VideoHelp Forum
Closed Thread
Page 3 of 4
FirstFirst 1 2 3 4 LastLast
Results 61 to 90 of 110
Thread
  1. Originally Posted by lordsmurf View Post
    It's recommended in the same way that it's suggested that you put gas in car. It's not really optional, but required.
    - For the task of driving, you need the car, and all that it entails. Keys, fuel, license, etc.
    - For the task of converting consumer analog video, you need the proper tools. VCR, TBCs, capture card, at minimum.
    Bad analogy. A car would not run without gas, but video can be captured without TBC, often with acceptable quality.

  2. Captures & Restoration lollo's Avatar
    Join Date
    Jul 2018
    Location
    Italy
    Search Comp PM
    A car would not run without gas, but video can be captured without TBC, often with acceptable quality.
    No. A lineTBC is always needed, being in the player, in the capture card (rare), or as additional component. A frameTBC is often needed (I am one of the not so common cases where is not strictly needed).

    edit: added positioning of the lineTBC

  3. mr. Eric-jan's Avatar
    Join Date
    Apr 2018
    Location
    Netherlands
    Search Comp PM
    Originally Posted by ConsumerDV View Post
    Originally Posted by lordsmurf View Post
    It's recommended in the same way that it's suggested that you put gas in car. It's not really optional, but required.
    - For the task of driving, you need the car, and all that it entails. Keys, fuel, license, etc.
    - For the task of converting consumer analog video, you need the proper tools. VCR, TBCs, capture card, at minimum.
    Bad analogy. A car would not run without gas, but video can be captured without TBC, often with acceptable quality.
    Correct, i did some experiments with scalers and converters, and got steady pictures from normal vcr's onto semi pro's recorders, like Video Asist and Hyperdeck Shuttle HD,
    although, you do get to see more details, than you would see on a CRT monitor/tv, composite stays a bad connection to capture from, component works better with converters,
    with some the aspect ratio needs to be "adjusted" depending on the (cheap) converter used, it stays experimental, but do-able indeed, you don't need the "straightjacket" TBC like some think, TBC is for most people also no option, easy to recoment though.
    component is available on Panasonic ES10/ES15/ES35V on any HD consumer equipment HD is blocked for the component output. (legal reasons).
    Last edited by Eric-jan; 7th Jun 2022 at 05:14.

  4. Captures & Restoration lollo's Avatar
    Join Date
    Jul 2018
    Location
    Italy
    Search Comp PM
    Eric-jan, we have ssen your captures in the past:
    https://forum.videohelp.com/threads/390558-Artifacts-on-SD-capture
    https://forum.videohelp.com/threads/384945-Opinions-What-is-the-best-VHS-to-digital-converter/

    Provide use some sample to prove your statements, otherwise you are not credible.

  5. Video Restorer lordsmurf's Avatar
    Join Date
    Jun 2003
    Location
    dFAQ.us/lordsmurf
    Search Comp PM
    Originally Posted by ConsumerDV View Post
    , but video can be captured without TBC, often with acceptable quality.
    Nonsense.

    Some form of TBC is required, be it an actual TBC, or some sort of kinda-sorta quasi TBC(ish) sort of something. Signals must be timed for a capture card to not choke, and either capture with massive problems, or outright reject the capture.

    Originally Posted by lollo View Post
    Eric-jan, we have ssen your captures in the past:
    you are not credible.
    Indeed.

    Originally Posted by Eric-jan View Post
    i did some experiments with scalers and converters,
    All you've done here is create a baked-in signal, where the card input is "timed" but timing was lost pre-card. Yes, that is possible, but it rapes the quality. If you don't care how bad the video looks, how bad audio is out of sync, etc, then sure, have at it. Not something I'd want to watch.
    Last edited by lordsmurf; 7th Jun 2022 at 08:44.
    Want my help? Ask here! (not via PM!)
    FAQs: Best Blank DiscsBest TBCsBest VCRs for captureRestore VHS

  6. Originally Posted by lordsmurf View Post
    Originally Posted by ConsumerDV View Post
    , but video can be captured without TBC, often with acceptable quality.
    Nonsense. Some form of TBC is required, be it an actual TBC, or some sort of kinda-sorta quasi TBC(ish) sort of something. Signals must be timed for a capture card to not choke, and either capture with massive problems, or outright reject the capture.
    This, of course, is not true. While the signal is within tolerance, it will be accepted. Mind you, I don't argue with the usefulness of TBC, I am just saying that it is not a required component as you make it.

    Going with your analogy, VTR is like an engine, ADC is a transmission - without them you cannot play and convert video. TBC is something like a catalytic converter, which cleans up the exhaust and can make up for occasional misfires. A very desired component and mandated by law in most countries, but not essential for basic functionality. A car will drive without it.

  7. Member DB83's Avatar
    Join Date
    Jul 2007
    Location
    United Kingdom
    Search Comp PM
    Most noticable that the OP has not contributed to his topic for over 2 years. Wonder if he ever got his project completed.

    And as for the 'discussion' remind me who thought it necc. to dig up a two year-old topic just for repeats of the arguements that were raised back then. ?

  8. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    These debates never end, Let me through in my wrench too, While line TBC is technically required to having stable scan lines, frame TBC is needed for consumer capture cards that use the ancient USB 2.0, USB 2.0 is limited to how much data can pass through it so most of the time the capture software is unable to receive the frames on time resulting in out of sync audio to video, Capture cards that are built in frame synchronizer or frame TBC don't suffer from this problem.

  9. Originally Posted by dellsam34 View Post
    These debates never end, Let me through in my wrench too, While line TBC is technically required to having stable scan lines, frame TBC is needed for consumer capture cards that use the ancient USB 2.0, USB 2.0 is limited to how much data can pass through it so most of the time the capture software is unable to receive the frames on time resulting in out of sync audio to video, Capture cards that are built in frame synchronizer or frame TBC don't suffer from this problem.
    First of all, when TBC was invented in 1973, there was no way they could afford frame storage. It was strictly about timing and "having stable scan lines". Back then people were making up to four dubs without a TBC before losing sync, which means that just a single capture from a well-recorded tape is certainly not a problem in most cases. I had flagging/skewing on some EP/LP tapes from small labels, but SP tapes from big Hollywood studios usually play just fine.

    Frame TBC is a later development. Its functionality can be replicated in an NLE.

    If you do a lot of paid work then having line TBC is a must and frame TBC is highly desirable to reduce the amount of time spent on each tape. But for someone who wants to capture a dozen of tapes, a TBC is not an essential item, at least not until the necessity in it is established.

    As for USB 2.0, this is not true as well. USB 2.0 throughput in Hi-Speed mode is 480 Mbit/s, while D1 uncompressed video is 173 Mbit/s. On good tapes I get as few as just two dropped frames for an hour of VHS video captured with the Dazzle DVC100.

  10. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    Originally Posted by ConsumerDV View Post
    As for USB 2.0, this is not true as well. USB 2.0 throughput in Hi-Speed mode is 480 Mbit/s, while D1 uncompressed video is 173 Mbit/s. On good tapes I get as few as just two dropped frames for an hour of VHS video captured with the Dazzle DVC100.
    You wish, USB 2.0 speed is around 50-70 MB/s, Specifications are not always feasible.

  11. Originally Posted by dellsam34 View Post
    Originally Posted by ConsumerDV View Post
    As for USB 2.0, this is not true as well. USB 2.0 throughput in Hi-Speed mode is 480 Mbit/s, while D1 uncompressed video is 173 Mbit/s. On good tapes I get as few as just two dropped frames for an hour of VHS video captured with the Dazzle DVC100.
    You wish, USB 2.0 speed is around 50-70 MB/s, Specifications are not always feasible.
    That is what I said: 480 Mb/s = 60 MB/s, which is more than enough.

  12. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    60MB/s can barely pass full lossless 4:2:2 AVI even at 8bit.

  13. Originally Posted by dellsam34 View Post
    60MB/s can barely pass full lossless 4:2:2 AVI even at 8bit.
    Lossless 4:2:2 8-bit SD video, that is, D1 is only 173 Mb/s as I mentioned above, so it comfortably fits in a 60 MB/s pipe.

  14. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    It's 270MB/s not 173MB/s, That figure is the peak or the maximum @ 10bit sampling, To achieve it you will have to use SDI, PCIe, Thunderbolt or USB 3.x, However the average lossless file is around 200GB/hour which is roughly 55MB/s, Barely on the edge for USB 2.0, any data spike equals dropped frames.

  15. Originally Posted by dellsam34 View Post
    It's 270MB/s not 173MB/s, That figure is the peak or the maximum @ 10bit sampling, To achieve it you will have to use SDI, PCIe, Thunderbolt or USB 3.x, However the average lossless file is around 200GB/hour which is roughly 55MB/s, Barely on the edge for USB 2.0, any data spike equals dropped frames.
    Maybe you want to consult with, I don't know, Wikipedia before losing your credibility. This is 4th grade math after all.
    • First of all, I haven't said anything about 173MB/s. I said 173Mb/s.
    • Second, how come you have switched from 8-bit to 10-bit?
    • Third, 8-bit 4:2:2 SD video defined in D1 standard has constant rate of, you guessed, 173 Mb/s, while USB 2.0 has maximum signaling rate of 480 Mbit/s - I think I am repeating this for the third time - with maximum theoretical data throughput 53 MB/s.
    • Finally, could you share, where 270 MB/s comes from? Taking D1 bitrate and adding extra two bits raises the bitrate to 207 Mb/s.

  16. Member
    Join Date
    May 2005
    Location
    Australia-PAL Land
    Search Comp PM
    Originally Posted by Dellsham
    However the average lossless file is around 200GB/hour
    SD is 30-40GB/hour here HUFF. I can't select 10bit for capture using HUFF.

  17. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    Originally Posted by ConsumerDV View Post
    [*]First of all, I haven't said anything about 173MB/s. I said 173Mb/s.[*]Second, how come you have switched from 8-bit to 10-bit?[*]Third, 8-bit 4:2:2 SD video defined in D1 standard has constant rate of, you guessed, 173 Mb/s, while USB 2.0 has maximum signaling rate of 480 Mbit/s - I think I am repeating this for the third time - with maximum theoretical data throughput 53 MB/s.[*]Finally, could you share, where 270 MB/s comes from? Taking D1 bitrate and adding extra two bits raises the bitrate to 207 Mb/s.[/LIST]
    270MB/s is a standard for 10bit 720x486, it's slightly less for 8bit but I don't have that number. Your 173 figure is for D1 component tape format, it is slightly different than AVI 4:2:2 that we capture, Just because your wikipedia diploma says 173mb/s, doesn't make it 173 mb/s. It's 173 MB/s. You don't have to take my word for it, capture lossless video 4:2:2 for one hour and do your own math.


    Originally Posted by Alwyn View Post
    SD is 30-40GB/hour here HUFF. I can't select 10bit for capture using HUFF.
    HuffYUV is an output lossless compression within the hard drive, The capture card outputs lossless uncompressed stream thru the USB port.
    Last edited by dellsam34; 8th Jun 2022 at 01:36.

  18. Member Cornucopia's Avatar
    Join Date
    Oct 2001
    Location
    Deep in the Heart of Texas
    Search PM
    This has been gone over before. Yes, the stated max bitrate of USB 2.0 IS 480Mbps. But notice they say MAX. That is instantaneous, not continuous. The asynchronous, host/node, hub nature of USB means it cannot sustain that, which is one reason it didn't translate to supporting DV transfer very well, even though DV would have been 25+ Mbsp stream (the other difficulty was the inability of using isochronous protocols).
    Real-world tests have shown usb can usually only sustain 1/3 to 1/6 of that max, which means 80-160Mbps. (Those special drivers from the likes of pinnacle probably also assisted with handling the isochronous to asynchronous shift).

    D1 SD SDI streams are 270Mbps. Yes, they are 10bit instead of 8, and even if the source only uses 8 bits, the stream protocol is designed to accommodate 10bit, and it does have overhead, so that is the bitrate it arrives at and the one that must be supported. Usb doesn't necessarily need to support all that, however, so the rate of 173 is a reasonable expectation (not counting audio or other ancillary data). That still can mean that USB 2.0 would be borderline sufficient.

    Regarding the issue of needing TBCs, and their history, yes PRO tbcs did arrive in the 70s, and then they were not capable of holding more than a few lines' worth. But at that time the users were all Pros, using them for Quad, 1"B/C, Umatic, and later Betacam/SP and M1/M2. Those formats could handle 2-4 generations of copying without being so bad as to be unusable, but it still wasn't something one wanted to work with. And so even those formats had a use for TBCs.
    But they were pro enough to not have such major issues with timing that they varied their frames. It wasn't until the 80s when frame syncs became available (expanded buffer sizes), and part of the need for them at that point was the fact that while those other pro formats could be genlocked to support online editing, the introduction of consumer formats such as the VHS/SVHS, Betamax, and 8mm families into common use (even in post production) required they have a frame sync because they at that time did NOT have genlock capability, AND their timebase was so wild that they couldn't be used as-is in a production environment otherwise. And, from my recollection, at the time, only Betacam SP had decks with built-in line TBCs (which were very handy since they could use info from the heads & capstans and provide PLL feedback to the motors). That tech moved into the mainstream of higher end decks in the 90s. But it wasn't until the late 80s/early 90s that full frame tbc became commonplace, yet it also wasn't until the 90s that CONSUMERS could afford good TBCs at all. And those consumer formats were never good from the 3rd generation onward - not just for production, but for digitizing, and even for direct playback to displays.

    It probably is not a good idea to boast about "just a couple of dropped frames per hour". Doing it right with both line & fullframe TBCs and good decks and capture gear should mean NO dropped frames for days on end, which is what I experienced and expect.

    Scott

  19. Member
    Join Date
    May 2005
    Location
    Australia-PAL Land
    Search Comp PM
    HuffYUV is an output lossless compression within the hard drive, The capture card outputs lossless uncompressed stream thru the USB port.
    Rojer copied, thanks Dellsam.

  20. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    Originally Posted by Cornucopia View Post
    Regarding the issue of needing TBCs, and their history, yes PRO tbcs did arrive in the 70s, and then they were not capable of holding more than a few lines' worth. But at that time the users were all Pros, using them for Quad, 1"B/C, Umatic, and later Betacam/SP and M1/M2. Those formats could handle 2-4 generations of copying without being so bad as to be unusable, but it still wasn't something one wanted to work with. And so even those formats had a use for TBCs.
    Not to mention that TV's back in the day have analog line delays so playing back consumer tapes wasn't an issue, The average consumer needed to copy only once a 8mm tape to VHS or a VHS movie to another tape and most of the time with baked in errors even in the first try, there is no chance for a second gen copy. Prosumer and videophiles used low budget mixing consoles to duplicate, edit or copy one tape format to another, those mixing consoles are built in TBC and proc amp. So the need for TBC was never an issue until the capturing to digital started to emerge, Even then capture cards from back in the day coped with consumer formats, the built in MPEG-2 or DV chips had some sort of signal timing, firewire and USB were more than enough for DV and MPEG-2.

    Until a decade or so ago when capture cards chips where so poorly designed and capturing lossless becomes the new norm choking the poor USB 2.0 port, the need for a memory buffer becomes a necessity, Either a full frame TBC or some sort of signal stabilization like a DVD recorder.

    The problem is when you try to explain this stuff to newbies they think you are pushing them over the cliff because some smart mouth people here with google diplomas told them you don't need this or that. that's one of the reasons I don't recommend hardware anymore, I discuss it with other members, that's about it.

  21. Originally Posted by dellsam34 View Post
    Your 173 figure is for D1 component tape format, it is slightly different than AVI 4:2:2 that we capture, Just because your wikipedia diploma says 173mb/s, doesn't make it 173 mb/s. It's 173 MB/s.
    No, wikipedia says neither 173 mb/s nor 173 MB/s. It says 173 Mb/s.

    Originally Posted by Cornucopia View Post
    Real-world tests have shown usb can usually only sustain 1/3 to 1/6 of that max, which means 80-160Mbps. (Those special drivers from the likes of pinnacle probably also assisted with handling the isochronous to asynchronous shift). ... It probably is not a good idea to boast about "just a couple of dropped frames per hour". Doing it right with both line & fullframe TBCs and good decks and capture gear should mean NO dropped frames for days on end, which is what I experienced and expect.
    My real-world tests show throughput good enough for my use, clearly enough for 4:2:2 uncompressed SD, so I guess I am slightly above that 160 Mb/s number with my short USB cable and no USB usage while capturing. I am not pretending to have found a silver bullet for pro usage, I look at this from a point of view of someone who wants to digitize a dozen of family tapes. For this, USB, even USB 2.0 works quite acceptable. I dou't mind a couple of dropped frames. Heck, I don't mind twenty. I do mind A/V going out of sync, but this does not happen with the Dazzle. It does happen with AverMedia, which is advertised as a professional solution. So much for pro vs consumer products. So I find recommending everyone and their aunt to get a TBC disingenuous (pro users don't need recommendations like these, they know better what works for them).

    Originally Posted by Cornucopia View Post
    But at that time the users were all Pros
    There were users who used 1/2-inch reel-to-reel machines and later Umatic without TBC. Not the best choice, but they did.

    Originally Posted by Cornucopia View Post
    using them for Quad, 1"B/C, Umatic, and later Betacam/SP and M1/M2. Those formats could handle 2-4 generations of copying without being so bad as to be unusable, but it still wasn't something one wanted to work with. And so even those formats had a use for TBCs.
    Yes and yes. Not from my experience, obviously, but from reading the stories from the trenches. I watched Signal 7 recently, does not look that bad. Shot on Ikegami HL-79 and recorded on Sony 3/4-inch BVU machine. Rob Nilsson said, "For us, after five or six dubs, it was almost unwatchable. It would sometimes break up so badly we'd have to use a special-time base corrector to get an image that wouldn't roll over."

    Originally Posted by Cornucopia View Post
    it also wasn't until the 90s that CONSUMERS could afford good TBCs at all. And those consumer formats were never good from the 3rd generation onward - not just for production, but for digitizing, and even for direct playback to displays.
    Consumer formats used in pro setting were considered like negative film - you shoot on Hi-8, then dub to Umatic SP for editing. When Sony released Hi-8 it also released Umatic SP and advertised it as an online solution for Hi-8. Sony even made a VTR for Hi-8 having the same design as Umatic. In the early 1990s Fox recommended using SVHS camcorders for news reporting and claimed that they can do as many as four dubs. So later Sony made one for [S]VHS too. These semi-pro models had built-in TBC. There are some working SVO-5800 on eBay for $1K from Japan. Hmm, maybe I should consider getting one

  22. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    Originally Posted by ConsumerDV View Post
    No, wikipedia says neither 173 mb/s nor 173 MB/s. It says 173 Mb/s.
    You are aware that anyone can change wikipedia contents, If that's what you go by please stop spreading miss information.

  23. Member
    Join Date
    May 2005
    Location
    Australia-PAL Land
    Search Comp PM
    Originally Posted by Del;sam43
    The problem is when you try to explain this stuff to newbies they think you are pushing them over the cliff because some smart mouth people here with google diplomas told them you don't need this or that. that's one of the reasons I don't recommend hardware anymore, I discuss it with other members, that's about it.
    Double-edged sword there, Dellsam. Silence by the experts on recommendations pushes newbys to make their own decisions, probably going for the cheap capture cards. There would be a good percentage of people who would listen to suggestions, who want to do a good job, but don't know where to start. I said "good" because there would be a lesser number that are willing to spend 1000s (even if you can try to resell it) on the "only" setup to use, as espoused by some here. My way or the highway comes to mind.

  24. Member
    Join Date
    Feb 2008
    Location
    Poland
    Search Comp PM
    Originally Posted by dellsam34 View Post
    You are aware that anyone can change wikipedia contents, If that's what you go by please stop spreading miss information.
    Stop showing your ignorance please. It is simple math calculations on primary school level:
    720x480x30 fps x24 bits=248 832 000 bits/s
    248 832 000/8=31 104 000 Bytes/s
    31 104 000/1024=30 375 KBytes/s
    30 375/1024=29,66 MB/s=237,28 Mb/s - full uncompressed RGB quality.

  25. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    Originally Posted by Pinto007 View Post
    Originally Posted by dellsam34 View Post
    You are aware that anyone can change wikipedia contents, If that's what you go by please stop spreading miss information.
    Stop showing your ignorance please. It is simple math calculations on primary school level:
    720x480x30 fps x24 bits=248 832 000 bits/s
    248 832 000/8=31 104 000 Bytes/s
    31 104 000/1024=30 375 KBytes/s
    30 375/1024=29,66 MB/s=237,28 Mb/s - full uncompressed RGB quality.

    Huh? Talking about ignorance? What is 720x480x30 fps x24 bits, You just pulled that out of your ass? or you are another google graduate? And it's YUV not RGB, who would capture RGB?
    On the other hand, I'm aware what bit and byte are smart ass, I was learning Fortran in 1993 when the screen was yellow, My point is still valid that USB 2.0 is barely enough for lossless AVI, it can work for most of the time but any spike in data will drift the audio.

  26. @dellsam34, attacking forum members and information sources will not earn you points.

    You brought USB 2.0 into discussion about TBC. Your claim that "most of the time the capture software is unable to receive the frames on time resulting in out of sync audio to video" is a gross exaggeration to say the least.

    Then you misquoted me, rejected 173 Mb/s from wikipedia and insisted on 173 MB/s. For someone who doesn't know the difference between mega and milli and between bit and byte you seem too picky. Maybe you can explain where 173 MB/s comes from. A simple formula will suffice. I hope that your experience with FORTRAN will help. (Why were you learning FORTRAN in 1993, and why was your screen yellow is a question for another day).

  27. Member Cornucopia's Avatar
    Join Date
    Oct 2001
    Location
    Deep in the Heart of Texas
    Search PM
    Some technical clarification for this thread...

    For fully uncompressed video: H rez * V rez * bitdepth/color primary * framerate = bitrate.

    The primary can be R,G,B, or it can be Y,U(Cb),V(Cr). 8 or 10 bits each. Subsampling would just mean that for the U & V primaries, the resolution may be fractionalized (1/2, 1/4).

    So
    4:4:4 YUV or RGB at 8bit is (720*486*8*29.97) + (720*486*8*29.97) + (720*486*8*29.97), or (720*486*24*29.97) = 251690457.6 bits, or 240Mbps for video alone.
    4:2:2 YUV at 8bit is (720*486*8*29.97) + (360*486*8*29.97) + (360*486*8*29.97), or (360*486*32*29.97) or (720*486*16*29.97) = 167793638.4 bits, or 160Mbps.
    4:2:0 YUV at 8bit is (720*486*8*29.97) + (360*243*8*29.97) + (360*243*8*29.97), or (360*243*48*29.97) or (720*486*12*29.97) = 125845228.8 bits, or 120Mbps.

    4:4:4 YUV or RGB at 10bit is (720*486*10*29.97) + (720*486*10*29.97) + (720*486*10*29.97), or (720*486*30*29.97) = 314613072 bits, or 300Mbps for video alone.
    4:2:2 YUV at 10bit is (720*486*10*29.97) + (360*486*10*29.97) + (360*486*10*29.97), or (360*486*40*29.97) or (720*486*20*29.97) = 209742048 bits, or 200Mbps. ***This is the one most commonly referenced by SDI devices & applications (for "NTSC" 525line video systems).
    4:2:0 YUV at 10bit is (720*486*10*29.97) + (360*243*10*29.97) + (360*243*10*29.97), or (360*243*60*29.97) or (720*486*15*29.97) = 157306536 bits, or 150Mbps.

    Add audio: #channels * bitdepth * sample rate
    16bit stereo is (2*16*48000) = 1536000 bits, or 1.45Mbps
    24bit stereo is (2*24*48000) = 2304000 bits, or 2.20Mbps
    24bit 16ch is (16*24*48000) = 18432000 bits, or 17.58Mbps. ***This is the one most commonly referenced by SDI devices & applications, whether the full 16ch are used or not.

    Add ancilliary data (timecode, camera/device data, user-specific data), and packet/stream buffering, and error correction, and it is pretty clear how they came up with the 270Mbps number.

    ***************

    There were users who used 1/2-inch reel-to-reel machines and later Umatic without TBC. Not the best choice, but they did.
    They may have used them this way for direct playback-to-display, but they wouldn't have used them without a TBC for broadcast nor for editing purposes unless they were scraping the bottom of the barrel in their budget (which meant not really being able to reuse their edited material as further sources). I know this from firsthand experience.

    @ConsumerDV, I am not a fan of either Dazzle or AverMedia. Both come from quick-to-market wholly-consumer-focused enterprises. Both are passable for non-critical consumer application, but I would consider both to be unacceptable non-starters for any professional use.


    Scott

  28. Lossless capturing of VHS and similar:
    An analog SD composite YUV video signal which comes out of the VCR is sampled at 13.5 MHz (PAL or NTSC). Given that the subsequent high quality A/D converter has 16 bit resolution (USB dongle or similar) this results in a data stream of 13.5x16=216 Mbit/s, plus some audio on top of it, plus some overhead. This is far below the spec of USB 2.0 of 450 Mbit/s. There are no spikes at all. Fixed sample rate, fixed resolution, fixed data rate. All the rest happens in the PC. So if there are glitches it's not a matter of the USB 2.0 capacity but the culprit is with the (overloaded) PC.

  29. @Cornucopia, you've ruined all the fun. The formula along with some examples could be found in Wikipedia, where everyone can write whatever they feel like.

    Originally Posted by Cornucopia View Post
    They may have used them this way for direct playback-to-display, but they wouldn't have used them without a TBC for broadcast nor for editing purposes unless they were scraping the bottom of the barrel in their budget (which meant not really being able to reuse their edited material as further sources). I know this from firsthand experience.
    Oh, it was absolutely not broadcastable. BTW, how did they edit video before the invention of TBC? As you said, pro gear had tighter tolerances. Still, I've read that quads were not used much for editing from tape to tape. If anything, tape was spliced. Dubbing quad or even 1-inch tape would significantly drop the quality because these were composite systems mimicking TV signal. True?

    Originally Posted by Cornucopia View Post
    I am not a fan of either Dazzle or AverMedia. Both come from quick-to-market wholly-consumer-focused enterprises. Both are passable for non-critical consumer application, but I would consider both to be unacceptable non-starters for any professional use.
    I have never suggested using Dazzle or AverMedia for professional work, neither I sell them or profit from advertising them. But I felt like giving a counterpoint to the sweeping statement that an average Joe who wants to capture a dozen of family Hi-8 tapes needs a TBC.

    @Sharc, I agree. Capturing over USB has never been as dramatic for me as some paint it. 4:2:2 SD is only about 164 Mbit/s including audio or 1/3 of USB 2.0 rate.

  30. Member DB83's Avatar
    Join Date
    Jul 2007
    Location
    United Kingdom
    Search Comp PM
    Fun ? A credible help forum should be built on fact and not on fallacy.

    After the fact we now have a link that preports to confirm the true formula yet even that fouls the issue by using 24 bit in its examples.


    But pray tell where that mysterious wiki entry that quoted 173 (and I do not give a damn - better to paraphrase Abott and Costello - if this is Mb or MB)


    And this discussion is now so far removed from the original Q. that any new member who might stumble across the topic down the road will wonder what the respondants are smoking.


    In a word or three many of the replies give no credibilty to the forum and merely serve to massage the individual egos of the contributors (mine included). Or to put it another way, the topic 'died' two years ago and there was no justification in resurecting it.




Similar Threads

Visit our sponsor! Try DVDFab and backup Blu-rays!