Pinnacle DV format (AVI files) vs. MPEG-2s

gary · #1 (**permalink**) 12-09-2003, 04:31 PM

I have been using Pinnacle's Studio 8 for some time now to produce "movies" of 1 - 11/2 hours each. I use Studio's DV codec to capture AVIs. I understand this produces best results as I am not reliant on real time MPEG conversion. I capture full quality at 200MB per minute. i.e. 12GB per hour.

So far I have output my finished productions to VHS or VCD and archived the "original" back to my camera. However, i have now spashed out on a DVD writer and am thinking of archiving to DVD as well as or instead of using DV tape.

If I stick with the AVI files I will need to split them into 4.7GB chunks - about 3 discs per hour. However, an MPEG at 10000 bit rate (i.e. highest possible quality in Studio

of the same production would fit on a single DVD. Studio can work with AVI, MPEG or a mixture of both in the same project so from the perspective of later use it doesn't matter which format I use.

Does anyone know what (if any) quality I would lose in this process or is the MPEG at such bit rate effectively loss free? Do you have a link to an info site on the subject?

Marc Peters · #2 (**permalink**) 12-09-2003, 05:21 PM

To the naked eye, you won't notice any difference in quality. Its much like comparing a JPEG image to an orginal BMP or a MP3 to WAV. The problem comes when you start re-encoding your footage - with each re-encode, you lose a bit of quality. Copying from the source to destination is lossless however. So it depends if you want to edit the footage later or not

gary · #3 (**permalink**) 12-09-2003, 07:45 PM

Thanks for this.

I have a DVD version of the productions in question for general viewing and would use that as a master to produce other copies on DVD or VHS. The purpose of the DVD archive is to avoid the need to capture from tape if and when I want some or all of the footage to edit and use in a new production.

Presumably the losses would result from the re-encoding to AVI from MPEG which would happen if I pull some clips off the archive to use in a new production but presumably only if I render the clips to AVI rather than MPEG? That production would eventually find its way onto DVD, i.e. MPEG with a bit rate of about 8000 if you use Studio 8.

I appreciate that if one continually encodes and decodes then it would be like continually copying an analogue tape but what would be the visual impact of taking a clip from a 10000 bit rate archive, remastering to AVI (possibly) before converting to MPEG for a DVD run (in studio

? I doubt that I would intentionally re-encode more than once with any particular clip as I could always revert to the archive version in that event.

Are we talking real quality degreadtion that would be visible on the DVD produced at the end of the process or is it in reality an academic discussion?

Marc Peters · #4 (**permalink**) 12-09-2003, 08:20 PM

Yer, shouldn't be a problem. This is the method I've had to use to edit some footage from a MicroMW camera - only way I could capture was to MPEG, the I converted that to AVI DV to edit (I get annoyed trying to edit MPEG), then back to MPEG for the DVD. I'm by no means an expert, but theoretically the MPEG to DV AVI would be lossless, so you'll only lose quality in the conversion back to MPEG after editing (and then not much!)

As I say, an expert would probably say, "ah, but...", but to be honest, if if the picture looks perfect, it is perfect

gary · #5 (**permalink**) 12-09-2003, 09:43 PM

Cheers. I agree. If you can't see the degredation then it doesn't exist (for you).

I think I'll go with the MPEG option, though I might keep a tape copy for the great grandchildren!! But that is a DVD-R vs tape longevity issue, rather than quality of picture.

Marc Peters · #6 (**permalink**) 12-09-2003, 10:32 PM

A DVD should last longer than a VHS - both from a physical (the tape wearing out etc) and technological (i.e no-one actually owning a VCR) point of view.

gary · #7 (**permalink**) 12-10-2003, 07:03 PM

I agree.

By tape I meant Digital 8. Not sure which one would last longest in the form of a seldom-used archive. Tape is fairly proven technology but can one say the same about writable DVD? I don't know. Both media must deteriorate with time and there is of course that question of technology to actually use the media.

For instance about 20 years ago I kept some backups of works data on a 10" reel of 1/2" tape. My guess is that that tape, rucked away in a corner somewhere, is probably useless. Computers have moved on as has the software. Could I ever get the data off the tape?? I don't need it so I don't care but it just shows that archiving is not simply a question of storing data. One must ensure that the archive is kept "up to date" as tecnology moves on so that it is transferred to new media beofre the old becomes unreadable.

Food for thought!