Home » Forums » Users Forums » Audio Effects

Audio out of sync from Video - Kdenlive 0.9.2 - audiocodec aac

5 posts / 0 new
Login or register to post comments
Last post
Fri, 06/01/2012 - 21:36
#1
vylaern
Offline
Joined: 06/11/2011
Posts:
Audio out of sync from Video - Kdenlive 0.9.2 - audiocodec aac

Hi

I am trying a new Kdenlive and I have a huge problem - video is losing sync with audio.

I was trying to render a part of raw file - everything was FINE.

After adding some seconds black and short title before that raw file - after rendering - audio starts immediately (with those few seconds of black + title), so when the video start - audio is few seconds before of video.

here how my project looks like (so everyone can easily see what is a problem):
http://img715.imageshack.us/img715/6382/problemdck.png

UPDATE - I have ungrouped audio from video - and doesn't matter I have moved few seconds before or after video - after rendering audio ALLWAYS start at the begining of the movie.

UPDATE 2 - I have realized, that the problem is only with h.264 profile, as other profiles -> HDV and MPEG-2 and MPEG-4 profile works fine...

UPDATE 3 - It looks like the problem is only with aac codec from h.264 profile.

Should I put it on a bug list?

Kdenlive - 0.9.2
ffmpeg - 0.10.3
mlt - 0.7.8
faac - 1.28-r3

UPDATE 4 - For the waiting time for any answer on my question - I have made in my favorite profile -> a copy of H.264 but with small change -> acodec=mp2 instead of acodec=aac. On my laptop this file works fine (by Mplayer2) but on my PS3 I can not hear an audio. PS3 shows I use AAC codec, ffmpeg -i shows I use mp2:
Stream #0:1(und): Audio: mp2 (mp4a / 0x6134706D), 48000 Hz, 2 channels, s16, 384 kb/s

Why PS3 think I use AAC not MPEG-2?

Bellow technical details for movie clips for PS3:
http://manuals.playstation.net/document/en/ps3/current/video/filetypes.html

0
Your rating: None
Top
Tags:
Sat, 06/02/2012 - 07:34
#2
hvdwolf
Offline
Joined: 07/08/2009
Posts:
Re: Audio out of sync from Video - Kdenlive 0.9.2 - ...

Can't answer the audio out of sync issues.

==
Why PS3 think I use AAC not MPEG-2?
==

Well, the specification on your PS3 page already mentions it:
- MPEG-4 SP (AAC LC)
- H.264/MPEG-4 AVC High Profile （AAC LC）
- MPEG-2 TS（H.264/MPEG-4 AVC, AAC LC）
MP4 file format
- H.264/MPEG-4 AVC High Profile (AAC LC)

So, your PS3 only supports mpeg-4 in combination with AAC (LC).

Your ps3 doesn't check the contents of the mp4 container, it assumes that the audio is aac.

This is due to the fact that the original mp4 standard (before the numerous additions) was for mpeg-4 ASP/AVC with AAC audio (as that's how Apple wanted it). Later on other audio streams were allowed and subtitles etc.

Your PS3 just follows the original standard.
Videoplayers on your computer like mplayer and VLC examine the contents of the video container and play the appropriate video/audio stream.

Top
Sat, 06/02/2012 - 20:17
#3
vylaern
Offline
Joined: 06/11/2011
Posts:
Re: Audio out of sync from Video - Kdenlive 0.9.2 - ...

Thx HvdWolf for answer.

So I will be waiting for answer what is wrong with AAC.
There is a new mlt and ffmpeg so mybe this will solve the prolem, if not - I will put is on the bug list.

Top
Sun, 12/16/2012 - 10:00
#4
jeffgerritsen
Offline
Joined: 12/09/2010
Posts:
Re: Audio out of sync from Video - Kdenlive 0.9.2 - ...

Was this issues ever resolved?

I'm having the same problem with title clips and video. Once rendered the audio starts immediately while the video is way out of sync. In my example, I'm rendering roll in clips for a live cable access show. Each clip starts with a 3 second clip number followed by 3 seconds of black so the control room video switcher / director can start the roll in with a smooth transition from our discussion.

The current work around is to place the video on video line 2 and the title clips on video line 1. I extend the video clip on line 2 to the beginning of the timeline and place a mute audio effect on the first six seconds. It works but it's not pretty

However, this problem only seems to occur when using the MPEG-4 or the H.264 rendering option. I've downloaded custom rendering profiles that are called Custom H.264 1280x720 Normal, HQ Slow, HQ Slower, Lossless slow, and Lossless slower. All of these profiles render correctly without issue and I don't have to "monkey" with the timeline to correct the audio sync issue. Also MPEG2 and HDV formats render correctly.

Could the problem I'm experiencing be related to an audio codec issue? Should I choose another audio codec? If so which one do you recommend?

Update: I created a custom rendering profile based upon the existing H.264 profile, switching the acodec option from "aac" to "mp2". So far so good - it seems to work. Why is that?

Update: using the mp2 audio codec encoding doesn't work for playing on Windows based systems. Only the aac option works which leaves the messy editing method when working with title clips to avoid the audio sync problem - oh boy, looks like a bug report time!

Thanks,

Jeff

kdenlive: 0.9.3
MLT: 0.8.7

Using the batch script compile option to create a sandbox environment

Top
Wed, 12/19/2012 - 05:05
#5
jeffgerritsen
Offline
Joined: 12/09/2010
Posts:
Re: Audio out of sync from Video - Kdenlive 0.9.2 - ...

I recompiled the latest source code version - kdenlive 0.9.3 (rev. 836ab97) as of 1900 PST 12/18/2012, and this issue seems to be resolved - Thanks guys for fixing that.

Top