PDA

View Full Version : How much quality is lost if I convert DVD to AVI (no compression)


Salva Veritate
2007-09-04, 09:59 PM
I'm not looking to seed these specific shows here, I'm just curious since I appear to be totally out of luck on *this topic* (http://www.thetradersden.org/forums/showthread.php?t=44711). I'd like to know exactly what the damage is and if the DVD is still tradeable after re-encoding to AVI and re-syncing the better sound source, then converting it back to DVD using TMPGEnc.

Silver Stallion DVDs
2007-09-04, 10:12 PM
I'm not looking to seed these specific shows here, I'm just curious since I appear to be totally out of luck on *this topic* (http://www.thetradersden.org/forums/showthread.php?t=44711). I'd like to know exactly what the damage is and if the DVD is still tradeable after re-encoding to AVI and re-syncing the better sound source, then converting it back to DVD using TMPGEnc.
What you're talking about doing is expanding mpeg - that is at best 1/3 the size of the orginal video - and then crunching it back down to the 1/3 size mpeg again.

It really goes without saying - you're going to lose a considerable amount of quality.

I can help you out, but not with all of them - I have too many projects in the hopper. If you want to send one or two of them to me, I'll reauthor it with the alternate audio, and I won't re-encode the video.

PM me if interested.

Randy

pawel
2007-09-05, 07:08 AM
MPG (DVD) is lossy thus when you convert it to AVI and back you will use original quality - level depends on what software and setting is used.

Re-synching doesn't require such conversion you mention because what you need is to demux (separate) video and audio stream. Then audio can be replaced/mastered/whatever in a dedicated prog. However, most MPGs contain AC3 (Dolby Digital) audio format which is lossy. There is no any editor which works directly on AC3 format, and input file is converted to WAV or AIFF (and back to AC3, lossy).

If the source material is good and conversion is done properly, it's hard to recognise quality loss. Anyway, mastering of native lossy files should always be specified in the lineage.

KustMichaels
2007-09-06, 06:05 AM
I second what pawel said.

And as he said there is no need to go the .avi route. Demux the audio and video of the .vob files and mux again with new audio.

If you only have an .avi rip of a DVD it has to be a damn good rip if you want the .avi -> DVD re-conversion to go unnoticed.