[gephex-devel] Fwd: yuv4mpeg from ffmpeg?

[Jay Thompson]

Hi George,

Thanks for the reply. It helps a lot though I had to switch over to  
XP temporarily cause dv1394 works fine in Gephex there. I can use it  
for 30 days before it has to be activated (used the copy from another  
machine of mine), enough time to complete an upcoming show. I have 9  
days to put about 8 hours of visuals together for 6 very different  
acts. It's enough time to produce the visuals but not enough for  
visuals and configuring a system. It does mean I can use vvvv again,  
another program I quite like.

After this show is done, I will be deleting XP and loading linux  
again. I'll have more time to set things up the way I want 'em. I  
noticed that Sven has a dv1394 module in the Arch repository I would  
like to play with a bit.

I am also looking for ways to bring some OpenGL eyecandy into Gephex.  
I found a project called Madrigal (http://lekernel.lya.eu/ 
madrigal.html) that implements ProjectM in a client/server model  
which is kinda interesting. I'm dreaming something like this would  
run it's own daemon and Gephex could grab it's output to mix with a  
live video source. I don't know what can be done with something like  
this but what I'm hoping for is for a visual system like that seen in  
the Wolfman's segments on the Hilarious House of Frightenstein (two  
youtube links at the bottom for reference). Halloween is big here and  
I'd like to do something like this for my nephew - there's always a  
kids party. Anyway... After my current gig is complete this is  
something I'm going to try to do in one way or another.

Best,
jt


HHF links - if you've never seen HHF, check out some of the other  
clips on youtube. In loving memory of Billy Van:
- http://www.youtube.com/watch?v=3k6o0uwnj1U
- http://www.youtube.com/watch?v=I-s6bv70RsY

On 7-Aug-07, at 11:10 PM, Georg Seidel wrote:

> Hi jt,
>
> sorry, I don't have much time at the moment, so just some short  
> comments
> below.
>
>> Hi everyone... I tried to post to the user list but it doesn't  
>> seem to
>> be responding so I am forwarding my question to the development list.
>> Please let me know if I shouldn't send my noob questions to this  
>> list.
>
> It's fine to post your question to this list, though there might be
> more people lurking on the user list...
>
> [...]
>
>>> What I'm trying to accomplish is a yuv4mpeg stream from ffmpeg that
>>> Gephex can read. It seems ffmpeg will do this but I'm going in  
>>> circles
>>> and could use some advice. I've read many things on the web, man
>>> pages, readme's, etc... but am missing something. Does the Gephex
>>> yuv4mpeg module read from a fifo file or is the stream piped from
>>> ffmpeg to Gephex?
>
> I think you would have to use a fifo.
>
>>> The Gephex y4m module won't even see any of my mkfifo files.
>
> What do you mean with "see"? Can you enter the file name?
>
>>> With other attempts Gephex just shows a green screen - I
>>> probably need to convert the video from 4:1:1 to 4:2:2 or 4:2:0 er
>>> something. This doesn't really matter at this point because mostly I
>>> get unrecognized header errors.
>
> Regarding the header errors, I will have to take a look at the source
> code (maybe I can do that tonight). But off the top of my head: try
> to open the fifo in gephex _before_ writing to it with ffmpeg (the  
> guess
> is that the header is only sent once at the beginning and gephex is
> somehow missing it when opening an already "streaming" fifo).
>
> So the steps would be:
>
>    a) mkfifo x
>    b) open the fifo x using the y4m module and start the gephex engine
>    c) start ffmpeg (configured to write to fifo x)
>
>
> Hope that helps!
>
>
> Regards,
>
>
> Georg
>
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