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Discussion Starter · #1 ·
I've been using TIVOs for several years (although I haven't been back to this forum for a couple years), however I just noticed something that I hadn't been aware of.
I'm using an old series 1 standalone TIVO, which is networked and have an old version of TIVOWEB and a couple other applications installed.
What I just noticed (not sure why I never noticed this before), is that I just made a 4 hour recording of 2 PBS programs (about French & Indian war, so there is plenty of action if that matters), and also made a recording of a 3 hour 40 min NFL football game (also plenty of action). I expected the 2 recordings to take up about the same space on the disk, however the 4 hour PBS program took up 5 GB of space on the hard drive, according to TIVOWEB, and the 3 hour 40 min football game took up over 7 GB of disk space.
I know this is probably a dumb question, but WHY. Both programs came from an an analog connection to a DTV displaying local channels. I thought that perhaps .mpg files might be smaller for programming with less action meaning less compression is possible, but both programs seemingly have quite a bit of action.
Anyway, WHY does the football game take up so much more space than a PBS show about colonial wars? Is it because there is more action and less compression possible for sporting events?
Thanks, and sorry for the dumb question.
 

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Discussion Starter · #3 ·
a4wanman said:
Where is TivoWeb can you check the size of each recording?
As I said, it's been a couple years since I've kept up with new things with TIVO. THe original TIVOWEB thing was at http://tivo.lightn.org/ , but it's been replaced by newer versions. I'm still using the old version, and I have no idea of what the new version does and doesn't do, and/or which versions of TIVO it works on. But yes, the version of TIVOWEB I'm using has a module which shows you your now-showing recordings, and shows their size and other things, and lets you edit the names, delete and undelete recordings, etc.
I just happened to be looking at recordings of similar length in time, and noticed that there were big differences in the amount of disk space they used, which I thought was unusual, but it probably has something to do with compressability.
 

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Compression ratios are more a function of how long a particular scene lasts, than the amount of action, per se. Despite there being lots of action in a war movie, given scenes go on for several minutes. In a football game, the camera angles are changed much more frequently.

When a scene change occurs, a new index frame must be written, which is full frame of video. After that, the MPEG alogrithm only records changes to that scene, until a new index frame is written. Bottom line is that a football game will likley have more index frames than a film.

So, assuming the same compression setting in the TiVo, the football game will be larger.
 
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