Disk space bar accuracy with HDTV files?

[jbuszkie]

Ok.. This was being discussed in the Hidded extras thread.. So I thought I'd move it here. I thought it might merit it's own thread....

This is all about the Disk space indicator not being accurate for HD files.

I've updated the diskspace bar to check for default recording quality of an encoder and assigned a custom bit rate for it. It all seems to work fine.

But there is a dilema...

I believe in Sage the priority

If airing has a quality assigned use it
Else if the encoder has a quality assigned use that default encoder quality
Else use the default recording quality.

Now I implemented this in the diskspace bar. BUT.....
Now if you have a favorite that has some set quality the disk space bar will use the airing quality number, not the encoder quality in it's calulation. but in real life it will still get recorded on the digital tuner and might be different.

Now If I change the priority to:

If the encoder has a quality assigned use that default encoder quality
ElseIf airing has a quality assigned use it
Else use the default recording quality.

But then this would make the calculations inaccurate for other situations.

Now I guess I could check to see if an encoder was a digital encoded and change the priority based on that, but that might get a little messy..

What do you guys think?

I think we should keep sage's priority scheme and live with the inaccuracy that happens when a favorite with and assigned quality is recorded on a digital tuner..

Jim

[Opus4]

Originally Posted by jbuszkie

Now I guess I could check to see if an encoder was a digital encoder

That is pretty much the only way to do it, since the recording quality settings have no meaning to a digital tuner. As was mentioned before, you would have to just make up some number for a digital recording (via properties, I suppose).

Other considerations:

Many recording qualities are variable bit rate, so they won't be entirely accurate.

Then, there are the custom network encoders that are in use... I'm not sure how you would determine a size estimate for their recordings.

- Andy

[jbuszkie]

Well the thought was to make it more accuate.. not perfect.

Maybe I'll see if I can do the Digital decoder detection.. I'm just worried that if I add too much code and loops it might make the refresh too slow?? It works fine for my test setup with only a couple fake shows to record, but if it has to calculate for 100 show???

[malore]

If you mostly record HD shows on your digital tuner than you could just use IsAiringHDTV to check for HD airings and base you space requirements off of that. An additional problem might be that I've noticed that shows vary is size from network to network for example my Fox shows are almost half the size of NBC shows.

[Kirby]

Originally Posted by malore

If you mostly record HD shows on your digital tuner than you could just use IsAiringHDTV to check for HD airings and base you space requirements off of that. An additional problem might be that I've noticed that shows vary is size from network to network for example my Fox shows are almost half the size of NBC shows.

Exactly. You've just picked a good example, NBC being 1920x1080i, and FOX is 1280x720p. That alone equates to roughly 15% size difference, and I am quite sure that FOX sends out a lower bitrate than what 720p can handle, accounting for the other 30% or so.

After thinking more about this, I am thinking it might be best to leave well enough alone. The only way to get accurate numbers is going to be on a per channel/per provider basis. FOX-HD on Comcast might be lower bitrate than on Charter, but both are probably higher that whats on DirecTV or Dishnetwork. Then throw in the whole HD-lite mess that satellite providers are sending, the move to MPEG4, statistical multiplexing, cable rate-shaping that can vary from headend to headend.....

What a mess!

[Humanzee]

If you can't detect which tuner it was recorded on can you detect what channel the program was recorded on? Our HD channels are distinct from the regular line up and I think are at a constant bit rate.

[jbuszkie]

Originally Posted by Humanzee

If you can't detect which tuner it was recorded on can you detect what channel the program was recorded on? Our HD channels are distinct from the regular line up and I think are at a constant bit rate.

Now there's a thought...
We could get the airing channel name and use that to determine the digital status... At least for me if anything ended with DT[0-9] in the channel name I could say that it was recorded digitally and used my 9GB/hr estimate.

Then from there it could be enhanced to look up a value from some text file based on the channel name and the ISAiringHDTV and grab a bitrate value..

hmm....

[Humanzee]

Originally Posted by jbuszkie

look up a value from some text file

There was some talk at one point about using show analyzer to detect things like aspect ratio so that it could be used by a plug in like neilm's automatic aspect ratio switcher. Jere said at the time that his program already detects lots of information about the recording that "could" be output as another file type.

If SA output a file that contained the overall length of a program, the overall file size, the bit rate, resolution, aspect ratio, etc. That info could be used in a variety of ways, combined with xml data from the web server about the favorite, the channel, the tuner, etc to create a matrix or database of information about a recording. Then when looking at upcoming recordings you could project what disk usage could be expected based on how the favorite/channel/encoder was recorded at in the past.

Now that would be a nice mountain to build out of a mole hill. We often hear complaints about not being able to access the mysteries inside of the wiz.bin, maybe its time we start an open source database in parallel with wiz.bin so that we can use it for our own purposes.

[Opus4]

Originally Posted by jbuszkie

We could get the airing channel name and use that to determine the digital status... At least for me if anything ended with DT[0-9] in the channel name I could say that it was recorded digitally and used my 9GB/hr estimate.

You may know this already, but just in case... search the default STV for "Digital_TV_Tuner" to see how to determine if something is a digital tuner.

The ParallelSchedules menu shows how to grab the schedule by encoder device. You should be able to walk through the schedule that way too, checking device type/quality settings once per tuner.

- Andy

[jbuszkie]

Wow! Now that would be complex! Having the program *learn* based on previous recodings to deterime future space requirements......

That's a little more accurate than I need.

I'll be satisfied If the estimate is greater than needed.
I just don't want to run out of space because the estimate
was too low.

I think what I'll do is

1. Release the modification as is... which basically will look for to see it the encoder has a default quality if there is no airing quality...

2. Then later...Enhance it to look for a digital tuner to override any Airing quality.

3. And much later...Then see about reading in a look up table that the user can set to base a bitrate based on channel name and HD status...


Jim

[jbuszkie]

Originally Posted by Opus4

You may know this already, but just in case... search the default STV for "Digital_TV_Tuner" to see how to determine if something is a digital tuner.

Yeah.. I already do that for some of my other plugins......

Originally Posted by Opus4

The ParallelSchedules menu shows how to grab the schedule by encoder device. You should be able to walk through the schedule that way too, checking device type/quality settings once per tuner.
- Andy

Yeah.. That's what I'm doing now...
for each encoder I look in it's schedule for the current airing to see if it's there then do the rest of the calc...

The channel name thing would be a way to get rid of doing the encoder loop...

Maybe the loops really won't be a big deal in terms of creating a delay...

[rfutscher]

You also have to check to see if Sage is recording the transport stream or the program stream. This is an option that can be set either way.

Originally Posted by Kirby

Exactly. You've just picked a good example, NBC being 1920x1080i, and FOX is 1280x720p. That alone equates to roughly 15% size difference, and I am quite sure that FOX sends out a lower bitrate than what 720p can handle, accounting for the other 30% or so.

After thinking more about this, I am thinking it might be best to leave well enough alone. The only way to get accurate numbers is going to be on a per channel/per provider basis. FOX-HD on Comcast might be lower bitrate than on Charter, but both are probably higher that whats on DirecTV or Dishnetwork. Then throw in the whole HD-lite mess that satellite providers are sending, the move to MPEG4, statistical multiplexing, cable rate-shaping that can vary from headend to headend.....

What a mess!

[Kirby]

I've never recorded a PS, how do they compare in size?