Hi,
I've got audio and video out of sync in rendering a kdenlive project with variable frame rate clips. The frame rates reported by clips tooltips on kdenlive varies (23.89, 23.92, 23.99 fps, ...). The issue appears only in rendered film. I've ever tried many workarounds found here and on some other forums but none of them worked. What should I do ?

>What should I do?

First, give us more information.

Please post kdenlive version number and mlt version number.
What are the technical details of the input material and what is you project profile?
Which workarounds did you already try?

Thanks. Here is more infos.
Versions :
kdenlive : 0.9.8-12.3 (last version from Packman repository). I've also tried a complete daily build from http://build.mltframework.org/overview.html?guest=1 )
mlt : 0.9.0-9.12
ffmpeg : 2.2.4-4.3

project profile : DVD/pal
clips : .3gp files, titles, static images. Here are 2 mediainfo reports from clips :
--------------------------------------------------------------------------------------------------------
Format : MPEG-4
Format profile : 3GPP Media Release 4
Codec ID : 3gp4
File size : 1.90 GiB
Duration : 1h 6mn
Overall bit rate : 4 110 Kbps
Law rating : (empty)
Released date : 0
Encoded date : UTC 2013-06-18 12:29:22
Tagged date : UTC 2013-06-18 12:29:22
Classification : (empty)

Video
ID : 2
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Baseline@L3.0
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Format settings, GOP : M=1, N=30
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1h 6mn
Bit rate : 4 000 Kbps
Width : 640 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate mode : Variable
Frame rate : 24.000 fps
Minimum frame rate : 3.571 fps
Maximum frame rate : 24.390 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.543
Stream size : 1.85 GiB (98%)

Audio
ID : 1
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 1h 6mn
Bit rate mode : Constant
Bit rate : 96.0 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 45.4 MiB (2%)
--------------------------------------------------------------------------------------------------------
Complete name : 2013-06-18_15-35-40_810.3gp
Format : MPEG-4
Format profile : 3GPP Media Release 4
Codec ID : 3gp4
File size : 1.01 GiB
Duration : 35mn 2s
Overall bit rate : 4 107 Kbps
Law rating : (empty)
Released date : 0
Encoded date : UTC 2013-06-18 13:35:47
Tagged date : UTC 2013-06-18 13:35:47
Classification : (empty)

Video
ID : 2
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Baseline@L3.0
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Format settings, GOP : M=1, N=30
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 35mn 2s
Bit rate : 4 000 Kbps
Width : 640 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate mode : Variable
Frame rate : 24.000 fps
Minimum frame rate : 3.279 fps
Maximum frame rate : 24.390 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.543
Stream size : 1 005 MiB (98%)

Audio
ID : 1
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 35mn 2s
Bit rate mode : Constant
Bit rate : 96.0 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 24.1 MiB (2%)
--------------------------------------------------------------------------------------------------------

Workarounds tested :
- kdenlive daily build : same issue.
- some other rendering profiles (not all yet) : same issue.
- extracted audio at 48000 bps and added it as sound tracks : same issue.
- another project and rendering profiles similar to clips (640x480 24fps with parameters copied from clips) : same issue.
- rendering two .3gp clips pasted one just after the first, no effects, no titles, no images : OK.

--------------------------------------------------------------------------------------------------------

I don't know how to get more useful infos and therefore I really need some help ! If some tests can help please tell me how to get more infos about what happens during the rendering process.

Thank you for the information.
One more workaround idea: You could try to transcode the footage to a lossless format with fixed frame rate.

capslock wrote:One more workaround idea: You could try to transcode the footage to a lossless format with fixed frame rate.

Thanks. I will do so as it seems to be the only way to reach my goal quickly, BUT the fact that a/v sync is OK with only my rushes pasted one after the other reveal that there is a bug somewhere when my project contain titles, images, and some others clips. If there is a way to get more debug information about a/v sync issue, I would be glad to help with more tests, to find the source of the bug.

Actually, a workaround is to follow an advice found on kdenlive website : splitting my whole project in small parts first, and merging them after.

A fixed frame rate solved these issue. BUT it would be useful to investigate more to find why clips with variable frame rate bug when the same clips are properly transcoded to constant frame rate. I suspect a bug in melt, because transcoding to cfr from kdenlive menus work and rendering from fixed rates clips worked too.
I also noticed that the pan and zoom effect sometimes have a bug revealed by preview errors (the preview window show the previous clip with these effect instead of the last one). May be it is related to some of my a/v sync issues.
I haven't got enough infos to fill a useful bug report, but I hope somebody will investigate that a bit more.

Many thanks to kdenlive community.

I have the same problem with kdenlive worth ubuntu 14.10 and render the output file is obtained without sound !!!

We would like to get an answer how to fix it?

arootkov, as this thread is marked as solved and deals with a/v out of sync your decision to write the same message here: viewtopic.php?f=272&t=124415
was fine.