01-30-2016, 02:24 PM
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The Wikipedia quote at the bottom is correct. AVI doesn't indicate how the video is actually encoded.
All Digital8 tapes are DV format, as is the passthrough function of these camcorders. It's around 13GB / hour. I forget whether that's with or without audio, off the top of my head.
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RDM56 (01-31-2016)
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01-30-2016, 07:00 PM
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Quote:
All Digital8 tapes are DV format, as is the passthrough function of these camcorders. It's around 13GB / hour.
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PAL 13+ GB
NTSC -13 GB
whether Digital 8 or Mini DV
Another advantage of Digital 8 ....... better colors.
Band at D8 is also wider and has more space for image
transferred WinDV under W7 64 bit
Recorder Sony DSR and Panasonic AG-DV2700e
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01-31-2016, 01:09 AM
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So, given that uncompressed DV video is recorded to Digital 8 tape at about 85 GB per hour is there a way to transfer it off of my tape to my hard drive at 85 GB per hour too? In other words, keep it completely uncompressed? Or is it by necessity recorded at 85 GB to tape but passed through at 13GB/hour?
Second, if I use my Sony camera to transfer VHS tapes to my drives, can it be passed through uncompressed? Or can that only happen with another capture device? I am trying to figure out the closest I can get to the original raw video for archival purposes.
Thanks.
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01-31-2016, 03:31 AM
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Quote:
So, given that uncompressed DV video is recorded....
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DV AVI is already heavily compressed see picture
and is in 4: 2: 0
50% of the color information will be lost in the DV Stream
Quote:
Second, if I use my Sony camera to transfer VHS tapes to my drives, can it be passed through uncompressed?
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never tried
Camera drives are still very imprecise.
what's going on at many D8 camera from the head drum signal in 4: 2: 2
in uncompressed output of video 8 and Hi8 movies.
For VHS movies you take precise Feeder
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01-31-2016, 03:44 AM
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For archiving, I suppose
Lagarith
YUY2 original [or UYVY] 4: 2: 2 and then edit in Lagarith YUY2 4: 2: 2
see Screen
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01-31-2016, 09:10 AM
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Quote:
Originally Posted by RDM56
So, given that uncompressed DV video is recorded to Digital 8 tape at about 85 GB per hour is there a way to transfer it off of my tape to my hard drive at 85 GB per hour too? In other words, keep it completely uncompressed?
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Professional processing lab equipment is available for that purpose, either purchased outright or under licensed rental from SONY and the like. Be prepared to take out a second mortgage to pay for it and to spend at least 6 months or more doing intensive study for a very steep learning curve. You will not be able to use your iMac.
Quote:
Originally Posted by RDM56
Second, if I use my Sony camera to transfer VHS tapes to my drives, can it be passed through uncompressed?
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No.
Quote:
Originally Posted by RDM56
Or can that only happen with another capture device?
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Only with another capture device, none of which will work on a Mac OS. You might be able to get an ATI or Diamond Multimedia USB capture device for analog video that would possibly work in Win7 running in parallel mode or Bootcamp, but reports have it that the hardware won't work with Windows running in those modes. The cheaper USB ripoffs, even if they work, are a waste of money.
Quote:
Originally Posted by RDM56
I am trying to figure out the closest I can get to the original raw video for archival purposes.
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For VHS, the answers are already in the capture guides. You can't capture to lossless media with hardware and software that aren't designed for it.
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01-31-2016, 01:19 PM
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I'm not sure what sanlyn is suggesting with reference to lab equipment.
Quote:
Originally Posted by RDM56
given that uncompressed DV video is recorded to Digital 8 tape at about 85 GB per hour is there a way to transfer it off of my tape to my hard drive at 85 GB per hour too?
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I've been trying to tell you that DV, at ~13GB/hr, is a compressed format that's recorded to the cassette: whether that be Digital8, MiniDV, or DVCAM. When you transfer a Digital8 cassette via Firewire, the resulting file on your hard drive is a bit-for-bit copy of what's on the cassette (provided that the player didn't have any obvious read errors due to dropouts or the like). There is no 85GB/hr involved here at any step of the process.
This is also the same format that's used for the passthrough function. In this case, the incoming video signal is first converted from analog to digital by the camcorder's internal ADC and then passed to the hardware DV compression chip. There is no way to bypass the compression and access the uncompressed "85GB/hr" signal. Firewire itself doesn't even have a standard for uncompressed video transmission.
Perhaps your confusion stems from the fact that DV stood for Digital Video? It's just a name. "Digital Video" (the DV format) is a form of "digital video" (the lowercase term can refer to uncompressed or any compressed format). I put this together in MS Paint...
digitalvideo-venn.png
Quote:
Originally Posted by Goldwingfahrer
and is in 4: 2: 0
50% of the color information will be lost in the DV Stream
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4:1:1 for NTSC. Both are 50% of 4:2:2. (4:2:2 is itself 50% of 4:4:4, as you know.)
Quote:
Originally Posted by sanlyn
Only with another capture device, none of which will work on a Mac OS.
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Uncompressed and lossless capture can be done on Mac, though the hardware and codecs available are a lot more limited in selection.
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01-31-2016, 03:15 PM
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Msgohan, thanks so much for the visual representation. I really appreciated your taking the time to send it.
The following was sent to me in an email from the B & H Photo Video Department over a year ago when I first asked about capturing video off of my VHS tapes. If you agree or disagree, let me know.
The Blackmagic Intensity Shuttle won't help me with my current iMac since I don't have Thunderbolt or USB 3.0 connections, but maybe it is time I buy a new computer, although prior to wanting to convert all my VHS tapes I was doing fine with my mid-2010 iMac with USB 2.0 and Firewire ports.
B & H Photo Video Department:
"The Blackmagic Intensity Shuttle is a great choice for capturing high quality video. The connection to the computer is USB 3.0 or Thunderbolt (which is on newer Macs). This is required on the computer in order to use this hardware. The Shuttle's also come with a Capture software that can capture the video as a high quality Uncompressed video file. This ensure the videos will be captured at the very highest quality (As there is no compression on the files). It is surely the best option if you have a compatible computer.
H.264 is a codec that heavily compresses the file. The benefit of compression is that it takes up less file space. The downside to compression is that it can degrade the image quality. There are different levels of compression within an H.264 file. The level of H.264 compression within the Elgato software will but much more compressed than a Professional editing Software (such as Adobe Premiere of Final Cut Pro X) which allows you to control the level of H.264 compression. Less, compressed H.264 encoding should be relatively complimentary for a VHS tape, while heavier compressed H.264 encoding will detract from the final quality of footage.
The file size you have mentioned of 4GB per hour of footage is one of many which depend on how the file is compressed. So you could absolutely get an hour of H.264 compression in a 4GB file. In contrast, recording an hour of Uncompressed footage could take up around 85 GB of storage space. Now will there big a huge difference in quality between uncompressed and high quality codec that can encode at half the file size? That is debatable (and in my opinion there will not be a viewable difference). Thus the trick to compression is finding a quality that is good enough for your needs, but also compressed enough to not take up all of your drive space.
Regarding S-Video vs. Composite, you are absolutely correct. Whenever possible, always use an S-Video connection as opposed to a Composite Video connection. This has much better color information and all around a better signal. "
The following excerpts are from Video Maker review, but you can read them in their entirety by clicking on the link below:
"The Intensity Shuttle can capture high quality and analog footage through several ports, which includes HDMI 1.3, Component, Composite and S-Video. The shuttle allows you to simply plug in and bypass your camera's video compression, pulling directly from the image sensor for capturing the highest quality possible."
"The Intensity Shuttle is ideal for monitoring uncompressed HD, HDV and even DV footage on your big screen TV or video projector by simply connecting to the built-in HDMI port."
"The Intensity Shuttle now allows editors to capture and display high quality 10-bit HD uncompressed video at a fraction of the cost of a few years ago, all wrapped up in a simple-to-use external device. Editing with 10-bit uncompressed video allows editors to apply intensive color effects without degrading their footage. Having the ability to play back that footage in its 10-bit uncompressed glory makes this a must-have accessory for any serious editor's workstation."
http://www.videomaker.com/article/c5...terface-review
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01-31-2016, 07:23 PM
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So, RDM56, when are you going to test the BlackMagic? Isn't the word of B&H and Videomaker good enough?
msgohan, RDM56 wants to capture DV and VHS to lossless media on an iMac using his SONY DV camera. Your comment on doing so was Interesting. Can you fill the rest of us in with details about how this is done?
Last edited by sanlyn; 01-31-2016 at 07:40 PM.
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01-31-2016, 08:22 PM
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The Blackmagic Intensity Shuttle is useless for VHS if you don't add in something to do time base correction before it. Even then, there are other complaints about it if you search this forum.
Quote:
Originally Posted by sanlyn
msgohan, RDM56 wants to capture DV and VHS to lossless media on an iMac using his SONY DV camera. Your comment on doing so was Interesting. Can you fill the rest of us in with details about how this is done?
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You already told him he can't do this with the camcorder. I agree with that of course, and added some detail about why this is impossible. You seemed to state that there are no alternative capture devices that can be used for uncompressed/lossless capture on Mac. I don't know if there are any good ones compatible with his particular machine, and it's certainly going about things the hard way, but some Mac options do exist.
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01-31-2016, 08:22 PM
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sanlyn, I don't want to make unnecessary purchases until I have a plan. Right now I am gathering information and advice. I am too inexperienced, so I am listening to many voices. This forum has been very helpful in sorting things out and helping me develop an understanding. It seems that it would be wise to save my old videos in the best possible media before throwing away my old tapes. I don't have USB 3.0 or thunderbolt ports, so owning a Blackmagic Intensity Shuttle for the sake of trying one out would be a heavy expense to purchase both a new computer and the Blackmagic Intensity Shuttle. Obviously I am hearing more from owners of Windows PCs than Macs, so help seems limited toward Windows PCs. And not everyone is confident that running Windows on my iMac is going to work either. Plus I am trying to understand what is the closest to saving in uncompressed video. The forum says that DV is compressed to 13 GB per hour from my camera - if I use my Sony DCR TRV330 to create DV. There would be no other choices coming directly out of the camera when playing Digital 8 tapes but what about playing VHS tapes through a different capture device? Anyway, I am simply looking to see what other possibilities exist and if any make sense or are futile. Some would say just to capture directly from VHS to an hour of H.264 compression in a 4GB file. Well, is that really a good idea? Or can I save in a better media for future use? And what about H.265 later on as it becomes more available and used by everyone? The list goes on...
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01-31-2016, 09:02 PM
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Quote:
Originally Posted by msgohan
The Blackmagic Intensity Shuttle is useless for VHS if you don't add in something to do time base correction before it. Even then, there are other complaints about it if you search this forum.
You already told him he can't do this with the camcorder. I agree with that of course, and added some detail about why this is impossible. You seemed to state that there are no alternative capture devices that can be used for uncompressed/lossless capture on Mac. I don't know if there are any good ones compatible with his particular machine, and it's certainly going about things the hard way, but some Mac options do exist.
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I have no other ideas for lossless capture on Mac machines. You seem to imply that you do. Thanks for sharing. RDM56 will want to know more.
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01-31-2016, 09:43 PM
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I am open to using Windows 7 on my iMac if that is a possibility. Obviously I would prefer something that easily works on my iMac native to its operating system and internal hardware, etc. But if Windows on my iMac is the only environment for capturing VHS video on an iMac then I will explore that option. Hopefully someone has experience with booting up Windows 7 on an iMac to capture VHS tapes and transfer Digital 8 tapes. Right now I want to start with my VHS tapes.
From what I am hearing, capturing VHS with my Sony DCR TRV350 is going to be very compressed in DV, and perhaps not the best media for archiving. So, what or how should I capture my VHS tapes for future archive purposes? I could simply capture using cheap capture devices and inadequate video software and be done but end up with a low quality media and regrets.
Since it seems that I cannot save my VHS videos in an uncompressed raw video based on this forum's experience (and the practicality of doing such is probably nonsensical because of the huge space requirements for 106 VHS tapes), then what is the next best media format whether that means capturing on my iMac using OS X Yosemite, iMac booted up in Windows 7, or buying a Windows PC in lossy or lossless that still retains the closest quality of the original VHS video and future sharing abilities in other formats or ease of editing, etc.?
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02-01-2016, 04:05 PM
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Going back to your earlier posts before the technical format questions side-track... Did you ever manage to capture VHS using your DCR-TRV350 on the iMac at all?
I saw one note saying that you connected the SVO-2000 to the camcorder using composite. Use S-Video. Sanlyn already addressed your misconception that a VHS signal cannot be sent over an S-Video wire.
Quote:
Originally Posted by RDM56
I have attached a video taken of my computer monitor using my iPhone since I am unable to record the VHS video using the Sony DCR TRV350 and iMovie. You will see the flickering.
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Hmm. I don't see any video attached to this post.
Quote:
Originally Posted by RDM56
Since it seems that I cannot save my VHS videos in an uncompressed raw video [...] what is the next best media format [...] in lossy or lossless that still retains the closest quality of the original VHS video
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I think you may be confused about what lossless is. The output from a lossless codec is literally identical to the original uncompressed "raw" video: mathematically, bit-for-bit. Lossless isn't "next-best" to uncompressed, it's at least equal and for most of us it's superior. To be clear, and to repeat, it's superior for reasons other than quality: the quality is the same.
Advantages of lossless vs uncompressed: - Storage space savings
- More frames stored per MB means you can edit and encode faster (lower HDD bottleneck)
Advantages of uncompressed vs lossless: - More cross-compatible due to technical simplicity (partially negated by Windows, Mac, and Linux software each preferring different pixel formats/FourCCs)
- No CPU overhead (negated by HDD bottleneck unless you store everything on SSD)
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02-01-2016, 04:59 PM
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possibly a solution.
The tapes provide a prof.Digitalisierer
he is then all films [VHS]
in Apple Component Video YUV422 see picture
save on a formatted Mac hard drive.
even better .............. everything capture and edit Windows-PC.
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02-01-2016, 08:20 PM
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msgohan, I did not have success capturing my VHS tapes to my hard drive using my Sony DCR TRV350 video camera. The video flickered a lot and although iMovie said it was in record mode during the import mode, I did not see the file created in the same location in the iMovie library as Digital 8 tapes that were transferred from the camera.
You make a very good point about "output from a lossless codec is literally identical to the original uncompressed "raw" video."
I read a number of explanations on differences between lossless and uncompressed. I cannot be sure of the accuracy of everything that I read, of course, but it basically confirms what you said.
I found the AVPS Codec Primer very informative and helpful (you'll need to open the PDF to see the diagrams being referenced in the following statements copied and pasted below):
"If the encoder uses no compression or lossless compression we retain the ability to recreate original data (as long as the technology and knowledge to do so is sustained)."
"An encoder is responsible for packaging data according to certain rules. For instance a digital video stream may consist of samples of luma (represented here by ‘y’) and chroma (represented here by ‘u’ and ‘v’) which can be packaged inside a wrapper in variable formations4, such as ordering the code as ‘yuvyuvyuv’ as opposed to ‘yyyuuuvvv’. The set of rules which defines how the data is encoded and packaged is what we refer to when we speak about a ‘codec’, and each codec has a name and an identifier. This identifier consists of four characters, such as ‘yuv2’, and thus is called a four character code (FourCC). ‘4cc1’ and ‘4cc2’ are used at the left to represent four character codes for hypothetical codecs."
"This 4cc is embedded in with the packaged data, either as part of the essence (audio and video) or as part of the container (file or wrapper). In the diagrams we see that the same video stream can be encoded in a different order by the differently defined codecs. This is not a problem as long as the same codec is used to decode the data and unpacks it in the correct order."
https://www.avpreserve.com/blog/a-primer-on-codecs-for-moving-image-and-sound-archives-2/
I also read the following about archiving uncompressed video:
"Uncompressed video is useful for archiving, but the files are so large that they are really not useful for anything else. In fact, many computers cannot even play back uncompressed video without dropping frames. No common means of distribution (DVD, internet, broadcast, etc) can handle files this large. You could say, uncompressed is best -- if you never actually need to play your video file!"
"For archiving, uncompressed or a lossless codec (such as Animation or PNG) is preferable, while for distribution a lossy codec (such as MPEG2 or H264) is preferable."
http://retnull.com/Video%20Compression.html
I then found good information on estimating storage capacity for uncompressed formats on pages 8 and 9 in the following AJA manual.
https://www.aja.com/pdf/support/AJA_KONA_LHi_manual_v10.3.pdf
I also found a couple of calculators for finding the storage capacity for any format (uncompressed or compressed):
On the App Store you can download the AJA DataCalc or use the following online calculator: https://www.digitalrebellion.com/webapps/videocalc?format=dv_ntsc_f&frame_rate=f120&length= 1&length_type=hours
In all cases it seems that estimates for 8 bit Uncompressed Standard Definition is about 76 to 85 GB per hour.
I estimated 17 TB of storage for uncompressed video is needed for 100 VHS tapes, each playing 2 hours of standard video. I don't have any S-VHS tapes. I asked Black Magic Design to confirm this. The technician said:
"From the information you've given me, the storage amount seems to be about right. By my calculations, I would estimate roughly 15.5TB of data for the amount of video you need to capture. In my opinion, I do not think it is necessary to capture in uncompressed with VHS tapes unless it is absolutely necessary, for example if the tapes were rare and needed the highest quality for archival purposes. In any case, uncompressed is going to take up a huge amount of space no matter what. On the App Store you can download the AJA DataCalc for your computer or phone and put in your specific values for resolution, frame rate, etc. for a more precise amount, just to make data calculation easier. Hope this helps."
With regards to using an USB 3.0 device to capture uncompressed video through my USB 2.0 port, on the Apple Support website, there are FAQ's:
What happens if I plug my USB 3 device into a USB 2 port?
Your device should be backwards-compatible with USB 2 ports. However, you won't get USB 3 speed and power may be limited to 500mA.
I asked Black Magic Design support: "What happens if I plug your USB 3.0 capture device (Blackmagic Design's Intensity Shuttle) into my iMac's USB 2.0 port?"
His answer was the following:
"So although there may be devices out there that allow for backwards compatibility and would allow you to use USB 3.0 devices on USB 2.0 ports, our devices only support USB 3.0 speeds and will NOT work with USB 2.0. Keep in mind that even if it were possible, USB 2.0 would not allow you to capture in uncompressed video."
Just to be clear, everyone has confirmed that using my Sony DCR TRV350 will only capture my VHS tapes in a very compressed DV format. The camera will provide a line TBC and DNR. With regard to my Digital 8 tapes, the camera will transfer the video bit-for-bit in DV format. DV uses lossy compression of video. I did read on Wikipedia that "Baseline DV uses 4:1:1 subsampling in its 60 Hz variant." I have no idea at this time what VHS does in relation to chroma sampling or modulation or how that relates to the 4:1:1 subsampling used in baseline DV.
I think Goldwingfahrer has been trying to show me what subsampling needs to be used when capturing VHS tapes. I need to read his posts closer and figure out what his screen prints are telling me. What video editing program is generating those windows being captured in the attached screen prints?
As far as the iPhone video sample, I have attached it here. I thought it had been attached.
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02-02-2016, 03:27 AM
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Quote:
What video editing program is generating those windows being captured in the attached screen prints
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It was a screen from Canopus Procoder 3
I also have a BM Shuttle USB3 and the more expensive BM Studio 2 card [+ HDMI SDI]
The Blackmagic support has in many ways quite ..
So Uncomprimiert of VHS or Hi8 / video 8
in RGB = 90 GB
in YUY2 or in UYVY = 75 GB
in Lagarith YUY2 = 35GB
There are problems when capturing the BM own codec Blackmagic SD 4: 2: 2
when I open the in VDub
VDub recognize the stream as RGB
Solution there with the install of drastic codec of Mikey Lee Jones.
Read in the Doom9 Forum
The issue we had in German Gleitz Doom9 Forum
Unfortunately I can old man did not speak English, we have here in Switzerland only 3 foreign languages.
The young people learn English course
I capture in uncompressed ...... to filter and uncover the margins and for the archive I save in Lagarith.
For disclosure to customers of Stream in MPEG2 with 14000 kbps
delivered, still interlaced.
On request also in MP4 [interlaced or progressive in]
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02-02-2016, 11:24 AM
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Quote:
Originally Posted by RDM56
I found the AVPS Codec Primer very informative and helpful (you'll need to open the PDF to see the diagrams being referenced in the following statements copied and pasted below):
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Readers and writers in this and other tech forums have known this for years. That's not to dismiss your extensive research, which is laudable. The conclusions are well-known, which is why certain hardware and procedures are recommended in the capture guides here, while others are not. Some of the hardware and software in the guides have changed or been updated, but the principles remain the same.
The recommendations also show why a Mac or iMac is not desirable for what you want to do concerning VHS capture: http://www.digitalfaq.com/forum/vide...html#post37312. The author of that post is lordsmurf who has been involved professionally in VHS transfer and restoration for many years. What he says is echoed by many others, professional and advanced amateur alike. I should add that lordsmurf does indeed use Macs for video work, but not for capture or most restoration projects.
Quote:
Originally Posted by RDM56
Just to be clear, everyone has confirmed that using my Sony DCR TRV350 will only capture my VHS tapes in a very compressed DV format. The camera will provide a line TBC and DNR. With regard to my Digital 8 tapes, the camera will transfer the video bit-for-bit in DV format. DV uses lossy compression of video. I did read on Wikipedia that "Baseline DV uses 4:1:1 subsampling in its 60 Hz variant." I have no idea at this time what VHS does in relation to chroma sampling or modulation or how that relates to the 4:1:1 subsampling used in baseline DV.
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In essence this has already been stated here several times, and elsewhere.
I can confirm that even if you decide to use WinDv to transfer VHS as DV in Windows 7, many have insurmountable difficulties with WinDV and similar Windows DV transfer apps when WIndows is run inside a wrapper environment as it is on a Mac. You can research this or try doing it if you want, but don't be surprised at the results. At least winDV is free. Many paid and free Windows encoding and authoring apps won't run in that environment. Some even have problems with WinDV in a genuine Windows 7 PC designed specifically for Windows.
Quote:
Originally Posted by RDM56
In all cases it seems that estimates for 8 bit Uncompressed Standard Definition is about 76 to 85 GB per hour.
I estimated 17 TB of storage for uncompressed video is needed for 100 VHS tapes, each playing 2 hours of standard video.
....
I think Goldwingfahrer has been trying to show me what subsampling needs to be used when capturing VHS tapes. I need to read his posts closer and figure out what his screen prints are telling me.
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You can capture uncompressed if you wish, but I don't know anyone who does unless there is some need for it. I believe Goldwingfahrer is saying what others have said may times, so I'll summarize here:
When a capture device capable of lossless capture from analog source is used, the output is uncompressed. The color matrix used in NTSC VHS storage is 4.2.2 YPbPr. The recommendation for best retention of this stored data is to capture to lossless YUY2 (4.2.2) and direct the capture drivers to losslessly compress this output with lossless video codecs such as huffyuv or Lagarith or UT Video codec, all of which are designed for high-speed real-time lossless compression during capture and for high speed decompression during playback and post-processing. The audio is captured as uncompressed PCM. This is the method used for post-processing such as editing, denoising, repair of defects and other undesirable elements, color correction, and fancy operations such as fades, transitions, title overlays, etc. Intermediate working files outside of the original capture are rarely saved. Huffyuv compresses only YUY2 and RGB. Lagarith works with RGB24, RGB32, RGBA, YUY2, and YV12. UT video only says it handles "YUV and RGB" and I've used it occasionally for YV12 and RGB, but I don't know what else it works with. I do know that a couple of my favorite PC media players won't play it, so if I get a UT video sample I recompress with Lagarith.
If you would like graphic examples of differences between subsampling as 4.1.1, 4.2.0, and other subsampling schemes, look here: https://en.wikipedia.org/wiki/Chroma_subsampling.
Adding to what mcgohan noted earlier about the advantages in lossless media, that format is (a) able to be decompressed and recompressed as an identical copy of the original with no digital compression loss or added compression artifacts, and (b) can be modified and recompressed into intermediate working files with no generational loss from version to version. Huffyuv and Lagarith have been integrated into workflows for so long and are so widespread in use that almost all media players are able to decode it, and others can do so if the codec is installed on the system. UT Video is not so widely used except for those who like to hassle with complex setup dialogs, and some media players will not recognize it. Neither huff nor Lagarith can be used with Mac; UT Video is recognized by Mac but not by Mac NLE's such as Final Cut Pro. For archiving, you can set up many parameters with UT codec for higher lossless compression, but the higher compression takes more time so is not used for capture.
For archiving, I do save some of my losslessly compressed captures, but certainly not all of them. All of the saved caps have been edited to remove unused or unwanted content. After more than a decade of capturing over 400 hours of VHS tapes, the archives I saved total less than 4 TB. Many others are archived with very high bitrate MPEG2 or h.264, which can seriously reduce file size and which give good clean encodes that look effectively lossless. Such high bitrates are not practical for final output to disc or other final format deliverables, but it certainly works for archives. People I know who have saved DV captures (there aren't many) will leave them as DV but with unwanted segments removed, or will reencode to the very high bitrates I mentioned.
DV itself, regardless of any faults that dissuade me from it, is an intraframe format (which means that every frame is a complete video image. Interframe formats like h.264, etc., have I-frames or key frames that are complete images, followed by a string of frames that are not complete images but include only the data that has changed since the previous frame or key frame. http://wolfcrow.com/blog/intra-frame...e-compression/). DV can be cut into pieces and the pieces rejoined with no loss or recompression. But if any part of those images are changed, such as color correction, denoising, masking head-switching border noise with a black mask (not the prettiest way to do it), applying transitions or title overlays between shots, etc., that DV video or a visible portion of it will be re-encoded with further generational compression loss. There is no way around it. It's one of many reasons why DV is almost always decoded to lossless media by those who expect to do anything more complicated than simple cut-and-join and still maintain quality.
Your research is a thorough learning process, but you've only scratched the surface. At this point you're not yet past capture. Much more happens after capture. What would you do with the head-switching noise present in all VHS captures, or side borders, both of which are present a little or a lot depending on how the player and the capture device translate the analog signal. Bottom border head switching noise of 4 to 12 pixels is almost always later removed in a lossless environment. The process is simple in Avisynth with lossless files: crop off the offending noise, then add black border pixels to maintain the original image proportions and the display aspect ratio. If 8 noisy bottom pixels are removed, you can add 4 pixels each to top and bottom, thus centering the image. Since the area outside of the image is black anyway, the repair is indiscernible.
What about luma and chroma input levels? Most players pump contrast and/or output video levels that are OK for your TV or CRT, but those levels are stored as values outside the desired YUV range of 16-235 for digital video. Upon encoding or further processing, unacceptable values outside that range are clipped (effectively destroyed), leading to lost detail and even color changes in darks and brights. We see plenty of VHS to DV captures with high IRE levels and blown-out highlights. Most analog devices allow some form of level control during capture, or a proc amp can be used if no controls are available. Even then, levels and some chroma defects and noise can be corrected easily but only in the original colorspace. Feed that video with bad levels and other problems directly into an NLE that works only in RGB, and you soon learn that the way data is stored in YUV and the way it displays in RGB is affected, often detrimentally. Some NLE's don't convert YUV to an RGB workspace properly; some don't treat interlaced chroma correctly, with visual damage you can't yet imagine.
At the risk of beating a horse to death, note that the audio in your Dv capture sample is sampled at 32KHz. I can't say I've seen that figure earlier (maybe it's common, I haven't noticed), but most DV I've seen has 44.1KHz audio. That sampling rate is fine for internet mp4's, but if you want DVD or BluRay/AVCHD, audio must be 48KHz. It's a no-brainer to fix this, but it's a sample to suggest that more detail awaits.
You might be making the assumption that many newcomers make, which is that analog source such as VHS when captured to digital media, whether lossles or not, will look like a digital source or will even look like DV. It won't. It will look like VHS. DNR in a player is of course helpful, but the cap will still look like VHS. The magic is in post-processing. You can compromise as much as you wish, or strive for perfection (which is not possible), or simply dispatch the worst of it with simple quickie filtering and live with it. But cleanup at some level is almost always evident with VHS.
If you have 100 VHS tapes to capture, it won't happen in a week or two. Or a month or two. I started in 2002 with over 200 tapes. Working off and on, sometimes for a week at a time, mostly a few days now and then, I still have about 30 tapes. But I do more cleanup than most people would, simply because I can't stand watching ugly videos. Others are not very troubled by it, or simply do a quickie and find it acceptable. I captured a few retail tapes directly to DVD with a good DVD recorder years ago, and now I wish I'd kept the tapes (fortunately those movies are in DVD release since then, so R.I.P. for those old tapes). I'd estimate that capturing all of your tapes in one fell swoop is very unlikely. One capture itself is boring and tiring enough, two is really trying. After 4 consecutive captures you never want to see another tape, LOL!.
I suggest that you start with one tape, capture small segments or capture all of it if you want, and learn from the results. What you learn from a single capture can reveal workarounds that will save time later. It will also acquaint you with what VHS capture really looks like.
If it's not possible to obtain the hardware and software for lossless capture that actually works, and on a Windows computer and tape player that can handle it, get a Canopus for your iMac and capture to DV in Windows 7 using the Canopus drivers, or cap to Canopus DV in your iMac. Either way, you won't know what's happening until you have a VHS capture that you can work with. To paraphrase, a single capture is worth a thousand conjectures.
Last edited by sanlyn; 02-02-2016 at 12:11 PM.
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02-02-2016, 03:46 PM
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DV typically uses 48kHz 16-bit but also offers 32kHz 12-bit (apparently the latter uses non-linear coding, not LPCM, to more efficiently use those bits). I guess the original Digital8 recording camcorder was set to 32kHz?
If you end up using the camcorder for passthrough, set it to use 48kHz in the menus.
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02-02-2016, 04:57 PM
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See whether this open source program called Vidi has the same issues with VHS passthrough as iMovie:
http://www.mitzpettel.com/ (I've never used it.)
https://www.youtube.com/watch?v=rVqkSlaTr-k
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