USB to VGA/DVI adapters?

[Jarod Wilson]

On Wed, Jan 13, 2010 at 6:52 AM, Dan Ritter <dsr-mzpnVDyJpH4k7aNtvndDlA at public.gmane.org> wrote:
> On Tue, Jan 12, 2010 at 09:40:45PM -0500, Scott Ehrlich wrote:
>> I have an Intel Atom w/GMA 500 PC, so the video isn't that great.  I'm
>> using Ubuntu 8.04 out of box, which seems to produce the best video
>> for the GMA 500   Would a USB to VGA/DVI adapter help improve
>> streaming video (from hulu, youtube, etc)?
>
> No. For one thing, Flash is not currently hardware-accelerated
> in Linux. (This is expected to change sometime this year.)

And hopefully, sooner than later. An excerpt from the crystalhd linux
userspace library source:

        uint32_t        cpbEmptySize;   /* supported only for H.264,
specifically changed for
                                         * Adobe. Report size of CPB
buffer available.
                                         * Reported by DIL */
        uint64_t        NextTimeStamp;  /* TimeStamp of the next
picture that will be returned
                                         * by a call to ProcOutput.
Added for Adobe. Reported
                                         * back from the driver */

I can neither confirm nor deny that Adobe might be working on flash
decoding offload to the Broadcom CrystalHD decoder, but based on the
above snippet, you do the math... :)

>> One adapter I'm looking at is the Sabrent/Arkview USB-dh88.   One
>> thing I've seen from video processing of my existing system is high
>> cpu utilization.   Will I experience that, or worse, with one of these
>> adapters?  Or, will performance be offloaded to the devices and video
>> and processing power improve?
>
> Nope. The driver for the SIS USB-VGA chip is completely
> unaccelerated.

See also: http://www.displaylink.com/shop/index.php?product=5

There's a linux displaylink driver, but its probably equally unaccelerated.

> Do you have any expansion slots?

Doubtful that matters. The GMA500 is actually a very capable graphics
chip, the main issue is the complete lack of any hardware flash
acceleration under linux right now. Even a dual-core atom with nVidia
graphics that can do 1080p h.264 playback using vdpau chokes miserably
on flash content (hulu desktop is mostly unusable on it, its like
watching a slideshow). If Adobe were to add decoding offload via
va-api, the GMA500 would actually work quite well (as would nVidia
cards, vdpau can function as a backend to va-api).

-- 
Jarod Wilson
jarod-ajLrJawYSntWk0Htik3J/w at public.gmane.org