Video out of sync after audio track substitution (MKV)

[ConverterCrazy]

I have two video files in MKV format with following specifications:

1 - Duration 02:01:33, Language French, Video = good, subtitles = perfect
2 - Duration 02:01:37, Language English, Video = poor, subtitles = none

Using MKVtoolnix, I added the English track from video #2 to the video #1 above.
The video runs without any problem, but video is slightly advanced than audio (lips move before audio). Subtitles are perfectly in sync with audio. The duration is shown as 04:03:15!

How can I precisely sync the video?

Thanks.

[Baldrick]

If it's a constant out of sync can you try add a delay in mkvmergegui, add the audio track, click on it and under format specific options adjust the delay(in ms). Use a negative value.

[ConverterCrazy]

Hi Baldrick,

Thanks for the reply. I tried with -9 setting but it didn't work.

Please let me know how to go about the duration correction (4 seconds) between the two files - the one I want is video that has duration of 02:01:33 and the the audio has duration of 02:01:37.

Thanks

[manono]

Why would you try -9? It's -9 milliseconds which is far below anyone's ability to tell any difference at all. If you want to add in a negative delay of four seconds, try -4000.

[manono]

Sorry, double post.

[ConverterCrazy]

Thanks.

Will give it a try.

[ConverterCrazy]

@manono

Doesn't work

[manono]

@manono

Doesn't work

Nice post. What doesn't work? It's still off by 4 seconds? It's still off but by a different amount? The delay is progressive and the amount it's off increases as the movie goes along? It doesn't mux at all? What?

Rather than going only by the relative lengths of the audio and video, I'd find out the actual delay first, and then remux with the correct delay.

[ConverterCrazy]

If it's a constant out of sync can you try add a delay in mkvmergegui, add the audio track, click on it and under format specific options adjust the delay(in ms). Use a negative value.

Why would you try -9? It's -9 milliseconds which is far below anyone's ability to tell any difference at all. If you want to add in a negative delay of four seconds, try -4000.

In the video track and under format specific options, I entered a value of 400 and now its almost in sync.

Thank you both for your help. as you can see, I am not very good at it!

[Todd Sauve]

Don't feel too bad, CC! Syncing audio to video is a bit of a mind-bender, and depending on the software being used can seem totally counter-intuitive.

I have a similar problem with one of my files and it has me stumped, because going - or + seems to make little, if any, difference to the outcome!

[budwzr]

It's not really a mind bender.

When audio gets compressed using a variable bitrate, it can cause playback anomalies.

[ConverterCrazy]

I never use variable bit rate for audio.

@Todd Sauve
My problem was solved as I posted in my previous post. Maybe variable bit rate is your problem.

I agree a lot depends on the software used; but, a lot more depends on how to use that software.
At this site, I get all the guidance and help.

[Todd Sauve]

Actually, my problem had nothing to do with variable bitrate audio.

I followed Baldrick's advice and finally figured out how to use MKVToolNix's audio sync feature. As it turned out, my audio (the 2 channel .ac3 taken from the DVD and adapted to a satellite recording of the same concert) was slow by one full second! The program I was trying to use to correct it, VideoReDo Plus, could correct up to about one second forward or backward but did not automatically update the file. Thus I just couldn't really tell whether I was getting closer or farther away from what I wanted.

So when I tried out Baldrick's advice, I set MKVToolNix to go backwards (-1000ms), and surprise-surprise, after the correction was completed the audio magically synced up like it was there from the beginning.

I suspect MKVToolNix is a very useful and powerful program once a person knows everything it can do--and how to do it!

*******************

For those interested, what I had was a HD (1280x720) satellite recording of John Fogerty's "The Long Road Home" concert that only had Dolby 5.1 and no 2 channel or chapter breaks at all. (The file was about 6.5 GB in size and in .mpeg2 format.) While I already had the retail DVD of the same concert, I like the HD video much better, even though the SD DVD video is extremely good, as well. Using MKVToolNix, DVDFab, Handbrake 0.96, Audacity 2.0, WinAmp with the SRS WowThing module, MP3Gain and finally tsMuxerGUI I was able to do the following:

- remove the 2 channel .ac3 from the DVD and insert it into the HD video with MKVToolNix, after using Audacity to change it to .mp3 and run it through the WinAmp SRS WowThing module to apply its beautiful effects. (SRS makes almost any audio sound more like a "live" performance, recapturing the clarity and richness of tone for everything in the audible audio spectrum that was suppressed in the original recording process, and wonderful articulation to the bass strings in a rock, country or jazz band. Moreover, it adds real heft to the drum kit, so prepare for your sub-woofer to make an appearance! Purists will eschew this--but who cares? The final sound of the disc will vastly improve any home hi-fi speaker's reproduction--unless it is ultra high end with active crossovers and separate amplification of each driver, in a tuned listening environment and costing upwards of $10,000!) Then I used MP3Gain to normalize the audio and finally Audacity 2.0 again to change the .mp3 back into .ac3. Alas, SRS can only be processed with 2 channel audio in this fashion. I wish I could do it for the 5.1 tracks but the module only supports 2 channels. (To compensate for this, play the 2 channel audio back using Dolby ProLogic II in the "Music" mode on your AV receiver and you will have perfectly good surround sound. I have used this method on all of my .mp3s and does it ever sound awesome! You can even burn the .mp3s to a CD and play them in the car--which also sounds awesome! This can also be done to wave files ... think about that ... )

- strip the chapter information from the DVD and add it to the HD video by turning the ripped DVD into an .mkv with Handbrake 0.96, then using MKVToolNix to add the information again to the HD video. (Do the same thing to strip the .ac3 audio from the .mkv.)

- then I synced the DVD 2 channel .ac3 audio to the HD video with MKVToolNix's sync feature.

- finally I used tsMuxerGui to change the .mkv into a Blu-ray formatted .m2ts file with attendant BDMV and Certificate folders, and used ImgBurn to record it all to a DVD9 disc.

Now I have the HD recording with 5.1 and 2 channel .ac3 (the 2 channel also encoded with mild SRS effects--no more than 15% on WowThing and 33% on Bass on this particular recording), all the chapters embedded and burned to DVD in Blu-ray format, and all in high resolution. While this disc will not play in every Blu-ray player, there are a fair number that have no problems reading and playing back a DVD encoded in this fashion. I know my Oppo BDP-80 plays it just fine. (The fellow who built the BD Rebuilder program was the first to use this compilation and burn method and has a list of compatible BD players on this webpage: http://forum.doom9.org/showthread.php?t=163260.) Moreover, if you burn this type of compilation to a real Blu-ray 25 GB blank disc it will play in any Blu-ray player--and it will be region free!

I have loved Creedence Clearwater Revival since I was a kid, (Cosmos Factory was the first LP I ever bought back in 1972 when I was 14!), so this is as close to a Blu-ray production of this 2005 CCR greatest hits concert as we are ever likely to see.

By the way, all of the software mentioned here is FREE and this same process can be used by anyone who wants to do what I have done with any HD video captured from broadcast, and who also has the same concert on DVD!

PS Please note that I am not endorsing piracy of any video or concert here. I already have the retail DVD of this concert and there is no Blu-ray of this concert currently available.

[Baldrick]

Great!

[ConverterCrazy]

@Todd Sauve

Excellent narration.. almost a tutorial on how to tweak video files and add sound-effects. I am saving it as document.
Thanks.

[Todd Sauve]

@Todd Sauve

Excellent narration.. almost a tutorial on how to tweak video files and add sound-effects. I am saving it as document.
Thanks.

You're welcome CC.

It is actually a little more involved step-by-step wise than what I have written here, but anyone familiar with these programs will hopefully be able to figure it out.