Render to larger File size ???

fosko wrote on 10/31/2001, 12:59 PM
I was working with a video I shot last night. It was shot on my panasonic PVDV 400home digital camcorder and converted through an ATI All In Wonder Pro video card. The file size of the AVI was about 1.7 gigs.

I then did some editing, added about 4-5 transitions, about a 1 minute wav. file which was about 24 mgs, and a 3 second still. I rendered to a new track and the new file wound up being about4 gigs.
Where did all this extra file space come from ?? Does rendering natually increase the size of the file ??

Comments

Dreamawake wrote on 10/31/2001, 1:19 PM
What format/codec did you use for your final render?
fosko wrote on 10/31/2001, 1:28 PM
Hmmm
good question. I just used the default for AVI on my machine. I'll have to check that when I get home.
SonyEPM wrote on 10/31/2001, 4:40 PM
sounds like you rendered as uncompressed- that would account for the monster file size.
fosko wrote on 11/3/2001, 10:29 AM
YOu are right, I did render uncompressed . .but why would that INCREASE thesize.

for example, right now I'm tryingto SAVE AS a 14 minute video that I cur about1.5 minutes off of and was to just save it back to AVI. it's taking about 48 minutes.
Curious..
Chienworks wrote on 11/3/2001, 11:32 AM
My guess is that you captured your file in to some sort of compressed
AVI format originally. Full uncompressed broadcast quality video can
take around 1GB per minute. This is probably the sort of settings you
are using for your final render. On the other hand, the capture you did
with the ATI card probably had various compressions applied
automatically during the capture.

On another topic, i noticed you were using a digital camcorder, but
capturing with an analog card. Do you not have a firewire port in your
computer? If you don't, you should pick up any OHCI compliant 1394
card (probably around $40) and a firewire cable (about $25) and go
straight digital for your captures. DV takes about 220MB per minute,
and if you render with the DV templates, you'll have output files of
similar size with much faster rendering since there won't be any format
conversions. Also, DV captures are vastly superior to analog.
fosko wrote on 11/3/2001, 10:49 PM
hmmm, VERY good point. THANKS
I think that's exactly what happened. It used the ATI compression.

OK
fosko wrote on 11/4/2001, 8:34 PM
Well,
I picked up a firewire card an cable. ATI must have SOME compression progeam becasue I did a 60 minute video and it was 1.17 gigs. I just did a 16 minutes that comes out to 1.32 gigs. WOW !!!

At this rate I may have to stick with the analog card for capture . .at least until I get a larger HD. But I like the 1394 performance and may even get a Firewire Hard drive, since I hear they are faster.

Is there anyway to use the ATI compression outside of the ATI card ?
fosko wrote on 11/6/2001, 1:55 PM
By the way . . I didnt notice it at first, but after looking back at some of my edits I do see a very noticable differnece in video clarity from what I brought in with the ATI All in Wonder Pro card and bring in my video through the firewire port.

The Firewire is MUCH clearer !!!!

Just wanted to pass that on and thanks again chein for the tip
Chienworks wrote on 11/6/2001, 4:21 PM
*Whew* now we're getting into some complex territory. There are quite
a few issues you have to consider:

- what is your target audiance? dial-up modem or cable/dsl?
- if dial-up, do you wish to ask them to endure very long download times?
- if both, do you want the faster connection people to put up with poorer quality?
- are you aiming for real-time streaming?
- how much drive space do you have on your server?

Most dial-up users connect between 36K and 50K. In order to stream a
file to them, it must be encoded at about 36Kbps or less. Both Real and
Windows Media have 56K encoding settings which result in 34Kbps for
Real and about 37Kbps for WM. These files can be downloaded in about
the same length of time as the video lasts and are therefore streamable
to dial-up users. The quality is scummy though. The audio is slightly
garbled and the video is very fuzzy and jerky. This is the trade off you
must face to produce a file with that low a bit rate. Files encoded at this
rate are about 250 to 270Kbytes per minute.

If you want to have a much higher quality image, you need more bits per
second. The template you mentioned is the 256K encoding, which results
in 225Kbps for Real and 253Kbps for WM. This is fine for cable/dsl users
who get transfer rates in the 300 to 1000kbps range and they will really
appreciate the clearer picture and sound. However, dial-up users will need
at least 7 minutes to download each minute of your video. Some users
will feel it's worth the effort, but many won't bother. Files encoded at
this rate are about 1.6 to 1.9Mbytes per minute.

Another option is to include two versions of each video, one encoded at
56K and the other at 256K, and allow the user to click which ever one
they prefer. That just means that you'll have to spend more time
rendering both versions and use up more drive space on the server.

If you'd like to see some examples of what the different encoding rates
look like, browse to http://chienworks.com/media/ in that directory are
files named jeff2-xxxx.rm, where xxxx is a number specifying the bit
rate it was encoded at. I have 6 versions from 28K to 1000K and you can
see how they relate to each other in file size too. Click on the .rm version
to download, or the .ram version to stream it to RealPlayer. The clip is
only 11.5 seconds long, but the version encoded at 1000Kbps would take
over 4 minutes for a dial-up user to download.