[Asterisk-video] [rizzo at icir.org: call for testers for team/rizzo/video_v2]

[Luigi Rizzo]

On Thu, Sep 27, 2007 at 10:20:37AM +0200, Matteo Brancaleoni wrote:
> (already posted on asterisk-dev, also there for reference)

sorry then, missed the message on -dev

> Hi,
> 
> Il Tuesday 18 September 2007 18:16:41 Luigi Rizzo ha scritto:
> > In a nutshell, this branch lets you send and receive (and display)
> > H263+ video with chan_oss (tested) and chan_alsa (not well tested),
> > using either a webcab or an X11 window as source.
> >
> > The requirements are SDL, a recent ffmpeg (July 2007), and optionally
> > Video4Linux v.1 to use the webcam.
> 
> Any plan to optionally use video4linux2 ?
> do you think that can be difficult to add ?

currently i don't have plans to do it but it is not terribly difficult,
you only need to touch two functions - video_open() in the part that deals
with webcam (the ioctl() to set the format etc. are different in V4L2),
and video_read() in the part that reads from the camera (as far as i
know V4L2 does not support the read() interface so you have to mmap
a buffer).

> about resolution...
> H263+ can handle formats up to 1408x1152 
> (should be 128x96, 176x144, 352x288, 704x576, and 1408x1152) and
> ffmpeg supports all of them, is possible to raise the limit of 352x288 ?

there are no restrictions on the resolution other than
memory and CPU power.
A side problem might be that at the moment the transmission is still
bursty - especially in I frames, we pass the entire list of ast_frames
to the channel driver at once, and at high resolution the list might
be very long. Ideally we should implement some form of shaping to
release the ast_frames at a fixed maximum rate.
This is something that we plan to do.

cheers
luigi
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