Re: [mythtv-users] Image quality of HD3000 for OTA sources
Scott wrote: On Jun 9, 2005, at 7:20 PM, James Stembridge wrote: If you play interlaced content on a progressive display then it will indeed look bad. Use deinterlacing. Sure. I know this :) But the question is more of is the tst.ts file provided on the pchdtv.com download page a 1080i or 720p native HDTV stream Yes. 1080i60 direct from the broadcast source. or was it a 480i upconverted to either 720p or 1080i? I'm not sure how I could tell w/o knowing the details of the source it was recorded from. That's the beauty of the pcHDTV 3000 (and *all* ATSC and *all* DVB tuner cards)--they don't record images. Digital TV tuner cards simply demodulate a signal and dump the data from within that signal to the computer. ATSC specifies that the data within the signal will be an MPEG-2 encoded stream. The specification defines 18 formats, of which 2 high-definition formats are commonly used--720p60 and 1080i60. The 720p60 format has 1280x720 pixels per field, 60 fields per second, and 60 frames per second (i.e. each field is a complete frame). The 1080i60 format has 1920x540 pixels per field, 60 fields per second, and 30 frames per second (i.e. 2 fields are interlaced together to create a single 1920x1080 pixel frame). For more information see http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html . Therefore, the pcHDTV is not encoding video and the video it provides to the computer is the *exact same* video that was transmitted by the broadcaster. It's also a very good thing that the pcHDTV doesn't have to encode the video because hardware capable of real-time encoding of a 1080i or even a 720p format is currently /way/ too expensive (>$3000). Both 1080i60 and 720p60 have about six times the number of pixels as 720x480 SDTV (480i30), so real-time high-def encoding would basically take 6 PVR-150's each encoding a portion of the video plus the circuitry required to coordinate the encoders. Put another way, simply decoding the stream takes pretty good quality hardware and decoding is significantly easier than encoding. While the pcHDTV does have an NTSC tuner, it's a frame grabber--so even for NTSC, the pcHDTV doesn't encode the signal (the encoding is left to your CPU). The card doesn't do any upconversion of SDTV. Either way, the tst.ts clip is of very poor quality it seems and I'm concerned that it represents the same quality levels I can expect from the HD3000 adapter. I hope that's not the case. The clip is not meant to show off the quality of the image (because you get exactly what's transmitted), but to allow you to determine if your hardware has what it takes to decode a 1080i signal. Mike ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Image quality of HD3000 for OTA sources
On Jun 9, 2005, at 7:20 PM, James Stembridge wrote: If you play interlaced content on a progressive display then it will indeed look bad. Use deinterlacing. Sure. I know this :) But the question is more of is the tst.ts file provided on the pchdtv.com download page a 1080i or 720p native HDTV stream or was it a 480i upconverted to either 720p or 1080i? I'm not sure how I could tell w/o knowing the details of the source it was recorded from. Either way, the tst.ts clip is of very poor quality it seems and I'm concerned that it represents the same quality levels I can expect from the HD3000 adapter. I hope that's not the case. -- Scott <[EMAIL PROTECTED]> AIM: BlueCame1 ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Image quality of HD3000 for OTA sources
On Jun 9, 2005, at 6:56 PM, Mudit Wahal wrote: I've a sempron 3000+, 512mb ddr, geforce2 mx440 card and HD3000 card. I can playback fine without stuttering using the nvidia 7174 driver with about 80-90% cpu busy. I can play both 720p and 1080i. Though 1080i has more cpu usage. You didnt say what video card do you have on the intel pc. That really depends on the processing of the HD. Nvidia drivers do offload mpeg2 to VGA conversion on the hardware so it does help. Thanks for the detail. I never saw a problem with stuttering during playback of the sample tst.ts file provided by pchdtv.org. I also tried a few other HDTV demo clips I have and didn't see a stutter problem with them either. The problem is mainly the over all quality of the image in the tst.ts test file offered on the pchdtv.com download page. My own demo clips from other sources look just fine and my concern is that the test clip provided by pchdtv.com shows how poor the video recorded from the HD3000 is. I hope that's not the case! :) The card in the P4 (the current MythTV box) is a lowly ATI 7500 PCI running at 1280x720 and hooked via DVI to my Panasonic HD L500U projector. When I get the HD3000 card (I haven't ordered yet, I'm still concerned about image quality of the sample clip as described above) I'll also be updating the ATI video card to something better. -- Scott <[EMAIL PROTECTED]> AIM: BlueCame1 ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Image quality of HD3000 for OTA sources
On 6/9/05, Scott <[EMAIL PROTECTED]> wrote: > builds. In all cases the quality was shockingly bad. The most > noticeable problems had to do with what appeared to be interlacing > (shouldn't even be there?!) and edge artifacts like around the > engineers head in the opening clip. If you play interlaced content on a progressive display then it will indeed look bad. Use deinterlacing. James. ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Image quality of HD3000 for OTA sources
I've a sempron 3000+, 512mb ddr, geforce2 mx440 card and HD3000 card. I can playback fine without stuttering using the nvidia 7174 driver with about 80-90% cpu busy. I can play both 720p and 1080i. Though 1080i has more cpu usage. You didnt say what video card do you have on the intel pc. That really depends on the processing of the HD. Nvidia drivers do offload mpeg2 to VGA conversion on the hardware so it does help. Thanks Mudit On 6/9/05, Scott <[EMAIL PROTECTED]> wrote: > Greets - > > I have a working MythTV box that I'm going to be updating to use with > OTA - ATSC HDTV channels. I'm looking at using the HD3000 adapter > like everyone else. On the pchdtv.com site there is a sample HDTV > video clip (tst.tar aka tst.ts) at the bottom of the downloads page: > http://pchdtv.com/downloads_right_down.html > > I downloaded and played this clip on a few of my systems (Dual 2Ghz > G5, AMD64 3Ghz, and P4 2.8Ghz) using current mplayer and xine > builds. In all cases the quality was shockingly bad. The most > noticeable problems had to do with what appeared to be interlacing > (shouldn't even be there?!) and edge artifacts like around the > engineers head in the opening clip. The background zooming by the > train in the second scene also showed noticeable problems with edges. > > I'm curious if this is the quality that is expected from the HD3000 > or if this is just a recording of a poor quality 480i stream that > might have been uprezed to some HDTV format. Is anyone willing to > post 5 - 10 second clips of HDTV streams they've captured with the > HD3000? > > -- > Scott <[EMAIL PROTECTED]> > AIM: BlueCame1 > > > > ___ > mythtv-users mailing list > mythtv-users@mythtv.org > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users > > > ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
[mythtv-users] Image quality of HD3000 for OTA sources
Greets - I have a working MythTV box that I'm going to be updating to use with OTA - ATSC HDTV channels. I'm looking at using the HD3000 adapter like everyone else. On the pchdtv.com site there is a sample HDTV video clip (tst.tar aka tst.ts) at the bottom of the downloads page: http://pchdtv.com/downloads_right_down.html I downloaded and played this clip on a few of my systems (Dual 2Ghz G5, AMD64 3Ghz, and P4 2.8Ghz) using current mplayer and xine builds. In all cases the quality was shockingly bad. The most noticeable problems had to do with what appeared to be interlacing (shouldn't even be there?!) and edge artifacts like around the engineers head in the opening clip. The background zooming by the train in the second scene also showed noticeable problems with edges. I'm curious if this is the quality that is expected from the HD3000 or if this is just a recording of a poor quality 480i stream that might have been uprezed to some HDTV format. Is anyone willing to post 5 - 10 second clips of HDTV streams they've captured with the HD3000? -- Scott <[EMAIL PROTECTED]> AIM: BlueCame1 ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
