50i vs 25p

PizzaDeOveja

Standard Member
Hi there guys...first let it be said that (from the internet)


“An interlaced display is capable of displaying each field separately. Because of this, an interlaced video will play much more smoothly than a progressive video when using an interlaced display. Therefore, if you're planning to watch your output video on a TV (through an SVCD, for example), it's best to leave your video as interlaced.

On the other hand, if you want to watch your video on a progressive computer monitor, it's a good idea to deinterlace your video. Because a progressive display updates both fields of a frame at once, you won't see the increased smoothness of interlaced video that occurs on an interlaced display. Instead you'll see interlacing artifacts, which don't look very good. That's why it's recommended to deinterlace your video if you'll be watching it on a computer”.

Taking that into account I think that both my plasma tv and surely my projector both display progressive, while my cannon HfG10 shoots either in 50i or 25p Either way both bluerays also feed the tv/proj a progressive signal, thus I understand that deinterlacing will take place for sure if I shoot in 50i (which is the standard for the cam) but as I’ve read that 50i would produce more smooth pans and better moving images I keep wondering if it wouldn’t be better to shoot in 50i.

Any ideas??:)
 

grahamlthompson

Distinguished Member
Only CRT displays are truly interlaced because the picture is built on the display not in memory the picture is down to the persistance of the screen phosphors. This includes the old fashioned 3 tube projectors.

The electron beam from the tube gun scans the odd lines first 1, 3 etc in a field scan which takes 1/50 second it then repeats for the even lines in second field scan. Next up is the odd lines for the next frame. In effect you are blending the frames which gives smoother motion but produces interlaced jaggies between odd and even lines if the object or camera is moving quickly.

Matrix displays are said to handle interlaced content differently between makes and dependent on which fancy processing options you have enabled on the TV.

Best advice is try both and use what looks best with your TV/Projector

Broadcast HD is almost invariably 1080i although Freeview-HD has some 1080p25 content.

If your camcorder offers it also try 720p50 (1280 x 720).
 
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PizzaDeOveja

Standard Member
I guess the question is reduced to whether 50i converted to progressive will be of better quality than 25p. I am not sure but I think that deinterlacing 50i will produce 25p so given that, I suppose shooting directly in 25p would be better, but there are a lot of posts in a lot of forums stating that interlaced and 50frames is better and produce a more fluent motion.
Im not really sure that computer monitors always go in interlaced as is stated categorically in many internet sites because I remember seeing and option to deinterlace on the nvdia config.
 

rogs

Well-known Member
If your camcorder offers it also try 720p50 (1280 x 720).
Or, even if your camera doesn't record as 720p, you can always convert 1080i to 720p in your editor, for your final output. No interlace artefacts, and nice smooth pans.
Best of both worlds, IMHO.
Use that format all the time myself!
 

chrishull3

Well-known Member
Regarding 50i 25P i dont know if the G10 is the same as my GH2 regarding resolution but 50i is 17 MBPS and the 25P albeit in a wrapper is 24 MBPS the same as 24P ,i dont like 24P,for me both have their benefits but i like 25P and used it with my HV30 as well.
 

PhilipL

Member
Hi

Hi there guys...first let it be said that (from the internet)


“An interlaced display is capable of displaying each field separately. Because of this, an interlaced video will play much more smoothly than a progressive video when using an interlaced display. Therefore, if you're planning to watch your output video on a TV (through an SVCD, for example), it's best to leave your video as interlaced.

On the other hand, if you want to watch your video on a progressive computer monitor, it's a good idea to deinterlace your video. Because a progressive display updates both fields of a frame at once, you won't see the increased smoothness of interlaced video that occurs on an interlaced display. Instead you'll see interlacing artifacts, which don't look very good. That's why it's recommended to deinterlace your video if you'll be watching it on a computer”.

Taking that into account I think that both my plasma tv and surely my projector both display progressive, while my cannon HfG10 shoots either in 50i or 25p Either way both bluerays also feed the tv/proj a progressive signal, thus I understand that deinterlacing will take place for sure if I shoot in 50i (which is the standard for the cam) but as I've read that 50i would produce more smooth pans and better moving images I keep wondering if it wouldn't be better to shoot in 50i.

Any ideas??:)
50i when shown on a progressive HD TV or computer monitor is de-interlaced to produce 50 frames per second, this maintains the temporal information. Each generated frame though doesn't contain the full resolution due the interlacing which is 50 samples a second at half resolution. So you have less details especially during movement.

25p is something different, it has half the temporal information of 50i but each frame contains the full resolution, and will give judder on movement and pans.

So if you want the video look with smooth movement then your choice is 50i, if you want a more film type effect with any interlacing artefacts then 25p.

To shoot at 25p/24p successfully you need to use a slow shutter speed (1/50th sec) and avoid fast camera pans or anything moving quick across the frame, it's quite a skill, so 50i is generally the best option.

Regards

Phil
 

chrishull3

Well-known Member
25p is nothing like 24P which gives the judder effect on motion,the choice i have is 17mbps 50i or 24mbps 25P no contest,for films with a lot of panning and fast action i would use 720P reluctantly as that is less sharp than 50i.
 

PhilipL

Member
Hi

25p is nothing like 24P which gives the judder effect on motion,the choice i have is 17mbps 50i or 24mbps 25P no contest,for films with a lot of panning and fast action i would use 720P reluctantly as that is less sharp than 50i.
24p is 24 frames per second and 25p is 25 frames per second, visually you'd be hard pressed to tell the difference.

24p has the added judder of Telecine of course, which is largely eliminated now with Blu-ray and TVs supporting 24Hz.

720p is pretty good, often looks better and more pleasing than 1080/i.

What you could do with is 1080/50p, now that's something else.

Regards

Phil
 

grahamlthompson

Distinguished Member
25p is nothing like 24P which gives the judder effect on motion,the choice i have is 17mbps 50i or 24mbps 25P no contest,for films with a lot of panning and fast action i would use 720P reluctantly as that is less sharp than 50i.
Given the same bitrate resources there is no difference in 25p or 24p. In fact 25p ought to be slightly superior. 24P is used for blu-ray because most movies were filmed at 24 frames/second the standard frame rate used for Cine. Movies transmitted on UK TV have to converted from the original 24fps to 25fps. Much harder for the yanks they have to get to 29.97 fps.
 

rogs

Well-known Member
720p is pretty good, often looks better and more pleasing than 1080/i
Agree with that -- and of course looks better on 'progressive' computer monitors, without having to worry about any interlace artifacts.

Film itself is slightly different. Although shot a 24fps, each frame is actually shown at least twice, so effectively 48fps, with the 'smoother' results that brings.

'Pull down' from 29.97 is just a mess!! :)
 

chrishull3

Well-known Member
Given the same bitrate resources there is no difference in 25p or 24p. In fact 25p ought to be slightly superior. 24P is used for blu-ray because most movies were filmed at 24 frames/second the standard frame rate used for Cine. Movies transmitted on UK TV have to converted from the original 24fps to 25fps. Much harder for the yanks they have to get to 29.97 fps.
yes i know all that and did say 25P is superior in motion ,regarding sharpness resolution it may depend on the camera /cam they have the same on mine but for the look i wont touch 24P.
 

chrishull3

Well-known Member
Hi



24p is 24 frames per second and 25p is 25 frames per second, visually you'd be hard pressed to tell the difference.

24p has the added judder of Telecine of course, which is largely eliminated now with Blu-ray and TVs supporting 24Hz.

720p is pretty good, often looks better and more pleasing than 1080/i.

What you could do with is 1080/50p, now that's something else.

Regards

Phil
AS i said 25P looks a lot better for me even if its in a wrapper which is good as there is no problem with it on BLU Rays,720P can look good but the lower resolution on blu ray shows up
 

grahamlthompson

Distinguished Member
AS i said 25P looks a lot better for me even if its in a wrapper which is good as there is no problem with it on BLU Rays,720P can look good but the lower resolution on blu ray shows up
What lower resolution on blu-rays :confused:
 

chrishull3

Well-known Member
What lower resolution on blu-rays :confused:
WHAT I SAY ,if i record some footage in 720P some in 50i and some in HBR which is 24mbps and mix it on a blu ray time line the final footage looks identical resolution as the raw clips as i have done many times 720 followed by 50i and 25P hbr the sharpest by far,you could put vhs on a blu ray but it would only have vhs resolution.
 

grahamlthompson

Distinguished Member
WHAT I SAY ,if i record some footage in 720P some in 50i and some in HBR which is 24mbps and mix it on a blu ray time line the final footage looks identical resolution as the raw clips as i have done many times 720 followed by 50i and 25P hbr the sharpest by far,you could put vhs on a blu ray but it would only have vhs resolution.
I thought we we were comparing 1080p24, 1080p25 and 1080p50.

1080p50 from a camcorder is 1920 x1080 at an average bitrate of about 28mbps. You can't view it on blu-ray. 1080p24 from a blu-ray is the same resolution but around double the bitrate as the camcorder. 1080p25 at the same bitrate as the blu-ray would look just as good.
 

chrishull3

Well-known Member
I thought we we were comparing 1080p24, 1080p25 and 1080p50.

1080p50 from a camcorder is 1920 x1080 at an average bitrate of about 28mbps. You can't view it on blu-ray. 1080p24 from a blu-ray is the same resolution but around double the bitrate as the camcorder. 1080p25 at the same bitrate as the blu-ray would look just as good.
well I get 24mbps from 24 & 25P on my camera,50P never came in it for me because as you say its not BD compliant,regarding 1080P 24 on the rare times i have used it on BDs it looked the same as the raw clips,as you say 1080P25 looks good only better IMO than 24,we pretty much agree on these things.
 

PizzaDeOveja

Standard Member
Yep I think that what the camera each of us allows you to do, has blurred the original concept of the thread. Mine records in 1080 and you get to choose between 50i and what I think means 25p though it not being stated like that cant be good:(. Then you can choose quality which goes from 17MB to full blown 25MB. So you get 4 possible record modes.

Then in Vegas, you can do all shorts of things, from converting it to 24p to whatever...but DVD architect studio, the tool I use to get them videos in blueray is another story.

Apparently it only allows you to produce 50i or 25i disks, even to the point of converting your video from progressive to interlaced! I cant believe that is the only option the sofware has so I'll try to get some more info about how to burn in 24p.
 

PizzaDeOveja

Standard Member
Woh! check this out:eek:

- How to create a 24fps NTSC DVD in DVD Archtect?

Could I render a project in 24p and burn it in 24p or always have to burn in 29.97i?


- DVD is either 29.97 or 25fps interlaced. A 24P encode is done as 29.97 interlaced with flags for the 3:2 pulldown.


EDIT: http://www.kenstone.net/fcp_homepage..._nattress.html

This is getting better and better...

"DVD Architect will only recompress if your stream is not DVD compliant. I believe that the only compliant stream that is progressive is 24p. So if your media is flagged as being 24p DVD Architect will not re-encode but if you are creating a 30p or 25p stream, DVD Architect will make them 60i and 50i respectively because this is what the DVD specification calls for. This is obviously for compatibility reasons with existing DVD players".

And also...

"Progressive scan is something different then 24 frames a second.
DVD's have no difficult at all with progressive material at 25
(PAL) or 30 (NTSC) frames a second. Creating a 24 frames per
second DVD is a whole different ballgame and requires a
special authoring of the disc".


But...


"DVD Architect will always reencode as interlaced independent of the source".


Ok...apparently dvd authoring will re compress anytime you feed it with something not DVD/Blue-ray compilant video/audio.

As for Blu-ray compliant:

1080i/60 - 1080i/50
1080p/24
1080p/23.976

Final conclusion: dvd supports 25p but blue ray dont. So I guess shooting in 25p only makes sense if you intend to go DVD. They could have stated that someplace cause I think it is a really important issue!

The Canon Hfg10 sold in Europe comes only with 25p or 50i recording. This sucks as the US version can record in true 24p among other modes(4 in total). I wonder what they were thinking having a product that can record in 24p to castrate it for the Europeans while the Blue rays dont support 25p...perhaps they didn't know about that in canon...
 
Last edited:

chrishull3

Well-known Member
Woh! check this out:eek:

- How to create a 24fps NTSC DVD in DVD Archtect?

Could I render a project in 24p and burn it in 24p or always have to burn in 29.97i?


- DVD is either 29.97 or 25fps interlaced. A 24P encode is done as 29.97 interlaced with flags for the 3:2 pulldown.


EDIT: http://www.kenstone.net/fcp_homepage..._nattress.html

This is getting better and better...

"DVD Architect will only recompress if your stream is not DVD compliant. I believe that the only compliant stream that is progressive is 24p. So if your media is flagged as being 24p DVD Architect will not re-encode but if you are creating a 30p or 25p stream, DVD Architect will make them 60i and 50i respectively because this is what the DVD specification calls for. This is obviously for compatibility reasons with existing DVD players".

And also...

"Progressive scan is something different then 24 frames a second.
DVD's have no difficult at all with progressive material at 25
(PAL) or 30 (NTSC) frames a second. Creating a 24 frames per
second DVD is a whole different ballgame and requires a
special authoring of the disc".


But...


"DVD Architect will always reencode as interlaced independent of the source".
Treat your self to PINNACLE ultimate it has no problems mixing with what ever frame rate you recorded with,i dont know why you are making DVDs from HD footage,AVCHD discs are HD albeit restricted to 35min if you dont want to go the whole hog with BLU RAY.
 

PizzaDeOveja

Standard Member
Ok....despite what most sites on the internet says, all; the ps3, my denon blueray and, I think, the plasmaTV can display interlaced signals. On screen it says 1080i (Im hoping it means not just that it is receiving an interlaced signal but also that it is displaying it as such) so with any luck 50i will look a lot better than 25p made progressive from an interlaced blue ray(As you cant have a 25p blue ray I wonder what 50i built from a 25p original amounts to). 25p looks pretty bad when the camera moves both in the tv and in the camera's viewfinder when recording, not so 50i on the camera so I think it will be obvious if the tv can display 50i or not when I have the recorded video on blue ray to test it.
 

chrishull3

Well-known Member
Ok....despite what most sites on the internet says, all; the ps3, my denon blueray and, I think, the plasmaTV can display interlaced signals. On screen it says 1080i (Im hoping it means not just that it is receiving an interlaced signal but also that it is displaying it as such) so with any luck 50i will look a lot better than 25p made progressive from an interlaced blue ray(As you cant have a 25p blue ray I wonder what 50i built from a 25p original amounts to). 25p looks pretty bad when the camera moves both in the tv and in the camera's viewfinder when recording, not so 50i on the camera so I think it will be obvious if the tv can display 50i or not when I have the recorded video on blue ray to test it.
The only 25P cams/dslrs i have owned -own the HV30 and 550D THE 25p on those was converted by Pinnacle to play smoothly but with the 25P look on BLU RAY or whatever other format i needed as does my GH2s 25P in a wrapper,i dont know what your canons 25P is like to work with,is your tv a full 1080P tv,on the other hand if you are happy with 50i use it its a lot better than some say.
 

PizzaDeOveja

Standard Member
The only 25P cams/dslrs i have owned -own the HV30 and 550D THE 25p on those was converted by Pinnacle to play smoothly but with the 25P look on BLU RAY or whatever other format i needed as does my GH2s 25P in a wrapper,i dont know what your canons 25P is like to work with,is your tv a full 1080P tv,on the other hand if you are happy with 50i use it its a lot better than some say.
Thx chrishull3:). I intend to but I still havent seen the final results so, Im hoping it will look better than the pseudo 25p you get when transferring to BluRay.
25p must be intended to produce AVCd dvd's but given the 17MB data rate (with 25MB it gets only worse) I wonder who uses that:confused:. A 4gbDVD can handle what? about 20 minutes?? My travel videos are usually more than an hour long and I like to record 2 travels in a single disk!
They should have included 24p in the european version too, but given the fact that the light versions of editing programs doesn't process 24p...who has 500€ to buy vegas pro!:rolleyes:?
I need to check out those free programs they tell me about in the thread, hopefully this weekend
 

PhilipL

Member
Hi

Thx chrishull3:). I intend to but I still havent seen the final results so, Im hoping it will look better than the pseudo 25p you get when transferring to BluRay.
It isn't pseudo 25p on Blu-ray, it's full 25p but carried in 50i if done correctly.

25p must be intended to produce AVCd dvd's but given the 17MB data rate (with 25MB it gets only worse) I wonder who uses that:confused:. A 4gbDVD can handle what? about 20 minutes?? My travel videos are usually more than an hour long and I like to record 2 travels in a single disk!
DVD wasn't intended to hold HD video, the fact it does is a bonus with the limitation of lower bit-rates and space for not much than 20-30 minutes of HD video.

You really need Blu-ray for HD, and writers are not that expensive now.

They should have included 24p in the european version too, but given the fact that the light versions of editing programs doesn't process 24p...who has 500€ to buy vegas pro!:rolleyes:?
This is normally only an option for more professional cameras, in addition the reason it isn't done for UK models is 25p is easier to handle in 50Hz land and is the same thing as 24fps apart from 1 extra frame a second.

Sony Movie Studio 11, which is essentially Vegas with some pro-features removed that most will never miss, is around £30.00 on Amazon.

Regards

Phil
 

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