sinusjog

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I'm alsow making a live video delay, or buffer (I allready found some very helpful posts)

Only I want it to buffer / delay up to 30 minutes... is this possible ?

What do I need to do so that it doesnt freez after about a coupple of minutes. I have 2Gig of RAM in my computer. Would it work if I had more ?

I'm alsow making a live video delay, or buffer (I allready found some very helpful posts)
Only I want it to buffer / delay up to 30 minutes... is this possible ?

buffer-live-video-up-to-30-minutes

your memory buffer is limited, for 30min its best you use disk based buffer

> ----------------------------------------------------

> I'm alsow making a live video delay, or buffer (I allready found some very

> Only I want it to buffer / delay up to 30 minutes... is this possible ?

> What do I need to do so that it doesnt freez after about a coupple of

> minutes. I have 2Gig of RAM in my computer. Would it work if I had more ?

your memory buffer is limited, for 30min its best you use disk based buffer
using jit.qt.record

>
>
> ----------------------------------------------------
>
> Hello good max/jitter people !
>
> I'm alsow making a live video delay, or buffer (I allready found some very
> helpful posts)
> Only I want it to buffer / delay up to 30 minutes... is this possible ?
>
> What do I need to do so that it doesnt freez after about a coupple of
> minutes. I have 2Gig of RAM in my computer. Would it work if I had more ?
>
> Thank you very kind,
> Charles
> --
> www.charlessarah.com
>

a delay of 30min might be outside the realm of possibility, but one 

could do a setup where one records a file of x length and after 30min 

begin playing the file from the top while one initiates another file 

recording. off the top of my head, and without a clue of how to do 

On Jan 17, 2008, at 1:41 PM, charles wrote:

> I'm alsow making a live video delay, or buffer (I allready found 

> Only I want it to buffer / delay up to 30 minutes... is this 

> What do I need to do so that it doesnt freez after about a coupple 

> of minutes. I have 2Gig of RAM in my computer. Would it work if I 

"Sometimes the appropriate response to reality is to go insane."

a delay of 30min might be outside the realm of possibility, but one  
could do a setup where one records a file of x length and after 30min  
begin playing the file from the top while one initiates another file  
recording. off the top of my head, and without a clue of how to do  
it. ;-)
cheers
bruce

>
>
> ----------------------------------------------------
>
> Hello good max/jitter people !
>
> I'm alsow making a live video delay, or buffer (I allready found  
> some very helpful posts)
> Only I want it to buffer / delay up to 30 minutes... is this  
> possible ?
>
> What do I need to do so that it doesnt freez after about a coupple  
> of minutes. I have 2Gig of RAM in my computer. Would it work if I  
> had more ?
>
> Thank you very kind,
> Charles
> --
> www.charlessarah.com

"Sometimes the appropriate response to reality is to go insane."
Philip K. Dick


In a room there are several camera's. Each camera is connected with my max patch on different inputs (right now I'm only using two camera's). Using a motionsencor sending it's information to an arduino device, my max patch gets a "bang" whenever a person comes in front of a camera.

Now in a second room there would be a projection that shows what is happening in the first room. But it should be that you could see yourself. So it has to record the live video, buffer it for about 30 minutes and then be replaced by the new live images.

This should result in a 'movie' where the visitor would see himself 'acting'.

I need to find a way that the video is show'n "live" but with a 30 minute delay or buffer. I don't see how the 'jit.qt.record' object can help because it has to be live...

In a room there are several camera's. Each camera is connected with my max patch on different inputs (right now I'm only using two camera's). Using a motionsencor sending it's information to an arduino device, my max patch gets a "bang" whenever a person comes in front of a camera. 

Thank you for reading !
anny sugestions are more then welcome.

> I have 2Gig of RAM in my computer. Would it work if I had more ?

when you use jit.matrixset to buffer the video, it is uncompressed.

when you would use a ram disk, and record to it and read from it, you 

(provided that you have the CPU power to spare).

using a ram disk instead of a hard drive eliminates latency problems 

that you mey get when reading and writing simultaneously to the same 

As you cannot read and write from one file at the same time, you have 

to split the file in chunks smalelr than 30 minutes.

this introduces some file name bookkeeping, but is not hard to do.

instead of using a ram disk, go for a solid state disk (if you have 

It helps to make two separate processes, one for recording, one for 

you can achieve this with max by building a standalone for one of the 

two processes, and using max for the other

When on windows, you may use an application like WinDV to do your 

recording. it will split the files for you and number them.

We used a winDV based patch for a 10 minute delay of a DV quality 

the playback was not linear. we recorded two minute chunks to ram 

disk, and right after recording copied the chunk to a hard drive. 

just before playback the chunk was copied back to RAM disk and played 

the hard drive was there for its storage capacity, the ram disk was 

On 17-jan-2008, at 19:41, charles wrote:
> Only I want it to buffer / delay up to 30 minutes... is this  
> possible ?
> What do I need to do so that it doesnt freez after about a coupple  
> of minutes.
> I have 2Gig of RAM in my computer. Would it work if I had more ?

when you use jit.matrixset to buffer the video, it is uncompressed.
when you would use a ram disk, and record to it and read from it, you  
may compress the video
(provided that you have the CPU power to spare).
using a ram disk instead of a hard drive eliminates latency problems  
that you mey get when reading and writing simultaneously to the same  
drive.
As you cannot read and write from one file at the same time, you have  
to split the file in chunks smalelr than 30 minutes.
this introduces some file name bookkeeping, but is not hard to do.
instead of using a ram disk, go for a solid state disk (if you have  
the $$ to burn)

It helps to make two separate processes, one for recording, one for  
playback, to use multi-core CPUS.
you can achieve this with max by building a standalone for one of the  
two processes, and using max for the other
When on windows, you may use an application like WinDV to do your  
recording. it will split the files for you and number them.

We used a winDV based patch for a 10 minute delay of a DV quality  
stream.
the playback was not linear. we recorded two minute chunks to ram  
disk, and right after recording copied the chunk to a hard drive.  
just before playback the chunk was copied back to RAM disk and played  
from there.
the hard drive was there for its storage capacity, the ram disk was  
there for smoothing the stream.
worked reliably, with no dropped frames.

Just have one computer recording inputs to files and saving them to a server which is networked to the other room where you playback those segments. 

Just as well not to have your playback running on a machine with live inputs and recording anyway. All the file accessing would result in horrid amounts of freeze-ups in Jitter.

Just have one computer recording inputs to files and saving them to a server which is networked to the other room where you playback those segments.  
Just as well not to have your playback running on a machine with live inputs and recording anyway.  All the file accessing would result in horrid amounts of freeze-ups in Jitter.


On Jan 17, 2008, at 3:14 PM, charles wrote:

> I don't see how the 'jit.qt.record' object can help because it has 

well, a 30 minute delay is definitely not "live"... the record object 

will help you record 30 min of video and then play it back.... 30 min 

> I don't see how the 'jit.qt.record' object can help because it has  
> to be live...

well, a 30 minute delay is definitely not "live"... the record object  
will help you record 30 min of video and then play it back.... 30 min  
later!
but leo has the best idea i think.
b

as a follow up to our off-line discussion, here are the details of my 

you need a RAM disk of at least 4 times the segment size.

WinDV records to RAM disk. make it write file segments of 25*60 

in your max patch, [folder] polls the RAM disk and when a segment is 

[doshack] copies the file to the hard drive and deletes it from the 

two [jit.qt.movie]s alternatingly play a segment from RAM disk.

just before a new segment needs to come up, [doshack] copies it from 

when the one player has reached the end of its segment, the other 

you begin sending bangs to the other player.

[doshack] deletes the previous segment from the RAM disk

with this set up, the transition from one segment to the other is 

even when the recording is in progress. This was on a dual core machine.

If you would go for a solid state drive, I expect that you can do 

as a follow up to our off-line discussion, here are the details of my  
recipe for XP.
you need a RAM disk of at least 4 times the segment size.

recording:
WinDV records to RAM disk. make it write file segments of 25*60  
frames or so.
in your max patch, [folder] polls the RAM disk and when a segment is  
completed,
[doshack] copies the file to the hard drive and deletes it from the  
RAM disk.

playback:
two [jit.qt.movie]s alternatingly play a segment from RAM disk.
just before a new segment needs to come up, [doshack] copies it from  
the hard disk to the RAM disk.
when the one player has reached the end of its segment, the other  
player reads the new segment and
you begin sending bangs to the other player.
[doshack] deletes the previous segment from the RAM disk

with this set up, the transition from one segment to the other is  
hardly noticeable,
even when the recording is in progress. This was on a dual core machine.

If you would go for a solid state drive, I expect that you can do  
without the RAM disk,
but I have not yet tried it.

buffer live video up to 30 minutes