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Thread: 544x480, etc: changing recording resolution

  1. #31
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    Re: Resolution #4

    Originally posted by finster869
    Resolution #4 on a standalone under 3.0 is the same resolution as "BEST" quality, which is 544 x 480.

    The standalone cable settings resolutions are:
    0 = 720 x 480
    1 = 352 x 480
    2= 480 x 480
    3 ?????
    4 = 544 x 480
    I concur with this, having tried each setting myself. I believe that 3 is 352x240 but I have not verified this, nor do I know what the bitrate would be.

    The standard Constant Bit Rates for the above are 5.8Mbps, 1.47Mbps, 2.6Mbps, ???Mbps, and 3.5Mbps respectively.

  2. #32
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    Somebody asked about max bit rates the encoder supports.

    I have a 2.5.1 SA Sony set to 720x480, 100% quality, using the DBS S-Video IN and no VBR.

    9M gave visible artifacts on APEX DVD screensaver
    8M gave minimal artificts on screensaver
    7.5M did not appear to give any artifacts even with a full buffer and doing a Turbonet FTP download the whole time

    I haven't looked at an actual DVD (need to get the Macrovision off this APEX, it makes my TV look crappy), but watching my crappy antenna input at 9M, same settings as above, looked fine.

    I have replaced the hard drive with a 120Gb 7200RPM 8Mb Cache WD, so IDE performance shouldn't be an issue.

    --------

    I couldn't get the 'resource edit' thing to work at first either, to anyone else having this problem, you can only change 1 parameter at a time and you have to click 'Update' when you're done and reboot the box.

    My unit seems to randomly alternate between Bitrate and AuxBitrate so you need to change both.

  3. #33
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    My experience w/tivoweb is that for each setting that you change, you have to press 'Enter' in order for the setting to 'take'. You can't for example change-then-Tab to the next field, nor can you change-then-Click in the next field, you have to change-then-Enter. When you're all done you need to Update and then re-boot your Tivo.

  4. #34
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    Re: Resolution #4

    Originally posted by finster869
    Resolution #4 on a standalone under 3.0 is the same resolution as "BEST" quality, which is 544 x 480.
    The standalone cable settings resolutions are:
    0 = 720 x 480
    1 = 352 x 480
    2= 480 x 480
    3 ?????
    4 = 544 x 480
    As I posted earlier, I set ALL my "medium" settings to RecordQuality=100, Resolution=0, VBRBitrate=5215000, MAXBitrate=5960000.

    For the results, see my post further in this thread.
    Last edited by artships; 08-01-2002 at 02:04 PM.

  5. #35
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    I have a Sony running 3.0 also. I am able to get 720 x 480 using resolution "0". From everything I read the "quality" should not make a difference. However, I have my quality set at "25", while yours is 100. That is the only difference I can see. Why don't you try setting the Medium quality back to "25" at the top and see what happens.

  6. #36
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    Artships---

    Did you hit return after each setting, then go back? You can't tab through the fields and then only hit return 1 time. Rather, you must hit return after each individual change.

  7. #37
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    Did you do the obvious?

    Originally posted by finster869
    Artships---
    Did you hit return after each setting, then go back?
    Yes. I'm an *****, by I try to find more creative ways to demonstrate it.

    I had changed the "quality" setting to "100" because, well, I wanted the best quality! Pretending, of course, that I know what the numbers actually mean.

    Update:

    I changed the quality settings to 65, for no other reason than a) it's not 100, and b) that's what TMPGEnc defaults to. I now have a Moby video (from MTV (sat dish)) and a piece of Sheena (off-air antenna), both at 720x480. I'll adjust my ToDoList to get the Gene Wilder mystery on A&E this afternoon at 720x480 so I can investigate the next steps: Mux the m2v and m2a files (How's it going, Josh?), use Ulead MovieFactory to make VOB's with chapter marks, and IFOEDIT to get the chapter marks to slide past the adverts.

    John
    Last edited by artships; 07-21-2002 at 10:23 AM.

  8. #38
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    I have tried in vain to discover what these mysterious "quality" numbers mean or do (I mean the zero to 100 settings). I hope someone here knows, or can find out where I have failed.

    I've done a little bit of testing and can see no effect, but maybe I'm not looking in the right place. I don't see them affecting Resolution (720x, 544x, 480x etc) and assumed they might have something to do with bitrate; but then I have never used VBR--maybe they relate to VBR somehow??? IIRC variable bit rate is used when you tell Tivo to "Save Disk Space".

  9. #39
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    I too would like more information on how the Quality settings actually work. My understanding is they control how 'accurately' the MPEG encoder does it's job- which makes them important in VBR.

    I am unsure about how they would effect CBR though. I think there is probably some advantage to _not_ setting them to 100 all the time, especially for 720x480 because of the bitrate requirements.... IE:

    TiVo says 544x480 at best quality (100) needs 5960000 Max bitrate. If we bump the resolution to 720x480, the math says we now need nearly 7900000 to encode the information. Seeing as I don't think most of us _really_ have source material with that kind of resolution, a lower Quality setting might be a little more bandwidth efficient without an overall quality reduction- Ie, 75% of 720 is 544, though I really doubt that's how it actually works...

    I posted the other day about having problems with motion artifacts on my 2.5 TiVo running at 8000000 CBR and 100% quality. I've found that reducing the quality to 90% seems to have significantly improved things.

    One thought I've had is that reducing the quality setting (and being a little less precise with the encoding) leaves more bandwidth available for 'motion compensation', thus a reduction in artificats.

    My goal is to have the TiVo encode at absolutely the 'best' resolution, bitrate, quality it can, and then transcode the recordings to a more realistic VBR format using a Linux box. Yes, I've got plenty of spare CPU, RAM, Disk, and free-time :)

    can anyone with more MPEG experience go into more detal about 'Quality' when using CBR?
    Last edited by khmann; 07-21-2002 at 12:25 PM.

  10. #40
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    Does this work in the UK?

    Hi folks,

    Does anyone know if you can use these hacks on the UK TiVo?
    (v2.5.5, 2x120G)

    I have TivoWeb 1.9.3 installed, but the Resource Editor doesn't work - I just get a heading "Resource Groups" and the link "Update Resources".

    I have been told this is normal for UK boxes.

    I would love to increase the horizontal resolution, as I am always noticing jaggies on diagonal lines that aren't on the orginal.

    Is there a file I can edit that contains these values?
    Presumably that's what the resource editor does....

    Any help greatly appreciated,

    Cheers,
    Mike
    Mike Gregory

  11. #41
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    Originally posted by khmann
    ...can anyone with more MPEG experience go into more detal about 'Quality' when using CBR?
    You ask good questions khmann and I hope someone has some answers. One thought that occurs to me is that we could try doing some testing as follows:

    I've noticed that Tivo records scheduled programs quite precisely in that shows of the same length (time) and that are recorded with the same CBR quality (Best, High, Medium, Basic) tend to have identical filesizes (a series of half-hour shows I recorded recently in CBR Basic were all 368Mb for example). So it should be easy enough, shouldn't it, to vary only the 0-100 Quality setting for a Season Pass to a half-hour show or something, and observe whether/how the filesize changes from numerical Quality setting-to-setting.

    If the filesizes for Best quality shows recorded CBR at say 100, 50, and 0 are exactly the same length, then I'd assume that these settings have nothing to do with CBR at all, and we can stop worrying about them (!).

    If these settings don't appear to affect CBR, then what's left: they must relate to VBR only--just like the bitrate settings in the Resource Editor are for VBR-only. Testing would be more difficult w/VBR because using a Season Pass for a 1/2 hour show, for example, wouldn't be controlled enough--program content changes from episode-to-episode and VBR would thus result in different filesizes; you would have to manually record a specific, fixed program (e.g. from tape or DVD disc) onto the Tivo at VBR and different Quality settings in order to evaluate the impact.

    I'm unlikely to have any time to try this in the near future but maybe khmann you can look into it...?

  12. #42
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    My one extraction at 720x480 on a Sony SA

    I recorded an Andromeda episode at 720x480, 65 "quality", CBR. While it was recording, the video was fine, but the sound changed in pitch on occasion, telling me that tivo's bitrate was maxed-out. Fortunately, the recorded show played just fine on tivo. And, interestingly, it occupied the same number of tystreams as any other hour-long show recorded at 544x480 and "best (100) quality".

  13. #43
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    Mike,

    I have not been able to get this working on my UK box. I have tried various quality / bitrate / resolution settings and can't get anything other that 480x576.

    Not that my failure implies that it will never work, it probably just needs a bit more effort.

    Jim

  14. #44
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    Thanks dattrax,

    I'll just have to keep hoping someone finds a solution for UK resolution changing then.

    I don't know anything about how the TiVo stuff works (I'm just a user of this code), so I'm not likely to find it myself, but if I get some spare time (ha!), I'll have a dig round and try and find out what's going on....

    I managed to extract a small MPG clip yesterday using TivoApp2.3 , but anything more than about 5 minutes ends up corrupted and won't play in anything (WMP+MPG2 codec, WinDVD, PowerDVD, etc), and just crashes the player. I've tried ExtractStream (suplied with TivoApp) & Sendstream v0.2, with no difference. Again, I'll do some more experimenting when I get some time, and try TyTool & mfs_stream too.
    (I do have a 240G, and TivoApp says it may have trouble with big disks)

    Cheers,
    Mike
    Mike Gregory

  15. #45
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    Originally posted by mccg
    ...I'll just have to keep hoping someone finds a solution for UK resolution changing then....
    I don't know anything about UK Tivos or how TivoWeb works (or doesn't) with them. Maybe you need to start a new TivoWeb thread.

    I do know that if you are able to get the Resolutions/Bitrates screen up in the Resource Editor of tivoweb, that changing the settings requires your entry number and 'Enter' key FOR EACH SETTING, then you have to click the Update button and finally reset the Tivo (simple reboot). A number of people have been bit by this including me, ie. you can't enter a number and the tab to the next, or click-into the next field, you have to enter it and hit Return for each field.

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