Hi folks, glad to be here, this is my first post
I've done some experimenting around as i wanted to capture some vhs footage. I managed to do it using the "analog passthrough" method, i plugged my video recorder trough svideo to some old hi8 sony camcorder then firewire it to my PC. Then i thought that using a Canon XL1 which i could get hold of the results would be much better, but they weren't. I have now a panasonic nv-gs400 and it looks exactly like the same quality.
Could anybody explain me how the analog conversion through analog pass-through works? which part of a camcorder is responsible for it on and how come i achieved the same quality using a low end oldie camcorder and a top quality "semi-pro" one like the canon XL1?
I wonder if this is the best place to ask for this, as it's probably as much related to capturing video as to camcorders in general so please do not hesitate to point me out on the right direction if I may ask
Cheers!
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AtoD pass thru on a DVcam is done with an additional video and audio capture electronics in the camcorder. This is normally not availabled on the low/est end model.
The main intention is to transfer existing S/C/VHS/hi/8mm analog video to DV. But it will do pass-thru if you have the firewire setup to go.
The video and audio quality is limited by the original quality of the existing video, and less of the capture circuit of the DVcam. So there will not be big different bewteen different DVcams, whose quality are defined by their len/optics and sensor size/type/sensitivity/configuration. -
What SingSing said plus:
The A-to-D conversion is done with a hardware DV encoder. In theory, there could be differences in quality from one encoder to another, especially between manufacturers. The DV specification is quite loose when it comes to encoding. You can follow the spec and get wildly different results depending on the algorithm.
Having said that, since you are capturing from a lower resolution source - and VHS is about as low as it gets! - you are unlikely to see any difference. The differences in encoder quality show up when dealing with sources that have a lot of high frequency detail.John Miller -
Wow thanks ever so much for 2 great and quick replies!
I suppose i'll settle for that on my thirst for knowledge.
I will ask another question if I may then:
let's assume i was to buy a new camcorder that doesn't have any analog inputs. Is there such a thing like an external usb or firewire capture card that could encode in DV and output the data to my pc very much like my camcorder could do AtoD passthrough? -
Absolutely.
http://www.datavideo.us/products/dac_100_main_page.htm
http://www.canopus.com/products/ADVC110/index.php
But it might be cheaper to keep your existing camcorder to use for conversion if you get a new one. (I assume you are planning to sell your existing one?)John Miller -
Yup i am actually. Looking at selling my nv-gs400 in order to get a HD one
Gee the HW on your links is indeed expensive...
Do you reckon i could achieve a somewhat comparable quality using another sort of external box encoder (not necessarily DV)? actually could one supposedly aim at getting a better quality than DV? -
The Hauppauge WinTV PVR USB2 is an external USB 2.0 capture device that uses hardware MPEG-1/MPEG-2 encoding.
It can capture direct to a file that is DVD compliant OR you can capture at the highest rate it is possible of ... 15,000kbps CBR video with 384kbps MP2 ... then use that as a "master" to re-encode.
Another good choice is the ADS Instant DVD 2.0 although it is no longer made and getting hard-to-find now.
- John "FulciLives" Coleman"The eyes are the first thing that you have to destroy ... because they have seen too many bad things" - Lucio Fulci
EXPLORE THE FILMS OF LUCIO FULCI - THE MAESTRO OF GORE
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Originally Posted by kamaleonJohn Miller
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Thanks Fucilives
So is your method of an onboard mpeg2 encoder able of outputting a good quality compared to A-to-D passthrough? What puts me off with onboard mpeg2 encoders is that it makes it impossible to later on tweak and filter the capture on virtualdub...
@JohnnyMalaria i don't know yet, but i don't think i would be using its DV function much, not when i can get HD
Ideally a panasonic 3ccd on AVC, hard disk, big lens and nice big screen but unfortunatly it doesn't exist yet!! -
Originally Posted by kamaleon
VirtualDubMod can read MPEG files. You can also run the capture through DGMPGDec and use AviSynth scripting.
- John "FulciLives" Coleman"The eyes are the first thing that you have to destroy ... because they have seen too many bad things" - Lucio Fulci
EXPLORE THE FILMS OF LUCIO FULCI - THE MAESTRO OF GORE
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The DV format capture method (either camcorder pass-through or from a DV capture device) creates a sequence of individual fields with no interframe compression (i.e. motion compression). This is a better format for editing, filtering or creating effects since individual frame data can be derived. The disadvantage is a second encoding step is needed to convert DV format to DVD MPeg2.
For PAL DV, the two methods of DV capture yield similar results although I've seen some analog levels issues with some consumer camcorders that result in conversion to other than 16-235 digital levels. It is wise to calibrate the path.
For NTSC DV there is a problem with current consumer camcorders that causes 7.5-100 IRE analog NTSC to be captured to incorrect digital levels 32-235 or 32-255. This is the well known "washout problem" that requires digital levels filtering to correct. Most DV transfer devices like the Canopus ADVC include a 0IRE/7.5IRE switch to allow for capture to correct levels.
http://pro.jvc.com/pro/attributes/prodv/clips/blacksetup/JVC_DEMO.swf -
or NTSC DV there is a problem with current consumer camcorders that causes 7.5-100 IRE analog NTSC to be captured to incorrect digital levels 32-235 or 32-255. This is the well known "washout problem" that requires digital levels filtering to correct
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Originally Posted by edDV
(As per this link: "We do it differently in North America because back in the Jurassic Age of television this 7.5 IRE black level was needed to make TV's work correctly. The rest of the world came up with a less-complicated way to do it.")John Miller -
Originally Posted by JohnnyMalaria
At the broadcast level all these manufacturers have the switch and do it correctly. I think they thought nobody would notice at the consumer level but the washout is clearly visible. -
hehe please don't get too carried away, i've got a pal camcorder as i live in europe (though i appreciate reading your great posts!)
@ FulciLives so your idea of a high cbr rate might be a good thing for me after all, i'd never thought of it actually. I didn't know you could do a lot of the stuff one can do on virtualdub(mod) to mpeg2 files.
So which solution can produce the better final result: capture un mpeg2 cbr or dv then reencode in mpeg? -
Originally Posted by JohnnyMalaria
I think the USA market missed the boat in the late 60's when color became mainstream. The problem was that it would obsolete many legacy TV sets (monochrome and color) made in the 50's. They should have bit the bullet like Japan did. Blame American lawyers maybe?
It wasn't a problem in Europe because color came in 12 years later and they changed the scan standard to 625/50 which by definition obsoleted all older monochrome TV sets. -
Originally Posted by kamaleon
When they can't find any stationary pixel blocks, the encoder is forced to use more intraframe (in frame) compression that severely reduces quality. For this reason you should ask for minimal compression for DVD encoding to maximize quality. This means HQ (high quality) or >9000Kb/s (CBR )
If the cameraperson has a steady hand, or if a tripod is used, then lower bitrates can work. -
i don't get the gist of your last post, edDV... i'm talking about capturing footage from an analog source using a capture card/box... not shooting footage with an mpeg2 camcorder...
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Originally Posted by kamaleon
The solution is application of noise reduction filters while in DV format, so the MPeg2 encoder detects real motion and is less confused by noise. Too much noise reduction causes loss of detail. -
Doing a MPEG-2 capture at 15,000kbps CBR video bitrate with maxed out audio bitrate (usually you have to use 384kbps MP2 since that is how MPEG hardware capture devices tend to work) is the alternative if you will to doing a DV capture via pass-through (with a DV cam) or using a device ala the Canopus ADVC-110 or DataVideo DAC-100 etc.
This only makes sense of course when the original is not DV to begin with ala a VHS video or LaserDisc or cable TV broadcast or some other analog form of video.
Why stop at 15,000kbps CBR you may ask? That is the "limit" of most (if not all) consumer level hardware MPEG-2 capture devices.
As I said popular USB 2.0 models include the Hauppuage WinTV PVR USB2 or the Instant DVD 2.0 by ADS. For PCI the Hauppauge WinTV PVR 250 and 350 models are popular. These are all hardware MPEG-1/MPEG-2 capture devices.
- John "FulciLives" Coleman"The eyes are the first thing that you have to destroy ... because they have seen too many bad things" - Lucio Fulci
EXPLORE THE FILMS OF LUCIO FULCI - THE MAESTRO OF GORE
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I agree that if hardware MPeg2 is used for capture, high capture bitrate will reduce the VHS noise effect. Then noise reduction can be applied before final MPeg2 encoding for DVD.
Recommends: Kiva.org - Loans that change lives.
http://www.kiva.org/about -
Thanks ever so much for your precious help.
Would you have any advice on this particular box: Pinnacle DVC 170?
Someone I know from another board was telling me wonders about it. Reading through its specs though it seems to only be able to 10,000kbs. Suppose this would be drastically not as good as ripping to DV?
anyway i will ask another question: another vhs ripping method i know of is to use an analog pci capture card (like the old bt878 based ones, or some saaXXX) and capture the footage with a lossless codec like huffyuv or mjpeg then encode it later on to any desired format. Would this be possible with an external box? Would it require a bandwith that can't be achieved with usb 2.0 or firewire? (knowing that i've got a pretty fast system otherwise)
Would this method, if possible to achieve, outperform the mpeg2 HW encoder or the DV one? -
A hardware MPEG encoding capture card/device is made to capture direct to MPEG-1/MPEG-2 so you really can't use that to capture to an AVI file ala a BT chipset/Philips chipset PCI type capture card.
Now a BT chipset/Philips chipset PCI type capture card (especially the Philips or SAAXXX as you called them) will give you the best image/video especially when using a lossless codec such as HuffyUV or even PICVideo MJPEG (on the highest of settings of course) but then your biggest enemy becomes A/V sync and mis-matched frame rates (i.e., 29.971 or 29.969 instead of 29.970) and of course dropped frames can also be an issue.
A hardware MPEG encoding capture card/device or a DV AVI hardware solution (like analog-to-digital pass-through or using a Canopus ADVC-110 etc.) will result in less of the issues that I just mentioned that seem to be inherit in the design of the "traditional" PCI type capture card (BT/Philips chipset).
As for the Pinnacle DVC 170 ... never heard anything specific that I can remember on that particular model but most of the comments I have heard about Pinnacle products in general have been rather negative.
The main recommendations are (in no particular order):
DV AVI:
1.) Canopus ADVC-100 or ADVC-110
2.) DataVideo DAC-100
3.) Digital Camcorder (Digital8 or miniDV) analog-to-digital pass-through
HARDWARE MPEG ENCODING:
1.) Hauppauge WinTV PVR USB2
2.) Hauppauge WinTV PVR 250
3.) Hauppauge WinTV PVR 350
4.) ADS Instant DVD 2.0
Again all of those can do up to 15,000kbps CBR MPEG-2 although for some reason the Hauppauge say 12,000kbps in the documentation but real world experience and user comments and even the spec sheets (not marketing speak) say it really is 15,000kbps.
- John "FulciLives" Coleman"The eyes are the first thing that you have to destroy ... because they have seen too many bad things" - Lucio Fulci
EXPLORE THE FILMS OF LUCIO FULCI - THE MAESTRO OF GORE
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Nice one mate, once again your reply is more than i was waiting for
As i have a hauppauge wintv BT878 pci card i can use everyonce in a while (but unfortunatly not all the time as i lack of pci slots) i will do some testing at some point and try to compare the results with the DV capture method.
Regarding SAAXXX chipsets, would you recommend any specific one which is reputed to be somehow better? I ask this as i have experienced flickering on my BT878 and i wonder if this can be avoided by a more performant chip.
Oh and if i may ask again, can i expect to capture in mjpeg/huffyuv from an external box rather than a pci one and if so, do you any particular models pop up in your mind? -
I have used here the following devices for capturing (PAL) VHS stuff:
Pinnacle BT848 capture card
Hauppauge PVR150 Mpeg2 card
Sony DCR-TRV120 D8 DV Passthrough
While the BT848 and PVR150 can work nicely they will only give good results for VHS when a TBC is used for playback.
The Sony DV Passthrough from my camcorder gives me far the best results because it has a stabilizing effect on the the incoming analog (VHS) signal.
(It seems to use some form of simple TBC for the analog input) -
My impression is stand-alone TBCs can cost as-much-as or more-than camcorders, because they are not mass-produced consumer electronics.
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Well capture quality and a TBC are two different issues.
They go hand in hand but yes it is true that some digital camcorders have built-in TBC (or at least TBC like) enhancement of analog input.
However DV AVI is still DV AVI and not necessarily the best choice for VHS captures. This has been covered before.
edDV probably has a link.
It all has to do with the 4:1: color sampling issue BS.
- John "FulciLives" Coleman"The eyes are the first thing that you have to destroy ... because they have seen too many bad things" - Lucio Fulci
EXPLORE THE FILMS OF LUCIO FULCI - THE MAESTRO OF GORE
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Originally Posted by kamaleon
If you get a new HDV camcorder (I assume you're not shelling out for what I call a real HD camcorder - DVCPro HD and the like), when you aren't using it as a camcorder, why not use it for the passthrough in SD DV mode?
Also, the amount of money you might get for selling your existing unit problem won't cover the cost of a dedicated converter box.
Personally, I'd just keep your existing camcorder and use it for converting analog material (plus you'll also have a second "deck" to save wear-and-tear on your new baby (for rewinding etc)). (You can buy the NV-GS400 new for $667).John Miller -
Originally Posted by FulciLives
I doubt you will get better quality then when using the DV passthrough option.
Unless ofcourse you want to capture in MPEG2 format. -
Originally Posted by JohnnyMalaria
Should i get a new camcorder, i will definitly sell my nv-gs400 as i can't afford to keep them both, and i will be looking at some rather cheap solution to capture my analog footage.
Anyway, please keep your posts coming, i think i've learned more here about these issues than the in whole of last year
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