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Posted by PTravel on 10/06/18 11:51
"Tim Streater" <tim.streater@dante.org.uk> wrote in message
news:tim.streater-FA3BA7.12235028062006@individual.net...
> In article <9Qoog.124166$dW3.66877@newssvr21.news.prodigy.com>,
> "PTravel" <ptravel@travelersvideo.com> wrote:
>
> [Excellent and informative summary snipped]
>
>> Probably more than you wanted to know, but there you go.
>
> Actually not :-) , personally, I have been looking for good summaries
> like this without much success, so thanks for posting it. Hope it helps
> the OP, too.
>
> I want to know about editing software, though. I just bought a Canon
> MVX35i (might be an Optima 500 or so in the US) and have made a few
> quick shots and transferred to a DVD. Not entirely happy with the
> quality so far, but I am more curious about software at the moment.
When transferring digital video via the Firewire port, a bit-for-bit copy of
the data is created, so there should be no generational loss. I'm not a Mac
person, so I don't know anything about iMovie, but whatever is capturing the
video should store it as DV-codec-encoded AVI -- this preserves the native
format of D-25 video. If you're software is transcoding to anything else,
e.g. mpeg, you'll lose quality.
>
> I have a Mac and transferred from the camera using Firewire with iMovie
> and used iMovie/iDVD to make a DVD. Is the process of rendering the
> video onto the DVD a fixed process or do the various apps do it better
> or worse.
Video isn't rendered to DVD. The process should be this:
1. D-25 video is captured bit-for-bit to a DV-codec-encoded AVI.
2. The video is edited, i.e. transitions, titles, effects and corrections
are added.
3. The edited material (anything other than simple cuts) is rendered, i.e.
the software creates new frames that incorporate the title, effect,
transition, etc.
4. The resulting finished video is transcoded to mpeg2. Transcoding is the
actual translation of the D-25 video to mpeg2, which is required by DVD.
5 The DVD is authored, i.e. menus are added and the mpeg2 is sliced into
DVD-compliant VOB files. The video isn't altered, but merely repackaged to
comply with the DVD spec.
6. The DVD is burned.
Some software, mostly entry level, will do all six steps.
From the standpoint of video quality, step 4, transcoding, is the most
critical. Mpeg2 is a lossy, temporally-compressed format, i.e. data gets
thrown away by this step. Which data and how much of it gets tossed is
determined by the transcoding software. The transcoder has a lot of
decisions to make about how to compress the video. As a rule, the most
optimal compression takes the longest time. Accordingly, entry-level
packages usually introduce signficant compromises so that transcoding
doesn't take too long.
> That is, if I bought Final Cut, and used it instead of iMovie,
> do I just get a lot more editing capability, or do I get a better visual
> result on the DVD (starting from the same camera-video, that is) as well?
If you're getting poor quality video, it's not because of the editing
program (Final Cut Pro is an editing package), but because of the
transcoding. As I said, I don't know Mac, so I can't make any
recommendations. On my PC, I edit in Adobe Premiere Pro, a prosumer-level
editor comparable to FCP. Though Premiere can burn DVDs from the timeline,
I only use it for editing. Once my project is finished, I save it as AVI
(or frame serve, but that's another discussion altogether) and then use a
program called tmpgenc, which is a dedicated standalone transcoder. To give
you an idea of what I meant about compromise, transcoding a 2-hour video
with tmpgence tweaked to its most optimal settings for video quality can
take up to 20 hours on my 3.2 Ghz P4 with 1 gig of RAM. Once the video has
been transcoded to mpeg2, I author in Adobe Encore and burn with Nero. The
DVDs that I produce approach commercial DVDs in technical (if not artistic)
video quality.
>
> Thanks,
>
> -- tim
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