[gephex-devel] Fwd: yuv4mpeg from ffmpeg?

[Georg Seidel]

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