720p vs 1080p with HMC150

[Girlspitswater]

I have a few questions regarding 720p vs 1080p with the HMC150.

The bit rate is 24 mbps max for both 1280x720 and 1920x1080. I am concerned that the bit rate does not increase for recording in 1920x1080. Does this mean that there is image loss when recording in 1080?

I have also heard that the image chip in the camera is not large enough to capture true 1080 and therefore may be internally transcoding the image. Is this correct?

Finally, what are the pros and cons for recording in both 720p and 1080p for showing your work on both Blue Ray disk and for broadcast?

Any comments are appreciated! Thanks.

[Barry_Green]

The bitrate is the same. This does mean that, technically, the 720/24p is going to be less compressed than 1080/24p, and 720/30p will be less compressed than 1080/30p. In those cases the system has to cram twice as much image data into the same amount of bandwidth.

In 720/60p vs. 1080/60i, you're dealing with approximately the same number of pixels per second, so that should be more comparable; however, interlaced is harder to encode than progressive, so, still, I would expect 720/60p to be somewhat less compressed than 1080/60i.

In other words, yes, across the board, there's more compression efficiency for 720p than for 1080.

As for the chips, Panasonic's whitepaper on the chips shows them delivering about 1440 x 810 worth of resolved detail. 720p mode captures 1280x720. That means there is a tad more image detail available for 1080 mode to capture, but not enough to fully saturate the codec with detail. The captured resolved detail between 1080 and 720 will be a little different, maybe 10% different. However, 1080 mode allocates a lot more color information (they're both 4:2:0, but that means 960x540 chroma in 1080 mode, vs. 640x360 chroma in 720 mode). So you'll have more accurate color rendition in 1080 mode. But more compressed. BUT, not as much more compressed as you might think, because the codec, while having to handle twice as many pixels, isn't being asked to handle twice as much detail.

Net result is: I think 720/24p from an HMC150 is exquisite for that camera/codec combination.

As for 720 vs. 1080 for blu-ray or broadcast; well, for blu-ray it's up to you; I'd go 1080 to get the maximum detail. For broadcast, it really depends on whether you think it'll broadcast on a 1080 or 720 network. Either way it's pretty close. I like the look of the 720 footage, I think it's slicker and smoother than the 1080, but the 1080 does have a bit more resolved detail in it.

[Jordan Berry]

Thank you for that explanation Barry. As always... such a pleasure to learn from you!

[Girlspitswater]

Thanks once again Barry for clearing this up for me in great detail!

I'd like to extent my questions on the topic for Barry or anyone else that may help.

1) I agree with you that 720/24p from an HMC150 is exquisite for the HMC150’s camera/codec combination and I feel thus far more comfortable shooting in 720/24p. Although, my coworkers and myself are concerned that down the line a situation may arise where we would regret shooting in 1080 format. We are creating material for the web and for Blue Ray, but would also like to be sensitive to our Broadcast options as well.

2) Is there a difference in the two frame sizes (720 & 1080) when displaying on an HD television from a Blue Ray Disk; a difference that one would need to pay attention to in production and adjust their recording mode? From what I gathered from your last post, 720 or 1080 is a personal preference for going to Blue Ray. What is the technical description on how a Blue Ray Disk communicates with a Blue Ray Disk player and a HD Television? To be as simple as I can, will a Blue Ray disk created from a 1080 source file play in higher quality on a large HD TV vs. a disk created from a 720 source file?

I feel astatically and getting the best image out of the camera I’m leaning more towards 720p with the HMC150, although I’m concerned 1080 may be more conservative down the line for versatility in Blue Ray or for broadcast operations. Can Barry or anyone else ease my 720 vs. 1080 troubled mind? Haha, Thanks!

[Barry_Green]

720p and 1080p and 1080i are all ATSC-endorsed high-definition formats. All HDTVs have to be able to display all of them, and all blu-ray players have to be able to play all of them.

If the television is capable of 1080i only (no native 1080p) then I feel pretty confident in saying that few people will see a difference between 1080i and 720p unless you went to a massive screen (100" or more). But 1080p vs 720p, no question, 1080p is better/clearer/sharper. Once you get that pesky interlacing out of the way, and compare progressive to progressive, the bigger frame size will always win.

As for broadcast, I recently went through the list of HDTV stations on my cable service; 40% of the stations were broadcasting 720p, and 60% were broadcasting 1080i. So in America at least, it's a toss-up. In some countries (like Japan and Australia) it's pretty much 1080i-only. Over here it's near half-and-half. For ultimate future-proofing, things are likely to head to the 1080 side, if for no other reason than because it's a "bigger number" and bigger numbers are easier to market to end consumers who don't necessarily know what the numbers even mean.

If you make great-looking content you'll be safe with either, becasue blu-ray and broadcast support both forms of HD. And there's one area where 720 is clearly superior, and that's 720/60p vs. 1080/60i. But for 24p acquisition, it's gonna be a 1080/24p world. Interlace will (some day) die a hideous death and be out of our lives forever, progressive is today and the future.

[Baatfam]

Nice explaination Barry, thanks!

How about fast moving objects?
Most of the video I've shot during past couple years were for motorcycle drag racing DVDs...so most of the action is fairly quick.

Is there any advantage to using either 720p, 1080p or 1080i, with this camera, under those conditions?

[Oliax]

i have done extensive testing and comparison between 720p footage and 1080p footage with HMC. here is what i found:


1. i can tell you that 1080p does not show more compression than 720p. yes... technically, 1080p does compress more than 720... but the extra compression is NOT visable to the human eye whatsoever.

2. 1080 with HMC is a bit clearer and sharper than 720. the beautiful thing is.... even when 1080 footage is rendered out as a 720 file... it is sharper than 720 footage that is rendered out at 720! it's quite cool how that works out.

hope that helps.

[Hidef1080]

i have done extensive testing and comparison between 720p footage and 1080p footage with HMC. here is what i found:


1. i can tell you that 1080p does not show more compression than 720p. yes... technically, 1080p does compress more than 720... but the extra compression is NOT visable to the human eye whatsoever.

2. 1080 with HMC is a bit clearer and sharper than 720. the beautiful thing is.... even when 1080 footage is rendered out as a 720 file... it is sharper than 720 footage that is rendered out at 720! it's quite cool how that works out.

hope that helps.

I concur.:beer:

[Girlspitswater]

Thanks for all your impute everyone thus far!

[Aje]

Thanks for all inputs that certainly stretched out many questionmarks.
Some questions remain though for me.

Why is 720/24 and not 720p/25 stated as "native recordig" in the manual?

I have HMC 151 and can shoot both 50Hz and 59,9 Hz.
I have never tested 720/24p because I live in PAL land (Sweden)

Have shooting 720p/24 any advantage over 720/25P when end product is mpeg2 DVD stream?

If so can I mix 724p/24 with PAL material (other cams) in Vegas?

Is this a HMC shortcoming for PAL users - not to be able to shoot native?

Can anyone explain?

Regards Aje

[pwalker]

i have done extensive testing and comparison between 720p footage and 1080p footage with HMC. here is what i found:


1. i can tell you that 1080p does not show more compression than 720p. yes... technically, 1080p does compress more than 720... but the extra compression is NOT visable to the human eye whatsoever.

2. 1080 with HMC is a bit clearer and sharper than 720. the beautiful thing is.... even when 1080 footage is rendered out as a 720 file... it is sharper than 720 footage that is rendered out at 720! it's quite cool how that works out.

hope that helps.

Oliax,

What kind of set up and monitor did you use to view your tests?

pw

[dauid]

Why is 720/24 and not 720p/25 stated as "native recordig" in the manual?

I have HMC 151 and can shoot both 50Hz and 59,9 Hz.
I have never tested 720/24p because I live in PAL land (Sweden)

Have shooting 720p/24 any advantage over 720/25P when end product is mpeg2 DVD stream?

Regards Aje

Maybe 25p is stored in a 50p stream (with everey frame duplicated) and 24p is stored as 24p natively? I know the JVC hdv camera that I use save 25p as 50p.

I live in sweden too and I never shoot in 24p since everything here from tv to dvd is 25 frames per second. From what I hear even film is shot at 25 fps here.

[mcsmooth]

25p simply isn't a native profile for AVCHD, so it has to be put in a 50p/i stream. Same goes for 30p in NTSC. 24p and 25p are so close that you are best sticking with your intended output

[david61]

Hello All,

Is someone can tell me what is the best way to record in highest quality (PH Mode) with progressive mode..

I'm sorry but i don't see differences in progressive mode between:

1080/25p (over 50i), 720/50p and 720/25p (over 50p).

What kind of mode is the best according to you? I mean: best image quality, best definition?

I'm working under PAL european system.

Thank you so much.

[shaun1970]

As for broadcast, I recently went through the list of HDTV stations on my cable service; 40% of the stations were broadcasting 720p, and 60% were broadcasting 1080i. So in America at least, it's a toss-up. In some countries (like Japan and Australia) it's pretty much 1080i-only. Over here it's near half-and-half. For ultimate future-proofing, things are likely to head to the 1080 side, if for no other reason than because it's a "bigger number" and bigger numbers are easier to market to end consumers who don't necessarily know what the numbers even mean.
And that 1080i broadcast can be somewhat annoying Barry.
Channel 7 here is 720p and channels 9 and 10 are 1080i (these are the 3 big players in Melbourne) problem is with 1080i is that when I watch the footy on 10, there is a big problem with interlacing and it looks like cr@p.
I have a Sony Bravia X 42" LCD, this is by no means a slouch of a screen but it seems to struggle to de-interlace fast motion 1080i sports programs. The 720p stuff from Channel 7 is sweeeeeet! They should be shooting sports in 720/50p and not 1080/50i.

The new bravia's have now come out with 120hz motion flow build in,, mines only 100hz but you'd at least think they'd cope with 1080i,,,,apparently not.

I'm all for the death of interlaced video, the sooner the better.

[shaun1970]

Hello All,

Is someone can tell me what is the best way to record in highest quality (PH Mode) with progressive mode..

I'm sorry but i don't see differences in progressive mode between:

1080/25p (over 50i), 720/50p and 720/25p (over 50p).

What kind of mode is the best according to you? I mean: best image quality, best definition?

I'm working under PAL european system.

Thank you so much.

Don't even bother with any interlaced modes, if your shooting any action stuff, stick with 720/50p, anything else 1080/25p all in PH mode. The 720/50p mode is awesome for slo mo playback as well,,,,, it will be far smoother than slowing down 1080/25p footage.