0002875: Audio out of sync with video when using title clips and rendering H.264 format

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Project

Category

View Status

Date Submitted

Last Update

0002875

Kdenlive

Rendering

public

2012-12-16 10:37

2012-12-19 04:51

Reporter

jeffgerritsen

Assigned To

Priority

high

Severity

major

Reproducibility

always

Status

new

Resolution

open

Platform

64 bit

Fedora

OS Version

Product Version

0.9.2

Target Version

Fixed in Version

Summary

0002875: Audio out of sync with video when using title clips and rendering H.264 format

Description

Creating a video timeline consisting of a 3 second title clip (in this case it's a clip ID number) followed by another 3 second title clip (in this case it's black), and finally followed by five min video all on the same video timeline.

Note the project monitor displays the audio / video sync correctly.

Once rendered the audio starts immediately while the video is 6 seconds 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 title clip number followed by 3 seconds of black title clip 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.

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.

Update: using the mp2 audio codec encoding doesn't work when playing on Windows based systems. Only the aac option works which leaves the messy time line editing method when working with title clips to avoid the audio sync problem

kdenlive: 0.9.3
MLT: 0.8.7

Using the batch script compile option to create a sandbox environment

Steps To Reproduce

Note project profile was HD 720p 29.97 fps
All video clips were 1280x720 29.97 with a h.264 encoding.

1. Using video 1 of the time line add a 3 second title clip.
2. Using video 1 of the time line add another 3 second title clip.
3. Add the video of your choice.
4. You will notice the project monitor plays all items correctly. The audio starts in sync with the video.
5. Render your project using either H.264 or MPEG-4 rendering profiles.
6. Your rendered video, the audio will be 6 seconds behind the video. Audio starts playing immediately while the video plays the title clips from the video time line.

Additional Information

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?

Issue History
Date Modified	Username	Field	Change
2012-12-16 10:37	jeffgerritsen	New Issue
2012-12-19 04:51	jeffgerritsen	Note Added: 0008833
2012-12-19 04:52	jeffgerritsen	Note Edited: 0008833	View Revisions
2012-12-19 04:53	jeffgerritsen	Note Edited: 0008833	View Revisions

Notes
(0008833) jeffgerritsen (reporter) 2012-12-19 04:51 edited on: 2012-12-19 04:53	I have rebuilt / recompiled the source code with kdenlive 0.9.3 (rev. 836ab97) as of 1900 PST 12/18/2012, and the problem appears to be resolved - thanks guys. The version I was having the problem with was kdenlive 0.9.3 (rev. 0c33635).

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