[AG-TECH] sending vic pre-encoded video

Andrew Ford acf0659 at rit.edu
Wed Feb 11 15:07:44 CST 2009


Hi Chris,

If not taking video from a camera, what about a hardware 264 encoding card?
I would imagine the latency could be lower - do you think vic would be able
to take video from one?

Also, what specifically would be required as far as code integration? Here
at RIT our primary goal is getting uncompressed video working, and I'm
willing to do some significant coding work if necessary to get there. Could
you clarify some of the differences in the codebase between UCL and UQ?

--Andrew

2009/2/8 Christoph Willing <c.willing at uq.edu.au>

>
> On 07/02/2009, at 1:44 AM, Gurcharan S. Khanna wrote:
>
>  hi,
>>
>> i just wanted to clarify how AG vic works. it seems to want a
>> raw digital stream to encode in h.261, h.264, or whatever. it
>> does not accept a stream that's already encoded, like mpeg2,
>> mpeg4, mjpeg, etc. is that correct?
>>
>> i understand that the AGDV for windows and the DVservices for
>> linux do accept HDV (mpeg2) as part of those modules. are they
>> the only add-ons that do so?
>>
>> anyone working on adding mp4 support for the HDV modules which
>> currently support mp2?
>>
>
>
> Gurcharan,
>
> The problem with doing anything with the firewire port mpeg2 streams (like
> converting to mpeg4 etc.) is the inherent 1/2 to 1 second latency incurred
> inside the camera when encoding the mpeg2 stream in the first place. Any
> further processing we choose to perform (like mpeg2 -> mpeg4 conversion) may
> cause even further latency.
>
> What we really need to be able to do is grab the camera video _before_ its
> encoded into mpeg2 i.e. before any latency is built into the signal. This
> signal is available on some cameras as a 1920x1080 YUV type signal via an
> HDMI connector - hence the previous talk about the Blackmagic Intensity HDMI
> capture card which can capture this signal.
>
> Work on it this patchy - lack of a Linux driver is the main stumbling block
> here. Some initial work by Doug with the Blackmagic card on OSX indicates
> the single threaded nature of standard vic may be a bottleneck preventing
> full frame rate at 1920x1080. Perhaps a multithreaded version of vic (like
> the UQVislab HDV enabled vic) would work at full frame rate but integrating
> that into the standard vic code would require a lot of effort. That
> integration was always planned but we ran out of time/budget. Its not clear
> who could afford that effort at the moment.
>
>
> chris
>
>
> Christoph Willing                       +61 7 3365 8316
> QCIF Access Grid Manager
> University of Queensland
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/ag-tech/attachments/20090211/ee7a8afa/attachment.htm>


More information about the ag-tech mailing list