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Discussion Starter · #1 ·
I have heard conflicting information on how FR mode works on this recorder.


Does it:


1:

Calculate the average bitrate required and record the whole movie at that speed?

e.g. 2h 10m program recording to a DVD-r

The whole move is dubbed at somewhere between XP and SP mode


2:

Record different parts of the movie at different bit reates.

e.g. 2h 10m program recording to a DVD-r

Records as much as possible in XP mode and the rest in SP mode

So the first 1h 50min is in XP mode and the last 20 min is in SP mode.
 

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The recording time duration set at the beginning of an FR recording determines the average bit rate used and an algorithm determines the instantaneous bit rate based on the detail in the picture and the action taking place (i.e., its a variable bit rate, real time encoder). It does not do what you describe in part 2. Note that recordings that will have a duration greater than ~2hr 20min will be made at a lower resolution (i.e., 352x480) than what is used for an XP/SP recording (i.e., 704x480) thus trading off resolution to compensate for the lower avg. bit rate associated with the longer recording. This lower resolution is applied to the entire recording. Another mode called hybrid vbr allows the both the bit rate and resolution to be varied as necessary throughout the recording. The default setting for hybrid vbr is auto, but many people set it to fixed because they find random "downshifts" in resolution for an XP, SP, FR recording less than 2hr 20 min undesirable.


Vic
 

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When "DVD-R Rec for High Speed mode" is ON, is the vbr set to fixed or auto? I believe when the E80 "DVD-R compatible mode" is on, vbr is set to fixed, according to the manual (which the on-screen menus call "normal"). Is the E100 the same?
 

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Discussion Starter · #4 ·
Quote:
Originally posted by doxtorRay
When "DVD-R Rec for High Speed mode" is ON, is the vbr set to fixed or auto? I believe when the E80 "DVD-R compatible mode" is on, vbr is set to fixed, according to the manual (which the on-screen menus call "normal"). Is the E100 the same?


My "DVD-R Rec for High Spped mode" is on, I will check tonight to see what the vbr setting is - I suspect it will be the same as the E80.
 

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DVD-R Compatible is VBR Fixed.


the MPEG stream is ALWAYS VBR. The 'fixed/automatic' referes to the deck switching 'on the fly' to different resolutions (704x480,352x480,640x480) depending on how much 'movement' is in the scene at the moment to make a 'more efficent' use of disc space.


in the E20/HS2 it was 'Hybrid VBR' and you wanted it set OFF (fixed resolution)

in the others it's VBR Fixed/Automatic and you want it set to FIXED (resolution)
 

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Hi folks - New E80 user here but I think my questions/comments apply equally to the E100. I'd like to better understand FR mode and its relationship to the "Hybrid VBR Resolution" setting.


From what I've read, when recording in "DVD-R compatible" mode using the FR setting, the Hybrid VBR resolution is "fixed". If I understand everything correctly, that means there are two constants: time duration of the recording (specified in advance) and available disk space (~ 4.4 Gb for an empty DVD-R). There are then two variables: bitrate and resolution, but there is a relationship between them.


Quoting the manual, in FR mode "The unit automatically selects a recording rate between XP and EP ..." that will ensure the best recording quality in the given time duration. To me that means it estimates the average bitrate required, yielding a given average resolution. This average bitrate is not limited to the specific levels defined by XP, SP etc, but falls somewhere on the continuum between EP and XP.


I would assume that this non-standard bitrate is set for the whole recording, resulting in a predictable number of Bytes at the end.


Vferrari's answer suggests otherwise - that in fact the instantaneous bitrate varies based on picture detail, but that the resolution is constant.


"The recording time duration set at the beginning of an FR recording determines the average bit rate used and an algorithm determines the instantaneous bit rate based on the detail in the picture and the action taking place (i.e., its a variable bit rate, real time encoder) ... Note that recordings that will have a duration greater than ~2hr 20min will be made at a lower resolution (i.e., 352x480) than what is used for an XP/SP recording (i.e., 704x480) thus trading off resolution to compensate for the lower avg. bit rate associated with the longer recording. This lower resolution is applied to the entire recording. "


I'm struggling with that - how can you get more picture detail without increasing resolution, or asked another way, if the resolution is constant, where are the extra bits coming from?


My guess is there are two aspects to resolution: the total # pixels (=Rows x Cols), and the resolution of each pixels (8 bits vs 16 bits etc), and the latter is what is varied during FR mode if Vferrari is right.


However this leads to the next question: Since the unit cannot predict what kind of content there will be, how can it guarantee an average bitrate, and more importantly, a maximum number of recorded Bytes of data?


In other words, if there is alot of detail and action within a 1 hour segment, you'll end up with alot more bits piling up which will force the E80 to arbitrarily drop the instantaneous bitrate towards the end, or the available disk space will be exceeded.


Hope I haven't muddied the waters. Thanks in advance for any insight.


-Tom
 

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Tom:

I think that I discovered that the FR actually produces a recording of about 4000 megs if the content is not full of action. In fact, every movie I have recorded in FR, whether it is black and white or color, produces a recording that shows up at slightly less than 4000 megs when I do a high speed dub to a DVD. The slack may be a safety buffer that is filled for an action-intense recording. On the other hand, it may be a safety buffer for finalizing if there are bad portions of the DVD.
 

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So Ray, is it fair to say your opinion is that FR mode attempts to estimate the rate that will produce 4000 Mbits, and reserves the remaining space in case the video content ultimately requires a higher bitrate?


Here's a more newbie question that you can no doubt help with:


If you record in FR mode to HDD, it's still assuming the ultimate target is a DVD, right? So how does it know what the time remaining is - does the target DVD have to be in the drive? Or does it just assume an empty DVD?


Thanks,

Tom
 

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Quote:
Originally posted by doxtorRay
Tom:

I think that I discovered that the FR actually produces a recording of about 4000 megs if the content is not full of action. In fact, every movie I have recorded in FR, whether it is black and white or color, produces a recording that shows up at slightly less than 4000 megs when I do a high speed dub to a DVD.
Well, thats interesting... I today did 4 movies at FR, each was set for a 1:38 minute recording and the actually ran between 1:30 and 1:34 (between 8 and 4 minutes under)


and the resultant file sizes ran between 4.0 meg for the 1:30 and 4.2meg for the 1:34
 

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troman,


When recording FR to the HDD, it always calculates the bit rate based on the disk capacity of an empty DVD (i.e., ~4 GB) unless the space remaining on the HDD is less than that.
 

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Londo,

I assume you meant 4 and 4.2 gigs?

Did you set the FR to record using the Function>Flexible Recording, or did you set up a timer event using FR? Could using the FR rec mode in the timer setting make a difference (that's what I've been doing)?

With timer recording and the rec mode set to FR, I always seem to end up with a file of about 4000 megs. if I cut the few minutes before and after using Divide Program, I end up with something like 3600-3900 or so when I get to the dub screen (depending on how much buffer time I include in the timed event specification).

I recorded a movie Sunday that was 2:27., and I set the timer to record at FR starting 1 min. before and ending 4 min. after the expected run. After cutting out about 5 minutes, I ended up with 3903 megs for the 147 min. edited movie, which implies that the original file was about about 4036 megs (3903÷147=26.55 megs per minute; 26.55x152 minutes=4036).

Is this math valid to use?

Your numbers indicate that the FR is getting you right at 4300 to 4400 megs for the 98 minutes, doing the same calculations.

I have FR envy!:D

If it's not the timer thing, maybe the movies I record are just really dull.

Maybe my E80 knows that a few of the DVD-Rs I've dubbed to had trouble with finalizing, and it has some sort of "lousy disc algorithm" that ups the buffer (curse those BeAlls!).:)
 

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Thanks Vferrari, so I guess in order to record something less than a full DVD in FR mode (so you can fit multiple programs on one DVD), you need to use a trick like Ray described in a different thread - where you record extra time and trim it off later.


Is this really the only way? The manual says it calculates recording rate based on "the remaining time on the disk", but I'm guessing that only works when you record direct to DVD-R, and only for the last program.
 

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Another related quesiton:


How did you guys determine the file size in Gbytes after recording? I can't find anything in the manual that explains how to display file size?
 

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troman9,

To find the file size (this is for the E80, but I bet the E100 is similar)...

Short version: pretend to dub, but don't

Detailed version:

Pop a DVD disc (-R or -RAM) into the drive.

Select FUNCTIONS (on remote)

Choose Dubbing, then press ENTER on remote

The dubbing list should appear, with the top highlighted in yellow.

Press ENTER (on remote) to add a recording to the dubbing list.

Select the recording on the HDD that you want to get the size of (you pretend to dub it, but you can abort the process pretty easily)

The available space will appear as well as the size of the selected recording.

To do another, just select the one you just added to the dubbing list using the up arrow, press ENTER on your remote, press the right arrow, and choose ERASE (you are just erasing it from the dubbing list, not your HDD). The top of the dubbing list is now clear, so press ENTER on the remote and choose another recording from the HDD.

There may be another way to check the size, but I have not discovered it (the STATUS button seems to display everything but file size; same for going into the Direct Navigator, right arrow, PROPERTIES).
 

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BTW...

I tried recorded two movies in FR. One using the timer recording and the other by using function>flexible recording. I checked the sizes without deleting anything from the recordings, and found that one recording was 4027 megs and the other was 4019, so the two methods of getting an FR recording seem to produce similar results on my E80.

Londo, I still want to know what you are doing right. Will my E80 like me more if I buy it a companion?
 

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doxtorRay


I too usually end up around the 4000 meg range with FR recordings on my E80. You may be right about there being a reserve for content that needs a higher bitrate and Londo is making recordings which make more use of that reserve.


Here's why I think you may be right: When recording snow at the end of a tape the recorder will manage to do a decent job on reproducing the snow on most of the screen, with a bar of low res. noise at the bottom. After a short time the low resolution portion spreads further up the screen. Presumably the reserve is used up and it has to drop back to the average bitrate.


David
 

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Quote:
Originally posted by doxtorRay
I assume you meant 4 and 4.2 gigs?
duh. .. (looks back.. counts again... takes off shoes, counts again)..


yeah, yeah... GB.. that's the ticket... I was busy with Morgan Fairchild...

Quote:
Did you set the FR to record using the Function>Flexible Recording, or did you set up a timer event using FR?
both actually... and it still gave the same (percentage) difference between recordings...


er... are you counting 4gb a 4,000,000,000 bytes or 4 *1024 *1024 * 1024 bytes??? right now I'm looking at a file on the HD that shows a BYTE COUNT of 4,596,992 bytes. the size shown by Windoes File Manager is 4.38gb.


a GB is not a GB is not a GB.


(and yes, getting it a companion is a good idea... they look nice in pairs..)
 

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Quote:
er... are you counting 4gb a 4,000,000,000 bytes or 4 *1024 *1024 * 1024 bytes???
I always get confused by that byte/bit stuff. I guess there's a lawsuit about it now.

I was just going by the megabytes the E80 was telling me I had, out of the 4411 the thing says I can cram on a DVD-R. Is that "4411 meg" 4.411 gig or 4.308 gig? If your file is 4.38 gig, how does that fit in 4.308 of space? Now, my brain really hurts. I want my mommy!
Quote:
(and yes, getting it a companion is a good idea... they look nice in pairs..)
I don't want the one I have to get lonely. I wonder if I can train my wife to use the second one...

Don't tell her about the gigabyte thing. That would queer the deal for sure.
 

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Quote:
Originally posted by doxtorRay
I always get confused by that byte/bit stuff. I guess there's a lawsuit about it now.
ok.. try this... take the disc and put it in your DVD-ROM drive in the PC. Open the VIDEO_TS folder

hit CTRL-A to select ALL the files in the VIDEO_TS folder

right click and select PROPERTIES


I just did this with one of my GAH discs I had finished...


it shows (in properties) as 4.34GB (4,665,668,064 bytes)


so, is that 4.34GB or 4.66GB???


and is the max size of a DVD-R 4.37 or 4.7GB


and you thought you head hurt before :)
 

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Blame it on the storage marketeers. They're the ones who started using the decimal calculation for storage sizes because it looked like you were getting more space. Non-storage sizes are calculated (correctly) using binary arithmetic.
 
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