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Atomike said:
This is not the problem. ALL movies are shot in 24 frames per second - it's the rate film is recorded as an industry standard.
That's not quite true. It is one industry standard, but not the only one. It is the most common. Imax films, for example, are shot at 60fps. Not only that, but many films today are shot in part on video. Also - I know this is a nitpick - it's the playback which is 24fps, or whatever. The film may be shot at 1 frame per second or even per minute, hour, or day for time-lapse photography and 100 fps or even faster for slow motion photography.

Atomike said:
ALL films are then converted to 29.97 fps - it's a process called 3:2 pulldown, and it is done all the time every day. If this was the problem, then all GhostRider DVDs would also exhibit this problem, since all DVDs are also converted to 29.97 fps (for north American NTSC anyway).
True.

Atomike said:
The more likely explanation for this problem is simply that the Tivo hardware can't keep up with the motion-intense bitrate of these scenes,
I seriously doubt that. After all, these are 480i SD content, and the TiVo can easily handle 1080i HD content whose compressed bitrate is over 5 times the bit rate of an SD stream. Note, however, the compressed bitrate does not vary only with scene complexity, but also with the level of compression. A highly compressed stream is harder to handle than a less compressed stream of the same content. On the other hand, the main burden is on the processor doing the compression, not the decoder.

Atomike said:
since they are almost certainly encoded at a variable bit-rate. As the complexity of the scene increases, so does the bit rate.
Yes, but the bit rate of even the most complex SD content doesn't match the bit rate of the average 1080i offering. Not only that, but the scenes they showed in the sample screenshots didn't look very complex. Of course, it's hard to say just from a still photograph, but the really difficult and complex scenes are things like drifting smoke, waving filelds of grain, or a swirling mob of people seen from above form a moderate distance. If every single pixel of the scene changes in value from one frame to the next, then it takes a huge bandwidth to comunicate the changes in the screen. If large areas have only moderate or no change from frame to frame, then communicating the changes takes much less bandwidth.

If someone has one of these Unbox videos on their PC, they could measure the bitrate in these areas to see just how high it is. I'd also be interested to know if they see the same artifacts on their PCs.

This begs the question, however. Why is there a problem with the Unbox videos and not the ones from CATV? I only have 1 Unbox video at this time. It's Hook with Robin Williams, Dustin Hoffman, and Julia Roberts. I'm not pleased with its quality, but only because it is SD, not HD. Nonetheless, it's average bitrate is 3.07Mbps. This falls pretty much in line with other SD recordings off CATV sources such as Finian's Rainbow at 2.70Mbps and Nova at 3.30Mbps. Compare that with HD offerings like Cellular at 16.0Mbps, Arthur at 13.0Mbps, and Planet Earth at a whopping 16.5Mbps average bit rate.
 

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Atomike said:
Hmmm. Not to be sarcastic, but do you think that Tivo (or Amazon) is sent rolls of film like the ones projected in movie theatres? No - I'd bet a donut that Tivo is SENT the film in a digital format, likely the same mpeg2 files that are on the DVD you buy at the store.
TiVo, meaning TiVo, Inc. isn't sent anything. This is an Amazon.com service hosted and maintained by Amazon.com. A TiVo is not required to utilize the service, nor does one have to own a TiVo or have any contract with or obligation to TiVo, Inc. to make use of the Unbox service. I'me sure TiVo gets a little bit of money from Amazon every time someone downloads an Unbox video to their TiVo, and there might be something with the TiVo hardware which is causing a problem with the Unbox videos not seen when using a PC, but TiVo, Inc. doesn't touch the video content.

Atomike said:
Also, although the images may not look complex to you, an encoder can find difficulty where the human eye cannot - many pixels may look similar, but are not. A completely white screen may in fact have each pixel as a slightly different shade, causing the bitrate to be be surprisingly large.
Well, half true. The first copy of the frame - probably an I-frame - would take a large amount of data. Subsequent frames would not take large amounts of data unless every pixel in the screen were changing. This would be noticed by the human eye. What's more, the reverse is not true at all. If it looks"busy" to the human eye, then it will be "busy" to the video processor. For that matter, a sudden change from solid black to solid white takes a large momentary burst of data. 'not as muchas from black to raster, but a heap nonetheless. So far, no one is reporting problems with visually busy scenes, just these apparently fluid scene transitions.
 
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