[Coco] Re: Help - There that got your attention.

[Gene Heskett]

On Sunday 14 August 2005 23:29, Dave Kelly wrote:
>Brett K Heath wrote:
>> Video streams in linux?
>>
>> google on the following names
>>
>> cinelerra
>> (a full blown quicktime based recording and post production facility)
>
>I had this up and running just before I went to supper. Could not figure
>how to make it reconize my video capture card.
>
>> transcode
>> (a modular and very flexible command line tool that can do capture,
>> denoise, encoding, translation between various codecs and container
>> formats, and a few dozen other things)
>
>Have this but it did not show  up in a search using 'apropos'.
>
>> VideoLan
>> (A set of tools designed to do network video streaming under linux)
>
>Have this. Been working most of the day trying to get it to access my
>video capture card.
>
>> I'm most familiar with transcode and cinelerra (cinelerra is the
>> successor to Broadcast 2000).
>
>This is the third flavor of linux I have tried to run Cinelerra  on and
>still have not been successful.
>Transcode: I don't need to edit anything. What I need to do is take the
>image from my camera and give it directly to you over the internet.
>
>My camera is a Sony Hi8 camcorder.  No USB. My TV capture card is
>Hauppage Win. Uses 'bttv' driver. I have 2 computers with Sempron 1.6
>CPUs and 1 gig memory chips. I have a 200gig HD I can install in 1 if
>needed. Sound will be added later when I get the video tested.
>
>I have had success with 'camstream' and 'webcam'. But they can only
>upload an image every 1 second and that looks kind of jerky.
>
>If you were going to use transcode, how would you construct your command
>line?
>
>> The real problem is that unless you have a hardware encoder or a truly
>> monster machine you have to capture raw, and this eats disk space at
>> an incredible rate (we're talking tens of gigabytes an hour, or more).
>
>As I stated above, this needs to pass as straight through as possible.
>Real time.

Unforch, based on 24 bit RGB color, realtime equals around 50 megs/second, 
sustained.  Your net connection is not going to be that wide, an uplink 
over an adsl circuit won't be at more than 100kbytes a second typically.  
So you must have at least a firewire interface from the camera to the 
computer, and computer horsepower enough to take that 50 megs/second and 
make mpg out of it in realtime.  Those Sempron 1.6ghz boxes will be short 
in the encoding to mpg thruput dept by quite a bit.  Your only route to 
success is a video capture card with a hardware mpg encoder on it, and 
AFAIK, no Happauge card has that.

We tried some rather pricey ($1500 a copy) canopus cards a couple of years 
ago that claimed to be able to do that, but despite some rather heroic 
efforts on the part of the canopus coders, they never were able to 
achieve a video stream out of them that could be played back on the 
industry standard Vela card, or on the commercial servers that were 100% 
compatible with the output of that $14,000 Vela card.  Based on their 
claims of compatibility, we had bought 14 of these cards, so we (wdtv) 
took quite a bath on that project.

Today, to do this, we would do as we are doing now, and use the Pioneer 
DVD recorder.  I don't know what its selling for today, under $700 I'd 
guess, but it has no output available at the video stream to/from the 
disk, only ntsc video/audio in and out.  But, the burned disk it makes 
could certainly be imported if the computers dvd player has digital i/o 
(something hollywood has nightmares about because it means their dvd 
releases are on the net for download an hour after the first sale).  The 
data rate there can be as little as 4 megs a minute.  Data quality is 
very good s-vhs.  dd would be used to pull the data from the dvd, and 
some data manipulation might have to be done, but its worth the try to 
find out if it can be made to work.

>
>Thanks for your feedback.
>Dave

-- 
Cheers, Gene
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Copyright 2005 by Maurice Eugene Heskett, all rights reserved.