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Posted by cwdjrxyz on 10/19/07 04:34
On Oct 18, 9:05 pm, "Delli" <de...@belli.com> wrote:
> hi folks, new at posting web videos; just converting from avi's down to
> WMV's and MOV's. need to post some little movies on a friend's site: want
> to give two options for both the WMV and MOV (pc / mac) users: dialup &
> broadband. using WME & QTpro for the conversions, which is going well, but
> two things I'm not sure of: bit-rate for the movies, which, I surmise, does
> a hand-shake with the person's ISP bandwidth factor, thereby optimizing
> their viewability.
>
> i'm working in the range of 200Kbps to 800Kbps (dailup up to broadband) for
> the bit rate of these movies. A dialup friend recently told me that her
> dialup connection (aol) took 20 min to download a 4 meg WMV movie. for
> some reason it didn't buffer & play, it dl'd the whole thing 1st. prob a
> tweak I overlooked.
>
> any opinions on bitrate for progressive DL movies and/or max file size for
> DU/BB connections?
For dialup, 40 kbps is about the best you can do, and about 32 kbps is
safer if you want to stream with a short buffering time. Some use both
a low and high broadband stream. The low one might be 100 to 200 kbps,
and the high one can range from about 500 to 3000 kbps. A movie of DVD
quality would require over 10000 kbps to stream, and even much more
for HD movies. Thus considerable compression is required even for high
broadband. I can handle about 5000 kbps with my broadband connection,
but others are considerably lower and a few are higher at least part
of the time. The kbps is what is important for streaming after a short
buffer time. I have broadband videos that are over 100 MB, but they
stream well since the kbps download speed is large enough to keep up
with the progress of the movie. Such a movie might work on dialup, but
then it would have to download nearly completely before it started
playing, and that might require many hours. The lower the kbps, the
smaller you need to make the image. Also the portion of the the
bandwith used by audio vs video should be considered. For a video of
someone reading the news, the bit rate of both the video and audio can
be kept low. For a recording of a symphony orchestra, the video can
use a low bit rate, but the audio needs a higher bit rate if the sound
is to be decent. For very fast moving sports, the video bit rate needs
to be quite high, but the audio can be at much lower bit rate when
required. For a rock concert where several players rapidly move all
over the place, both the video and audio bit rates need to be fairly
high.
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