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fpnc

macrumors 68000
Original poster
Oct 30, 2002
1,979
134
San Diego, CA
I just downloaded the newly released "HD" version of "Top Gear, Season 14" and although the video quality is quite good I noticed that the encoding size on the first episode is 960x720 (playback is stretched to 1280x720 to maintain the correct 16:9 aspect ratio). I suspect that Apple did this because the series is recorded in PAL at 25fps (BBC in the U.K.) and the Apple TV can only handle full-resolution 720p at 24fps. Note that 960x720 isn't even XGA which is 1024×768 (the latter is the LCD resolution on the iPad).

This seems like a case of false advertising since I'm pretty certain that 960x720 does not fall within the technical specification of 16:9 HDTV. It's clearly better than the standard definition version but this is a case where the decoding limits on the Apple TV are really starting to show.

It's also apparent that some of the location shooting in "Top Gear" is still being done in SD. You can definitely see when they switch to SD during some of the car interior shots while on the road. Of course, this latter is not Apple's fault and all of the exterior shots, roadside scenery, and in-studio portions are recorded in HD.

In any case, I really don't think Apple should be selling 960x720 as "HD." By the way, the SD version is encoded at 640x480 and then stretched to 853x480 (anamorphic or enhanced for widescreen TVs).
 

Ritsuka

Cancelled
Sep 3, 2006
1,464
968
Or maybe Apple didn't encoded them, and the one who did the encode used Compressor, known to do crappy anamorphic stuff if the video is 25fps.

AppleTV can handle 720p at 25fps.
 

fpnc

macrumors 68000
Original poster
Oct 30, 2002
1,979
134
San Diego, CA
960x720 is 720p, it is just a 4x3 frame. 1280x720 is 16x9.
Yes, but "Top Gear" is in 16:9 format, as I mentioned in my original post.

In fact, I just checked several more "HD" TV shows that I've gotten off of iTunes and it seems that many are encoded at only 960x720. Seems like only the TV shows that are produced at 24fps are done at full 720p (1280x720). Anything done at 25fps or 30fps is encoded at 960x720 (and this content is in widescreen, 16:9 aspect ratios, it's stretched to 1280 on "actual size" playback).

As for the comment about the Apple TV doing 720p at 25fps, that's not what Apple says in their literature about the Apple TV. Also, I recently tried to encode a 1280x720 video at 25fps and iTunes wouldn't allow that video to be transferred to the Apple TV (complained that it wasn't in the correct format). I then encoded that same clip at 24fps 720p and it transferred and played on the Apple TV.

As for who does the encoding, I don't think that Apple does any of it, it's done by the content providers but that still doesn't let Apple off the hook. In my opinion Apple shouldn't market these as "HD" if they aren't at least encoded at full 720p (1280x720 for 16:9 content).
 

dynaflash

macrumors 68020
Mar 27, 2003
2,119
8
I have several 1280 x 720 25fps movies on my atv, also as a note I used cabac ... which is also not in apples literature.
 

jaw04005

macrumors 601
Aug 19, 2003
4,514
402
AR
HD video is only defined by the number of lines in the vertical display resolution because of varying aspect ratios. In fact, technically anything above 480 scan lines can be considered HD. That’s why some of the early plasmas that had a resolution of only 800x600 were still marketed as HD displays.

While 1280x720 and 1920x1080 are common standard HD resolutions for TV broadcast, there are other non-standard resolutions like 960x720 that are classified as HD also.

If Top Gear is filmed in 16:9, I would report the videos in question to iTunes Store support. Clearly, there was an encoding issue. They probably won’t do anything about it (they never fixed the House episodes I reported or the music video I reported that was mislabeled), but they gave me free video credits.

As for 960x720, that would the correct “720p format” for films with certain aspect ratios that need to fit within 4:3. Disney’s Snow White and the Seven Dwarfs (960x720) and Pinocchio (976x720) would be an example or even The Wizard of Oz (992x720)*. There’s no other 720p alternative for films like this.

* These are just estimates from ripping the Blu-ray disc to 720 and may be slightly off due to encoding, cropping, etc.
 

ftaok

macrumors 603
Jan 23, 2002
6,487
1,572
East Coast
At one point, the CEA definition of HD (for equipment, not transmission) was any display of 16:9 aspect ratio with at least 720 horizontal lines. This allowed 1024x768 plasmas with rectangular pixels to carry the HDTV logo.

The ATSC (for us Americans) didn’t explicitly define HDTV, but the ATSC standard for HD transmissions is 1280x720/60p; 1980x1080/60i; and 1980x1080/60p. There are other resolutions under the ATSC banner, but they’re more or less EDTV resolutions.
 

jaw04005

macrumors 601
Aug 19, 2003
4,514
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AR
At one point, the CEA definition of HD (for equipment, not transmission) was any display of 16:9 aspect ratio with at least 720 horizontal lines.This allowed 1024x768 plasmas with rectangular pixels to carry the HDTV logo.

You mean vertical, right?

And here’s the CEA exact definitions:

HIGH- DEFINITION TELEVISION (HDTV): HDTV refers to a complete product/ system with the following minimum performance attributes:

Receiver—Receives ATSC terrestrial digital transmissions and decodes all ATSC Table 3 video formats
Display Scanning Format—Has active vertical scanning lines of 720 progressive (720p), 1080 interlaced (1080i), or higher
Aspect Ratio—Capable of displaying a 16:9 image*
Audio—Receives and reproduces, and/or outputs Dolby Digital audio

*In specifications found on product literature and in owner’s manuals, manufacturers are required to disclose the number of vertical scanning lines in the 16:9 viewable area, which must be 540p, 810i or higher to meet the definition of HDTV.

Apple would qualify under the CEA definition. However, it’s specifically referring to hardware not the encoded video, and not everyone follows the CEA. So, again, it’s practically a marketing free-for-all.

http://www.ce.org/PDF/DTV_Definitions.pdf
 

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dynaflash

macrumors 68020
Mar 27, 2003
2,119
8
To be honest I kinda get sick of this whole "HD" thing. As was said, it only refers to vertical lines of resolution. And as I have said before in other threads. I can make a 700 kbps 1080p movies that will look like crap. Imho the whole "720p" thing is a bit oversimplified to determine how good a video looks. Vertical lines of resolution will get you only one measurement which is the actual frame size ( and even at that only the vertical measurement ).

Consider for example that HB will use a specific width and scale height based on Aspect ratio. So a 1280 width will often times come up < 720 height as the aspect ratio increases, which is quite common. So are these encodes any less "HD" ?

If you were to say fix the height of a 1080p source at 720 ( so you could say it was true 720p ) and adjust the width for the aspect ratio quite often you would end up > a 1280 width.
 

ftaok

macrumors 603
Jan 23, 2002
6,487
1,572
East Coast
You mean vertical, right?
Nope, I mean horizontal lines. Vertical scanning lines refers to the horizontal lines running across your screen.

720p is the shorthand name for a category of HDTV video modes. The number 720 stands for the 720 horizontal scan lines of display resolution (also known as 720 pixels of vertical resolution), while the letter p stands for progressive scan or non-interlaced.

Link
 

tommylotto

macrumors regular
Jan 7, 2004
203
0
The CEA definition only applies to display hardware -- not the definition of HD signals which are only 1280x720p, 1920x1080i or 1920x1080p

This is a very old battle. DirecTV with its MPEG-2 broadcasts used to covert their 1080i signals from 1920x1080i to 1280x1080i by changing the aspect ratio of the pixels. That reduces the actual resolution from CBS, NBC HBO, etc. by one third. Is that an HD broadcast? I do not think so.

There is still a class action pending in CA on the issue, but it is having trouble getting certification...
 

tommylotto

macrumors regular
Jan 7, 2004
203
0
Consider for example that HB will use a specific width and scale height based on Aspect ratio. So a 1280 width will often times come up < 720 height as the aspect ratio increases, which is quite common. So are these encodes any less "HD" ?

You are talking about aspect ratios wider than 16:9 where there necessarily will be black bars on the top and bottom of the screen. When encoding that file, there is no need to encode the black as the bars can be generated by the AppleTV or whatever. The original poster is talking about something different -- reducing the horizontal resolution (to reduce file size) then changing the pixel aspect ratio (to make it 16:9). The former is necessary to provide the file in original aspect ratio. The latter is cheating quality to save bandwidth.
 

jaw04005

macrumors 601
Aug 19, 2003
4,514
402
AR
That can't be right; a standard PAL DVD (720x576) is certainly not considered HD.

The question is considered by who?

If it was 576p, it would be in the U.S. according to the CEA.

"In specifications found on product literature and in owner’s manuals, manufacturers are required to disclose the number of vertical scanning lines in the 16:9 viewable area, which must be 540p, 810i or higher to meet the definition of HDTV.”

See link in my post above. However, the CEA is referring to hardware not content.

As far as I know, there’s no standard for what classifies content as HD. In the United States, the ATSC provides a chart that specifies 720p and 1080i, but again that’s what the TV stations have to broadcast and clearly most of what gets broadcasts is just upscaled to those resolutions.

In Australia, apparently 576p50 is actually part of their HD standard broadcast resolutions.

http://en.wikipedia.org/wiki/576p

Interesting article that tries to define HD:

http://www.highdef.com/library/hddefined.htm
 

tommylotto

macrumors regular
Jan 7, 2004
203
0
In Australia, apparently 576p50 is actually part of their HD standard broadcast resolutions.

Wikipedia is hardly a definitive source. Anyway, when I checked that article (maybe someone changed it, who knows), it indicated that when the frame rate was doubled to 50, it was considered EDTV -- enhanced, not high definition. The equivalent of our 480p.

The question, I think is whether the consumer is being deceived. If the content provider is intentionally reducing the resolution and tinkering with the pixel aspect ratio to reduce quality and save bandwidth, then the consumer is being deceived. The solution, obviously, is to disclose the resolution (both horizontal and vertical) on the splash screen before a purchase is made. If they are reluctant to disclose the actual resolution before a purchase and are pawning their content as HD after playing trick to reduce quality and save bandwidth, then you know something shady is going on...
 

rayward

macrumors 68000
Mar 13, 2007
1,697
88
Houston, TX
FWIW, I understand that Apple TV will flag as "HD", anything that has a resolution greater than 480x. 481i, for example, would be flagged as "HD".
 

fpnc

macrumors 68000
Original poster
Oct 30, 2002
1,979
134
San Diego, CA
I have several 1280 x 720 25fps movies on my atv, also as a note I used cabac ... which is also not in apples literature.
But how are you getting these 25fps 720p movies to your Apple TV? Do you transfer them using iTunes or have you hacked your Apple TV to allow you to transfer content using FTP or some other non-iTunes method?

I've seen reports where people have used FTP to transfer 25fps 720p movies over to the Apple TV and these users report that the Apple TV will play that content. However, that's different than using a completely unhacked Apple TV where it appears that the iTunes application itself limits 720p movies to 24fps (maximum).
 

ss957916

macrumors 6502a
Jun 17, 2009
861
0
I work in TV - and that's why I haven't invested in HD. So much stuff is actually just upscaled. I've just done a 10-part series which was shot in SD but is being advertised as HD.

I suspect Apple are just doing the same.
 

fpnc

macrumors 68000
Original poster
Oct 30, 2002
1,979
134
San Diego, CA
fpnc said:
I noticed that the encoding size on the first episode is 960x720 (playback is stretched to 1280x720 to maintain the correct 16:9 aspect ratio).
Nermal said:
How did you determine that?
You can use the movie info feature of QuickTime Player and it will indicate the encoded resolution (960x720 in the case of the "Top Gear" episode) and also the current size of the playback (1280x720 for the video in question).

When I checked other HD TV shows that I had gotten from iTunes there was a definite pattern. Anything that was 24/23.98 fps had a horizontal resolution of 1280. However, HD TV shows that were either 25fps or 30/29.97 fps had a horizontal resolution of 960.

Standard definition TV shows were usually 640x480 with a 640x480 playback size for 4:3 content or an 853x480 playback size for 16:9 content (the latter enhanced for widescreen TV playback similar to anamorphic DVDs).

I guess this isn't too surprising since Apple indicates that the Apple TV can only decode 1280x720 at 24fps (maximum). Thus, anything higher than 24fps would be limited to 960x540 (one quarter of 1080i/p) or 960x720 (which seems to be common for a good number of the "HD" TV shows on the iTunes Store).

I'm going to check to see if networks that are known to broadcast in 1080i are encoding their iTunes HD content at 960x540. If so, that would even be worse than the 960x720 content that I've already found.

Of course, all of the above may be scaled even further depending upon the resolution setting on your Apple TV/HD TV. Thus, if you set your Apple TV for 1080i/p output then all of the above are further scaled to fit the resolution of your TV.
 

tommylotto

macrumors regular
Jan 7, 2004
203
0
I work in TV - and that's why I haven't invested in HD. So much stuff is actually just upscaled. I've just done a 10-part series which was shot in SD but is being advertised as HD.

I suspect Apple are just doing the same.

Once again, you are talking about acquisition, not transmission. The original poster was talking about transmission. The HD chain goes like this: acquisition, transmission and display. All three need to be HD to get a true HD experience. The Camera or telecine needs to capture the source at an HD resolution. Then it needs to be transmitted as an HD signal, or with the case of AppleTV downloaded in a file that is at HD. Finally the signal needs to be displayed on an HD capable TV. However, one transgression does not forgive another. If you watch HD on an EDTV, it is your fault. If the content provider just upscales the source material, it is the content provider's fault -- Or Apple's fault if they are the one who did the up scaling. Finally, what the original poster is alleging is transmission misrepresentation. If Apple takes an HD source from the content provider, down rezzes it and transmits a lower resolution version of the source material to save bandwidth, then Apple is cheating the consumer. It might be technically necessary due to the limitations of the AppleTV, but that is no excuse for not disclosing the reduction of resolution to the consumer before the purchase.
 

fpnc

macrumors 68000
Original poster
Oct 30, 2002
1,979
134
San Diego, CA
FWIW, I understand that Apple TV will flag as "HD", anything that has a resolution greater than 480x. 481i, for example, would be flagged as "HD".
I believe that is true. However, that's a little bit different than selling widescreen/16:9 content that has a horizontal resolution below 1280 and still calling it "HD TV."
 

fpnc

macrumors 68000
Original poster
Oct 30, 2002
1,979
134
San Diego, CA
...It might be technically necessary due to the limitations of the AppleTV, but that is no excuse for not disclosing the reduction of resolution to the consumer before the purchase.
That's the key to this issue. Apple really should state the encoded resolution for the "HD" content that they sell on the iTunes Store. I suspect that Apple isn't alone in this situation because if everyone else (Amazon, Microsoft, Vudu) was actually selling HDTV shows at 1280x720 or full 1080i/p then I'd suspect that Apple could be setting themselves up for a class action lawsuit.

I'd admit that this is kind of a gray area since bitrate can make as much of a difference as the encoding resolution. Case in point, is 1080p at 2Mbps really as "HD" as 720p at 4Mbps?
 

Nermal

Moderator
Staff member
Dec 7, 2002
20,644
4,044
New Zealand
You can use the movie info feature of QuickTime Player and it will indicate the encoded resolution (960x720 in the case of the "Top Gear" episode) and also the current size of the playback (1280x720 for the video in question).

Interesting. I have some video from iTunes that's definitely in 1280x720. I've also looked at an 853x480 SD video and confirmed that it's actually 640x480 internally (so I know that I'm looking in the right place).

So, not all of the HD content is scaled down.
 
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