60i, 50i, 30i, 24p,... at DVinfo.net

Norris Combs · October 12th, 2011, 03:21 PM

I'm confused about which to select. I believe my raw AVCHD footage is 1920 x 1080 29.xxi (that's rounded to 30i), right? Now when I render, from the dropdown menu, I have to select from several 1920 x 1080 with different "i" and "p" numbers. Is it best to select the same resolution as the raw footage? If my raw is 30i, and I select a different value, say, 60i, or 24p, will the resulting video be worse in quality than the original?

Thanks,

Rob Wood · October 12th, 2011, 03:39 PM

"Is it best to select the same resolution as the raw footage?"

Yep. The other option is to choose the format you are targeting for output (BD, DVD, web, etc). Generally I work in the same resolution as source.

Sometimes when there's multiple source sizes I work in target format... but I get less surprises working at the same size the footage was shot at; when reducing a project to lower resolution, things like scaling and interlacing may appear fine at the time of edit but then become a problem on render (blurred areas, interlace damaged text, etc). YMMV.

Steve Game · October 12th, 2011, 03:55 PM

Norris,

If your footage really is 1080i/29.97, and you want your distribution video to be the same, then go ahead and render it the same, (NB Sony describe 29.97 interlaced frames per second as 59.94i, where this time, the 'f' in fps changes to fields). Unhelpful.
If you need to convert it to any other frame rate, Vegas will convert it during rendering, but the resampling can only make the picture quality worse. Don't use 30(or 60) fps. This will force a frame error approximately every 33 seconds, causing an unnecessary judder.

Hope this helps.

Steve

Jerry Amende · October 12th, 2011, 04:01 PM

The 30 second course:

First you need to understand the difference between Progressive (p) and Interlaced (i) video. Interlaced video would oft-times have 29.97 frames per second, however it interlaces two fields to make a frame, hence the 60i (actually 59.94 fields per second) designation.

Progressive has 1 field per frame, i.e. it is not interlaced. This the designation 30p (normally that's actually 29.97 frames per second - at least in NTSC-land, although some cameras will shoot at 30.000 fps). Since it's not interlaced, the fields per second = frames per second.

Your renders will normally be best if you do not resize or de-interlace. If you resize interlaced footage or convert to progressive, make sure you set a "Deinterlace Method" in your project properties (normally "Blend" for low movement, "Interpolate" for fast movement). Also, if you resize during render, make sure you set your "Video Rendering Quality" to "Best" in the render template (project tab) as that determines the best resizing algorithm (BiCubic, as I recall).

Make sense?

...Jerry

Norris Combs · October 12th, 2011, 09:01 PM

Thanks all for the explanation. I want the resulting movie to be the best quality possible. In my case, it means the same as the source video. So I will select the template for rendering with the same resolution as the raw footage.

Graham Bernard · October 12th, 2011, 09:51 PM

I can't wait for a universally accepted 100p format and be done with it all. Fanciful? I don't think so, it'll happen. Or better yet, some "other" form of capturing that doesn't require this stupid frame by frame sampling but is a continous stream of light and sound like water through a pipe. And DON'T get me started on the stupidity of the binary system. Daft.

I can dream.....

Grazie

Jerry Amende · October 13th, 2011, 03:37 AM

In re-reading the posts here, let me add 10 seconds to my 30 second course, above.

Quality is also determined by other factors as well, notably bitrate and encoding format.

Normally, the higher the bitrate (set in render template), the higher the quality of the render.

Selection of a encoder for render is normally determined by the intended distribution of your render. For example, h.264 or Windows Media Video for web delivery. There are also codecs intended for video editing that have very little loss in quality (e.g. Cineform or DNxHD) however you will find that the file sizes are very large and not appropriate for web or optical disc distribution.

Gets confusing in a hurry, doesn't it?

...Jerry

btw: +1 for Grazie's 100p

Norris Combs · October 13th, 2011, 01:42 PM

Jerry,
I notice that by converting the hard-for-Vegas (on my weak PC) to edit footage from AVCHD to avi, using Cineform Neoscene, the file size ballooned to ten times. At least I can edit, before the conversion, Vegas would shut down in fear at the mere sight of AVCHD.

Jeff Harper · October 13th, 2011, 11:39 PM

Regarding Cineform, for mixed footage like 1440 x 1080 and 720p, etc., I resize, deinterlace, and convert everything to Cineform with HDLink so that is is all exactly the same frame rate, etc, and I have to say the results are very good. It is time consuming and the file sizes are astronomical, but the results are well worth it.

October 12th, 2011, 03:21 PM	#1
Norris Combs Major Player Join Date: Apr 2008 Location: OC, CA Posts: 344	60i, 50i, 30i, 24p,... I'm confused about which to select. I believe my raw AVCHD footage is 1920 x 1080 29.xxi (that's rounded to 30i), right? Now when I render, from the dropdown menu, I have to select from several 1920 x 1080 with different "i" and "p" numbers. Is it best to select the same resolution as the raw footage? If my raw is 30i, and I select a different value, say, 60i, or 24p, will the resulting video be worse in quality than the original? Thanks,

October 12th, 2011, 03:39 PM	#2
Rob Wood Regular Crew Join Date: Mar 2007 Location: Vancouver, Canada Posts: 146	Re: 60i, 50i, 30i, 24p,... "Is it best to select the same resolution as the raw footage?" Yep. The other option is to choose the format you are targeting for output (BD, DVD, web, etc). Generally I work in the same resolution as source. Sometimes when there's multiple source sizes I work in target format... but I get less surprises working at the same size the footage was shot at; when reducing a project to lower resolution, things like scaling and interlacing may appear fine at the time of edit but then become a problem on render (blurred areas, interlace damaged text, etc). YMMV.

October 12th, 2011, 03:55 PM	#3
Steve Game Major Player Join Date: Mar 2011 Location: London, UK Posts: 353	Re: 60i, 50i, 30i, 24p,... Norris, If your footage really is 1080i/29.97, and you want your distribution video to be the same, then go ahead and render it the same, (NB Sony describe 29.97 interlaced frames per second as 59.94i, where this time, the 'f' in fps changes to fields). Unhelpful. If you need to convert it to any other frame rate, Vegas will convert it during rendering, but the resampling can only make the picture quality worse. Don't use 30(or 60) fps. This will force a frame error approximately every 33 seconds, causing an unnecessary judder. Hope this helps. Steve

October 12th, 2011, 04:01 PM	#4
Jerry Amende Regular Crew Join Date: Aug 2010 Location: Wilmington, DE Posts: 129	Re: 60i, 50i, 30i, 24p,... The 30 second course: First you need to understand the difference between Progressive (p) and Interlaced (i) video. Interlaced video would oft-times have 29.97 frames per second, however it interlaces two fields to make a frame, hence the 60i (actually 59.94 fields per second) designation. Progressive has 1 field per frame, i.e. it is not interlaced. This the designation 30p (normally that's actually 29.97 frames per second - at least in NTSC-land, although some cameras will shoot at 30.000 fps). Since it's not interlaced, the fields per second = frames per second. Your renders will normally be best if you do not resize or de-interlace. If you resize interlaced footage or convert to progressive, make sure you set a "Deinterlace Method" in your project properties (normally "Blend" for low movement, "Interpolate" for fast movement). Also, if you resize during render, make sure you set your "Video Rendering Quality" to "Best" in the render template (project tab) as that determines the best resizing algorithm (BiCubic, as I recall). Make sense? ...Jerry

October 12th, 2011, 09:01 PM	#5
Norris Combs Major Player Join Date: Apr 2008 Location: OC, CA Posts: 344	Re: 60i, 50i, 30i, 24p,... Thanks all for the explanation. I want the resulting movie to be the best quality possible. In my case, it means the same as the source video. So I will select the template for rendering with the same resolution as the raw footage.

October 12th, 2011, 09:51 PM	#6
Graham Bernard Old Boot Join Date: Aug 2002 Location: London UK Posts: 3,633	Re: 60i, 50i, 30i, 24p,... I can't wait for a universally accepted 100p format and be done with it all. Fanciful? I don't think so, it'll happen. Or better yet, some "other" form of capturing that doesn't require this stupid frame by frame sampling but is a continous stream of light and sound like water through a pipe. And DON'T get me started on the stupidity of the binary system. Daft. I can dream..... Grazie

October 13th, 2011, 03:37 AM	#7
Jerry Amende Regular Crew Join Date: Aug 2010 Location: Wilmington, DE Posts: 129	Re: 60i, 50i, 30i, 24p,... In re-reading the posts here, let me add 10 seconds to my 30 second course, above. Quality is also determined by other factors as well, notably bitrate and encoding format. Normally, the higher the bitrate (set in render template), the higher the quality of the render. Selection of a encoder for render is normally determined by the intended distribution of your render. For example, h.264 or Windows Media Video for web delivery. There are also codecs intended for video editing that have very little loss in quality (e.g. Cineform or DNxHD) however you will find that the file sizes are very large and not appropriate for web or optical disc distribution. Gets confusing in a hurry, doesn't it? ...Jerry btw: +1 for Grazie's 100p

October 13th, 2011, 01:42 PM	#8
Norris Combs Major Player Join Date: Apr 2008 Location: OC, CA Posts: 344	Re: 60i, 50i, 30i, 24p,... Jerry, I notice that by converting the hard-for-Vegas (on my weak PC) to edit footage from AVCHD to avi, using Cineform Neoscene, the file size ballooned to ten times. At least I can edit, before the conversion, Vegas would shut down in fear at the mere sight of AVCHD.

October 13th, 2011, 11:39 PM	#9
Jeff Harper Inner Circle Join Date: Jun 2005 Location: Cincinnati, OH Posts: 8,425	Re: 60i, 50i, 30i, 24p,... Regarding Cineform, for mixed footage like 1440 x 1080 and 720p, etc., I resize, deinterlace, and convert everything to Cineform with HDLink so that is is all exactly the same frame rate, etc, and I have to say the results are very good. It is time consuming and the file sizes are astronomical, but the results are well worth it. __________________ "The horror of what I saw on the timeline cannot be described."