ProRes versions of VHS tapes for archival purposes

I recently archived about 400 hrs of original VHN footage shot back in 1985-95 era. Majority of them were captured directly via s-video cable and rca audio. The codec I used was DV25 and few DV50. Pro Res is quite overkill for VHS. The format is a mere 240 lines. Quite outdated to today's 1080p TV standards. Used FCP 7 and no tc needed. When comes to edit, switched to FCP X.

When you're doing DV on any deck, you're adding another layer of hardware decode and encode. DV has a 5:1 compression ratio w/ 4:1:1 sampling. It's not the best intermediate format. I'd try to minimize anything via DV and get it directly by using real time hardware. But this needs a decent capture card to do the job right the first time.

But for Betacam SP w/ analog component, I did capture via DV50 and Pro Res std. That should preserve ther analog 4:2:2 Beta SP tape formats.

Another potential answer is to use the EyeTV Hybrid from ElGato. It attaches to your VHS deck through the composite cables (RCA jacks), but can handle coax and S-Video as well. It attaches to your Mac with USB.

You can set various levels of capture quality in the EyeTV 3 software. As I recall, you can get up to 960x540 in h.264 or up to 1080i in MPEG2.

Once in EyeTV 3, you can EXPORT USING QUICKTIME using any codec installed on your system, including ProRes 422.

I have about 40 tapes captured in MPEG2, and so for I have been editing in iMovie, but going forward, I will be using the ProRes version in FCP X.

Lonewolf2Koc wrote:

I recently archived about 400 hrs of original VHN footage shot back in 1985-95 era. Majority of them were captured directly via s-video cable and rca audio. The codec I used was DV25 and few DV50. Pro Res is quite overkill for VHS. The format is a mere 240 lines. Quite outdated to today's 1080p TV standards. Used FCP 7 and no tc needed. When comes to edit, switched to FCP X.

When you're doing DV on any deck, you're adding another layer of hardware decode and encode. DV has a 5:1 compression ratio w/ 4:1:1 sampling. It's not the best intermediate format. I'd try to minimize anything via DV and get it directly by using real time hardware. But this needs a decent capture card to do the job right the first time.

But for Betacam SP w/ analog component, I did capture via DV50 and Pro Res std. That should preserve ther analog 4:2:2 Beta SP tape formats.

The question might seem a bit off topic at first, but anyway here is my question:

You say DV has 4:1:1 while ProRes had 4:2:2. I once noticed that when you capture with iMovieHD6 the DV files in the project folder are DV, when you read the file info in MediaInfo. But, when you export the project-movie out of iMovieHD6 and select "best quality" (I am not talking about an export/import to iDVD!!!) it will create a DV file that MediaInfo sees as DVCPro50. So, it does reencode the file instead of just saving the file again just without the cut scenes (as you would expect, since DV is a file format, where you can chop of a part everywhere and just save the file again, other than let's say h.264, were you always have to cut at the i-frame and/or re-encode).

Isn't this an unnecessary further step that further alters the image?

Am I right that DV is 4:2:0 in PAL and DVCpro50 is always 4:1:1 ?

I mean it isn't a problem, since I learned to take the actual project clips via ctrl+click -> show package content, and then open and cut it in mpegstreamclip-Application, which will just cut of stuff and re-save it, instead of re-encoding/transcoding/encoding it. That's not my problem! My Problem is the unnecessary alteration of the image and possible quality-loss.

lime-iMacG3 wrote:

Am I right that DV is 4:2:0 in PAL and DVCpro50 is always 4:1:1 ?

Yes. Please seethisfor more detail.

As to your iMovie questions, there are some people here who are more familiar with iMovie 6 than I am and perhaps they will comment. Otherwise you could post those questions in the iLife > iMovie forum.

Russ

Thanks, I will consider asking in the iMovie Forum maybe later.

Also thanks for the link, I only looked up DV some time ago and also, I only red the German version, the english subsampling article is a bit more detailed, though I am not sure I understood everything, but it is probably not important neither or for my general understanding, anyway.

But iMovie or not, shouldn't it be of disadvantage to capture in DV (I hope that my German iMovieHD6 version captures in DV 4:2:0, since otherwise it would be NTSC and 4:1:1 for the original DV, right?) and then save the file and it gets transcoded to DVCpro? I once had someone look at the pictures with a professional tool and it showed differences (at least on paper - I don't know, if there is a visible difference).

Does Final Cut capture in progressive as well as interlaced, depending on the source? I ask this, since people have to have a Problem since some version of Toast (when using it for transcoding DV to mpeg2) and iMovie (since iMovie 8 every material gets interlaced upon import). I wonder, if that phenomenon has to do with DV becoming DVCpro, too.

lime-iMacG3 wrote:

Does Final Cut capture in progressive as well as interlaced, depending on the source?

Yes.

Again, I'm not very conversant with iMovie versions. I would have thought that it would not do any de-interlacing upon import (which I assume is what you are talking about). Perhaps the default export settings de-interlace?

To your Pro Res question, I don't know how you can do that without additional hardware.

Karsten Schluter, a frequent contributor to this forum, knows a lot about iMovie. If he sees this and chimes in, I'm sure we'll both learn a lot about best practices.

Russ

Russ H wrote:

To your Pro Res question, I don't know how you can do that without additional hardware.

Thanks for your answer. What Pro Res question are you referring to?

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The iMovie questions aside, am I right that first importing as DV and then again saving the file as DVCpro is changing the material and a further (unnecessary) step that degrades quality?

I'll answer my own question from back then.

I tried to look at the issue (wether iMovie does a re-encode or why the label of the file is DV before edit an passthrough export and then DVCpro50 after the passthrough) with someone in the doom9.org forum and he looked at the same frame from both before and after and said they are bit-identical. In other word, are the same. He assumed that since the application was written with NTSC in mind Apple might have done something wrong with the labels for PAL, after passthrough, so an App like mediainfo (or others) would report a different codec (DV vs DVCpro50). If that is the reason... who knows.

But I am a bit more satisfied now, to know, that it is bit-identical - that is, if it says that both files are the same.

In the meantime I am still searching for a better "work"-codec for S-VHS captures. I mean the codec the editing/capturing software uses,

- while saving the analog material digitally to disk

- I am working with the file (editing, cutting)

TERRATEC Video-Rescue e.g. allows YUV422, AIC, DV, DVCpro, DVCpro50, mpeg4, H.264. mpeg4 and H.264 are obviously not suitable.

I understand that AIC would be better than DV (guessing from the chart here 3.3MB/S versus more https://en.wikipedia.org/wiki/Apple_Intermediate_Codec#Format_Details

What about YUV422? What other codec not tied to using iMovie10+/FCP or Pro-Software (Adobe, Edius,..) would be better? I understand ProRes would be the best of all but overkill for VHS, right?

The wiki article about AIC says

Both MPEG-2 HDV, AVCHD and the Apple Intermediate Codec record a 4:2:0 component (Y´CBCR) digital video signal. Each sample (pixel) has a resolution of 8 bit. This is not much of a concern for editors as HDV and AVCHD records in a 4:2:0 color space anyway. In fact you may actually lose data if you decide to use 4:2:2 codecs like DVCPRO HD

It is quiet interesting that more can look worse.

I Won't slog thru the entire thread but I did not see a direct comparison between the information density of the original tape and the various codecs. Just because a codec holds more bits than another does not mean the image is better. It never gets any better then the original. You can run VHS analog through a time base corrector, frame sync, and image enhancer but the results remain confined and clipped by the available bandwidth, chroma capacity, and horizontal resolution of pal or ntsc analog video As it was recorded to and comes off the tape.

We have transferred hundreds of hours of 16mm films, VHS, 3/4", Betacam, and beta tapes to DVD and DV and directly to ProRes 422 and then, after extensive editing and culling, encoded them all, through one software tool or another, to h.264. We have decided image quality is secondary to preserving the scientific and cultural material For future generations of researchers And archivists.

David Bogie Chq-1 wrote:

I Won't slog thru the entire thread but I did not see a direct comparison between the information density of the original tape and the various codecs.

You saw right. I assume your company didn't do such a comparison as well since you just took one (ProRes 422) that you probably knew/that might be overkill, having in mind that you will encode with to h.264 anyway, right?

Correct. VHS is what it was. The 3/4" originals are falling off the acetate backing and are largely lost for all time. But I've got 80-year old 16mm film and 120-year old negatives I can still view or print.

Thanks for your reply. I see you understood my sentence anyway, allthough I made several errors. 🙂

Too bad, one can't edit replies very long.

It should have read "that you probably knew/thought might be overkill, having in mind that you will encode with to h.264 anyway, right?"

Dub the VHS to tape and capture from there. The tape because your digital master.

You could also try Quicktime Player.