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IDProjectCategoryView StatusDate SubmittedLast Update
0001384KdenliveRenderingpublic2010-01-16 15:132010-01-20 06:51
Assigned To 
Platform64 bitOSSidux (Debian Sid)OS Version2009-4
Product VersionRecent git 
Target VersionFixed in Version 
Summary0001384: ogg-render-profile need change
DescriptionKdenlive ignore parameter audio bitrate ("ab") at rendering.

I seems like, that vorbis can only use variable bitrate (meens quality) and not constant.
The audio-quality is at the moment bad (only at ogg-render).
The Problem seems, that FFMPEG use the default audio-quality ("aq") with value of 10.

I think quality of 30 would be better.
Please change this in the render-profile. Thanks :-)

Steps To ReproduceExport/render a Video-File with one of the Ogg-Profile and listen this file.
Change the audio-bitrate parameter, export and listen this file.
The qudio-quality will be the same: A not very good audio-quality.
Additional InformationI use FFMPEG, MLT and Kdenlive from SVN

http://www.vorbis.com/faq/#quality: [^]
"For now, quality 0 is roughly equivalent to 64kbps average, 5 is roughly 160kbps, and 10 gives about 400kbps. Most people seeking very-near-CD-quality audio encode at a quality of 5 or, for lossless stereo coupling, 6. The default setting is quality 3, which at approximately 110kbps gives a smaller filesize and significantly better fidelity than .mp3 compression at 128kbps."
TagsNo tags attached.
Build/Install MethodManual build from SVN
Attached Files

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-  Notes
j-b-m (administrator)
2010-01-19 00:34

Ok, I updated the theora profiles so that profiles > 800k now have the aq=30 parameter.
soeren (reporter)
2010-01-19 04:53
edited on: 2010-01-19 04:56

Thanks - but, oh - sorry - i think i've report to early. Now i tested some more with ffmpeg.
I find a easier way to fix this:
Just change from "vorbis" to "libvorbis", then it's take the audio-bitrate.

ddennedy (developer)
2010-01-20 06:49
edited on: 2010-01-20 06:50

The reason it is "vorbis" is for when ffmpeg is not configured with libvorbis. We have code in Kdenlive that says "if 'vorbis' is not available but 'libvorbis' is then use 'libvorbis'." I guess we need to invert this logic and put libvorbis into the profile.
However, what do we do with ab and aq options depending on which codec is used? Will it be ok with either codec if we set both ab and aq options?
soeren, we would appreciate your help if you can make that experiment since you are already familiar with how to test the results.

- Issue History
Date Modified Username Field Change
2010-01-16 15:13 soeren New Issue
2010-01-19 00:34 j-b-m Note Added: 0004527
2010-01-19 00:34 j-b-m Status new => feedback
2010-01-19 04:53 soeren Note Added: 0004530
2010-01-19 04:53 soeren Status feedback => new
2010-01-19 04:56 soeren Note Edited: 0004530 View Revisions
2010-01-20 06:49 ddennedy Note Added: 0004538
2010-01-20 06:50 ddennedy Note Edited: 0004538 View Revisions

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