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What is a jackpack HD-SDI output? |
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GL2guy Posts: 121 Joined: 10/10/2006 Status: offline
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I have been looking at Canon's new XH A1 high-def camcorder and noticed that one of the differences between this camera and their higher-priced XH G1 is that the G1 has a professional jackpack with HD-SDI output. Could someone kindly explain what an HD-SDI output is and what it can do? The Canon website doesn't explain it and searching some forums I have come up blank. Also, I have never editted HD on my personal computer and am a bit unsure how my system would be able to handle the load. Perhaps you could offer your "best guess" as to whether or not you think my system is capable of editting HD footage relatively pain-free. It is a 3.8 Ghz Hyper-Threaded Dell XPS w/ 2 GB Ram and a GeForce 6800. It runs all my SD editting stuff great, including photoshop, illustrator, etc. Never have any problems, but then again... never did HD editting. Thanks for your help and advice! |
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What is a jackpack HD-SDI output? - 
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MikeM Posts: 2347 Joined: 2/25/2005 From: Germany Status: offline
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SDI (Serial Digital Interface) is a standardized digital video interface for transmission of uncompressed digital video with optionally embedded audio and timecode. The most common data rate of (SD-)SDI is 270 Mbits/s. HD-SDI is the high-def counterpart with a nominal data rate of around 1.5 Gbits/s. Both interfaces are used only in professional environments and are limited in the supported line lengths (due to the high data rate). They both use a BNC connector and 75Ohm cables. To use SDI or HD-SDI you would need a hardware with provides such connections to your computer. _____________________________ Michael Lt. Cmdr. Data: If the warp drive fails to activate, the results could be... unfortunate. Lieutenant Worf: Very unfortunate. We will be dead. i7 / Win7 64 Bit SP1; Avid MC 6.5; Adobe CS6 PP; Nuendo 2-6; Wavelab 7; C4D R12 (in reply to GL2guy) |
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whtwolf Posts: 266 Joined: 9/19/2006 From: Ottawa, Canada Status: offline
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HD-SDI (High Defenition - Serial Digital Interface), HD-SDI is a single cable (Fibre cable) with a BNC at both ends. It is used to transport uncompressed HD footage threw the cable. At the other end you will need a uncompressed video capture card such as the AJA Kona3 to capture the footage Ie. 1920x1080i at 60fps (1 minute of footage works out to 7gigs of hard drive space). As far as your system your computer will not handle full uncompressed HD footage I am ussing a 3Ghz intel core Duo with 16gigs of ram and use a apple Xserve raid to store the footage. Firewire 800 can't keep up witht the data transfer. My dual 2.5Ghz with 6.5 gigs of ram handles the footage with the Xserve raid but freezes with the firewire 800. I also think (Not Shure) that Adobe's Premier Pro 2.0 doesn't have any settings for supporting uncompressed HD. Other systems that work are the Avid symphony or Nitro. There is also SD-SDI (Standard Defenition) works the same way just with uncompressed Standered Defenition. Hope that this helps. _____________________________ Citius Altius Fortius (in reply to GL2guy) |
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whtwolf Posts: 266 Joined: 9/19/2006 From: Ottawa, Canada Status: offline
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Looking into the camera, the video is recorded to a mini DV tape in HDV that is a compressed format of mpeg-2. A mini DV can not handle the full quality of HD 1920x1080. You still would need a 3rd party capture card like the AJA Kona3 to capture the footage. That particular camera can not transport sound threw the SDI interface. the best thing would be to call canon up and ask what the data rate of the HD-SDI port is and that will give you a better idea of hard drive space needed for editing the HD video. HDV's standard size scren of HD is 1440x1080.
_____________________________ Citius Altius Fortius (in reply to whtwolf) |
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MikeM Posts: 2347 Joined: 2/25/2005 From: Germany Status: offline
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Just to get a correct perspective regarding the 1440x1080 resolution: even the high-end format HDCAM subsamples from 1920 to 1440 before the picture goes to tape.
_____________________________ Michael Lt. Cmdr. Data: If the warp drive fails to activate, the results could be... unfortunate. Lieutenant Worf: Very unfortunate. We will be dead. i7 / Win7 64 Bit SP1; Avid MC 6.5; Adobe CS6 PP; Nuendo 2-6; Wavelab 7; C4D R12 (in reply to whtwolf) |
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whtwolf Posts: 266 Joined: 9/19/2006 From: Ottawa, Canada Status: offline
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All camera's do, since the bandwidth on the tape can't support the full res. Panasonics D5 can support 1920x1080 but unfortunatly it is not a shooting format. From 1920 to 1440 on tape and off tape threw HD-SDI from 1440 - 1920. A way around this is shooting with the p2 camera from panasonic onto cards. It will shoot full 1920x1080 unlike the hdcam. Even 720p on tape is not really 720p since the tape can't handle the full bandwidth. _____________________________ Citius Altius Fortius (in reply to MikeM) |
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MikeM Posts: 2347 Joined: 2/25/2005 From: Germany Status: offline
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Yes, but your previous could give the impression that this was a specific problem of HDV - which it is not. But we got that straightened now. The newer highend format HDCAM SR (targeted to movie making industry) can store uncompressed as 4:4:4 RGB to disk. That is the best recording quality you can get with HD, but that comes at a price. _____________________________ Michael Lt. Cmdr. Data: If the warp drive fails to activate, the results could be... unfortunate. Lieutenant Worf: Very unfortunate. We will be dead. i7 / Win7 64 Bit SP1; Avid MC 6.5; Adobe CS6 PP; Nuendo 2-6; Wavelab 7; C4D R12 (in reply to whtwolf) |
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whtwolf Posts: 266 Joined: 9/19/2006 From: Ottawa, Canada Status: offline
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Sorry your right. HDV the only problem is that it is a compressed MPEG2 format, that simulates HD. I really do not think that threw the HD-SDI on the canon camera upsizes the video to 1920 i'm shure that it leaves it at 1440 max res. As far as the new HDCAM SR that shoots to disk it is the same as the new Panasonic camera that shoots 4:4:4 to disk at 1920 aswell.
_____________________________ Citius Altius Fortius (in reply to MikeM) |
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GL2guy Posts: 121 Joined: 10/10/2006 Status: offline
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Thanks for the very informative posts guys. I am starting to understand how this HDV compression stuff works. The one thing I am unsure about is how good of quality HDV is, as opposed to uncompressed HD. About 99.99% of all the video I shoot will be for viewing on the web, so that is why I am so enthusiastic about HD. I am sick of watching a fuzzy picture when I stretch the 720x480 SD frame size to the full screen of my computer monitor. And no matter how hard I try, I just can't even come close to matching the videos on the net that are shot in HD. Problem is, I don't know if they were shot in HDV or if they were shot uncompressed. Take for instance, DJTV... those videos are shot with HD camera (which one?).. does anyone know if they shoot in HDV or do they just shoot uncompressed. I am sure DJ has the resources and equipment to handle uncompressed HD... however I am not sure if I do nor if I will be able to in the next year (upgrade). I saw this video that was shot by a fellow in a DVXuser.com Forums using the HVX200... and this is exactly the quality of online video I am seeking. Can anyone tell me if this kind of sharpness and quality of picture can be attained with HDV compression? I can't afford the Canon XH G1 (the one with the HD-SDI), as it is almost twice as much as the A1 (which I can afford - only miniDV). I have placed a link to that quicktime video I would like to match as far as clarity and sharpness. http://beaverhillproductions.com/freeman_qt_preview.php What about fullscreen video much like what is found on Quicktime's websites (like their movie trailers)? Can I produce online videos with this kind of sharpness and clarity with using HDV? I have never seen the difference between HDV and uncompressed, so I have not a clue what level of degradation occurs in the compression. Thanks so much for any light you can shed on this for me. Lord knows I appreciate it so much. As an aspiring videographer, hopefully very soon I can begin contributing more to this site as my skills advance. Thanks again. (in reply to whtwolf) |
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whtwolf Posts: 266 Joined: 9/19/2006 From: Ottawa, Canada Status: offline
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HDV video looks great don't get me wrong the CCD chips in the camera are amazing. Tones of documentries on the discovery channel most of the videos shot in HD are shot with a HDV camera. Lighter, less expensive and final output is what it is really about. Not to many people can even play an HD DVD yet so HDV will be downconverted to SD 720x480, When HD-DVD's are less expensive and more people are out there buying them they won't be able to tell the difference if it is shot in HDV or HD. If you are shooting all your video in HDV and then downconverting to SD or HD web video's HDV will look like a million dollars. The camera's are really good as far as what type of camera to get that would be based upon what your budget is. Do not get discuraged with what type of camera you should get HD or HDV, HDV will be more then perfect for what you need. My recomendation is also to look at what Sony and Panasonic are offering. You do not need HD-SDI if you are not planning on buying a 3rd party video card like the AJA Kona3, so HD-SDI is not for you. Firewire can transport HDV footage with no problem and you do not need an extremly expensive xserve raid system you can use Premier Pro 2.0 with external firewirre drives. If you get a camera that supports (shoots in HDV) with no HD-SDI out put since you do not really need it, just make sure it has firewire out. HDV will look like the video on apples web site that say HD gallery.
_____________________________ Citius Altius Fortius (in reply to GL2guy) |
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GL2guy Posts: 121 Joined: 10/10/2006 Status: offline
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Wow... thanks for the great reply whtwolf. I really appreciate it. You pretty much nailed my concerns, as I have never seen a side by side comparison of uncompressed HD vs. HDV... let alone that comparison in the form of an encoded web video. I do mostly documentary style work... so I would imagine HDV would perform much better in this scenario as opposed to if I was filming NASCAR races. Perhaps one of the DJ staffers could answer a few questions about our beloved DJTV... 1) Does DJ shoot DJTV in a compressed HD format? Or are they shot uncompressed HD? 2) What cameras are used for DJTV? Thanks! (in reply to whtwolf) |
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whtwolf Posts: 266 Joined: 9/19/2006 From: Ottawa, Canada Status: offline
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The DJTV are shot in a SD format HD will give you a 16x9 screen, The camera's that they are using to me looks like a Sony HDV camera or the Panasonic HVX-200. I don't think that the are recording to a digital hard disk I think they record to tape.
_____________________________ Citius Altius Fortius (in reply to GL2guy) |
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