when is VOB/MPG2 re-encoding triggered?

[vdmsss]

Hello.

 

Can anybody explain how Toast decide to re-encode VOB/MPEG2 files when burning a DVD? My setting is "re-encode=never", I feed Toast (8, but the same happens with 7) with files which I expect are DVD-compliant, yet:

 

1. it always remuxes the files (do I expect it must first demux) -- and in doing so often the size increases

 

2. it sometimes starts to re-encode, and apparently there is no way to convince it not to.

 

Does this means that during the muxing phase Toast has found the file is not DVD-compliant? And is this the reason why remuxing is always run? If that is so, anybody knows what the parameters Toast looks for are?

 

Hope the question is not too vague, it's not as though Toast gives me many more details to relay, but I'll try if required.

 

Thanks

[tsantee]

In authoring the title sets in a new VIDEO_TS folder Toast must multiplex the audio and video streams when creating the VOBs. With a muxed MPEG file this process involves demultiplexing and remultiplexing.

 

As for the need to re-encode this usually is when the specs of the MPEG are too far from the video DVD specifications. However, it sometimes can be that Toast encounters some non-standard aspect of the file. In the latter case it sometimes can work to open the MPEG in MPEG Streamclip, choose Fix timecode breaks, and Convert to MPEG (there's no re-encoding involved). I've also had Streamclip export the MPEG as separate .m2v and whatever is the audio format. When using separate streams in Toast just add the .m2v and Toast will take care of the audio stream.

 

Don't use VOBs in Toast. Use Streamclip to convert them to MPEG. If the VOBs are in a VIDEO_TS folder you can use Toast's Media Browser to extract the video as MPEG files. This is done by placing the VIDEO_TS folder on the desktop and choosing DVD with the top button of the Media Browser. The browser can access titles or chapters for extraction.

[vdmsss]

Thanks for your reply.

 

I have not tried the trick with StreamClip, I will.

 

Indeed, I do not use VOBs, I meant muxed MPEGs (typically created by mplex, or mencoder, or ffmpeg). But you say that I don't really need to mux, as Toast will redo it anyway. Do you know how the audio track is chosen in case there is more than than one in the same directory as the m2v/mpg?

 

And is there a way to know exactly what Toast is unhappy with when it starts to re-encode?

 

Thanks again.

[tsantee]

Thanks for your reply.

 

I have not tried the trick with StreamClip, I will.

 

Indeed, I do not use VOBs, I meant muxed MPEGs (typically created by mplex, or mencoder, or ffmpeg). But you say that I don't really need to mux, as Toast will redo it anyway. Do you know how the audio track is chosen in case there is more than than one in the same directory as the m2v/mpg?

 

And is there a way to know exactly what Toast is unhappy with when it starts to re-encode?

 

Thanks again.

When you add the .m2v file to Toast it automatically adds the corresponding audio stream if it is in the same folder and has the same name except for the extension. Otherwise Toast asks for you to select the audio stream.

 

I don't know what triggers the encoding other than if the video's bit rate, resolution or frame rate are well out of spec or exceed the video DVD spec. Possibly a there could be a problem with a header, an incomplete GOP, dropped frames or problematic timecode breaks. Just guessing about that, however.