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2 hour SP mode actually = 2 hours 9 minutes.

Discussion in 'Blu-ray & DVD Players & Recorders' started by Jules, Oct 7, 2004.

  1. Jules

    Jules
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    If you record directly to DVD-R in SP mode (Panasonic E85), the recorder allows 2 hours worth of material to fit. The machine then treats the disc as 'full'.
    However, I've never yet seen a 2 hour recording in SP mode exceed more than around 4GB and its often less, both on my old E60 and on the E85.
    That means there's about 10% unused space, which equates to about 10 minutes of SP quality material.

    However, if you record 2 hours 9 minutes to the HDD in SP mode, you''ll find you can high speed dub all of it to a DVD-R no problem.

    So I reckon if you need to record something around 2hours 9 minutes long, don't use FR mode. Use SP mode via the HDD, and it will still fit on a DVD-R.

    Don't know if anyone does this already, but if not it could be useful tip.
     
  2. tdale

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    Hi Jules, yes, Im aware of this too. I posted at Afterdawn the following, but got no response
    "Im aware that the max size is 4438Mb, is that the same if the DVD is written and finalised on a Recorder? I have an E85.

    I notice that with FR mode, the siz eappears to be more like 4100Mb, I assume this "buffer", is due to what is required if the max titles and chapters for the E85 is used? It would be ideal to use those megs, but i guess unles you recorded in say SP mdoe for a bit over 2 hours, for example, there isnt a way to fool FR mode to record more megs?"

    So, as I see it, you can assume and allow for 5% or so. You cant use this in FR mode, unless you are making mutliple titles in FR mode, then you can deduct that "allowance" off the minutes. I.e. if you had 3 one hour shows, set FR mode for say 167 minutes instead of 180 when you record each hour (stopping the record after the hour long show, leaving you one hour at a FR mode of 167 minutes) After dividing you then have your 180 minutes recorded at a rate of 167 minutes, hence you have utlilised that 200+Mbs.
     
  3. apreading

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    The 4438 actually already seems to allow for the menus. I have actually used 4434 on a DVD-R but that is about as close as I have gotten it. My guess has been that the 4100 gives a margin of error - I think RAM discs have slightly less than 4438 available, so there must be some variation in what will be available. I can understand this if you use FR on the HDD to transfer later, but when you use FR direct to disc I dont see why it doesnt read the available space and take it from there - it does this if LESS than 4100 is available...

    As said though, it seems once you have got over 4100 or 2 hours (not sure which drives it) it will no longer let you record on the disc OR tranfer in realtime - only high speed file copy works, otherwise it tells you space available is 0.

    The last 3 minute file I wanted to add but wouldnt quite fit last night, has to be re-encoded to DVD-RAM at a lower bit rate, then copied back to HDD and over to the -R. Bit silly, but easy enough I guess.

    So yes, use SP for items you think will come in under 2hrs 9mins or so. I allow a little leeway just because I wouldnt want to get caught out but running over slightly, but 2hrs 5 certainly is no problem.
     
  4. tdale

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    Yes, the 4100 does allow for the menus, but the space used by motion menus which is used, is very real. If your making a DVD on the PC, and you turn off motion menu, there is a significant amount of space saved.
     
  5. OARDVD

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    Bear in mind that the MPEG encoders in these machines use variable bit rate compression (VBR) so the bit rate varies, within a given range, according to the proportion of detail which changes from frame to frame. Busy, high action sequences of video generally require a higher bit rate than those which are ‘slow’ for a given resolution/recording mode. Typical video sequences tend to involve a mixture of busy & slow scenes. But when you design an encoding algorithm intended for real time you have to provide enough headroom to allow for the unusual circumstance of 100% of the video being busy.

    SP mode (for example) has to be able to record for a maximum 2 hours. The encoder has no way of knowing if any future scenes coming up will be busy or slow so it has to be a bit conservative so that it doesn’t get bit starved towards the end of the two hours. Nonetheless, I agree that Panasonic still appear to have been a bit overcautious in this instance.
     
  6. tdale

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    Good point OARDVD.
     
  7. apreading

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    I dont think the Pannys use VBR if you have 'enable high speed dub to DVD-R' set. Not sure how VBR would work in FR mode either...
     
  8. OARDVD

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    Yes they do.
     
  9. sweat100

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    I thought there is this hybrid VBR thing that you can turn off such that the bit rate is fixed? or is it resolution? This is what i thought so but when i look at the bit rate, it still varies. Why? :confused:

    If i am not wrong when you turn of the high speed dub mode, it have to be disabled.
     
  10. OARDVD

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    You're referring to making the RESOLUTION fixed or variable. The Pannys always record in VBR regardless of mode or setting.
     
  11. sweat100

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    What is the Hybrid VBR thing that can be turned on and off? is it the resoultion?
     
  12. sfc

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    As an extension on this I have found with the E50 that if you use the rams on the pc using the movie album software and then put them back in the E50 the space available goes up to 1 hour 3 mins on xp and 2 hours 6 mins on sp.

    Why the extra space is not available when you use the ram disks just on the machine is a bit puzzling - the more space the better surely?
     
  13. OARDVD

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    As I was trying to explain earlier: The parameter that is called "Hybrid VBR resolution" refers only to resolution.

    If you set it to "Fixed" then it maintains the resolution, regardless. This is important if you later want to import the video into a package on your PC. However, under some circumstances it could cause macro blocking (see below).

    If you set it to "Automatic" then the resolution may vary. For example, if the encoder comes across a scene which is "busy" and would potentially cause bit-starvation, then in order to avoid macro blocking it downshifts to the next resolution.

    The parameter is a bit of a misnomer as it could be taken to imply that it changes from VBR to CBR. However it doesn't, the recorder ALWAYS records in VBR and the parameter actually applies only to resolution.
     
  14. Zedmeister

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    Yeah, I've noticed this too. If I format a DVD-RAM disc on my LG-4120 burner in my PC and then put it into the Panny, it says 4 hours 15 mins in LP. If you reformat it on the Panny, it goes back to 4 hours. Strange!
     
  15. tdale

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    "I dont think the Pannys use VBR if you have 'enable high speed dub to DVD-R' set. Not sure how VBR would work in FR mode either..."

    VBR is the encoding type. It will encode busy parts with a higher bitrate, and less bitrate for "easy" parts.

    When you FR, that will encode at the bitrate (still variable) to fit 4.7Gb. If you XP, that will encode to one hour per 4.7Gb, still variable. VBR is more efficient, no point in using high bitrates for "easy" scenes.

    High speed dubbing is not encoding, its burning a DVD exactly as you do on your PC, about 17 mins if using 4X DVDR's. Realtime dubbing is playing the title, and re-encoding it to fit 4.7Gb
     
  16. sweat100

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    Btw, what software you used to format your dvd ram? can recommend? I am also using the 4120B as well. I am using the Panasonic dad ram driver. (downloaded from Panny's website) Tried it and it showed only 4 hrs in LP. Using the E100 here.
     
  17. sweat100

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    I see... now i finally understand.Good explanation. :smashin:
    By the way, you have any idea what resoultion the drive switches between? And it applies in all mode(XP SP LP EP)?

    You said that " if the encoder comes across a scene which is "busy" and would potentially cause bit-starvation, then in order to avoid macro blocking it downshifts to the next resolution." You said downshift? why isnt it upshift? By increasing the res, wont you elimate the macro blocking? Or is it by downshifting, u can encode in a higher bitrate as the total data output for the scene must be equal?
     
  18. OARDVD

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    Referring to PAL machines - it can change between:

    Full DVD resolution (720/704 H x 576 V) & SVCD (352 x 576)
    and
    SVCD resolution & VCD (352 x 288).

    Now when the parameter is set to 'fixed', XP/SP are DVD resolution, LP is SVCD, and EP (6 hour) is VCD (MPEG1). When the parameter is set to 'auto' you may get a downshift to the next lowest resolution. You will not get a shift to a higher resolution than that permitted for each mode. Thus, you won’t get an LP recording upshifting to DVD resolution (for example). However, I don’t know exactly under what circumstances the shifts will occur (perhaps Rasczak or somebody can enlighten us a bit more here?).


    I think that you may be confusing bit rate & resolution? Increasing the resolution would need substantially more bits - and if macroblocking is occurring, or about to occur, then it means that there is not enough 'bit headroom' to sustain the current resolution without distorting the picture. So you need to drop to the next lowest resolution, not rise to a higher one. If you downshift from full DVD resolution (704 x 576) to half (ie SVCD 352 x 567) then it will encode half as many horizontal lines. This means that (on average) only half the number of bits are required to encode the same scene. Hence there will now be sufficient bits to encode it without distortion (macroblocking, etc), albeit at a reduced resolution.
     
  19. Zedmeister

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    I'm using the DVD-RAM driver but I also have Roxio Drag-to-disc installed. I think it is using the Roxio driver while formatting as the DVD-RAM driver always reports the drive as busy. Have found the Roxio drag-to-disc reliable but have not used a Roxio formatted disc in the Panny for TV recording, only in the LG for PC data and MPEG4 movies. Will give it a try in the Panny at some point but I was worried by the fact that it was giving "extra time" and assumed that the formats were incompatible and may lead to problems later. Can anyone comment on this?
     
  20. OARDVD

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    I've heard of this before. It shouldn't cause any problems.
     
  21. sweat100

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    A bit of the OT here, Zedmeister you said you use DVD-RAM for MPEG4 movies, are you saying you do a dubbing from the Panny recorder to dvd-ram? If it is so, how are can you view the movies? I tried but windows said that i do not have the appropriate codec to playback the movie. Can you help me with this?
     
  22. sweat100

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    I think i get what you mean, but just to fully undertsnad you words.

    1.Macroblocking is those big blocks you see in VCD movies in a "busy" scene right?

    2. At a reduced resolution you can encode the same scene at a lower size thus you have more "space" for a higher bit rate? (Since bit rate is not the same as resoultion)
     
  23. OARDVD

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    Yes.

    Sort of. The overall bit rate is not higher - it stays the same, or is lowered, but the detail in the picture is reduced (thus eliminating macro blocks). Basically, the overall lower resolution (or reduced picture detail) allows you to divert a greater proportion of the available bits to the areas of the scene which are potentially causing a problem (ie “busier”).
     
  24. Zedmeister

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    I only use DVD-RAM as disc space to hold MPEG4 movies on my PC. I do not watch them directly on the Panny. You would have to convert into MPEG2 first to watch them on it. The Panny unfortunately will only read -VR format on DVD-RAM and fails to read DVD-RAM with DVD-Video content on it. I initially wanted to convert the movies into something watchable on the Panny and tried every bit of software I could find to convert and write a decent -VR disc but could not achieve what I wanted. In the end I bought a whole load of DVD-RW and DVD+RW discs (the Panny has no probs playing either) and record the movie on my PC in DVD-Video format on to those. When I have watched them, I just wipe them and record again. If you need details on how to convert, etc. let me know.
     
  25. sweat100

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    Have some questions in mind.
    1.What is the average bit rate of the different modes? (XP, SP, LP, EP)? Wanted to record a movie to fill up all the space on the dvd-r. Usually upon FR will only give 3.95Gb. This problem as discussed earlier. And the dubbing utility in the Panny recorders recgonise 1gb=1024mb or 1000mb?
    2. If anyone knows what is the threshold of the bitrate can vary between different modes. That would be nice. So i can do a better calculation when i set the the FR mode depending how "busy" a movie is.
    3. If i recorded everything on XP mode and i do a dubbing in FR mode to fit the data on the disc (usually a show is between 1 to 2 hour) disc. How big will the quality difference of the recorded show be as opposed to using FR straight away? Have anyone seen the difference. As i know there is recoding of a mpeg movie. But i dont know how bad is it. Anyone can share his/her experiences?
     
  26. Jules

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    I'll probably get bashed for saying this, but as an E85 owner I say it with confidence.

    I now always record to the HD (in high speed compatible mode) at the appropriate FR rate.

    This is because the machine induces a lip sync problem each time the material is encoded real time.
    One pass of realtime encoding to the HDD or directly to a DVD-R is ok, because it isn't noticeable.
    But 2 encode cycles, and the cumulative effect of the lip sync problem is pretty obvious to me.

    As a test to prove this, I did the following experiment:
    - recorded an episode on Sky+.
    - then transferred the episode to the E85's HDD in XP mode
    - then real time recorded it to DVD-R in FR mode.
    - then real time recorded it back to the HDD in XP mode
    - then again back to DVD-R in FR mode

    The result.
    The recording on Sky+ was ok, but with each 'generation' of recording on the E85, the lip sync became more and more noticeable until it was way out on the final DVD-R dub.

    So, I'd suggest you don't go down the route of recording in XP mode to the HDD in order to 'exact fit' later to DVD-R. Just use FR mode and high speed dub!
     

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