mpeg 2 re-rendered, quality problem?

[frappawotsit]

Hi, I recently converted one of my home movies to dvd but in my "excitement" at having completed it, I made a glaring silly mistake.

Once i'd finished cutting and moving my clips around, adding transitions, altering sound levels etc I was so pleased i'd finally finished that i moved onto authoring the DVD then burning to disc.

Thinking i was done, i deleted all my original captured clips, authored file etc permanently from the hard drive.

The problem being... as soon as i'd deleted, i realised i had stupidly forgotten to add the background music tracks that i'd wanted to.

So, onto my question.....

The only file I still have available is the rendered mpeg2 file. If i use my editing program to open this file, then add my background soundtracks, and re-render the file, will this result in large quality loss as i'm rendering and already compressed file?

It took me hours to capture, edit, author etc, i don't really want to start from scratch, but if i'm going to get bad loss, then i'll have to do it.

Or is there another way i can add the soundtracks to an existing mpeg2 file without quality loss of the existing file?

thanks for all your help.

[GeorgeW]

What software are you using to author your dvd?

You'd basically want to get the mpeg video stream from your current disc, create a new audio track, and re-author (without re-compressing the video).

Regards,
George

[ZippyP.]

Try MVW, free for 30 days. Open your file, add audio as you wish (MP3, MP2 etc.), save as a new mpeg with no quality loss at all.

[frappawotsit]

I used sony dvd architect to author the dvd.

what program do i need to open the dvd, add the audio and be able to render the two together without the video being re-rendered?

or am i misunderstanding something?

[vico1]

what program do i need to open the dvd, add the audio and be able to render the two together without the video being re-rendered?

As ZippyP. said, try MVW (Womble MPEG Video Wizard)...

[jagabo]

Redo your project with the software you have. Don't worry about reencoding. When you're done, demultiplex the video from the original, the audio from the new version, and multiplex them together.

[frappawotsit]

Thanks, i've just had a look at the MVW software, and to be honest, it looks like it will do what I want very easily....

however, this is not a problem i expect to face regularly, it's (hopefully) a one off, so i can't really justify $$$ for a single use.

Will i lose much quality if i just re-render?

Or is there any freeware that will acomplish this task?

[jongov]

Hi,
Re-encoding mpeg-2 video is not a good idea if you don't want to lose quality. After decoding the MPEG-2 stream there are block artifacts coming from the mpeg-2 compression. Encoding again will spend too much bits to encode those artifacts and you'll lose quality.


The best way would be to demultiplex the streams, edit the audio and multiplex them without re-encoding the video.

Regards,
Tsviatko Jongov
http://tsviatko.jongov.com

[FulciLives]

RIP the DVD to your computer using DVD DECRYPTER.

Use IFO MODE and pick STREAM PROCESSING. Make sure you go into the options and select NO FILE SPLITTING.

If you do it correctly you will end up with two large files. A video only file (filename.m2v) and an audio only file (filename.ac3 or filename.mpa or filename.wav ... depends on what you used to begin with).

Now you should be able to load these into your video editing program although if you used MPA (aka MP2) or AC-3 audio you might want to first convert back to a PCM WAV audio file.

Go ahead and add your background music etc.

In the end see if you can just export just the audio. This should be an option. Now you will have to re-author using the original video file (ripped from the DVD you made) and your new audio file.

If you export the video and audio (i.e., if no audio only export option is available) then you should end up with a single MPEG-2 file. You can demultiplex (aka demux) that into a separate video file and audio file. Use the new audio file with the original video file. Discard the new video file.

To demultiplex you would want to use DGIndex aka DGMPGDec.

- John "FulciLives" Coleman

[GeorgeW]

I use Ulead's MovieFactory 5Plus. It can Import from DVD (to extract from your current disc), and then it will let you add background audio files (and also set its audio level so it plays in the "background").

Also, DVD Architect 4 (maybe earlier versions will work also) will let you drag a VOB to a project, but you'll have to be able to create the extra audio separately and replace the audio track. This doesn't work as well if your VOB spans multiple 1gb VOB's, but if it's all within one VOB, then it should work for you. If it's in multiple VOB's, then you would drag all of them separately, but where the VOB's "join" might have a slight pause during playback...

Regards,
George

[ZippyP.]

Thanks, i've just had a look at the MVW software, and to be honest, it looks like it will do what I want very easily....

however, this is not a problem i expect to face regularly, it's (hopefully) a one off, so i can't really justify $$$ for a single use.

Use the trail version, fully functional and free for 30 days (like I said).