmp=2 cmp=2 coder=1 flags=+loop flags2=dct8x8 qmax=51 subq=7 qmin=10 qcomp=0.6 qdiff=4 trellis=1 aspect=@16/9 pass=1 threads=1 real_\



If your source 'pin sharp' file is 640x360 then why are you using a 720p Project to then render out again to 640x360? You are scaling the video twice, no wonder it's blurred?

What results do you get if you use a 640x360 Project Profile to start with?

"My suggestion to all kdenlive users: take kdenlive to cut videos only, rendering doesn't work", sorry but that is plain incorrect, rendering does work and quality can be controlled very well with custom render profiles if the defaults aren't good enough. Obviously if scaling up and down happens, quality will drop regardless of render settings.

Thank you yellow! I've found a lot with your help:

Inserting my 640x360-mp4-file to a new project I get a warning, that I ignord so far:

Your clip does not match current project's profile.
No existing profile found to match the clip's properties.
Clip size: 640x360
Fps: 24,9904

The result is the 720p-project. If I don't choose "resize to 640x360" a blurred 1280x720-file is rendered.

Now I just tried to adapt the project settings, but there is no 640x360-template (360p) and no "custom settings". (@ 1/2 hour later: I found VGA NTSC template, that has 640x360, and indeed: rendering is pin sharp! Is that the solution?) How can I adapt project settings? - I asked google for "kdenlive 640x360" but nothing found.
Perhaps you will suggest to take 1280x720 (720p) and let youtube to make it smaller. My experience is that video becomes blurred. Even if youtube presents a 720p-video, the the video is definitely first reduced to 640x360 an then wided to larger resolution. In my videos are screen recorded sequences and these sequences get extremly blurred if converted by youtube. My videos on youtube are pin sharp if I generate the videos with 640x360.

More background information what I am doing (if you are interested):
My aim are sharp 640x360 videos for youtube and my own homepage. I've a JVC GZ-E10 camcorder that produces 1920x1080 only :( , files are *.MTS. kdenlive seems not to cope with *.MTS, so I convert them to m4v using handbrake and I downsize the stream to 640x360 in one shot. So I get a excellent sharp stream.
Another "problem": I'm working on a laptop core i3 , M 370 @ 2.40GHz, 6GB RAM that ist very slow if I use kdenlive with resolution 1920x1080. So, even if kdenlive could cope with MTS files, I couldn't work with it. So I need to reduce the resolution and the best is to reduce it to 640x360 in one shot. So I urgently need kdenlive to handle a 640x360 profile. How can I convince kdenlive to handle 640x360?

my video, rendered to 640x36 with handbrake, from MTS to m4v:
$ mediainfo land_teil1_640x360.m4v
Complete name : land_teil1_640x360.m4v
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 22.5 MiB
Duration : 6mn 58s
Overall bit rate mode : Variable
Overall bit rate : 451 Kbps
Encoded date : UTC 2013-03-18 19:46:51
Tagged date : UTC 2013-03-18 19:50:52
Writing application : HandBrake 0.9.8 2012071800

ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.0
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 6mn 58s
Bit rate mode : Variable
Bit rate : 286 Kbps
Width : 640 pixels
Height : 360 pixels
Display aspect ratio : 16:9
Frame rate mode : Variable
Frame rate : 25.000 fps
Minimum frame rate : 8.333 fps
Maximum frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0


Use the settings > Manage Project profiles to create a custom profile to match the source clip.


THANK YOU ttguy! Thats the solution! In "settings" I can edit/ change.



I'm also struggling with a blurry render-result and i just found this post. But my Problem seems to be a bit different:

I imported some Quicktime clips (png codec) with an alpha channel: 1920x1080, 25fps, progressive, rgba.
My Projectsettings are: HD 1080 25fps and I'm trying to render to H.264.
So the resolution should match, I guess? :)

The render-result is fine, if i just export the clips. But as soon as I add a transition (composite) to blend my clips with a background image the result gets blurry.
I tried playing with the transition-settings, but without success.

Have you got any hint for me?


I could solve my problem: It was my alpha channel which caused the blur. So nothing is wrong with the composite transition or the rendering. :)


is the background blurry on its own? What resolution is it ?