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Roamio tuner internal/buffers..

Discussion in 'TiVo Roamio DVRs' started by dvdvids, May 6, 2014.

  1. May 6, 2014 #1 of 21
    dvdvids

    dvdvids Member

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    I noticed that when I saved programs on (what I assume) different tuners...
    and some went and picked up different starting times (some went back 45 minutes and some little over 30 minutes)

    So, is there difference in the internal buffer sizes for each of the 4 Roamio (basic) tuners? :confused:
     
  2. May 6, 2014 #2 of 21
    nooneuknow

    nooneuknow TiVo User Since 2007

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    I see this as well. I've seen live (non-recording) buffers go back an hour, while others go back 30 minutes, as well as "anything else".

    Sometimes it is due to what the tuner was doing before it became just a live TV buffer (like it recorded a show first), and sometimes it can be due to SDV (Switched Digital Video). SDV tends to "time-out", if it's not the active (viewed) tuner, in the foreground. Even in the foreground, if the TV is turned-off, the HDMI link status can cause a SDV channel to lose authorization, and only get it back once the TV is on.

    Sometimes, none of these scenarios fit, and just leave me to wonder what the deal is.
     
  3. May 6, 2014 #3 of 21
    aaronwt

    aaronwt UHD Addict

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    I thought it had to do with the blocks on the hard drive? Or something like that.

    The TiVo records the program in chunks and each chunk or whatever is a certain size and not time based. SO if part of a program is a small portion of the chunk, it will still have the whole piece which increases amount of video it has. More for a lower bitrate show, like SD and less for a higher bitrate show, like HD. At least something like that. I'm sure someone else can explain it much better than me. I know it's been explain in the past but I can't remember the proper wording.
     
  4. May 6, 2014 #4 of 21
    nooneuknow

    nooneuknow TiVo User Since 2007

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    I've often wondered if the size of the hard drive cache buffer could have any effect... I doubt it does. TiVo used to go with the smallest buffer that they could get on each model drive (maybe to save money).

    You are right about TiVo writing the data in large bulk transfers, in large block sizes. It's still written as regular data, with regular error handling, at a maximum host rate of 133-150MBps, and still not using the A/V streaming features of the AV drives.

    Old explanations may no longer fit, now that tuner counts have gone up, Minis came out, and more data streams are being handled for the one drive in a TiVo. That might be why they now use drives with retail size buffers, rather than the old way of the smallest they could get. The switch to AF/4K/512e drives may have forced their hand on not using smaller buffers. The read-change-write operations of 512e (emulating) drives, do require bigger buffers to keep the performance from dropping off a cliff. Although, if the drive is aligned, those bulk transfers should keep the R/C/W operations to a bare minimum on bulk transfers in large blocks...
     
  5. May 6, 2014 #5 of 21
    tatergator1

    tatergator1 Active Member

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    Bottom line is that you'll usually get at least 30 minutes from the buffer for any particular channel a tuner has been on (unless the tuner changed to that channel less than 30 minutes ago). In many cases, you'll get more. I think the most I've ever recovered out of the "30 minute buffer" was 52 minutes.
     
  6. May 6, 2014 #6 of 21
    jrtroo

    jrtroo Chill- its just TV

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    "saving" implies "recording"- using a buffer to save something is a sure way to lose something. Hit the record button and be sure you'll keep it.
     
  7. May 6, 2014 #7 of 21
    nooneuknow

    nooneuknow TiVo User Since 2007

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    I can't argue with that! It's exactly what I've trained myself to do! :D

    While I don't think the person who said "saving", was necessarily complaining about the matter... If they were, that's one way to make sure they don't "lose" anything they might want to come back to.

    OTOH, it's hard to use that method, if you just turned the TV on for the day, unless you feel like making your first actions recording all buffers.

    Another OTOH, if another program has already started, pressing record on that buffer will actually cause you to lose any of the prior buffered content that isn't part of what the guide has currently slotted. This sometimes does annoy me. I feel like if it is in the buffer, I should be able to record it.

    Older platforms on older software did tack the full buffered content onto the beginning of whatever program was currently slotted in the guide. I can imagine some would consider that a "bug" or undesired operation, and may have complained to TiVo about it, leading to that no longer happening.
     
  8. May 6, 2014 #8 of 21
    aaronwt

    aaronwt UHD Addict

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    Yes. i would not want to get a 30 minute buffer at the beginning of a program I recorded. I would only want that program. No need for 30 minutes of teh previous program when that is not the one I'm recording.
     
  9. May 7, 2014 #9 of 21
    dvdvids

    dvdvids Member

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    That is the biggest gripe I've with Tivo system! WHY!?!? it's already in buffer.. just let me save it dammit! :mad:
     
  10. dvdvids

    dvdvids Member

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    So as some of you pointed... the buffer size could depend on the quality (bit rate) of program.. I will keep an eye on this...

    Not sure I quite get that HDMI link status part of it...:confused:
     
  11. aaronwt

    aaronwt UHD Addict

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    But I say just the opposite. Why the heck would I Want part of the preceding program? When I hit record I expect to only get the program on at that time. Not some extraneous stuff.
     
  12. CrispyCritter

    CrispyCritter Purple Ribbon Wearer

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    I agree, but just to be a devil's advocate, there have been several times when I've hit record to save the show I'm currently watching, only to later find out that I was behind in the live-tv buffer and what got recorded was the show that was then being broadcast, not the one I wanted.
     
  13. nooneuknow

    nooneuknow TiVo User Since 2007

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    If you have a TA (which uses SDV), and the HDMI link status is down, or some other factor is reporting you aren't actually actively using that channel/tuner (or aren't "recording" it), the SDV system design is to "time-out" or de-authorize that channel, until it detects active use again. The TA can tell the difference between a TiVo just buffering, and when it actually "recording" that specific SDV channel. It's part of the SDV design.

    As far as bit rate goes: I used to see differences in buffer length (longer on SD), on older platforms, and/or with older software, but don't anymore. I'm all Roamio now. I've also been using TAs/SDV for a while now... I think, in my case, any >30 minute buffer now means that tuner recorded the previous program that had been in the buffer.
     
  14. nooneuknow

    nooneuknow TiVo User Since 2007

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    This sums it up nicely, showing there are times when the statement "If you don't want to miss it, press record", doesn't always work/apply. It also shows that telling people this, may just tick them off...

    There have been numerous times I've pressed "record", only to unintentionally clear the buffer of the tail-end of something I wanted to watch later. It's usually something on the news, or the end of a movie I'd missed the end of in the past, that I wouldn't ever think to record ahead of time, and just happen to see it's in the buffer.

    TiVo did used to tack the buffer left-over on, when the record button was pressed. It would have been better if it could've split the two segments. That would require them to be able to "cleave" a stream, like they have been trying to do with overlapping recordings (and not doing well enough at, to keep the perfectionists happy).

    I was never bothered by the record button behavior including the extra buffer. I accepted it as part of using the button, as opposed to scheduling ahead of time. I'd still like it that way. That's my preference, not me declaring that it's the "way it should be", as these things tend to turn into, once a few select members of the forums realize they just found a new fight to pick...
     
  15. dvdvids

    dvdvids Member

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    No, it does not record previous program!
    Lets say Program A (8-9), Program B (9-10)
    When I'm at 9:15 and I press REC, it only records Program B and I lose the buffer for 8:45 to 9
     
  16. dvdvids

    dvdvids Member

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    (for tivo analysts)
    simple solution .. just record whatever is in the buffer.. if it was in the middle, record later part of previous program and start recording current program.
    better solution.. ask me if I want to record previous buffer
     
  17. aaronwt

    aaronwt UHD Addict

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    Yes it behaves like I would want it to. But some people prefer to have what is in the buffer be added to the recording. The only way to please everyone would be to have an option.
     
  18. jrtroo

    jrtroo Chill- its just TV

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    I'll never understand why so many folks play games with the buffer. It is a recipe for disaster for content. I know once in a while there may be something "on" in the buffer, but if you record everything, and use suggestions, the tivo should get most things of moderate interest. To each their own.
     
  19. nooneuknow

    nooneuknow TiVo User Since 2007

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    I use the actual guide view for, at most, 5% of what I record. I make extensive use of any other means, including KMTTG for searching for Season Premieres.

    I've noticed that even the non-technical members of my family don't use the guide for much. They search, and like me, make little use of the guide. These are the same people that used to use the newspaper TV listings to record VCR tapes, before I introduced them to TiVo. Like me, they don't find the suggestions useful, hate how suggestions can interrupt Live TV viewing if they aren't right there to dismiss the notification, and will ultimately turn suggestions off.

    I don't know how suggestions ever works for anybody. I gave my best effort to rate things, time and time again, and have no idea what bodily orifice TiVo pulls suggestions from. I asked the others to give it a try again with the Roamio, and found they accidentally hit the different thumbs buttons so often, that their favorite shows would have a 3:thumbsdown: rating, while something they don't even recall ever watching would have a thumbs-up. They'd rather have the ability to schedule further into the future, and could care less if TiVo removed the thumbs buttons, and suggestions function. I'd guess the proximity of the :thumbsdown: button to the volume button has something to do with them giving 3x:thumbsdown: to their favorite shows...

    The only things TiVo ever accurately suggested for me were the repeats on repeat-running channels for shows I have set to 1st-run only. That might have helped, if I was interested in repeats, but certainly not CSI: Whatever.

    I usually know what I want to record by other means, and have it set as well in advance as TiVo allows me to. I have over 100 SPs per TiVo, sometimes an ARWL when I know something is coming, but the scheduling isn't in the guide data yet (one of my big annoyances with scheduling new things in the future).

    Sometimes things are just spontaneous "I want to see this" things, noticed at random, on a channel I paused, but the buffer has filled and started playing from the back end of the buffer. If I press record, poof, gone, I'm recording something else I don't want to see, and there's no getting back the lost buffer at that point.

    So, I take "just use the guide" about the same as some who take being told "just press record". That may work fine for you. Just don't assume it's what everybody else wants, or what happens is the way everybody wants it to happen.

    If the Live TV buffer is such a dangerous thing to use, how on earth has it survived all this time? Shouldn't TiVo protect us from accidentally watching the buffer, then? <--sarcasm

    Unfortunately, TiVo will usually just let us sling our preferences at each other as being "the way it should be" or "the way a TiVo is meant to be used", rather than give us choices. The last choice they gave us was "default recording options", which created a war over "keep until" not being part of the default profile choices, and people saying those with different opinions were wrong. That seems to be the way this is headed.

    Two people who probably couldn't use their TiVos any more differently, even if they tried, would be me and aaronwt. He'll never see some bugs that I see, and I'll never see some of the bugs he sees (on the rare occasions he admits to seeing any bugs :D ).

    [/end There's no one single right way to use your own TiVo rant.]
     
  20. slowbiscuit

    slowbiscuit FUBAR

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    The lack of user-configurable options for what I consider to be basic stuff (like live TV buffer and Mini tuner timeout) is probably my biggest beef with Tivo. Well that and the snail pace of development there (see: lack of Android streaming, completing the HDUI etc.).

    But I'm sure it's because of two reasons - you have to use it the Tivo Way (tm), and they don't want the extra support phone calls that come with more options.
     

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