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I've seen it on a few Unbox videos as well. I think the worst one I saw was Casino Royal, which had several scenes which were just painful to watch.

Glad to hear the "Bourne" movies are OK though. I was going to download them to watch again before seeing the new one, but I was a little worried about the quality after having watched Casino Royal. Sounds like they're OK though, so I think I'm going to give them a shot.

Dan
 

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One possible explanation for these quality problems could be framerate conversion. TiVos only support video with a frame rate of 29.97fps. Some movies are actually filmed at 24fps. That means that Amazon has to use some sort of framerate conversion to make them compatible with TiVo. There are various methods for doing framerate conversion, and some work better then others. These sort of motion artifacts are actually characteristic of some of the poorer techniques.

If it is a framerate conversion problem, then it would explain why it only effects some movies as only some use the 24fps "film mode".

Dan
 

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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. 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).
While it may be true that most movies are shot at 24fps, not ALL are converted to 29.97fps by the studio. For DVDs 24fps "film mode" is a legal framerate, so there are movies out there that are simply encoded to MPEG2 in their native 24fps. The reason most studios do the conversion on their end is because when a DVD is in 24fps "film mode" it has to depend on the hardware in the DVD player to do the 3:2 pull down. And since, as you pointed out below, there are some really cheap and crappy DVD players out there most studios do the conversion on their end to prevent quality problems.

I have no idea where, or in whatformat, Amazon is getting their content. I assumed that they were simply ripping it from DVDs or using the same MPEG2 data stored on DVDs as their source. However it could be anything from uncompressed original digital conversions to already compressed MPEG4. But in any case it's still possible that the source is 24fps and is having to be converted to 29.97fps for TiVo. (PCs using the Unbox software can play 24fps content just fine, so the TiVo version would be the only one that needed converting)

In any case it was just a theory. Only Amazon, and possibly TiVo, knows what the real problem is.

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, since they are almost certainly encoded at a variable bit-rate. As the complexity of the scene increases, so does the bit rate. You will sometime see these problems in low-end DVD players for the same reason, and is likely the reason you see it in other cheap hardware.
As pointed out above the quality issues exist even on the S3 units, which have more then enough power to decode HD at 10 times the bitrate of Unbox movies. So seriously doubt this is a hardware issue within the TiVo itself.

Dan
 
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