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Nebula - silent recording problem


tvboy

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I was dismayed to find that the Nebula's .MPG recordings will not play properly in the players I use, WinDVD5 and PowerDVD4, so I can’t use it to record. Has this always been the case, and will the 3.12 beta version get around this problem if I record in the new DVD format? (I was using 3.114.)

The other feature I wanted to use was silent recording, but I had around 20% CPU usage on a 2.4GHz Celeron. Worse, it randomly and without notification stopped silently recording a short time after using players like WinDVD5 and PowerDVD4, or my VisionPlus card. I have no such silent recording problems with my NOVA-t (perfect recordings even while playing 3D games) and DVICO. Is this normal?

I had all four cards in the one PC running simultaneously using only native software, XP SP1, DirectX 9.0b, and tried GeForce4 MX440 and Radeon 9500 cards with new and old drivers. I’ve since rebuilt my PC and haven’t even bothered putting the Nebula in, as I wasn’t using it, so any help would be appreciated.

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I was dismayed to find that the Nebula's .MPG recordings will not play properly in the players I use, WinDVD5 and PowerDVD4, so I can’t use it to record. Has this always been the case, and will the 3.12 beta version get around this problem if I record in the new DVD format? (I was using 3.114.)

Yes 312b3 can record straight to DVD format so any s/w DVD player can play the MPG's fine.

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Yes 312b3 can record straight to DVD format so any s/w DVD player can play the MPG's fine.

Sounds great, look forward to trying it out in a couple of days. It’s interesting that DVD software player compatible MPG recording capability only became available for both the Nebula and DVICO in the last couple of months, despite the fact they’ve been on the market for some time. What really amazes me is that I took it for granted that all DVB-T cards could record .MPGs – after all, it’s the ONLY format supported by the native software for the VisionPlus, NOVA-t and AVerTV, and they’ve been out for over a year now. And I’ve only recently bought a Nebula and DVICO without realising that they’ve only just become suitable for my needs!

Having said that, I am having frequent problems with the DVICO's MPGs that I’ve never had with the NOVA-t or VisionPlus, and I don’t mean corrupted video because of Normal Base Priority.

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AFAIK ALL the DVB-T cards record the PVA MPEG2 as it is received off air straight to disk. The Nebula is the only one that now allows live transcoding to DVD MPEG2.

There must be subtle differences in muxing though as the PVA streams recorded by the VisionPlus (and apparently Aver, Nova-T) have always been able to be replayed by the various hardware MediaPlayers without transcoding. But not the Nebula and Dvico recordings.

PowerDVD5 + Latest Patch (and presumably WinDVD6 although I haven't tried it) now play PVA MPEG2 streams directly without problems. As does Moonlight (which always has anyway).

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AFAIK ALL the DVB-T cards record the PVA MPEG2 as it is received off air straight to disk. The Nebula is the only one that now allows live transcoding to DVD MPEG2.

There must be subtle differences in muxing though as the PVA streams recorded by the VisionPlus (and apparently Aver, Nova-T) have always been able to be replayed by the various hardware MediaPlayers without transcoding. But not the Nebula and Dvico recordings.

PowerDVD5 + Latest Patch (and presumably WinDVD6 although I haven't tried it) now play PVA MPEG2 streams directly without problems. As does Moonlight (which always has anyway).

I should put my statement in perspective, when I say I’m having frequent problems with the DVICO's MPGs, I mean that out of 12 to 16 hours of SD recordings a day, maybe once or twice a day I will get a glitch which causes WinDVD6 (and I think even FusionHDTV) to fail to play the file properly from a certain point in the file, and throughout all subsequent split files Filename000.mpg, Filename001.mpg, etc, until a new file is created by either a new schedule entry or manually pressing Stop, then Record. I suspect it is some kind of streaming bug, as there is no need to even change channels to get recording to work correctly again. Of course, all of this becomes apparent only after a recording has been completed, because the FusionHDTV has the very annoying property of locking all files in a sequence. Ie, it is not possible to play or copy Filename.mpg or Filename000.mpg even when the FusionHDTV is currently recording to Filename001.mpg (unlike the NOVA-t, I might add, or the VisionPlus if you are prepared to manually rename the .tmp to .mpg).

One of the strong points of the FusionHDTV scheduler, however, is that you can use multiple entries to record the same channel back to back into separate files with only a split second loss between them. So that’s what I’ve being doing to cut my losses for programs that I care about!

Speaking of scheduling, the NOVA-t relies on Windows scheduling, which requires a one-minute non-recording period between programs. The VisionPlus's scheduler is pretty good, but requires a 20 second non-recording period. The Nebula's looked pretty inflexible, with start and end times having to be in multiples of five minutes.

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Tvboy

Setting aside reception quality issues from (say) local electrical interference, impulse noise and the like as lets face it DVB is not a lossless transmission system my experience with DigiTv recordings has been good.

I have the impression that the direct to DVD option in DigiTv is still being tuned but my experience with a sequence of long recordings over many days of 6 hours each, then processed by DigiTv's DVDTool yields recordings that play back fine in DigiTv itself (of course) and PowerDVD5.

I observe on average 1 audio packet error (reported by the tool) per hour of recording which if you do the maths represents a very low error rate.

EDIT: As each packet is I gather 24ms of audio, in a temporal sense I think that equates to one error in 1.5 million. Given the The DVDConverter tool corrects the associated GOP etc the resulting recording will be playable

Your approach to recording using the Fusion seems to me to avoid the real problem perhaps of having a reliable recording application and/or good conversion tools

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The Nebula's looked pretty inflexible, with start and end times having to be in multiples of five minutes.

Try going into Windowed mode and selecting "7 Day Guide" from the EPG menu. You can use that dialog to set timers with as close together as you want, as well as set recurring timers.

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  • 4 weeks later...
The other feature I wanted to use was silent recording, but I had around 20% CPU usage on a 2.4GHz Celeron.  Worse, it randomly and without notification stopped silently recording a short time after using players like WinDVD5 and PowerDVD4, or my VisionPlus card.  I have no such silent recording problems with my NOVA-t (perfect recordings even while playing 3D games) and DVICO.  Is this normal? 

Since I wrote this, I’ve built a different PC, now with a P4, and tried DigiTV 3.12b3. Silent recording still stops when playing 3D games or HDTV files with WinDVD6. Can anyone confirm this or say they don’t have this problem? (Thanks for the tips so far on recording in DVD format and using the "proper" scheduler.)

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Since I wrote this, I’ve built a different PC, now with a P4, and tried DigiTV 3.12b3.  Silent recording still stops when playing 3D games or HDTV files with WinDVD6.  Can anyone confirm this or say they don’t have this problem?  (Thanks for the tips so far on recording in DVD format and using the "proper" scheduler.)

It is most likely that DigiTV is being starved of CPU cycles when you are playing games - try increasing the application priority to High (File->Settings->General Tab->Application priority radio buttons) and see if this makes any difference.

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I don't play many games, but on my XP2500+ I find that as long as I put DigiTV in high priority mode and give it its own physical HD, I can do some pretty intense multitasking without it having an effect on the recording. One game I do play, a Japanese train simulator, is pretty CPU intensive and doesn't effect the recording. Can also demux a file with ProjectX from the recording disk while a recording is active and it won't drop frames.

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