Lose Quality Extracting VOB2MPG? + a Couple Other Questions

[sonicdeth]

Ok, so what I’ve got a is DVD – what I want to do is extract the vid without losing quality – I understand that VOB2MPG can perform this task…. Then I need to cut about half of the video out – can anyone recommend a decent free program that can do this? And last I’d like to author a DVD and add chapters etc with the MPG file I’ve got left.. I think I can do this without re-encoding, correct? I’m sure re-encoding would reduce the quality of the original video? I’d be using the program DVD Styler to create the DVD.

[jagabo]

If you can live with cuts only on keyframes you can use Mpg2Cut2. There will be no loss of quality as nothing will be reencoded.

[sonicdeth]

Ok, cool... Also I don't think I need to convert VOB to MPG - I think DVD Styler will accept the VOB's and author without re-encoding, at least I hope. Does Mpg2Cut2 also work with VOB files?

[sonicdeth]

Also, do you know can merge a couple of the VOBs together properly?

[jagabo]

Mpg2cut2 works with VOB files and it can merge multiple VOB files together. It will output MPG files though.

Sometimes you have to use VOB2MPG first. Like when two veiws are interleaved within the VOB. VOB2MPG follows the instructions in the IFO file to de-interleave them. Mpg2Cut2 can't do that.

[sonicdeth]

Mpg2cut2 works with VOB files and it can merge multiple VOB files together. It will output MPG files though.

Sometimes you have to use VOB2MPG first. Like when two veiws are interleaved within the VOB. VOB2MPG follows the instructions in the IFO file to de-interleave them. Mpg2Cut2 can't do that.

Wouldn't changing format (VOB to MPG) change/reduce the quality of my original video?

[jagabo]

Wouldn't changing format (VOB to MPG) change/reduce the quality of my original video?

No. It's just taking the compressed video and audio out of one "container" and putting it in another.

[sonicdeth]

Cool. I'll just do VOB2MPG first anyway, just in case. Thanks much for the info, appreciate it.

[sonicdeth]

It seems like I don't have the option to "do not remultiplex/transcode" in DVDStyler - I found out this is because the mpg does not have "nav packets" - is there an easy way I can add nav packets to this so that I can author in DVD Styler so it gives me the option not to remultiplex/transcode?

[videobruger]

is there an easy way I can add nav packets to this

Why would you do that? The reason you don't have the option "do not remultiplex/transcode" is that remultiplexing is needed. DVDStyler uses ffmpeg for this. You could do the same thing manually (with the risk of mistakes) but it'll be the same process and take the same time.

What you want is to maintain quality, ie using stream copy which is something different and is done by "Copy" in DVDStyler.

[sonicdeth]

is there an easy way I can add nav packets to this

Why would you do that? The reason you don't have the option "do not remultiplex/transcode" is that remultiplexing is needed. DVDStyler uses ffmpeg for this. You could do the same thing manually (with the risk of mistakes) but it'll be the same process and take the same time.

What you want is to maintain quality, ie using stream copy which is something different and is done by "Copy" in DVDStyler.

I just thought when remultiplex/transcode is done there is a reduction in quality because some sort of conversion is being done with the video. I see what you mean by the "copy" option on here... So the remultiplex/transcode process won't affect my quality? If so, this is great news - I can get started putting together my DVD!

[sonicdeth]

Seems like a lot of people say "anytime you transcode there will always be some kind of quality loss" - I just want to be sure I don't lose anything as far as quality from my original video.

[usually_quiet]

Re-multiplexing does not change anything. It must be done whenever video and audio are moved to a different type of container file or edited, so both VOB2MPG and Mpg2Cut2 have already done it. Authoring a DVD from an mpg also requires copying your audio and video to one or more VOB files, which are a different type of container.

Transcoding would reduce quality, however DVDStyler should not do that unless the video that you want to author is too large to fit on the DVD media (DVD 5?) that you plan to use.

[videobruger]

So the remultiplex/transcode process won't affect my quality?

No. The "Copy" option in the image in post #10 means that the original video/audio is used. Not using "do not remultiplex/transcode" is just to multiplex to add the "nav packets".

And since you want to add chapter you migth want to have some menu buttons just to play a chapter and a button to play a whole title (?) in which case you'll need a conditional cell command as disccussed here.

https://forum.videohelp.com/threads/375256-Recommendation-for-DVD-Authoring

[sonicdeth]

So the remultiplex/transcode process won't affect my quality?

No. The "Copy" option in the image in post #10 means that the original video/audio is used. Not using "do not remultiplex/transcode" is just to multiplex to add the "nav packets".

And since you want to add chapter you migth want to have some menu buttons just to play a chapter and a button to play a whole title (?) in which case you'll need a conditional cell command as disccussed here.

https://forum.videohelp.com/threads/375256-Recommendation-for-DVD-Authoring

Got it, thanks! I'm not sure about "conditional cell command," but I've created a DVD before with DVDStyler of a concert and had a "Play" Butthon on the main home menu, and a "song selection" menu button on that page that led to the song listing where you could select each song (chapter) individually. I did this just by going into the button properties etc..

[videobruger]

If you have a MO that works it's fine and I don't want to confuse you.

But say when you used a button to select song 2 what happened when it finished playing? Did it continue with song 3 or did you return to the menu? If you don't use any cell command it'll continue with song 3. You may then use an unconditional cell command as "call last menu;" in which case you'll always return to the calling menu preventing you from playing the concert as a whole. With a conditional cell statment you like "if(g5==g6) call last menu;" you can have a button to play song 2 on it's own and another to play the whole concert.

The unconditional statment is shown below

[sonicdeth]

If you have a MO that works it's fine and I don't want to confuse you.

But say when you used a button to select song 2 what happened when it finished playing? Did it continue with song 3 or did you return to the menu? If you don't use any cell command it'll continue with song 3. You may then use an unconditional cell command as "call last menu;" in which case you'll always return to the calling menu preventing you from playing the concert as a whole. With a conditional cell statment you like "if(g5==g6) call last menu;" you can have a button to play song 2 on it's own and another to play the whole concert.

The unconditional statment is shown below

I see what you're saying. When I created the chapters for the last concert DVD I made I just had it so that it would continue to the next song and so on after selecting a specific chapter (song). If I want to do anything after the song plays it's easy to jump to the menu and go from there.

[sonicdeth]

A quick question - on that initial "create new project screen" - see below - It gives you the option to set vid quality and audio bitrate - seems default is 192 on the audio.... do I just leave video bitrate the same, and the default amount in audio bitrate? Does setting title properties to "copy" for audio & video just override these initial "Create New Project" settings?

[videobruger]

Does setting title properties to "copy" for audio & video just override these initial "Create New Project" settings?

Yes these are overridden by Copy using the bitrates of the sources. In case - as mentioned by usually_quit - this would exceed the capacity of your target DVDStyler issues a warning and offers to transcode.

[sonicdeth]

Does setting title properties to "copy" for audio & video just override these initial "Create New Project" settings?

Yes these are overridden by Copy using the bitrates of the sources. In case - as mentioned by usually_quit - this would exceed the capacity of your target DVDStyler issues a warning and offers to transcode.

Got it. Thanks so much for all the advice, this will make things go much more smoothly when I put this together this weekend.

[videobruger]

Just for info. I made a Youtube video on using conditional cell commands.

https://www.youtube.com/watch?v=w0jIx0dukXU