Camcorders: Pros and cons about Hard Disk Drives vs DV tape
and I neglected to mention that
by boya84 - 4/20/07 5:02 PM In reply to: Maybe this helps... by boya84HDMI is digital - and the other connections mentioned in my post are analog... um... I think that's it...
bombarded by serial numbers...
by Wanda-soo - 4/20/07 5:15 PM In reply to: and I neglected to mention that by boya84Again thanks for your technical radiance :^)
'Off the block' is what the rep was saying, which I understood to mean the signal is pre-processor/compression. I'm just a screen-writer who suddenly has the job of making docos for the clamouring hordes. I'm having to run like hell to understand the 'camera' BUT! I now have a V1p which is exciting to say the least.
What country are you?
thanks for your translations... it really helps.
PS I love Buckaroo too!
US...
by boya84 - 4/20/07 6:03 PM In reply to: bombarded by serial numbers... by Wanda-sooIf you like that hapa Doctor, that means you've been to my myspace site... but then, you would know I am in the US... hmmm... anyway, Welcome.
There is so much stuff that does not get posted there because I can't - per agreement with the subjects who do whatever they are doing with whatever I captured (video or audio-wise) for them.
Suggestion: Use the camera a LOT before you get sucked into our first shoot. Get used to the rig - the mics, etc... learn the factory reset process - and play in the menu... and do stuff.
Congratulations on the new acquisition! Come on in! The water's fine.
John Parker John Parker John Parker
by Wanda-soo - 4/20/07 6:19 PM In reply to: US... by boya84Actually I saw the BB quote in your CNET profile because I wondered what country you were from...
I used to have a band called YOYODYNE Propulsion, and I loved BB in the 8th dimension. Don't know about the MySpace...
I stayed up until 5.00am reading the manual, and I even got past the contents page!
:^)
I have shot a few bits if you're interested http://www.teone.com.au
in Gallery - short films.
Just now going to get my swimming cap on.
again thanks and bye!
ah... forgot about that reference!
by boya84 - 4/21/07 4:06 PM In reply to: John Parker John Parker John Parker by Wanda-soonice web site... Your artwork is... compelling and provocative.
Thank you for sharing.
art works
by Wanda-soo - 4/21/07 5:13 PM In reply to: ah... forgot about that reference! by boya84thanks for the feedback. So where is your MySpace....?
HDMI Digital versus Component Analog
by Steven W Rose - 12/23/07 11:15 PM In reply to: and I neglected to mention that by boya84When dealing with analog video, the quality of the cables is more important than with digital signals. With analog signals, any degradation (high resistance, poor shielding, bad connectors) directly affects the quality of the signal being transported. With digital signals, in general, the cable either works or doesn't work. It is possible with digital to have a cable that is on the borderline, and produces intermittent issues, but this has been rare in my experience.
HDMI cables, for the same length (e.g. 6') and connector style, can vary in price from about $7 to about $100. While there may be differences in connector quality or appearance, I have encountered no difference in their ability to transport HDMI signals. In a retail area where margins are small and decreasing (e.g. HDTV and computers), high priced cables and accessories represent a way of increasing margins.
When connecting a DVD to an HDTV, for example, it makes no sense to me to use unnecessarily expensive cables. It will be disconnected and reconnected just a few times in the lifetime of the equipment, and hopefully be hidden from view. On the other hand, if I were using an HDMI cable to connect my camcorder, where there might be many connection cycles, I'd pay close attention to the quality of the connectors. Note that the quality of the connectors may not be directly related to price.
By the same token, the quality of an analog cable may also not be related to its price. Many expensive cables with clear covers are configured so that the cover acts as a magnifying glass, making the cable look significantly larger than it really is. I'm also less than sold on "oxygen free" copper (see Wikipedia). In cables, generally, marketing rules.
And, of course, one last gotcha. Some "digital" signals (such as the QAM modulation used for digital cable use analog encoding for the digital signal, and are more susceptible to cable issues. QAM stands for Quadrature Amplitude Modulation, and relies on being able to discriminate many levels within the signal -- in other words, analog amplitude!
Bottom line: There is no need to pay too much for your cables.
Aloha,
Steve
I'm a real novice
by krsb13 - 4/20/07 10:26 PM In reply to: Agree with whizkid... by boya84I'm confused at this point. There are many statements listed against HDD camecorders, which i was also so close to buying (sony DCRSR42 or 62).
But for a simple guy that wants to record b-days and kid sporting events for memories. what would be the best way to go when i want to transfer the data to either my computer for viewing/editing or DVD's to give to family members.
Can you place miniDV tapes on to computer hardrives?
I understand it comes down to my money, but I would like to pick your brains if you don't mind. thanks for the time if you read my post.
Let's be fair - the higher end hard drive-based
by boya84 - 4/21/07 12:18 AM In reply to: I'm a real novice by krsb13camcorders are probably fine for your needs...
Yes, miniDV image quality is better. Yes, hard drive based camcorders transfer the file to the computer faster... but in the long run - if do take all the steps, I am not convinced that there is actually a time savings.
Yes, miniDV tape easily transfers from camcorder to computer - presuming your computer has a FireWire port (standard on Apple Macintosh computers; becoming standard on "traditional" Windows manufacturer's machines) - and easily and affordably added if your computer does not have one by way of expansion cards (PCI slots for desktops or PCMCIA slots for portables).
The reason I don't think it saves that much time (using a hard drive based camcorder) is with miniDV tape, the tape is the archive - shoot the video, fill the tape, pop out the tape, lock it, label it, pop in a new tape - that locked tape is the archive. With hard drive machines, you copy the file over to computer, burn DVDs to archive (which is not a good long term archive mechanism)... so the net-net savings, in my opinion, is rather small.
In either case, the DVD burned is usable in normal DVD players - and that DVD rendering takes the same amount of time regardless of camera type.
Two things we can get rid of: digital zoom and miniDVD based camcorders. Both are useless.
Anyway, given the small difference in process flow times between hard drive based and tape based camcorders, the better image quality of miniDV tape based camcorders wins in my book.
capturing the wee beasties...
by Wanda-soo - 4/21/07 12:43 AM In reply to: I'm a real novice by krsb13For editing, you'll need an iLink cable (I use Macintosh, so I apologise if this info is not PC-friendly) from your camcorder into your computer for editing. Around $35 from Radio Shack? We call it Tandy in OZ (I'm in Australia)
You'll then need appropriate software that enables you to sort your captured files into clips which you can then manipulate and add sound, delete the bits that aren't useful etc.
I use Final Cut Pro which again is Mac-specific, also there's iMovie HD (a simpler but usable tool) for Mac. PCs use Premiere and... other um,...PC things????
Capturing video from mini DVs onto your computer will chew through your computer drive's memory like a pack of starving rats on vacation at Sizzler... invest in an external Hard Drive (a firewire drive is best as a USB won't capture at a fast enough transfer rate). Lash out and get at least 300G or you'll be back on ebay trying to find the address of the guy you bought that last 80G drive from...
It seems very expensive to do all of this, but once you start editing, it's like the Hotel California.... you'll never leave!
Sorry to all the technical adepts who are horrified at my clunky attempt to explain how to enter the front door of editing...
I can lift heavy things, but I'm just no good with serial numbers!
good luck, you'll love it!
Quick compression overview
by Steven W Rose - 12/24/07 5:03 PM In reply to: good explanation! by fatalcureConventional NTSC video starts with about 30 individual pictures per second. There is a lot that can be done in the way each picture is created to reduce the amount of information that has to be digitized. For example, for DV, the number of red and blue samples is reduced to half, as green carries the most detail information (corresponding to luminance, or the "b&w" image information). (Technoids, please forgive the simplifications.) In this way, the amount of information that must be digitized is reduced to about half of what conventional NTSC requires, or about 125 megabits per second.
For DV, each image is then mildly compressed again by about 5:1, so the net bit rate of DV is 25 megabits per second -- not raw, but fairly clean. (To reliably get to 5:1 requires discarding some information during compression that the human eye would miss anyway, especially when the pictures are presented as a video sequence. This is termed lossy compression, since the decompressed image is not identical to the original.) Because each picture is compressed individually, it is easy to edit this video on frame boundaries, just like analog video.
MJPEG (motion JPEG) also compresses each frame individually, but uses the JPEG standard to compress each picture. DV and JPEG are very similar, but different.
To record high definition video at the same bit rate (e.g. HDV), additional tricks are required. MPEG-2 fills the bill by taking advantage of the fact that sequential video pictures in a scene are almost identical. An initial frame is compressed (called an I frame), which is a complete, separately compressed frame much like DV or MJPEG. Subsequent frames only contain the difference information. Since their content has been predicted by the earlier I frame, they are called P frames, and consume only about 1/2 to 1/3 as many bits. Since the uncompressed HD picture has about three to six times more information to be compressed than NTSC, this helps a lot.
But more is needed, so there is another trick: A frame not only has a lot in common with the previous picture, but also with the next one! If there were just some way to know what comes next, we could use even fewer bits (saving another 1/2 to 1/3 relative to the P frame). The only way to do this without affecting the space-time continuum is to buffer the incoming information, reorganize it, do the compression, then send the pictures out of order. The client device which presents the final product must reverse the process.
The group of related frames is called a Group Of Pictures, or a GOP. Frames which are rebuilt from earlier and later information are called bidirectional, or B frames, and are not used as reference frames. A typical GOP might have a structure of I B B P B B (repeating IBBPBB), so let's number the frames in the order they occurred (and the order in which they must be presented) as 1 through 6, with 7 being the I frame of the next GOP. But to decode B frames 2 and 3, I need both frame 1 (I) and frame 4 (P). So the frames must be transmitted in the order 1-4-2-3, and I have to process frame 4 since it is just the changes since 1, in order to decompress 2 and 3. Having done that, I need to send the decompressed pictures to the display in the order 1-2-3-4. Now, in order to decompress frames 5 and 6, I need the I frame from the next GOP (7). So the order in which the frames must be transmitted, known as the decode order, is 1-4-2-3-7-5-6!
So you can see that getting the additional compression we require introduces a lot of complexity when we want to edit the video. And there is yet another gotcha -- the first GOP depends on the second GOP, so we can't even make a clean splice between these GOPs! If we did, then the I frame of the second GOP would be different than the one used to encode frames 5 and 6, resulting in a strange and noticeable glitch in the decoding. It is possible to intentionally produce a closed GOP by ending the GOP with a P frame, for example, which only depends on what came before. A transition between a closed GOP and the following GOP is known as a "splice point", and represents where a clean switch can occur to a different (but similarly encoded) MPEG-2 stream, such as a commercial or station ID. An appropriately terminated MPEG-2 stream also ends on a closed GOP for program to program transitions.
AVCHD is similar, but even more complex than MPEG-2 (it uses MPEG-4 Advanced Video Coding, also known as H.264, MPEG-4 AVC, MPEG-4 Part 10, and MPEG-4 JVT -- they forgot to compress its name). It achieves an even lower bit rate, important for recording on smaller, solid state media such as SD cards. There are other variants of MPEG-4 in use in HD cameras as well. AVCHD is generally reviewed as not quite ready for prime time. It pushes hard on currently available chips and occasionally stutters, but is definitely a great forward looking standard -- that is even harder to edit. But the difficulty of editing is only a problem for the authors of editing software. Once solved, those difficulties should be transparent to the editor.
Finally, there is an HDMI jack on some camcorders which may (depending on model) allow you to record a genuinely raw feed from the camera's video and audio sensors. This has a very high bit rate (more than a gigabit per second), but can avoid any form of digital compression (e.g. HDV or AVCHD). It fundamentally requires a nearby desktop or server class computer with an HDMI input and massive storage array, and is still limited in quality to any compromises made by the manufacturer in the sensor array, but is definitely the best quality you can get from your camera if it supports real-time HDMI output.
What are the practical implications for all of this?
o First and foremost, always capture your content at the highest quality you can afford. The long term value is in the content, not the equipment. You can always transcode or reencode to lesser standards without loss, but you can't increase the quality of the original. And experience shows you can't predict how it will be used in the future.
o Second, archive your original work. Never erase a DV tape, for example. If you are using a medium which must be erased, such as a hard drive or flash based camcorder, make two separate copies of the content (on different drives or machines!) before erasing the original (please do the same for your still pictures).
My preference at this point, if I were starting from scratch, would be a Canon HV20 with an external firewire recorder or notebook, recording to HDV tape for archival purposes and simultaneously to the external hard disk for instant editing access.
Aloha,
Steve
great, but not for me
by b.k.m - 4/23/07 3:25 PM In reply to: The camcorders with built-in hard drives under by boya84This is a great explanation of the advantages of DV tape for someone who has much more time to manage their video than they do to shoot it.
Obviously if the video is very valuable, it may be worth all the expense, effort, and time to be so meticulous. Nevertheless, the kind of workflow this implies probably entails spending several hours managing video for every 30 minutes of shooting.
For me, just rewinding a tape and transfering it to the computer takes longer than I care to wait. I rewrite over the same media over and over again, and I can't imagine keeping a bunch of old tapes or DVD's lying around or in a safe.
For me, the biggest complaint I have with DVD is motor noise. Hard drives can make a lot of noise too. I imagine that tape is quieter as long as everything is working right. But the hassle of tape is too much to overcome. So far, I prefer flash.
I agree...
by whizkid454 - 4/23/07 4:12 PM In reply to: great, but not for me by b.k.mBut my only complaint about flash is the extreme lack of space and the amount of compression. Once flash technology takes off (to a big extent) and more storage is available for less $$, it will become more popular. Right now, a 4GB card only can hold about 25-30 minutes of good quality video.
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