On Sun, 25 May 2008, roger wrote: > > You're right, it seems to export the live stream via USB?
Of course. > > But, noticed this within the Specs: > "Note: the playback of high definition H.264 requires a fast CPU and at > least 256MB of graphics memory" That's because decoding h.264 is expensive in terms of CPU and memory. Note that it says _playback_. The device and its driver are all about recording; the system is "on its own" for playback (i.e. device and driver are not involved). This is true for any PVR setup except when using a Hauppauge PVR-350 with the ivtv driver (that device has mpeg2 hardware _decode_ abilities but it runs out of gas once you get past SD quality). The thing about this device is that since it encodes to a more 'expensive' format, then anything which plays back the captured video is going to need a lot of horsepower. > > Is the only difference between the two newly released ATSC recorders, > one exports MPEG2 and the other exports h.264 (aka MPEG-4 AVC)? (Also > noting the additional connectors for in & out processing.) The HD-PVR also lacks a tuner. The HD-PVR has component video inputs. The HVR-1950 is basically a souped up PVR-USB2 - same basic analog side as before plus a digital tuner. Like the older PVR-USB2, the HVR-1950 can also do composite / s-video capture, but HD quality streaming is limited to digital reception via its tuner. (In other words it can tune and stream HD RF signals but it can only still hardware encode SD.) HD-capture is in the domain of the HD-PVR. The HVR-1950 is the intended replacement for the PVR-USB2. The pvrusb2 driver now handles the HVR-1950 - analog *and* digital sides. Documentation for this is still forthcoming but the driver works now. Unfortunately I probably won't get a chance to work on the documentation today due to a silly family commitment :-) The HD-PVR by itself isn't a digital receiver. But it's an ideal device when paired with an HD tuner that has HD outputs via component video. It solves the problem of linking up MythTV to a DRM-infected cable box. (At least I think it does, I have no personal experience with this.) This is why the MythTV crowd is drooling over it. It just needs a Linux driver. An absolute killer device would be an HD-PVR with a tuner and FM reception. That would make it a complete HD-level evolution over what the PVR-USB2 was. But I have no idea if anything like that is in the works. > > > Guess I'll have to wait awhile to see the results of recording on lower > processor platforms. I'm sure you can use a very slow processor to record with the HD-PVR. It's playback that is the issue. And the root cause has to do with h.264 decoding, so it isn't going to get any better with driver improvements. More likely this will be less of an issue in the future and processor power improves. It's the same sort of thing that happened and HD tuners started to appear and the computers of the day could barely handle the decoding requirements. Nowadays just about any decent computer can do it. -Mike -- Mike Isely isely @ pobox (dot) com PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8 _______________________________________________ pvrusb2 mailing list [email protected] http://www.isely.net/cgi-bin/mailman/listinfo/pvrusb2
