Is there am advantage of DVCpro vs DV?

[Moppelkotze]

PS: link for frame by frame comparison https://www.dropbox.com/sh/6jh59umgo...inNUEnvBa?dl=0

this link shows the same frame of the "original" (the file that iMovie wrote to disk while capturing the VHS. This is the file hidden under package symbol, not directly user accessable) and the "after" (when you export the movie/frame out of iMovie).

[WorBry]

Originally Posted by Moppelkotze

Here is the movie of my steps done (4MB): https://www.dropbox.com/s/okyi1t66ty...w.mp4.zip?dl=0

OK, so, to cut a long story short, you've done what was suggested:

Originally Posted by WorBry

Simplest "in-use" test would be to put your DV source into iMovie and, without applying any edit effects, output to DVPro(25)...

...and you now have your input DV file and "pass-through" export DVCPro(25) file. Fine.

Originally Posted by Moppelkotze

Is it sufficient enough, if I cut out one frame from the same time code or should I upload the whole file, so you can be sure I selected the same frame?

No, a single frame is not sufficient. Again, short (5 sec) frame-matched samples from the two files would suffice, but if you are not confident doing that (how did you cut the samples before btw?), well I suppose, yes go ahead and upload the full files and I'll have a look at them. That way there's no question of mismatching. OK?

[WorBry]

Originally Posted by Moppelkotze

PS: link for frame by frame comparison https://www.dropbox.com/sh/6jh59umgo...inNUEnvBa?dl=0

this link shows the same frame of the "original" (the file that iMovie wrote to disk while capturing the VHS. This is the file hidden under package symbol, not directly user accessable) and the "after" (when you export the movie/frame out of iMovie).

You bumped my last post. Like I said, upload the full files so we can reach a conclusion on this.

[Moppelkotze]

OK, sorry.

here is 5sec of both (capture and passthrough) https://www.dropbox.com/sh/l21vgmcsc...QijhjdSva?dl=0

I know this is a rethoric question, but how I did it? I used the application mpegstreamclip to cut off the frames and now 5sec of both clips (the one untouched sitting hidden in the project folder and the passthrough being visible on whereever one selects to save it).

If I used iMovie the files would be rewritten and transformed.

[WorBry]

Originally Posted by Moppelkotze

OK, sorry.

here is 5sec of both (capture and passthrough) https://www.dropbox.com/sh/l21vgmcsc...QijhjdSva?dl=0

The "capture" (DV) and "pass-through" ('DVCPro') samples are bit identical. What's more, both have 4:2:0 chroma subsampling, which is interesting, as by definition DVCPro(25) is 4:1:1.

So why MediaInfo reports the export file as being "DVCPro" (Commercial Name), I really not sure. Something to do with "locked audio"... maybe ? Any thoughts Ghitulescu ? You're more knowledgeable about this type of thing than I.

Regardless, I think it's safe to conclude that it is a direct stream copy of the source DV. DV is not a lossless format, and if there was re-encoding going-on, you would expect to pick up some loss in quality on metric analysis. And there is none.

That basic question answered, what might be interesting to determine is whether iMovie truly supports so called "Smart Rendering" of DV, which most Windows-based NLE's do, by default or as an option. By that I mean, if an "effect" is applied to a section of a clip on the timeline, only those frames changed by the effect are re-encoded and the "untouched" frames are passed through (copied). So if only cut edits are applied, there is no re-encoding at all.

[Ghitulescu]

I do not know.
Locked audio is not a problem in non-linear editing, it was developed for real-time ones.

Now that both files are on the HDD, and they are identical, I would use any of them for future processing. The other one, if the space allows, I would keep it as a backup in the case of a complete "ruin" by editing.

[Moppelkotze]

Thank you both very, very, very much!!!!

Now I know, that I can't go wrong letting iMovie do the export.
I started doing some exports and cuts with mpegstreamclips, in the past, after I discovered that they are labeled DVC(pro) bei Mediainfo, if they come from iMovie. Because I thought since the export with mpegstreamclip is still being recognized as DV afterwards, I will be sure to not loose something or alter the file other than cutting.

That basic question answered, what might be interesting to determine is whether iMovie truly supports so called "Smart Rendering" of DV, which most Windows-based NLE's do, by default or as an option. By that I mean, if an "effect" is applied to a section of a clip on the timeline, only those frames changed by the effect are re-encoded and the "untouched" frames are passed through (copied). So if only cut edits are applied, there is no re-encoding at all.

I would have to compare the time it takes to do a passthrough (or writing a cutted file) with iMovie and how long it takes with mpegstreamclip. Maybe I'll do this out of curiosity in the next week and then post back, as this would give a hint.

Hehe, if I were in your country I would sent you a cheap old Mac (they go for 20-40,-EUR and USD) to try iMovie. But that would serve nothing more than curiosity and had little practical worth for you of course

[WorBry]

Originally Posted by Moppelkotze

Thank you both very, very, very much!!!!

You're welcome.

Originally Posted by Moppelkotze

Hehe, if I were in your country I would sent you a cheap old Mac...

Thanks, but I already have a rain coat
(http://www.yourdictionary.com/mac)

Actually the wife has just bought an iMAC, but I'm not allowed to dabble with it......yet.

[Moppelkotze]

Originally Posted by WorBry

You're welcome.



Thanks, but I already have a rain coat
(http://www.yourdictionary.com/mac)

Originally Posted by WorBry

Actually the wife has just bought an iMAC, but I'm not allowed to dabble with it......yet.

Beware, the included modern iMovie version is very limited anyway... (guessing, that she has a newer model).
Agree which each other to create a second account for yourself You could also connect a HDD/SSD via USB3 and install Mac OS X there, too, then start from the external one, if you want to mess arround with it without anyoing your wife.

[WorBry]

Thanks, but I'm really not interested to use it for anything other than maybe Skype - and then purely for convenience when it comes to family video calls. Ironically, I spent an hour last evening getting her set-up with MS Office for Mac.