My Tivo is wasting DVD space!

[Ipaqjoe]

Lately I have been archiving my weekly recordings of the Sopranos into a format to fit my ipod. I record the show from digital cable at the highest quality which my tivo tells me will fill up a blank DVD to 99% per 1 hour of recording, then take the DVD to my computer to do the re-encoding for my ipod.

Great 1hr of Sopranos at the best quality per DVD.

My question:
The DVD only has 1.6-1.9GB of data on it when I put it into my computer
A blank DVD holds 4.7 GB of data

Why does my Tivo say the 1 hr show will use of 99% of the blank DVD when it is not even using half of the disc? :confused:

Talk about wasted space!
Tonights 1 hr episode was 1.73GB
Tivo DVD unit is Humax DRT-800
Does anyone have a good explanation?

[petew]

The quality setting defines the resolution and Maximum bitrate, which in turn defines the maximum Mb/hr. However if you are recording a show with a stationary background the bitrate needed to record forground movement will be less than the maxium so the resulting file will be smaller.

3 Suggestions:

1) Try using High instead, most people won't notice the difference.
2) Use a DVD-RW for initial extraction and re-record to DVD-R on your computer.
3) Use Tivo To-Go to transfer to your computer.

[Stanley Rohner]

Don't you get eye strain watching the sopranos on the tiny ipod screen ?

Don't you have a TV ?

[gastrof]

This all sounds pretty odd to me.

My STAND ALONE DVD-recorder uses a full disc for each and every hour of recording that I do at the best quality setting.

Makes no difference what it is, it always fills the entire disc. (Okay...it leaves maybe a minute extra unused.)

You can even see the whole disc has been "laser etched" if you turn it over and compare it to an unrecorded disc.

[Ipaqjoe]

Stanley
Yes I have a TV & no I don't get eye strain watching shows on my ipod.
I have to have something to do at work :rolleyes:

Petew
I think you mis-understood my question.
I am recording at the best quality that my Tivo will produce and it tells me that my 1 hour show requires 99% of a full blank DVD (which holds 4.7GB when empty)

Once I record the show and put it into my computer the disc only contains 1.73GB of data (much less than 50% of what it can really hold) even though my Tivo told me it will use 99% of the space.

Why is the Tivo telling me the disc is full, when in reality it isn't even half full.
If the Tivo's space calculator were correct I should be able to fit 2 hours of the same bitrate/program on that DVD, not 1 hour.

If I request to put (2) 1hr episodes of the same exact show my Tivo would ask for (2) DVD's even though in total the data would only take up less than 1 blank 4.7GB disc.

What is my Tivo doing with all of that extra space on the DVD & why won't it let me put it to good use? It is basically closing the session before all the space is used up.


1) Try using High instead, most people won't notice the difference.
Not the point, if I could I would record in an even higher bit rate since my Tivo can't even fill up one blank DVD per/hour at the highest setting

2) Use a DVD-RW for initial extraction and re-record to DVD-R on your computer.
Doesn't apply either since I archive the DVD-R when I am done anyway, good idea if I were concerned with filling up half empty DVD's though.

3) Use Tivo To-Go to transfer to your computer.
My Humax Tivo is on wireless, waay to slow, plus moving from DVD to ipod is 100 times faster than suffering through tivo-to-go - ipod (it's all in the dvd ready codec the Humax records in)

Although your 3 ideas are appreciated, it doesn't address my question.

[Ipaqjoe]

This all sounds pretty odd to me.

My STAND ALONE DVD-recorder uses a full disc for each and every hour of recording that I do at the best quality setting.

Makes no difference what it is, it always fills the entire disc. (Okay...it leaves maybe a minute extra unused.)

You can even see the whole disc has been "laser etched" if you turn it over and compare it to an unrecorded disc.

Not so with my Humax.
A disc which my Humax said will fill a blank disc 99%
-Flip it over and you can see only half of it was used :mad:

[TydalForce]

there's different methods of DVD compression.

Some devices will use the same compression rate regardless of content. Depending on what its compressing, this can yield a variable file size

Others will compress "as much as needed" to fit a space. It'll use the least amount of compression needed to fit the video into the space provided.

It sounds like the former is how the OPs TiVo is working, using the "fixed" compression and leaving a lot of free space. Gastrof's standalone is saying"I've got 4.7GB and I'm gonna use all of it!"

[Ipaqjoe]

there's different methods of DVD compression.

Some devices will use the same compression rate regardless of content. Depending on what its compressing, this can yield a variable file size

Others will compress "as much as needed" to fit a space. It'll use the least amount of compression needed to fit the video into the space provided.

It sounds like the former is how the OPs TiVo is working, using the "fixed" compression and leaving a lot of free space. Gastrof's standalone is saying"I've got 4.7GB and I'm gonna use all of it!"

Do other DVD Tivo users see this or is this a Humax thing?
What do we have?
-Pioneer
-Humax
-Toshiba
-Is that it...

[Stanley Rohner]

When I burn DVDs on my computer at the highest quality settings I can get about 2 hours on 1 DVD.

I tried it again just now. I opened up a 1 hour episode of DR. WHO off the PC hard drive. It was recorded off DIRECTV via s-video using my PC video card. The file was saved on the hard drive in DVD quality setting.

The DVD burning software reports -Total space used: - 1.48 out of 4.38 GB.

The aspect ratio is set to: 4:3
The quality settings is set to - High quailty
The sample format is set to - progressive
The encoding mode is set to - high Quality (2-pass VBR)

[wscannell]

I believe what the TiVo does is to allocate space on the DVD based on the quality the show was recorded at. It does not seem to matter how much hard drive space is used to store the recording. As stated by a previous poster, the TiVo compresses the video as it recorded. When there is less motion in the video, the recording takes less space on the hard drive. When the video is recorded to DVD, the TiVo does not re-encode the video. It is copied as it is stored on the hard drive (although things are added such as menus and chapters and other DVD formatting). This will result in some space on the DVD being not used for a program that has less motion compared to say a sporting event where there is a lot of motion.

[Bai Shen]

I have a Pioneer unit, and I haven't seen this problem, but then I haven't looked either. I record at med quality('bout a gig an hour), an' I can fit 4 shows on one disc. So AFAIK, it's using up the full disc.

[evilipoo]

FWIW--
Pioneer dvr810H...
Always record on best quality b/c playback will be on a 60" monitor and there is a ginourmos difference between best and second best :)
I only get 1 hr per disc no matter what.

[rjlawrencejr]

Petew's suggestion of using a DVD-RW is right on. Whenever I have programming that I want to transfer to my unit, I always use RW unless it something I am also going to keep otherwise. As far as whether it used only about a third of the available disk space versus the entire disk, I think, is inconsequential.

To answer Stanley Rohner's question about eye strain when watching video on an iPod (or like screen), it sounds as though he/you has never used one since at a distance of about six to twelve inches away from your face, you will see about the about the same as a standard tv screen, "remember that a 2.5-inch screen a foot from your face fills as much of your vision as a much larger screen that's across the room" (Pogue, 2005, http://query.nytimes.com/gst/fullpage.html?res=9806EFDA123FF933A15753C1A9639C8B63).

[Dan203]

I just discovered this problem myself. I recorded a 1:05 recording at Best quality, and according to the Toshiba it was going to require 2 disks to burn. However when I copied it to my PC using TTG it was only 2.4GB.

It seems really stupid that they use DVD allocations based on CBR encoding, when the videos themselves are obviously encoded using VBR.

Dan

[wscannell]

Another thing for the TiVo enhancement list.

[Chester_Lampwick]

I recorded "9-11" on CBS last month. It was 2 hrs long and I recorded it in "Best". For some reason it wanted 3 discs! After I imported the discs I was going to combine them and use DVDShrink to put on one DVD. I didn't need to, all three discs added up to less than 4.7GB!
It's odd sometimes. Maybe I had "Save disk space" enabled, I don't know...

[Bill McNeal]

Another thing for the TiVo enhancement list.

Would this be an update from TiVo for DVD users only, or require a Humax/Toshiba firmware upgrade?

[wscannell]

I would assume that IF TiVo fixed this issue, it would be fixed in the TiVo software that gets periodically updated. It will only affect the DVD users, but my guess is that it would be done as part of a general update. However, there is no guarantee that it will ever get fixed.

[Dan203]

Maybe I had "Save disk space" enabled, I don't know...

There is no "Save disk space" option on the S2 TiVos. That was an option on the S1 units, but apparently the S2 units use VBR automatically for everything.

Dan

[Bai Shen]

There is no "Save disk space" option on the S2 TiVos. That was an option on the S1 units, but apparently the S2 units use VBR automatically for everything.

Dan

Really? My file sizes are pretty consitant across the board.

[IEBA]

A couple things seem to be going on here.

I do not know the exact compression TiVo uses for their DVD units, it could be CBR (constant Bit Rate) or VBR (variable bit rate) and even VBR has a couple ways of compressing to improve quality and reduce data rate (single pass ascribes different bits for different parts of the program as it encounters them, multipass looks over the whole program first, and then assigns bits knowing full well what is needed by different parts of the show.)

CBR and Single-pass VBR can be done in realtime by hardware. Multi-pass, by it's nature, needs to look at the whole program before compressing.

Note that non-DVD TiVo units use different compression than DVD units because they do not have to meet DVD specification for the compression of the video. Also, non-TiVo DVD units also allow for manual bit-rate selection and other options that TiVo does not, perhaps for the sake of simplicity. (I'm fine with that.)

I've not tried to record in Best because I prefer more content on a disk.
But I do television production and have been handling digital video on computers for over 12 years. You can specify "best" and the computer will "allow" the video 7 Megabits per second, but the video itself may not need it, and, after compression, doesn't use it- especially if VBR is used. For instance, if you recorded a nature program with lots of wide open shots, darkness, etc, it _will_ use a lot less data than if you tuned TiVo to a channel with no content and recorded "snow" for an hour. The random nature and constantly changing nature of a "snow" channel will require far more data to preserve than a 20 second pan of the sahara desert with a voice over.

So TiVo doesn't know what the video will need, so it seems allocates DVDV disk space based on CBR- the upper limit of data available at a given quality setting. At the same time, it looks like it uses VBR to keep the upper limit of the data only as high as needed. So instead of a 7 Mbps stream, a Best video may use only 5 Mbps at the most, and even lower. The DVD Spec allows for rates as high as 13 Mbps in commercial/ professional players. This data rate would likely choke consumer players. But I digress.

I record content for my father who lives in rural Alaska and has no TV. I record everything at EP because he devours content. So I put 6 hours of content on a disk. At this low data rate, TiVo is forced to use every bit available to it so that it can produce the best picture it can with allowable bits- usually a pretty crappy picture, especially with fast sports action. Compared to "best" not using all the bits and working well under the ceiling imposed by the "Best" quality selection, EP is too low to provide quality video and the compressor is smashed against the upper data rate threshold. Maybe the only time it doesn't use the maximum allowable data is when a show has faded to black. :)

So when I make disks of 6 shows, it is full to the edge, every single time.

Given that Best may be much more than is needed, except for a few seconds per show, you can probably step down to the next highest level and probably not see a difference. Maybe. Right now I'm frustrated with my video looking very dark, but I'm sure that's not a compression issue, it's a low luminance issue that I also see in the menu screens- which are not compressed video.

[Bai Shen]

That's possible. I do all of my recording at medium.

[wscannell]

A couple things seem to be going on here.

I do not know the exact compression TiVo uses for their DVD units, it could be CBR (constant Bit Rate) or VBR (variable bit rate) and even VBR has a couple ways of compressing to improve quality and reduce data rate (single pass ascribes different bits for different parts of the program as it encounters them, multipass looks over the whole program first, and then assigns bits knowing full well what is needed by different parts of the show.)

CBR and Single-pass VBR can be done in realtime by hardware. Multi-pass, by it's nature, needs to look at the whole program before compressing.

Note that non-DVD TiVo units use different compression than DVD units because they do not have to meet DVD specification for the compression of the video. Also, non-TiVo DVD units also allow for manual bit-rate selection and other options that TiVo does not, perhaps for the sake of simplicity. (I'm fine with that.)

I've not tried to record in Best because I prefer more content on a disk.
But I do television production and have been handling digital video on computers for over 12 years. You can specify "best" and the computer will "allow" the video 7 Megabits per second, but the video itself may not need it, and, after compression, doesn't use it- especially if VBR is used. For instance, if you recorded a nature program with lots of wide open shots, darkness, etc, it _will_ use a lot less data than if you tuned TiVo to a channel with no content and recorded "snow" for an hour. The random nature and constantly changing nature of a "snow" channel will require far more data to preserve than a 20 second pan of the sahara desert with a voice over.

So TiVo doesn't know what the video will need, so it seems allocates DVDV disk space based on CBR- the upper limit of data available at a given quality setting. At the same time, it looks like it uses VBR to keep the upper limit of the data only as high as needed. So instead of a 7 Mbps stream, a Best video may use only 5 Mbps at the most, and even lower. The DVD Spec allows for rates as high as 13 Mbps in commercial/ professional players. This data rate would likely choke consumer players. But I digress.

I record content for my father who lives in rural Alaska and has no TV. I record everything at EP because he devours content. So I put 6 hours of content on a disk. At this low data rate, TiVo is forced to use every bit available to it so that it can produce the best picture it can with allowable bits- usually a pretty crappy picture, especially with fast sports action. Compared to "best" not using all the bits and working well under the ceiling imposed by the "Best" quality selection, EP is too low to provide quality video and the compressor is smashed against the upper data rate threshold. Maybe the only time it doesn't use the maximum allowable data is when a show has faded to black. :)

So when I make disks of 6 shows, it is full to the edge, every single time.

Given that Best may be much more than is needed, except for a few seconds per show, you can probably step down to the next highest level and probably not see a difference. Maybe. Right now I'm frustrated with my video looking very dark, but I'm sure that's not a compression issue, it's a low luminance issue that I also see in the menu screens- which are not compressed video.
I do not disagree with what you are saying. However, the point in this thread is that the TiVo has already recorded the program on the hard drive. The size of the recording is already known when you Save to DVD. So why can't the TiVo put as much as will fit on the DVD, rather than allocate the maximum amount of space and only use what it needs to save the file on the DVD.

I have seen this because I accidentally saved a couple episodes of a series that did not record the correct channel. If you look at the space used on the TiVo for a black sreen recording, it is much less than an actual recording. However, the TiVo did not allow any more episodes to fit on the DVD.

[IEBA]

However, the point in this thread is that the TiVo has already recorded the program on the hard drive. The size of the recording is already known when you Save to DVD. So why can't the TiVo put as much as will fit on the DVD, rather than allocate the maximum amount of space and only use what it needs to save the file on the DVD.

Because it's not that smart?

I don't program the buggers (or there'd be a few things I'd change) but there's no way for TiVo to "know" the exact amount of data a show ended up using, if it didn't use all available bits, unless it was programmed not to use standard size chunks (XP, SP, LP, EP) and look at the infinitely variable amount of data that a program actually used.

To wit, if an hour program didn't fill a disk at XP, but more took 63.2% then what would you do with that DVD? You'd have to find a show that took 36.8% - minus the overhead for all the motion menus and other data, those do take up space on the disk too.

So it's not going to be another hour program at XP that takes up 36.8%, so maybe a half hour show. But then, as I speculated, any show will have a final size (in MB) that is dependent on the content within that show, which is infinitely variable. In fact, I bet if we recorded the same show twice using the same XP settings, the actual file size would differ a bit and not be exactly the same.

So, unless you also have a few shows you record at LP or EP where you know exactly how big the show is on the hard drive (17% or 25%, etc) then you aren't going to be able to use the rest of that DVD anyway.

It is far simpler, and faster (I think) for the system to only keep track of 4 compression settings and then base the potential size of the show copied to DVD on the top data rate. If you think you're wasting disk space, use a lower rate. But DVD-Rs are what? 29¢? I'm not going to sweat over wasting 36.8% of 29¢.

:)

[wscannell]

If you have a program that is already stored on the hard drive and takes up say 1.2GB, then since the TiVo does not transcode the video before storing it, it should know the amount of space it will take on a DVD. Maybe ass 10% to be safe? Then you can fit whatever programs will fit in the remaining space.

However, the probable reason that it does not do this is because the logic for deciding what shows could fit in the remaining space would be somewhat more complex. So what it does is go by the maximum amount of space that a program will use.

The point is, it does know how much space the program takes up. The program is already recorded to the hard drive.

[Chester_Lampwick]

It's much easier for the consumer to use a static time per DVD equation. Would you rather wonder why your 90 minute movie didn't fit on a single DVD when the last 140 minute movie did with the same quality setting?