dvdauthor giving errors on discontinuity of audio channel, remultiplex?

[veroslav]

Hi,

I will first explain exactly what I am trying to do and what kind of tools I am using when the dvdauthor gives me the following warning/error message:

"Discontinuity of 7200 in audio channel 8; please remultiplex input."

I am using Ubuntu 12.04 and I have a VIDEO_TS folder containing a DVD. I am trying to edit certain parts of the DVD and then re-author the DVD and create new menus.

I first join all of the VOB: s to a single VOB and open this resulting VOB in AviDemux. Here I cut out the parts I dont want to keep, and proceed to save the result as a new VOB (Audio->Copy, Video->Copy,Format(MPEG-PS). So far so good.

Then I launch DeVeDe (authoring tool that uses dvdauthor as a backend) and add a new title containing the newly edited VOB. I can't remeber the exact option in DeVeDe, but I choose something that allows the VOB to NOT being re-encoded, just copied.

I also choose a custom DVD background and a sound before I proceed with the authoring. During the process, I noticed that the authoring takes a significantly less time to complete then usual. When it completes, I open the resulting ISO in VLC player, and even though everything looks fine (menu showed correctly, ant the title can be played), I can only fast forward to a certain point in the beginning of the DVD, it wont go past that point. Same thing for rewind as well.

I tried to play the whole DVD from beginning to the end without fastforwarding/rewinding and it went just fine, no issues with either sound or picture.

However, when I took a look at the DeVeDe logs, one thing caught my attention, and it was an occurence of the following message:

"Discontinuity of 7200 in audio channel 8; please remultiplex input."

I read on this a bit, and it seems that it is the invalid audio that is causing it, seems that there are "holes" in the audio that progressively introduce gaps between the audio and video the further into the video you are.

Here, my knowledge comes to an end and this is where I really need your help. Is there any way I can fix the problem?

Also, I can open the original DVD (stored in VIDEO_TS folder) in VLC player and there, both the fastforwarding and rewinding works without any problems, which only confuses me more because I thought the error would occur there as well.

Any input is appreciated, thank you in advance.

Kind Regards,
Veroslav

[El Heggunte]

Maybe I'm wrong, but I think the problem began when you used Avidemux to edit the original VOB. AFAIK, there are some differences between a "normal" MPEG program stream and a VOB file.

If I were you, I would first demux the edited VOB, remux with mplex, and try dvdauthor again.

[veroslav]

Hi and thank you for your fast reply, El Heggunte!

I will definitely try your suggestions. However, I am still a noob and, just to be on the safe side, when you say "demux" the VOB, you mean that I should separate the audio and video into separate files/streams, correct? Also, can you recommend any particular application that does this?

Never tried mplex before, will have to read a bit about it first, but I suspect that I should use the result from demuxing above as the input to mplex, which will combine these into a new VOB, which I should use as the input to dvdauthor?

Could you just confirm that I am thinking in the (somewhat) correct way?

Thanks again, really appreciate your help!

[jman98]

For what it's worth I do NOT trust ANY free editors for MPEG-2/VOB editing. Period.

I originally bought MPEGVCR for this task and it has served me well and I still use it sometimes. Mostly I now use VideoReDo. I use free software when I can but sometimes paid programs are more reliable.

MPEGVCR has a simple to use demux option. Honestly I have no idea if it's even possible to demux or remux in VideoReDo as I have always just used MPEGVCR for those. Yes, demux means to separate the file into separate audio and video streams. VideoReDo contains some stream fixing software that often can fix weird problems in video files.

VOB files are a subset of MPEG program streams so all VOB files are MPEG program streams but not all MPEG program streams can be VOB files.

[El Heggunte]

but I suspect that I should use the result from demuxing above as the input to mplex, which will combine these into a new VOB, which I should use as the input to dvdauthor?

Could you just confirm that I am thinking in the (somewhat) correct way?

I confirm, that's exactly what I meant.

......
Never tried mplex before, will have to read a bit about it first,

What kind of Linux user are you? More of a newbie than I myself?

Straight from the manpage:

-f|--format format_code

This command allows one of a number of convenient preset output
formats or generic MPEG1 or MPEG2 output to be selected. For the
generic formats other function letters can be used to control many
aspects of the multiplexed stream. For VCD/SVCD/DVD compliant output
the corresponding formats \fImust\fR be used as the standards require the
multiplexer to enforce a variety of special constraints on the structure
of the output stream.

0 - Generic MPEG1. A simple general-purpose MPEG1 format primarily suitable
for software decoders. Buffer sizes and VBR must be specified.
Bit-rate can be auto-detected.
1 - VCD. Standard VCD. Overrides other option settings.
2 - User VCD. VCD format but buffer size, bit rate and VBR can be set
manually.
3 - Generic MPEG2. Like 0 except MPEG2.
4 - SVCD. Standard SVCD. Overrides other option settings.
5 - User-rate SVCD. SVCD format but buffer size bit rate and VBR can be set.
6 - VCD Stills stream (mixed mode with hi-res and standard-res image streams
multiplexed are supported).
7 - SVCD Stills stream.
8 - DVD (with NAV sectors). Don't get too excited. This is really a
very minimal mux format. It includes empty versions of the peculiar
VOBU start sectors DVD VOB's include. This is enough to persuade some
hardware players to play the stream but is a long way from full DVD authoring.
9 - DVD. As above but without the empty VOBU sectors.

Thanks again, really appreciate your help!

You're wellcome

[veroslav]

jman98,

thank you for replying. I understand what you are saying but lately I am trying to use open source software as much as possible. But I am very open to try something closed source and propriatery if it shows as a better alternative

I have obtained a trial copy of MPEG Video Wizard DVD, which I understand is a successor to MPEGVCR that you mentioned. As always, I will need some time to understand how to use this tool. I will come back if I have any more questions, but after a quick glance it looks promissing. Thank you for the tip!

El Heggunte,

thanks again! I am a not-so-newbie Linux user anymore (been using it almost for two years) but I must admit I am still fairly new to the video editing stuff (thus not having worked with mplex), but I will get there. I checked the man page for mplex after your last post but I always prefer to be 100% sure before attempting something

I now have a few things to try out so once again I would like to thank you both for the tips you gave me! I am liking this place more and more and I will be back in case I need help again

Thanks!

Kind Regards,
Veroslav