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What is the difference
between the Sony and JVC HDV cameras?
- The JVC cameras are 720p. This means they
have 720 lines of horizontal resolution, displayed/shot in
progressive frames. The Sony cameras have 1080 lines of
horizontal resolution, shot in interlaced frames. The
resolution of the JVC camera is 1440 x 720p, and the
resolution of the Sony cameras is 1440 x 1080i.
(when viewed at aspect ratio, the Sony
actually displays 1920 x 1080i. A 1440 anamorphic image
yields a 1920 display)
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Do I need a new computer to
edit HDV?
- Absolutely not. If you have a computer
that can edit DV, you have a computer that can edit HDV. HDV
in 1080i format is the same bitrate (25Mbps) as DV is.
However, depending on the system, you may experience choking
on the system, depending on whether you're editing Transport
Streams or with an intermediary codec such as the
Cineform Connect HD codec.
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How fast does the processor
need to be to edit HDV?
- If you have a processor of at least 2.6
Ghz or faster, you'll be plenty fast to edit HDV,
particularly if you use an intermediary codec.
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What is an intermediary
codec?
- An intermediary codec is like a
translator, or "in-between" codec, that assists the editing
software.
Connect HD
(for Sony Vegas) Aspect HD (for Adobe Premiere) and
Lumiere (for Final Cut Pro) are all intermediary codecs. You
capture in either native MPEG from the HDV camera, and the
video is converted to the intermediary either in real time
after capture, or during capture. This assists in the
editing process, as native MPEG transport streams are very
heavy on the processor, and may be difficult to edit.
Further, you don't want to be editing the raw MPEG transport
stream because you'll endure a potentially significant loss
of quality without the intermediary.
- When you render to print to tape, if you
wish to print to your HDV camera, the intermediary will
re-convert the intermediate stream to the MPEG format once
again, providing you with a great image.
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Why don't I want to edit
the transport streams?
- The Transport Streams/TS files from the
camera are MPEG data, containing I, B, and P frames. The
nature of the long GOP (group of pictures) format causes
generational loss during the encoding/decoding, not to
mention that it's very hard on the processor and very slow.
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What does the intermediary codec do to the transport
stream?
- The Cineform Connect HD codec takes the
15 Long GOP and converts it to a proprietary 2 GOP, into a
temporal wavelet format. This makes it scalable and a lot
more efficient so that the NLE and CPU can process the
information easier/more quickly. Read more at the
Cineform technology page.
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- Does the
intermediary codec come free with my camera or NLE?
- No. You need to purchase this separately.
Cineform recently announced a special price of $149.00 on
Connect HD for Sony Vegas, and they have special pricing for
Adobe Premiere users too. A company called
Lumiere
makes an
intermediary for FCP users.
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What is a transport stream? (A ts
file?)
- A Transport/ts stream is the multiplexed
packeted data that makes up the MPEG file. It is a muxed/blend
of audio and video. It has a fixed length for structure.
Demultiplexing is
achieved by unique packet IDs (PIDs).
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Is the Audio format of
HDV any good?
- The audio format of HDV is
MPEG 1 Audio layer II. It has a bitrate of 384 Kbps, and can
be very good. However, it's not suitable for heavy editing,
so audio like video, is best sent to the intermediary. (and
is automatically done so by the intermediary tools) Keep in
mind that while this format is not quite up to CD standards,
it is quite good. DV camcorders record audio in PCM format,
so it's the same as a .wav file. The HDV audio spec is
similar to very high bitrate MP3 audio.
- If you need high quality audio in a PCM
format, we suggest you use a DAT or other uncompressed
source that can do a true 16 bit/24 bit recording at
48k/96khz sample rate. Remember, when you use the Cineform
intermediary audio is converted to a 48K/16 bit format, so
you'll not need to worry about the audio quality in editing.
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How do I capture
HDV?
- HDV is captured in exactly
the same method as you capture DV. Using a capture
application like the ones offered by Cineform, you'll
capture media, and either conform it to the intermediary on
the fly, or conform it to the intermediary later. Because
HDV also has timecode embedded in the file, Batch Capturing
and previewing scenes for capture should stay the same. A
free capture application is available
here.
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heard that HDV has .5 second dropouts. Is this true?
- It is true that if you experience a
dropout in HDV that it will last for one-half second. This
is due to the MPEG format of HDV, and how GOP Iframes
determine the rest of the image and frame content.
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Do I need a new
monitor to preview HDV files?
- Maybe. You can monitor HDV
one of two ways. You can view it on a computer monitor that
is at least 1900 x 1200, or you can use an external HD
television monitor. If you want to use an external monitor,
you'll need to use an HD card similar to the MyHD card from
MIT systems, or something similar. Since HD will be
viewed on plasma and LCD screens in the future, you'll want
to view on a monitor similar to what the footage will be
viewed on so that color correction, etc are accurate.
- You can view HDV in your NLE
application on a lower resolution computer monitor, and
likely be reasonably accurate, but for critical video,
"reasonably accurate" just isn't good enough.
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How does the camera connect
to my computer?
- The HDV camera connects to your computer
via the same Firewire connection that you currently use to
capture DV, connect hard drives, scanners, etc. Some
proprietary hardware cards will also soon accept HDV
information over Firewire.
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Isn't HDV just too huge a
data rate/stream to edit with?
- HDV in 1080i format is the same bitrate
(25Mbps) as DV is. However, depending on the system, you may
experience slowdown on the system, depending on whether
you're editing Transport Streams or with an intermediary
codec such as the Cineform Connect HD codec. As mentioned
above, HDV editing experiences can be just about the same as
editing DV. A reasonably fast computer can manage the
bitstream without any trouble.
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How do I deliver HDV files to
a broadcaster or client?
- Eventually, HDV will be delivered via Blu-Ray
discs in most scenarios. Blu-Ray is still just around the
corner. Currently, your options are:
 | Deliver on WMV-HD |
| Downconvert to SD/Standard Definition,
and deliver on DV, Beta, or DVD |
| Upconvert to HDCam with an application
like Sony Vegas. You will suffer some loss, but in seeing
some footage upconverted to this format, it was pretty
impressive. |
| Deliver using
NERO's Recode H264 format,
playable on settop DVD players. |
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Can Vegas/Final Cut
Pro/Premiere/AVID control my HDV camcorder?
- Most applications can control the camera,
but don't have the ability to ingest the data currently. As
months go by, it's fairly safe to assume that all NLE
systems will be able to accommodate the HDV stream.
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In Vegas, my HDV images look squeezed.
Why?
- The aspect ratio of HDV is 1.333. Vegas
currently sees it as .909. Simply right click the file in
the Media Pool, choose Properties, and convert the aspect
ratio to 1.333. Vegas will then see/display the file
correctly.
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Is HDV interlaced the same way as DV?
Is it upper or lower field first?
- HDV, unlike DV, is upper field first when
working with interlaced modes.
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I
read that HDV has bad motion artifacts. What's the scoop?
- If you attempt to do very fast pans with
HDV, due to the way the frames are generated with MPEG and
GOP, you may see motion artifacts. However, this is not
nearly the issue as it's often painted to be. It's a good
idea to rent, borrow, or
download
images from a website to see for yourself, how HDV works
with fast motion.
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Can I edit HDV in real time?
- Of course you can. With the Cineform
ConnectHD codec, you will have the 29.97 or 24p with 3:2
pulldown that you are already used to. It will edit quickly
and easily. There is a lot of speculation about this, but
the truth is, with an upper end processor and a fair amount
of RAM, you should notice little difference between editing
HDV and DV. And depending on the application you're using,
you may not need the additional RAM.
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What is "Super-HAD?" Sony makes a big deal about it
in their advertising.
- Super HAD or the Hole-Accumulation Diode,
is a brilliant new technology that allows the HDV camcorder
to process more color and light information by using all
available area on the CCD, or Charge Couple Device, which is
what receives the analog picture information and converts it
to digital information. Sony has a great pictorial
explanation
here.
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In
Vegas, I'm not getting 29.97 or 25 fps playback with Cineform
intermediary files. Why?
- In Vegas, you'll need to set your RAM at
a high level to view files at 29.97 (NTSC) or 25 (PAL)
frames per second. Set your Preview Window to Preview/Auto
or Preview/Full for best results. Your
processor speed may be part of the
problem.
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I'm
confused by HDV and it's colorspace. I'm told it's different
than SD. Is this true?
- Yes. HDV is compliant with the ITU BT.709
standard, while SD is compliant with the more strict ITU
BT.601 standard. There are several
sites on the web that very clearly explain the somewhat
difficult concept of ITU BT.709 and how it differs from what
you may currently be familiar with. The HDTV standard is ITU
BT.709 regardless of where you live in the world.
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