MPEG II to MPEG (DVD): Transcode or reencode?

[Jeroen1000]

Hi you all,

I've done this stuff in the past but now that I am hung on video I started asking myself this question.

DVD VOB's are MPEG II and an MPEG II stream obviously is too. I know a regular MPEG II stream is not DVD compliant and somethings needs to make it so.
But what is the best way? Transcoding sounds like porting it to a different codec and reencoding sounds like encoding to MPEG II again, which is also pointless being it already is MPEG II.

Please untangle this web of confusement

[Baldrick]

What is a "regular mpeg2 stream"?

If it's not dvd compliant you must reconvert/reencode. The word "transcoding" is usually used when you just shrink mpeg2 using for example dvd shrink or rejig, you just make it smaller and don't change any resolution, frame rate, etc.

[thymej]

Most if not all DVD author tools will take a mpg files and save them into the .vob files needed for DVD as part of the tools build a DVD process. As long as the resolution and audio you have in your mpg is already complaint for DVD; Like AC3 audio and 720x480 video.

[Jeroen1000]

The streams are recordings from TV (captured) because the Set up box's hard drive is full. I spoke to my cable company and as long as they are used in the privacy of our home, there is no legal consequence.

I'm not making it smaller (it's a 576i capture) nor changing framerates or anything. Just making VOB's out of the Mpeg II file.
I've read that encoding also involes a loss in quality which strikes me as odd. I've used both CCE and TMPG with good results.

[PuzZLeR]

MPEG-2 is a video format which can include a countless number of specs (resolution, fps, etc).

Yes, DvD does indeed use MPEG-2. But the specs that make DvD compliant MPEG-2 are a subset of what you can do with MPEG-2. Not all MPEG-2 can theoretically be DvD compliant.

If your MPEG-2 stream is DvD compliant, you need not re-encode. Just author as is with an authoring app that will input it and build the DvD structure around it (menus, IFO files, BUP files, etc.) and burn.

If your MPEG-2 stream is not DvD compliant, then you need to re-encode to a DvD compliant MPEG-2 stream, and then you can author and burn. The top left-hand corner of this site for "What is DvD" should help with what is indeed DvD compliant MPEG-2.

I've read that encoding also involes a loss in quality which strikes me as odd. I've used both CCE and TMPG with good results.

Although two excellent encoders, you will still lose something in the encoding process. Re-encoding something to a "lossy format" (ex: MPEG-2) is like making a photocopy of an image - your copy is never like the original.

Only re-encode when necessary. Your results were great with TMPGEnc and CCE because they are great "photocopiers" and you probably used a sufficient amount of bitrate (like quality ink in copiers) . But you still lost something in the process at any rate.

[fatbloke88]

Might be worth giving VideoReDo TV Suite a try Its easy to use works well with my pvr files,allows editing without re encoding and burns a simple dvd as well.

[Jeroen1000]

Yes Yes!! it is starting to make sense here. I thought 'converting' a DVD compliant MPEG file (with audio in a separate file) to the DVD structure (so VOB's and IFO's and...) introduced the quality loss.

To me the compliant making part was just that (MPEG to VOB conversion). It is the internal structure of the MPEG file that needs to be compliant in order to be able to make a VOB out of it. Going from compliant MPEG to VOB is merely putting it in a different container and adding a menu structure and such but does NOT hurt the video and audio data.

Thanks! That really needed pushing to get in (unless I'm wrong again, that would really make me )

[thymej]

You can also try DVDStyler and drop the mpeg into it. It normally will popup a window if the mpg cant be used (remuxed into a VOB). DVDStyler is a free DVD auth tool I use for basic quick easy DVD auth. Drop a mpg into the menu editing screen and click build to make the DVD.

Another good encoder is HCenc; like PuzZLeR said, only re-encode if you have too.

[louv68]

I've used DVDStyler before too, but recently tried adding subtitles (.srt) and I could not figure out how??? I was however able to do it with DVDAuthorGUI which is another frontend for DVDAuthor.