It looks like Fox, in their infinite wisdom, used this on last night's Simpsons repeat. I did a frame by frame compare of the opening montage and there are clearly deleted frames. If anyone has a capture on computer, it's easiest to see in the scene where Lisa first goes to the Buddhist temple; when it pans from Lisa & Carl & Lenny over to Richard Gere you can see the video jump unnaturally.
I'm really starting to dislike this 'technology', as I've now encountered it on NewsRadio (A&E), Cheers (Nick) and now, worst of all, Simpsons. They better not start using this on first-run episodes, 'cause if they do ... *shakes fist*
Oh, and last night's repeat was approximately 15 seconds shorter than when it aired last year.
That's not "Time Machine" compression. What you saw during that repeat was the common Varispeed time compression method -- the type used by the syndicators.
"Time Machine" compression is "intelligent," leaving no tell-tale signs that it is being used. For instance, it will cut frames out of frozen scenes (like establishing shots of the Simpsons' house), but never out of camera pans (where missing frames would instantly be noticed). Varispeed machines are comparitively less meticulous. They simply remove frames at even intervals without paying heed to what's happening in the video. (If you set up a varispeed machine to remove approximately 15 seconds from a 23 minute show, it would blindly cut every 34th frame from the video, even if some of those intervals occurred within scenes -- like camera pans -- where the lost frames would become obvious to viewers.)
In the last year or two, Fox has used varispeed machines to time- compress ALL the repeats of almost ALL of its shows. (One way to spot varispeed time compression -- besides missing frames in camera pans -- is to look for the cyclic vertical sharpening effect it adds to video. If you look closely at the cartoon outlines in the next Simpsons repeat on Fox, you'll notice that they appear to pop back and forth between a vertically "sharpened" and "normal" appearance. Kind of similar to: <http://www.snpp.com/staff/brian/varispeed.gif>. When that effect is visible, you know varispeed time compression is being used. You'll see it in almost all of Fox's repeats, including in repeats of their live action shows -- if you look close enough.)
Believe it or not, but the producers themselves even used varispeed machines to time-compress the early seasons' master tapes. Watch the first act of "Blood Feud" (7F22) on Season 2 DVD #4 for example. At first, there's no time-compression. But when Homer makes his remark about there being no power to light the warning sign, the varispeed time-compression begins. (The cycling vertical sharpness artifact becomes visible.) And moments later, when Hibbert says "In layman's terms, it's quite simply a lack of blood," the varispeed compression comes to an end. Anyway, you'll see this happen throughout all the episodes on those DVDs, depending upon which scenes the producers originally decided to time-compress for "impact."
You were probably seeing varispeed time compression in those too. Again, "Time Machine" style time compression can't be seen. The only way to tell if the "Time Machine" is being used is to measure the actual length of the broadcast, and see whether it's shorter than normal.
P.S. - There are digital and analog versions of varispeed machines, but only the analog versions produce the cycling vertical sharpening effect. The digital ones simply make vertical resolution look blurry on a continuous basis. (You can see the difference in the syndicated Simpsons episodes. During the first 8 seasons or so, the syndicators used analog varispeeds. Thereafter, they used digital ones, and so if you watch some random season 11 episode in syndication, you'll just see that all the horizontal cartoon outlines look vertically "smudged.")
The easiest way for me to see it is when text scrolls across the screen, like the "Disclaimer - The producers don't consider the Grammy an award at all." thing. You can see the words jump every few frames.
Wow, this is fascinating and its the first ive ever heard about it. I know a litle about audio editing and when ever you want change the length of a piece of audio (like say a loop you want to match in a songs bpm) you have two options of compression, a time stretch (which seems to work like the varispeed time compression, therefore keeping the pitch the same) or simply playing the sample faster(sorry, bad description but I dont know its real name, it would sound like playing a 33 record in 45 basically).
My question is this......if you were to compress the the video in way by speeding it up by such a small percetage, basically playing say 40fps as oposed to 38fps(i have no idea on the actuall fps by the way) then im sure they could cut 30 seconds or more off without making the audio really silly and high pitched.........Another question, surely with both the previous methods of compression you would have clips and blips in the audio.......unless they are edited out, I assumed this was done like though.
Unlike analog audio, which can be played at any speed, analog NTSC video can only operate at 30 frames/second (25 frames/second for PAL). That's because the protocols defining NTSC/PAL demand as much. All analog VCRs, analog tape formats, analog cable/satellite decoders, analog transmitters, analog video processors, etc. are therefore made to work only at 30/25 frames/second. (That's why those who designed the time-compression process chose the frame-dropping method in the first place. They had no other choice.) (Yes, modern "multisync" TVs can handle analog video at varying frame rates. But that capability was only added to them for NTSC customers wanting to watch PAL videos, and vice versa. The rest of the analog video infrastructure, though, can only deal with the standard 30/25 frame/second rates.)
Of course, varispeed machines *do* play video tapes at speeds above and below 30 frames per second. They're specially designed to do so. But they first A/D that video into a digital frame buffer which either repeats (time expansion) or deletes (time compression) frames as necessary to ensure that the frame buffer's D/A output always yields exactly 30 frames/second. (Specifically, the frame buffer can hold up to one complete frame worth of A/D'ed visual data, and works like a FIFO chip. If the incoming video is 31 fps, then the buffer will D/A the data SLOWER than it A/D's the input, causing itself to slowly fill. By the time the buffer finishes A/D'ing the 31st frame from the input, it will have simultaneously finished D/A'ing the 30th frame to the output. So at that point, the buffer simply empties itself (deleting the 31st frame just received from the input), and starts over again.)
It depends on the type of varispeed machine used. Some cheap models send the audio into the same digital buffer as the video, where the snippets of audio that coexist with each doomed frame get dropped along with those frames themselves. (In that case, you DO hear ugly "blips" in the soundtrack where each frame was dropped. For a good example, listen to where Homer honks his car horn while trapped at 'Discount Lion Safari' in "Old Money"/7F17 on the season 2 DVDs.)
But better machines process the sped-up audio separately from the video: it comes off the original tape at an increased speed (like a 45 RPM record playing at 46 RPM), but is then pitched down by a harmonizer-like circuit before being recorded to the dub tape. That way, while the recorder receives a "46 RPM" soundtrack, its pitch has been restored to that of the "45 RPM" original -- so that even while the characters talk faster, they don't sound like chipmunks.
Oh yeah, I noticed this on the Season 2 DVDs, but I thought it was because of the file compression. I think the episode that suffers most because of this is "Bart vs. Thanksgiving", which is pretty painful to look at in some scenes.