Explorer 8000 DVR degrades analog channel PQ - AVS Forum
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Old 10-03-2004, 04:06 PM - Thread Starter
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Just got an Explorer 8000 two-tuner DVR from Charter cable. Mostly use it for recording basketball games, which of course have a lot of fast motion, from the analog cable channels (1 to 99). The DVR works ok, EXCEPT:

The PQ of the signal played off the hard drive (including so-called "live" play) is noticeably worse than the PQ of the same channel signal watched actually live. It is fuzzier and has far more motion artifacts. Stated differently, the channel will have better PQ if the cable is plugged directly into the TV, if the cable signal goes via my non-DVR cable box, or if the cable signal is routed through a standalone DVD recorder.

Worse, when you playback a game and use the 8-second replay button (an otherwise great feature), and especially when you use the slow motion feature (which only has one measly speed), the blurring and artifacting degrades the PQ to unwatchable 1949 rabbit ears levels.

Today, I did a direct compare with the same Oxygen channel WNBA game recorded simultaneously via a cable splitter onto my Panasonic E80 DVD recorder and onto the Explorer 8000. The E80 has four different recording quality levels, and I recorded the game at the highest level (XP) as I always do. The Explorer 8000 has no ability to record at different quality levels. The playback from the E80 was much clearer, sharper and with fewer motion artifacts than the playback from the 8000. Slow motion PQ was significantly superior on each of the E80's four slowmo speeds than on the 8000's one slowmo speed.

The two-tuner recording capability is great. But since the PQ of the analog cable channels is not that great to begin with, the 8000 really is an unacceptable recording device for me, PQ-wise, for basketball games. (Another deficiency is that the three fast forward and reverse speeds of 4X, 10X and 32X are too slow to zip through a recorded game.)

I have not tested the 8000's PQ against live or the E80 on the digital cable channels because I don't gets sports on any of them.

I had naively assumed that, as an integrated receiver-DVR, the Explorer 8000 would record at the highest possible quality level, and that the playback of the channel would be an indistinguishable clone of the channel signal input--as is the claim for programs recorded on the integrated Directv-Tivo box. But, clearly, the process of recording and playing back a signal from the 8000's hard drive degrades PQ.

Can anyone else confirm and/or explain this phenomenon?
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Old 10-03-2004, 07:55 PM
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I had naively assumed that, as an integrated receiver-DVR, the Explorer 8000 would record at the highest possible quality level, and that the playback of the channel would be an indistinguishable clone of the channel signal input--as is the claim for programs recorded on the integrated Directv-Tivo box.
You assumed incorrectly.

Channels 1-99 on cable are analog. Before an analog program can be recorded to a hard disk, it must be converted to digital. This is not a lossless process. It relies on a MPEG encoder just like your DVD recorder. For the analog channels, the SA8000 records exactly like your DVD recorder, except it only has one preset quality setting that you cannot change.

The SA8000HD does record the digital bitstream for digital cable channels, so recordings of channels 100+ are identical to the original broadcast. On DirecTV, all channels are sent digitally, and that is the reason that all DirecTivo recordings are 100% identical quality to the original.

As an aside, note you may be further degrading the analog recordings on the SA8000 by splitting the feed prior to the box. For the best possible picture, you'll need to connect the cable feed directly to the SA8000 without any splits.

I guess you frequently record multiple basketball or ABC/CBS/NBC/FOX programs simultaneously? If not, there is really no reason to have the SA8000 over a single tuner Tivo. Unlike the SA8000, Tivos can intelligently re-schedule programs so if two programs conflict, so the DVR will automatically record the cable program in conflict at its next available re-airing--even if that is 25 days into the future at 3am--without any user intervention.

The best quality picture setting on the Tivo produces a noticeably better picture than the highest level on the E80. And unlike the E80 and SA8000, Tivos can be expanded to virtually unlimited capacities -- I have dual 200Gb drives in mine, and others have dual 400Gb drives. This gives me about 450 hours at basic quality and 122 hours at best quality.
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Old 10-04-2004, 01:14 PM - Thread Starter
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bfdtv, thanks for the response.

(As preliminary asides, I have the SA-8000 not the 8000HD, but I'm assuming that doesn't change any of your points. I also understand that splitting a signal will degrade it.)

Your explanation that an analog cable channel must be digitally encoded (with losses) to be stored on a DVR hard drive explains it all to me. And since (again assuming) that the "live" signal from the DVR is actually a hard drive buffered signal, that would explain why the "live" channel through the DVR has worse PQ than when the signal does not go through the DVR. The E80 must do a higher quality job of digital encoding than the 8000 does.

Question: You talk about different quality levels on your Tivo. Are you talking about a standalone Tivo? My understanding is that the integrated Directv-Tivo box has no quality settings. I'm not interested in another standalone DVR, Tivo or otherwise.

My goal is indeed to record as many conflicting basketall games as possible (along with some other non-basketball timeshifting), many of which will be on the college sports tier digital channels, and then to get about 100 of them per year into my DVD recorder to archive onto disks. Preferably, I would like to get as many as possible onto my E80's hard drive in realtime as they are broadcast.

The SA-8000 and E80 working off a splitter can now record three cable channels simultaneously. But the E80 can't record an undecoded digital cable or satellite channel. And I now know that the 8000 has inadequate PQ on the cable analog channels, which will be further degraded for those games I would want to archive from the 8000 to the E80.

So, as a forever cable customer, I am now seriously thinking about switching to satellite to take advantage of the two-tuner capabilities of the Directv-Tivo or the Dishnet DVR 522.

Question: Should both of those integrated DVR's record SD satellite channels onto their hard drives losslessly (or at least with identical small losses)?

While going to satellite might improve the PQ of my DVR recorded games, I'm not sure I can use my E80 to record satellite channels in realtime at all, much less using it, as I can now on cable, to grab three programs at the same time in conjunction with the two-tuner cable DVR.
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Old 10-04-2004, 03:37 PM
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And since (again assuming) that the "live" signal from the DVR is actually a hard drive buffered signal, that would explain why the "live" channel through the DVR has worse PQ than when the signal does not go through the DVR.
That's correct. Whenever you pause, instant replay, or rewind on live analog programming (channels 0-99) with SA8000, it enters buffered mode.

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Question: You talk about different quality levels on your Tivo. Are you talking about a standalone Tivo? My understanding is that the integrated Directv-Tivo box has no quality settings. I'm not interested in another standalone DVR, Tivo or otherwise.
Yes, I was referring to standalone. Your DVD recorder is a crippled version of a "standalone" DVR with a built-in DVD writer. You mentioned the SA8000, which works just like a standalone DVR for channels 0-99, except it has two tuners, and less recording usability and functionality, including no quality settings.

As you note, the DirecTivos (and Dish DVRs) have no quality settings because they always record the original digital signal from satellite. They don't even have a built-in MPEG-2 encoder, so they have no way to take an analog input (cable or OTA) and convert it to digital for recording.

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Question: Should both of those integrated DVR's record SD satellite channels onto their hard drives losslessly (or at least with identical small losses)?
Yes.

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While going to satellite might improve the PQ of my DVR recorded games, I'm not sure I can use my E80 to record satellite channels in realtime at all, much less using it, as I can now on cable, to grab three programs at the same time in conjunction with the two-tuner cable DVR.
The E80 has a built-in NTSC tuner, which obviously does not work for satellite. The VCR+ TV listings do not support satellite. Rather, you would record manually through the s-video or composite inputs.

Whenever you select a recording on a Tivo / DirecTivo, you have several options, including: a) play it, b) delete it, and c) save it to VCR. When you choose the save to VCR option, the box prompts you insert a tape (or DVD for recording), and it puts a graphical screen with the title and the description at the beginning of the recording.
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