On Wed, Jul 22, 2009 at 11:01 AM, Jelle de Jong<jelledejong@xxxxxxxxxxxxx> wrote: > Funky timing of those mails :D. > > I saw only after sending my mail that Steve was talking about analog and > that this is indeed different. Dual analog tuner support should be > possible right? Maybe with some other analog usb chipsets? I don't know > what the usb blocksize is or if they are isochronous transfers or bulk > or control. > > I assume the video must be uncompressed transferred over usb because the > decoding chip is on the usb device is not capable of doing compression > encoding after the analog video decoding? Are there usb devices that do > such tricks? There were older devices that did compression, mainly designed to fit the stream inside of 12Mbps USB. However, they required onboard RAM to buffer the frame which added considerable cost (in addition to the overhead of doing the compression), and as a result pretty much all of the USB 2.0 designs I have seen do not do any on-chip compression. The example which comes to mind is the Hauppauge Win-TV USB which uses the usbvision chipset. Devin -- Devin J. Heitmueller - Kernel Labs http://www.kernellabs.com -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
