How to determine Hi8 DVD quality with original tape?

[theair]

I apologize in advance b/c I don't know how to put this concisely -- but basically:

I recorded several concerts in the '90s - mostly on a Sony hi8 camcorder. Several years ago, I had the tapes transferred to DVD. Is there any way that I can determine - solely by the files that are on the DVDs - if there was any significant quality loss during these transfers?

I am VERY sure the tapes weren't transferred with a camcorder and a computer; I know this b/c I was working at a post-production video company and had the wherewithal to befriend somebody with access to their utilities - but no color correction / editing was involved (during the xfers). I've always been more an audio person....my interest in recording on video was short-lived (too many variables).

The DVDs all have large VOB files on them, of course, and I've looked at the files via VLC; for example, the 'Media Information' of one's codec details says: "MPEG-1/2 Video (mpgv).... 720x480, 29.9780030, Planar 4:2:0 YUV, ITU-R BT.601 525 lines 60Hz, ITU-R BT.709, ITU-R BT.601 Range" and its statistics ~"Read at media 29418KiB, Input bitrate 4240kb/s, Demuxed 28337KiB, Stream bitrate 4077 kb/s | VID DECODED BLOCKS 3319, DISPLAYED FRAMES 1625, LOST FRAMES 0| AUD DECODED BLOCKS 3543, PLAYED BUFFERS 1771 LOST BUFFERS 0" - the part in caps is the part I suspect is more relevant - and this info is after the video has played for about a minute.

For all intents & purposes, let's just say it's logistically impossible for me to do an A/B comparison to what is still on these tapes vs what is on the DVDs now, so please don't say "create a $3K workflow and upload a clip from each" Honestly the videos look pretty decent to me - as good as I can expect - but I would like to Know. Thanks

[msgohan]

No guarantees, but your best bet is to attach a short sample (or a few, of varying content) cut directly from the VOB files. Then people here might provide their impressions compared to their own results.

http://www.digitalfaq.com/forum/news...ad-sample.html

[theair]

One of the reasons why this process is prohibitive is that I am not using a PC. Most (regular, under 50 - which I barely am) people aren't even using computers at this point. Sorry, but it's true. I have dBpoweramp Video Converter that I can use to convert a huge 1GB VOB file into various formats but I'm using a Mac. YES, I KNOW. Again, these videos/files are on DVDs - I've converted many of them into various formats that are viewable via VLC (and frankly I can't tell much difference - visually - between the end result of an encoded h264 with an average bitrate of anything bw 2.5 and 5 and unencoded file outside the fact that one ends up being ~200MB and then the other potentially is even bigger than the original VOB [=over 1GB]). I can trim an mp4 into an upload-able file here, I'm sure, but I don't know if it will suffice for your standard critical review. I like logic.

[dpalomaki]

It may be a moot point if you do not have access to the original tapes. Without the tapes you cannot do a recapture to make a better DVD.

All format conversions involve some loss - if nothing else quantization and truncation errors in the A-to-D and D-to-D processes, plus any compression artifacts, especially if the original video contains image noise.

If the DVD, when played in a decent DVD player to a good display, looks and sounds about as good as you recall the original tape being then you did not have any meaningful (to you) losses.

One other thing is the bit-rate of the DVD. If you try stuff more than about 90 minutes of video on a 4.7 GB DVD the video quality can start to suffer compared to DVD media's potential.

A straight dump of tape to a DVD recorder will not be as good as it cold be, but it may be sufficiently good for your purposes when weighed against the cost/effort/time required to make it better.

[theair]

I still have the original tapes - they're right beside me, actually; I even have the original hi8 camcorder [or at least one of them - one was stolen in '95 or '96; some tapes are from '94-'95, some are from '95-'99]. Regardless, the one I still own, a Sony CCD-TRV75, apparently doesn't have a TBC in it anyway - at least not according to a list posted at this site.

And I have a limited amount of time, resources, concern, and impetus to deal with all of this.
When the tapes were transferred at the post-production house 10+ years ago, a hi8 deck was used for playback...I remember looking at the giant room of equipment, but that was not my department and I didn't get to play, so to speak, with such or know any better to ask what the workflow process was at the time.

All the DVDs are fairly generic Verbatim 16x 4.7GB 120min DVD-Rs and have 3-5 VOBs each on them; each VOB is 1.05-1.07GB (except for the last VOB on each disc depending on how long the concert was).
I realize it is theoretically impossible for there to be no degradation between the original tapes and the DVDs - frankly, every time I look at the world through my eyes and the world through my phone, in 2021, I still think "ugh" but it's way better than through a viewfinder in 1994 - but, is there no way to do what I want to do without going back to my old tapes - or using a non-PC?

Is it truly impossible to assess any video here that is uploaded by way of anything except a PC?

[hodgey]

The CCD-TRV75 has TBC/DNR and stereo audio, so it would work great for capturing, I presume it's just missing from the list.

4240kb/s bitrate would suggest they're were not encoded to DVD with the maximum bitrate (which is around 9000kb/s). How much impact that has depends on the material. If the bitrate is too low you will get a lot of blocking and other compression artifacts, noisy video needs more bitrate to avoid it than soft clean video. If don't notice the compression artifacts much or at all it's probably fine though, you have to be the judge of that.

You can assess some things from a upload converted to something else, it should give an idea of whether a decent playback device was used at least. One can't quite tell to what extent compression artifacts are from the DVD source and what is from further compression though. (Also no idea if that converter app will deinterlace by default or not.)

There are some apps that can extract a lossless short segment from a .VOB that run on Mac too though. Such as Avidemux (no idea if it runs on latest macos or not) and ffmpeg (which is command-line), and probably more. For that matter it's possible dbPowerAmp can do it too but I've never used it.

[theair]

Oh wow, I was not aware about that with the CCD-TRV75. The list of "good cams w s-video | hi8 w TBC" I found here (after various unsuccessful searches) is several years old but skips the 75.

I do regularly use a more current macos (M1) but thankfully I also still have a 2012 Macbook Pro that I never upgraded past Mojave OS X 10.14 and I bought a Tevion ATI 600 USB clone from LS himself here several months ago - which per his info will work with Videoglide up to OSX 10.14.

I have yet to deal with it as it's really just a side 'project' at this point...and since most all of these tapes are already on DVD, I had hoped to not deal with them at all

While I'm at it - it's not possible for the camcorder to be used as a TBC device, correct?

Do you know about the (miniDV) DCR-TRV900? That's what I used to record a few things in 2000-2002.

thanks again

[ffmpeguserss]

To add to what dpalomaki, hodgey, & msgohan have already stated, I think it's great you have the original tapes and the original camera; if you can hang on to them longer that might be a good insurance policy for you in case you need to recapture (tapes need to be stored in a non-humid dirt-free environment; sometimes a box in a closet in an air-conditioned home suffices).

In some cases only the original camera can play the tapes; I think that's the case for Video8 if I recall correctly lordsmurf saying so.

The scenario sounds like the tapes were transferred in a professional setting, but the bitrate around 4Mbit/sec can be telling. A good encode might start at 7Mbit/s. Can you play them on a DVD player? Can probably compare with similar videos on youtube.

You do have a capture device; but I hear what you're saying; it's a hassle. At least you still have the original tapes, they could hold a good signal.

[theair]

Heh, well I definitely - for better or worse - tend to keep things, so the tapes and equipment remain. As far as the 'original' camera...that sort of brings me back to my original query in regards to why I'd like to ascertain the quality of what's on the DVDs as I know some of the tapes were made with a different camera. And I am all too aware of the potential issues and needing specific equipment to play original tapes.

As far as the bitrate goes : which bitrate are you referring to? (stream vs input)

I can definitely play the discs on a DVD player - any number of them - but I don't know how to readily compare any of the videos to others on YT because they're literally the only copy of them that exist. I mean, yes, there may be footage of the same band from the same tour on Youtube but I don't know how realistically "similar" that is to mine. That's partially what prompted me to think (again) about this 'project'.

Also (to anyone) - it's not possible to use the CCD-TRV75 or DCR-TRV900 as a pass-through TBC, is it? (This is for a more general project, out of curiosity.) I vaguely recall the latter having the ability, perhaps via firewire, but I certainly could be mistaken.....

thks to any/all.

[ffmpeguserss]

The input bitrate, 4240kb/s above. The playing rate (I think that's the streaming bitrate shown) varies between a minimum and maximum.

[theair]

Ok, thks again.....as everybody's favorite abbreviation goes

To
Be
Continued


PS: So that this isn't a completely pointless post, apparently per hodgey above, the CCD-TRV75 should be added to the "Hi8 stereo with TBC and s-video:" list in a LS post from 1-16-20 [under Capture, Record, Transfer]. Feels like several years ago!

[dpalomaki]

One way to determine the bit rates is to open one of the 1 GB VOB files with MediaInfo.

It should give you the bit rates for the video and audio, and tell you whether or not the video is constant or variable bit rate.

The following link provides simplified guide to bitrate vs. quality potential for DVDs. Obviously a lot depends on the content as well.
https://www.google.com/url?sa=t&rct=...6jw5fqWid_PJQJ