[PD] Re: Soft Rock EP

Claude Heiland-Allen claudiusmaximus at goto10.org
Wed Aug 23 21:51:06 CEST 2006


Paris Treantafeles wrote:
> Hi Claude,
> 
> I finally have downloaded and watched your Soft Rock EP and wow... great 
> stuff!
> I may be biased because it's quite similar to some of my own work - even 
> without the GridFlow abstraction that you shared :-)

Thanks - a friend of mine showed me a video made 40 years ago that looks 
similar in places:

George Maciunas - Artype (1966), 29 mb
http://ubu.wfmu.org/video/fluxfilm_20_maciunas.mpg
http://www.ubu.com/film/fluxfilm.html

I'll have to try harder to come up with something original!

> If you don't mind can you tell us how you captured the visuals?
> They look very good - were you writing to disk (say from Gridflow to 
> Gem?) or sending video out to another machine to capture.

I saved lossless ppm images direct from GridFlow.  To avoid using an 
excessive amount of disk space, I used a named pipe created with mkfifo 
to send these images directly to mpeg2enc (part of mjpegtools package, I 
believe).

Needless to say it works slower than realtime, I think it rendered at 
about 4 frames per second on my machine, including the time taken to 
encode the video to MPEG2 format.


I'm working on a build system that would enable you to create your own 
custom Soft Rock DVD, hopefully I'll get it finished and debugged before 
Christmas.  It will need a fair amount of intermediate disk space (maybe 
5-10 GB) because the following deadlocks after a few frames:

        / writesf~ WAV pipe -> toolame  encoder \
       /                                         \
Pd --<                                           >-- mplex multiplexer
       \                                         /
        \ GridFlow PPM pipe -> mpeg2enc encoder /

I believe the root cause of the deadlock is either or both of writesf~ 
and GridFlow using blocking I/O rather than non-blocking I/O, from what 
I have read mjpegtools is written to play nice with fifo's.

The intent is to generate a sequence of unique (but similar) DVDs from 
around 1 MB of pd/bash/make code and a small amount of seed data.


 > Thanks for sharing!
 > p

Thanks for the feedback!



Claude
-- 
http://claudiusmaximus.goto10.org





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