Douglas Kosovic douglask at itee.uq.edu.au
Sun Dec 14 22:32:06 CST 2008


>>>> 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;

                        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
>>>> My ideal would be to encode the presenter's laptop output and deliver 
>>>> that as just another video stream along side the presenter's video and 
>>>> the audience video and have autoplace lay them out nicely in a framed 
>>>> window, a la Adobe Connect or similar products, so the presenter, the 
>>>> slides, and additional commentary could be nicely recorded for later 
>>>> videoon demand playback.
>>>> Just my opinion (and need),
>>>> -gurcharan
>>>> Piers O'Hanlon wrote:
>>>>> Hi Derek,
>>>>> In principle VIC should be able encode and decode HD video - using one 
>>>>> of the codecs that support such resolutions e.g. H.264 or h261as.
>>>>> One needs to modify some of the configuration code in VIC to allow 
>>>>> selection of larger resolutions (ie HD one needs something from 720p 
>>>>> (1024x720) upwards). And of course an HD source is necessary. We don't 
>>>>> currently have access to any HD kit so haven't had a chance to work on 
>>>>> it but anyone is welcome to try!
>>>>> Cheers,
>>>>> Piers
>>>>> 2008/10/22 Vine, Derek A <Derek.Vine at usd.edu>:
>>>>>> Hello all,
>>>>>> I am doing some research to spec. up a new AG room, and the group 
>>>>>> with the money is interested in HD video.  I see that The University 
>>>>>> of Queensland has an HDV/DV VIC for Linux based systems already, but 
>>>>>> we would like to stay with Windows.
>>>>>> I was just wondering what kind of time frame I can give them as to 
>>>>>> when HD will be supported in AG on Windows.  In particular, an HD VIC 
>>>>>> that will  take its video from a capture card with an HD-SDI input, 
>>>>>> like the one attached in the PDF.

I didn't see the PDF, what colorspace does it support? If it's YUV 4:2:0, it 
would probably work with this vic:


(which contained a fix for 480i DV white line artifacts)

Anyway, I started working on adding support for more colorspaces to the 
Windows code a few weeks ago and I might get back to working on the code 

>>>>>> Thank you in advance for your help.
>>>>>> Derek Vine
>>>>>> Communication Network Specialist
>>>>>> The University of South Dakota
>>>>>> 414 East Clark Street
>>>>>> Vermillion, SD 57069
>>>>>> (605) 677-8215
>>>>>> dvine at usd.edu 

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