The Official AVS TiVo "Series4" Premiere topic - Page 62

Hi aaronwt

I think my issue may the compression. The Tivo may compress 1080i to anamorphic HD (1440 x 1080) when stored to disk, but, when played back you would see 1920 x 1080i but adegradation in PQ. This agrees with what the Tivo tech suppot said. in the Tivo 1080i is actually 1440 x 1080, 1080p is actually 1920 x 1080p. The compressing is Tivo doing the compressing on 1080i HDTV. Any 1080p programming is passed thru to the TV. Again, just a guess. This compression may acount for the fact that the Tivo can store 75 hours of HDTV in 500 GB. The ratio 1440/1920 is similar to the storage capacity between the Song DVR and the Tivo. I had read that the Sony output was 1920 x 1080i and could only store 60 hours of HDTV in 500 GB.

Thanks
James

Hi aaronwt

Your response is similar to many other forum members. The common thread it that those forum members that have great 1080i PQ and a 1080p option are not using the Tivo Premiere 4, with it's 4 receivers. Is this true?

Thanks
James
Edited by jebiggers - 11/25/12 at 9:53am

:-)

Thanks
James

Hi Joe

If we keep the Tivos (it may be hard to pry the Tivo out of my wife's hands) then I will take your advice.

Thanks
James
Edited by jebiggers - 11/25/12 at 10:51am

Thanks to every one for some GREAT comments. I need to collect my thoughts and have another round of Q&A with Tivo support. Again, my concern is not so much 1080i vs 1080p but the possibility of lossy compression with 1080i HDTV on the 4 receiver, Premiere 4 Tivo. Certainly, some further compression has to take place within the Tivo to store 75 hours of 1920 x 1080i HDTV in 500GB..........or am I wrong.

Sincerely
James
Edited by jebiggers - 11/25/12 at 10:52am

I used TiVo for over a decade and over the years compared its image (often A/B) to various other receivers. The latest a HTPC I'm now using for WMC. Others include Dish, DirecTV and Comcast receivers and when viewing 1080i sources the image was virtually the same. The only possible difference I would notice is dynamic contrast might be a little higher on some of the other receivers. Now I will say TiVo doesn't upscale very well... SD sources (such as streaming services at low bit rates) look much worse than other streamers upscaled.

I agree, for faster channel changes I use to have my output set at 1080i fixed but noticed 480i SD channels looked quite poor(obvious interlace lines in scenes with motion) 720p looked OK upscaled to 1080i but now I just use native and put up with the slower channel scan.

Hi Charles

I PQ issue is with the loss of fine detail, for example, watching good HDTV 1080i thru the TV tuner, no Tivo in the loop, I see all the wringles/blemishes in closeups of the face. Watching the same 1080i HDTV program thru the Tivo, that kind of fine detail is not there. It's like what you would expect to see if lossy compression was used.

Thanks
James

Hi jjeff

I only have the 1080i output format selected/checked. I'll go in a check all the formats, 480i, 480p, 720p and 1080i, and see if that makes a difference.

Thanks
James

Recording capacity on the standard Premiere is 46 HD hours, while the XL offers 156 HD hours. Both models officially support a 1TB external drive to add another 144 HD hours. DVRUpgrade.com and Weaknees.com also offer pre-upgraded TiVo Premiere DVRs with 317 HD hours. There are no quality settings to vary record capacity on digital channels; all digital content is saved to the hard drive as is, bit-for-bit identical to the original broadcast. Quality on live and recorded HDTV is identical.

The paragraph above is taken from Post #1 of this thread. It's the 5th paragraph. I don't know the source of the original information. Maybe forum member "bfdtv" will chime in at some point....

http://www.avsforum.com/t/1232191/the-official-avs-tivo-series4-premiere-topic#post_18246613

Two possible causes (I can think of off the top of my head)...

• The TV's inputs aren't calibrated the same (such as the sharpness setting).
• The TiVo is defective.

Swap TiVos and if you find the same result... go with something else... it's easy. In most cases differences are contrast related (one looks more 3Dish, pops, etc). The detail is actually the same one just appears more so since it's enhanced.

Hi WS65711

I would think that some compression would have to be made to store as much HDTV as Tivo is storing. In my case 75 hours of HDTV in 500GB. How do you do that without some compression of the digital streams?

When you select the Live TV button on the Tivo, are you actually watching straight from the Tivo receiver or are you actually picking off what was recorded on the hard drive? I may be wrong, but on the Sony DVR, we never watched straight from the tuner, but watched from the hard drive with a little time delay.

Thanks
James

Thanks Charles, I will do that.
James

James, we all have to live with the fact that our devices (TiVo & DHG) are very classy devices and share one thing in common (at least): they both show remaining space not consumed space and show a percentage only. Some other recorders are just the opposite. I have one of the 45-46 hour units. The desktop does show file size, so I will record two shows tonight, compare the size against remaining space on the box and see if any conclusions can be made. One is ABC and one is CBS. I have moved one hour of 1080i to the PC and it used about 8Gb, exactly what I expected based on other units but I wasn't paying close attention at the time.

If we trusted marketing data there would be a memory-pro slot on the back of my DHG. And isn't MPEG-2 already compressed and lossy? After my cable feed adds a 1080i and 720p onto one main channel I'm lucky my picture doesn't look like something from the 50's.

BTW, I feel anytime you can "pause live TV" you are watching a delayed picture.
Edited by JoeKustra - 11/25/12 at 1:00pm

You can speculate all you want but it doesn't change the facts. Anyone have last week's Survivor recorded on a TiVo? My copy on WMC is 7,387,480,064 bytes (1:02:58) and the station has your typical 2 sub-channels and averages roughly 15.8 Mbps (for football). And you are never viewing live TV... it is always buffered.

If you are looking for answers regarding recordings and whatnot they have been covered at TiVo's forum for years.

Again, thanks to everyone for your help. I think my question has been answered.

James

This has nothing to do with 1440x1080i or 1920x1080P. You need to select "test formats" then it will go through each resolution and you select that you are able to see it. When you get to 1080P24 and you are able to see the test screen, the TiVo will then have 1080P24 checked as a resolution you can view. The TiVo should get the info from the TV over the HDMI connection but sometimes this does not happen. This is the case with one of my TVs even though it has no issue with 1080P60 or 1080P24. I just go through the procedure I just mentioned during initial setup, then I have no issue playing back 1080P24 content from the TiVo Premiere.

And again, the TiVo can only pass through 1080P24. Otherwise it can scale it to a 1080i or lower resolution. But it cannot scale anything to 1080P24. And if 1080P24 is not checked in the video format section, then the highest resolution that the TiVo will output is 1080i. If that resolution is checked. If only 720P is checked then it will not output at 1080i.

This has always been the case with the TiVo Premiere boxes since they launched in March 2010.
Edited by aaronwt - 11/25/12 at 5:26pm

Again, thanks for all your comments.

A few things have happened since my last post.

1. I went back to the output format test and reran the test 5 or 6 times in a row. After the last test, the Tivo gave me the 1080p option, 24fps pass-thru. So now this agrees with what most of you are saying. This may indicate a problem talking over the HDMI interface.

2. Charles R indicated that his 1 hour CBS HDTV file was 7,387,480,064 bytes (1:02:58) and JoeKustra indicated 1 hour of 1080i comsumed about 8GB. This certainly supports the Tivo spec of 75 hours of 1080i on a 500GB drive.

3. I had a short _very short_ discussion with my wife about returning the Tivos and either going back to the Sony DVRs or not using a DVR. She quickly reminded me: happy wife, happy life.......so we are keeping the Tivos.

The only issue remaining is the degraded PQ. As many of you have mentioned, a problem may exist in my HDMI cable or the TV setup for the HDMI input. If the Tivos do not perform a lossy compression and record the input bit for bit, as many of you have said, then that's about the only place the problem can be. If I can't fix it then I will have to live with it.

Thanks for all your help
James
Edited by jebiggers - 11/25/12 at 9:23pm

Hi, I thought I had made it clear above. When recording digital source, the TiVo is capturing the transport stream exactly as it is being broadcast and simply spooling it to the HDD. It is not doing any extra compression or re-scaling or processing of the original transport stream. The information that the TiVo is rescaling 1920 to 1440 is wrong.

The size of an HDTV file is not dependent on the resolution but rather the bitrate of the broadcast. Fox broadcasts at 720p and NBC at 1080i; both encode at ~15Mbps and have 1 hr file sizes of ~5.8GB for the transport stream. Besides a TiVo I have a media-PC with digital tuners that also records the transport stream -- the file sizes for a program recorded on both is approx. equal.

I have a TiVo Premier 2 years old with Lifetime Service that is making a scratchy noise. Tonight, it stopped getting all channels = black screen. After a power On / Off sequence, it seems to be OK. Tomorrow I will try to lube the fan.

Maybe I should get the XL4 with Lifetime? Lifetime is $399 until tomorrow. Then send this one to WeakKnees to be fixed?

All advice appreciated.
cb

And as I said above, thanks for your input.

James

 

I would at least give component a try.

Edited by Rammitinski - 11/26/12 at 1:21am

I said that before, but he's picking and choosing what to try. Component cables are an obvious choice here if he thinks HDMI looks worse than the native source.

James, you can believe what you want but what we're telling you is that Tivo is NOT compressing or altering the source program in any way, either stored or displayed. What you see with the Tivo is the same mpeg2 transport stream that you get with a cable run into the back of your TV directly; i.e. if it's a 1080i program it's a full 1080i not 1440x1080.

You may have an HDMI issue between TV and Tivo, so that's why we say to try component cables instead.

Replacing the fan is cheap and trivial, once you find the right one. There's a thread on this over at TCF but I'm too lazy to search for it. But the noise could be the drive going out, you'd have to pull the cover to see what's making it. Which is again, a relatively cheap fix (less than $100) and will give you much more capacity than a stock Premiere.

More input. ABC, 1 hour, 3,794k file size. CBS, 1 hour, 7,426k file size. However, since I have a cable card and HD service, all I see is 1080i. Variations can be caused by SD or DD2.0 commercials. All data as shown by the TiVo Desktop after transfer to laptop. BTW, the CBS number indicates 43.1 hours on a 320Gb drive. That's close enough and not a surprize since my BV-980H and TViX (M6620N) showed about the same size with their .ts files. I guess I could look for a non-HD channel and see how it compares, but it's not high on my list of things to do.
Joe

I've been using TiVos for eleven years now. I've been using HD capable TiVos for 8.5 years starting with the DirecTV HD TiVo back in 2004.The HD TiVos have always recorded the HD stream as it is and played it back the same as if you were watching live.

I totally agree. The question was on HDD size vs. hours of storage. The TiVo Desktop let me look at the titles on TiVo.

Hi Rammitinski

I will. If component fixes the problem that will confirm a HDMI issue.

Thanks
James
Edited by jebiggers - 11/26/12 at 8:58am

Where do you get the lifetime for $399 unless it's a 2nd unit? TiVo just told me $499!

Hi slowbiscuit

I certainly will try the component cables.

It's not that I only believe what I want to believe, and please don't take this the wrong way, it's more, from the people giving me the answers, who should I believe. These are the first Tivos I've ever owned and my first time in the Tivo Forum. I am a technical person but I know very little about broadcast TV and certainly no idea what PQ to expect from a Tivo. My first tech questions went to Tivo tech support and that person gave me the Tivo 1080i is 1440 x 1080 picture quality answer. From the answers I've received from the forum members here......Tivo tech support is wrong. It will take a while for me to get a feel for which forum members are the real tech experts and which are not, although I do value everybody's input, tech expert or not. I have learned lots so far from the answers every one of you have given me. I know that once I am more knowledgeable with Tivo, I will try to support other newbies when I can even though I am not a tech expert. I think if you read all my posts, you can see that I'm am taking what you say to heart and channeling my troubleshooting in that direction. Know that I know that I'm keeping the Tivos. my troubleshooting will be ramped up.
I agree that my problem is HDMI related; cables or setup, as my 2 Tivos give the same indication. Also, as I stated in an earlier post, it took multiple tries to get the Tivo to enable the 1080p option over the HDMI line............A clear indication of a HDMI interface issue.

Thanks
James
Edited by jebiggers - 11/26/12 at 8:59am