[AG-TECH] HD on AG

Douglas Kosovic douglask at itee.uq.edu.au
Mon Dec 15 23:08:45 CST 2008


Hi Claus,


> Do you know which HD H264 camcorders are supported by the UVC video
> driver?
> 
> I would be very interested to play around with one...

Looks like it was wishful thinking on my part, sorry.

I just had a look at the linux UVC driver source code, it has no H.264
support, but does have DV.

The Sanyo HD H.264 camcorders although they support H.264 apparently use
a uncompressed lower resolution for UVC.

The Flip MinoHD Camcorder is a 720p H.264 camcorder that is UVC
compliant, but not sure if it supports H.264 USB streaming.

Looks like the non-tape based and/or non-firewire camcorders generally
seem useless for live streaming.


Cheers,
Doug

> Douglas Kosovic wrote:
> > Hi,
> >
> >>>>> I, too, am extremely interested in vic supporting HD formats,
> >>>>> (including uncompressed!) One of the issues is the encoding
> latency
> >>>>> problem. Not sure there's a nice low latency encoding solution
> out
> >>>>> there yet. Alternatively, we might look at cheap hardware
> encoders
> >>>>> as the answer or HDMI cards to take the input from the camera.
> >>>>> Can vic be made to take the output of, say, the BlackMagic
Design
> >>>>> HDMI card on a Mac?
> >
> > MacOS X UCL vic works out of the box with the BlackMagic Design HDMI
> > capture card, but gets scalled down to 640x480 for the large capture
> > option.
> >
> > A quick hack to add 1980x1080 support is to modify the following
> width &
> > height lines in video/grabber-macosx.cpp :
> >    switch (decimate_) {
> >                case 1: // full-sized
> >                        width_ = SP601_NTSC_WIDTH;
> >                        height_ = SP601_NTSC_HEIGHT;
> >
> > to:
> >                        width_ = 1920;
> >                        height_ = 1080;
> >
> > Windows UCL vic on the other hand crashes with the BlackMagic Design
> > HDMI capture card as it currently doesn't support the BlackMagic YUV
> > colorspace.
> >
> > I wouldn't mind adding support for USB HD camcorders that support
UVC
> > (USB Video Class) H.264 streaming over USB, but I currently don't
> have
> > access to one. Note: Not all USB based camcorders support UVC (e.g.
> Sony
> > Hanycams).
> >
> >>>>> I am currently using AGDV under windows but would like to move
to
> >>>>> linux and use the HDV/DV linux vic for the DV part; i don't
think
> >>>>> it's encoding the HDV, just accepting it as input from the
camera
> >>>>> already encoded??? [chris?]
> >>>>>
> >>>> It is possible to just packetise the compressed data from a
> camera,
> >>>> though as Chris points out it tends to have quite high latency.
> That
> >>>> is why the ultragrid and derivatives used uncompressed HD as
their
> >>>> sources. VIC doesn't currently support mpeg2 nor does support
> >>>> packetisation of an existing compressed mpeg2 stream.
> >>>>
> >>>
> >>> wait, i thought chris' vic supported HDV, which i assume is mp4???
> >>>
> >> AFAIK most cameras support HDV - which is closely related to
MPEG-2:
> >> http://en.wikipedia.org/wiki/HDV#HDV_720p
> >
> > Mostly just the DV firewire based camcorders, the harddisk USB based
> > ones are now mostly AVCHD (MPEG-4 AVC/H.264).
> >
> >>> also, how hard/easy would it be for vic to support packetizing
> >>> uncompressed HD?
> >>>
> >> Not that hard - one needs to read the [RTP and codec] specs and
code
> >> it up - or borrow someone else's....
> >>
> >> Piers.
> >>
> >>> :-)
> >>>
> >>> -gurcharan
> >>>>
> >>>> Piers




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