Re: new-B: xternal card for AD conversion?
- From: "Steve King" <steveSPAMBLOCK@xxxxxxxxxxxxxxxxxxxxxx>
- Date: Sun, 5 Mar 2006 11:47:31 -0600
"spud" <away@xxxxxxxxxx> wrote in message
news:8n1m029g4scuugbclk66t3scengjk0l5f9@xxxxxxxxxx
On Sat, 4 Mar 2006 03:47:44 -0800, "Richard Crowley"
<rcrowley@xxxxxxxxx> wrote:
"arrya deefmon" wrote ...I guess I should have been more specific. What I meant to say was a
Thank you, I have now read some reviews of the Canopus
ADVC on your recommendation and I still don't understand
what file extension I end up with after the proprietary
Canopus chip has transferred the video/sound.
The Canopus products (and many others from other vendors)
convert analog video (composite or Y/C) into DV (Digital
Video) via Firewire/1394.
Note that there are other ways of digitizing video/audio.
Particularly the method that digitizes/compresses analog
video & audio directly into MPEG, etc.
One user said the only problem is 1 hour = approximately
13GB,
13.7GB/hour is the standard for DV-encoded video.
which seems wrong to me. A DVD movie is about
2.2G per hour
MPEG is variable-rate and 2.2GB/hour is likely toward
the high end. It could be compressed even more than
that.
commercial DVD movie release being roughly 2 hours at about 4.7G is
somewhere around 2.2G per hour, way different than transferred
firewire digital at 13G, which will obviously have to be dealt with to
get back to a manageable size again. I see you clarified this for me
below.
Note that DV and MPEG are two different ways of
compressing digital video. DV is compressed ~5:1
in the camcorder, while MPEG is compressed up to
10x more than that. Video frames are compressed
separately and independently in DV
MPEG does not contain all the frames. It contains only
full frames every 5~10 frames, and "difference information"
about what changes inbetween frames. This is called
"temporal compression" It makes the files smaller
so they can fit many hours on a 4.7GB (single-layer)
DVD disc.
This is good. But the flipside of that coin is that the
video quality suffers due to irretrievably discarding
the majority of the video information. Commercial
DVDs are hand-encoded where skilled humans
decide, scene-by-scene, how much to compress the
video to stay within the "budget" of the overall disc
size vs. how much they want to cram in there.
that explains the size difference.
The kind of MPEG encoders most of us use at home
are not this good and produce results which may look
as good as commercial DVDs, but also has the potential
to look significantly worse, depending on the content
of the video and the static compression ratio setting
you selected (or the software selected for you).
This ratio is non adjustable in the ADVC 100, correct? The magic
on-board chip picks the best rate? Or are you saying I can control the
firewire device from software?
which are VOB files if I follow this correctly. (Mpeg2
is VOB?)
VOB files contain MPEG2 with the "VOB" file name
extension.
ok
Also, several users stated they used Scenalyzer,
Tempgen, Nero, etc in some hours long serialized
combinational process in order to end up with a
movie. I didn't quite follow this either.
If you want to just take analog video and make a DVD
disc from it, perhaps the easiest is to just use a stand-
alone DVD recorder. No computer required. As easy
to use as any VCR.
Or, if you just want to take over-the-air (OTA) video,
edit out the commercials, and make DVDs of your
favorite TV show, one of the MPEG encoding boxes
(or boards) may be more convienent for you.
no, I will eventually want to import video from a hand held consumer
digital cam and compose my own music as well as import dialog on a pc.
I've had a sound studio for many years and a devastating degree of
natural ability for virtually any undertaking so were well on our way
here.
As with most things, there are tradeoffs between the
smaller size and lower quality of MPEG vs. larger size
and higher quality of DV. The temporal compression
of MPEG files also means that the video must be de-
compressed and re-compressed if you do most any
kind of editing to the video. This decompression and
recompression almost always results in additional
loss of quality. But if you are only removing commercials
from cable or satellite TV (which was likely MPEG
compressed already) you can probably get away with it.
I'm sort of getting it. I buy the Canopus ADVC 100 (110?) for $239 and
play an hour vcr tape into my pc. An hour later I have a 13g file in
some as yet undetermined software. Then I edit out the
commercials/credits and crunch the file down to MPEG2 via what I hope
is the least grungy compression ratio the software offers. This is
where codecs rear their ugly head? Use of the Canopus requires no
codec for the initial transfer, does the software require it for the
transcoding?
I mentioned my audio card, a LynxOne with digital
clock synch on BNC because I assumed I would want
to clean up the sound, specifically 60Hz hum, in some
kind of editor.
DV stores audio as uncompressed PCM 48K samples
per second by 16-bits. This makes it very easy to edit/
process, etc. MPEG stores audio in a compressed form
(similar to MP3), and processing it (like removing 60Hz
hum, etc.) is more problematic.
If the S&V are locked I don't see how to do that.
The audio and video are locked by digitizing both of
them in the encoding device (The ADVC box/board or
the MPEG encoding board, etc.) It is not practical to
use your separete audio card unless you are using
professional video encoding equipment where the
sampling rate clocks can be synced together using your
BNC connector.
You said you wanted to use Firewire or USB which led
us to believe you were looking for a more consumer-
priced solution.
Note that it is FAR EASIER to eliminate the 60Hz hum
before you digitize the audio than having to do it in
"post-production".
that occurred to me after I posted, although the pc stacked pole
filters and dedicated noise reduction plug-ins are much better suited
than the outboard parametric eqs I have here.
I'd also like to remove the commercials and credits to
save space. Can you recommend software for this?
Many people seem to like applications like Video-Re-Do
to do simple editing (like removing commercials) from
MPEG-encoded files.
thanks, I will look into that.
This is where the rebuilding of the file takes so much time?
This is the tradeoff. You can avoid the transcoding (what
you are calling "rebuilding') between DV and MPEG if you
encode/record directly in MPEG. But you have to live with
the limitations. If you are just removing commercials, this
may be the best solution for you.
I'm not sure the Canopus does that. It's not clear in the advertizing.
It just says it does a splendid job etc.
Could you pause the recording on the pc during the initial
transfer and then FF/CUE the VCR and start again recording
to avoid this?
Probably. It depends on what software application you are
using to do the recording (whether DV or MPEG). There
are many different applicaitons with different featues available
for either MPEG or DV recording.
How would you find out which software would let you do this? All
products seem to be represented by the same ad copy at every site. No
vender seems to know anything specific about a product having never
used it.
If your video source is a VCR (like VHS, etc.) then your
video may already be low enough quality that using DV
is overkill, and MPEG may be a better compromise.
Some of it's pretty bad, especially the sound. It's in BW if that's
any consideration. Maybe smaller size?
Also, if you had to render in some absurd overnight process
It only takes overnight if you are running a 300MHz computer
(0.3 GHz). Is your computer really that slow? If you are
doing something that requires quick turnaround time, maybe
you should be investigating more expensive commercial
solutions. Most of us don't have the kind of time crunch it
takes to get the news ready for the 6pm broadcast, etc.
It's a 1.8g P4, 512MB memory, Sis650, 80G hd with a Sony DVDR burner,
6pin firewire, usb2. I use PowerDVD to watch movies. That should have
been stated I suppose.
could you open two instances of software and play out the
non-destructive edit program in real time and record it in a
loop as the Canopus ADVC 100 is a two way set up?
You will need to re-state what you are trying to do here
before I can respond. If you have the video in your computer
as a file already, why would you need to use the ADVC or
any other conversion box?
I'm trying to save time when transcoding the edited file. I thought it
might be faster to play back the edited one hour show in real time as
opposed to letting it crunch the numbers over an hours long period. (I
have no experience so I just assumed it would take many hours even on
a capable system). I was wondering if playing back in one software
instance out through the Canopus and recording back in with a dummy
loop of cable in another software instance would cut down on the
transcoding time. Some digital devices won't let you do this, but
require a device inserted in the loop who's controls can be put in
some kind of standby mode, at least this is how it works in audioland.
And I guess my budget it about $250usd.
Then you are likely looking at a lower-end solution like an
MPEG encoder. ADVC and other DV-encoding devices
tend to be higher-priced than that. Clean up the 60Hz
before going into the converter (whether MPEG or DV).
The Canopus ADVC 100 seems ok at $239 if it actually works. The Video
Guys. I didn't look closely, I just picked a few sites off the google
list for a general idea. The more expensive ADVC boxes just add more
editing and filters on the way in it looks like. Thanks again.
The ADVC100 is a simple and very useful device. It converts analogue video
(composite or SVHS video, left & right audio) to DV25 video/audio
(DVCAM/MiniDV) and outputs it through a Firewire connection. To
editing/capture software, the ADVC100 looks like a DV camera. The file that
results is an AVI compressed 5 to 1, just as if it would be in a DV camera.
The ADVC100 is a two-way device. Fed from editing software through the
Firewire port of the computer to the Firewire Input of the ADVC100, the
device will output analogue video (SVHS or Composite) plus analogue left and
right audio. That's what it does. I own one. I use it to digitize
analogue video (VHS, SVHS, even BetaSP). When those analogue signals are
fed into the ADVC100 my computer, using editing/capture software, sees and
stores to the hard drive an AVI file containing both video and audio
information in the DV25 compressions of 5 to 1. These AVI files can be
edited in the normal way in editing software. They can be converted to many
other, more compressed, formats such as MPEG1, MPEG2, Flash, etc. I also
use the ADVC100 to convert the Preview Window in Vegas to analogue, so that
I can make value judgments about the video quality of the material on a
video monitor, rather than trusting the often misleading presentation of a
computer monitor. I could use a professional video deck with Firewire input
to do the same things, but I'd prefer putting hours on the inexpensive
ADVC100 than the expensive video deck. Is there anything that I haven't
made clear. If so, I'll try again. Oh, I did not mention the (secret but
easily found on the Internet) ability to copy Macrovision protected
material, which is occasionally very useful. Here, I am speaking for
legitimate professional purposes not endorsing illegally violating
copyrights.
Steve King
.
- References:
- Re: new-B: xternal card for AD conversion?
- From: Richard Crowley
- Re: new-B: xternal card for AD conversion?
- Prev by Date: Re: Is a small picture size on TV possible?
- Next by Date: Re: Is a small picture size on TV possible?
- Previous by thread: Re: new-B: xternal card for AD conversion?
- Next by thread: Re: new-B: xternal card for AD conversion?
- Index(es):
Relevant Pages
|
