Field order "Frame Based" should I alter ?

[pedro26]

When creating DVDs from sony mini DV tapes. I followed the lower field first, LFF, in capture and project settings and then for the properties in the burn phase.

On these new clips I have just created I could not find the field order for interlacing, so I used the 'trick' of creating a new project and inserting the clip into the project time line, then as UVS tries to match the project properties to those of the clip, I find from the propeties that the field order of the clip is "frame based".

This is intended for a PAL DVD so is this something I have to change to either UFF or LFF in the project property settings, or can I leave it as frame based. Will this impact the quality ?

What does it do for lacing when it is "frame based" ?

Thanks,

Pedro

ps I believe this frame based busines is something to do with systems that do not use interlacing to fool the eye with 25 fps x 2 ~ 50 fps

[Ken Berry]

I'm puzzled as to why your new clips -- even using that round about method you described -- should show up as Frame Based. If you used the DV/AVI field order of Lower Field First throughout the project, including in the burn phase, the resulting DVD's mpeg-2's should also show up as LFF.

Do you first -- before entering the burn phase -- go to Share > Create Video File > Custom and change the default properties from Upper to Lower Field First; or even Create Video File > Same As First Video Clip -- which should also give you lower field first...?

Normally, in a DVD, you would use Frame Based only for a slideshow, where each photo is in fact a single, full frame. (Equally, a slideshow can be set to use either LFF or UFF, depending on the rest of the video being burnt to the DVD...) Notionally, having your video burnt as Frame Based could involve some degradation since VS is having to both interlace the two half frames -- the "25 x 2 = 50" you mentioned -- but then convert the result 25 interlaced frames to 25 single, full frames. But your eyes might only see the degradation in, say, fast moving panning shots.

Nevertheless, you should as far as possible try to produce DVD-compatible mpeg-2 clips using LFF wherever possible.

[pedro26]

Hi Ken,

Nothing is burnt yet, frame based is info onthe clip as introduced into a new project (see below).

Reading between the lines your reply suggests there was a much more straight forward route (I'm all ears, for next time ).

These were FLV clips that I snagged on the fly from free internet tutorials (which I wanted to watch on TV for convenience). Having them as FLV format I had to convert them to another format to get them into UVS10+, following the suggestion by Canuk I used the Freemake converter to do this. Here I could convert to a few different file types, but those of most interest to us would be *.AVI and *.MPEG, I guess.

Freemake provided the following info about the original *.FLV file/clip
Video H.642 640 x 360 16:9 436 kps 25 fps
Audio AAC 48 KHz 436 kps stereo

Within these file type 'wrappers' of avi and MPEG, one can choose between a few options for the method of video compression and audio compression (codecs).

I reasoned, wrongly or rightly, that in fact as I would not be doing much editing of these clips, and their destination was a DVD, (for this purpose, i.e. when editing, it seems the preference is to have the files as *.AVI), then I ought to convert them using Freemake to MPEG2, with the following settings, which I gleaned from a few tutorials and posts, but again may not be optimal in this case, but I thought would be reasonable close to a HQ DVD. (I used custom in freemake to have more of a free hand in te settings)

Video, in freemake convert to MPEG, you have two options of codec MPEG1 or MPEG2, I choose MPEG2, frame size I choose 720 x 575, frame rate 25 fps, bit rate 6000 Kbps.
Audio codec choice with MPEG is MP2 or MP3, I choose MP2 (blindly), channels = stereo, sample rate 48000 Hz, bit rate 256 kbps.

If I had converted to AVI, then freemake allows the choice of the video codecs h.264, Xvid or MPEG4, audio codecs MP3, AC3, and PCM.

Whilst doing the above there is no choice over frame order, you get what you get.

Only when I brought the clip into UVS10+ did I find out that the field order was frame based in the clip. My question is do I change the project settings to match these clips = frame based, or set the project to LFF (or UFF) ?

I see your answer is LFF, thanks.


Thanks,

Pedro
(Being in Pal land)

ps One could argue that the original clip's video at 436 kbps, is being vastly 'over-sampled' at 6000 kbps, enlarging its size unnecessarily, whereas wrt the audio 256kbps is less than the original, but again if you made it higher then you would get less on a DVD (least I think that is how it works.

[Ken Berry]

No -- I only plumped for LFF because you mentioned DV/AVI in the first line of your first post above. However, it now seems that this current thread should have been continued in your other flv thread, so the situation is different.

Now, with your explanation that the video you are dealing with is in fact derived from .flv, I think you could probably leave the frame based as it is. As far as I am aware, flash video is frame based, so it is therefore not surprising that in the conversion to mpeg-2, that the new files should also be frame based. So I would simply continue to use that. However, as I said above in relation to slideshows, while they can certainly be burnt to DVD using frame based, they can also happily be either UFF or LFF as well. I think you can treat converted flash video the same way.

As for your comment about the preferred editing format being AVI, that is only true if you are talking about DV/AVI. But Freemake only allows conversion to mpeg-4 formats which use the AVI wrapper, and are more by way of display formats and highly compressed. I certainly wouldn't go that route if your ultimate aim is to burn a DVD. So continue as you are with mpeg-2 and leave it as frame based.

[pedro26]

Thanks Ken,

If you add some comment re the bit rates chosen (CF the original) that might be helpful for other users, but I think 6000 kbps x 25 fps ~ 1hour high quality DVD (Pal). Lata gives some guidance on his pages.

Please tag on to the other post or leave as a standalone at your discretion.

Thanks again for clearing it up.

Pedro

ps I was thinking a table could be constructed so that you could look up the recommended codecs with footnotes for those interested as to what guides the choice between the options. The info is here but it's scattered, but perhaps I'm talking rubbish and the old phrase 'it depends' figures too frequently for such a table to be constructed.

pps Freemake allows other options in *.avi (see my earlier post) to activate them you click on the green plus sign and keep choosing the custom options. Here I am assuming that h.264 and Xvid are different to MPEG4, that context, but I don't know, perhaps you mean that they are all of the 'MPEG4' stable (i.e. having similar characteristics) ?

[Ken Berry]

Here I am assuming that h.264 and Xvid are different to MPEG4

No -- in fact the h.264 codec produces a variety of mpeg-4, though some cameras and other programs can use the .avi or even .mov extension with it. Moreover, it can produce both standard def and high def mpeg-4 files. The the latter variety (which is also called AVCHD), the .mts and .m2ts extensions can also be used...

XVid is an open source version of DivX (which as you know is a commercial program, albeit with a free codec component). Both are highly compressed mpeg-4, though both using the .avi extension. In fact there are over 800 different formats which call themselves .avi. Apart from true uncompressed .avi (huge at around 65 GB for one hour of video), however, they are mostly .avi in name only. Although DV calls itself .avi and is a good format to use when editing, it is also compressed -- about 5 times from uncompressed .avi, and runs at around 13 GB per hour of video.

As for your question about bitrate, well in a sense the question is "how long is a piece of string". In fact, if you are talking about an hour of video fitting on a single layer DVD, then you could use up to a bitrate of 8000 kbps. But given that you are converting to mpeg-2 from flv, there will ultimately be limit above which there is little point in using a higher bitrate since there will be no noticeable improvement in quality with a higher bitrate. I bet some people would argue that even 6000 kbps is too high for original flv material, but my motto is to use the highest bitrate that will fit on a DVD regardless of that technical argument. Given that DVDs these days are very cheap, you could always run your own experiment and burn two DVDs, one using 6000 and the other 8000 (or for that matter 4000) and see which one suits you best.

And as a footnote, if the DVD is PAL, then of course use 25 fps, and if NTSC it would be 29.97 fps.

[pedro26]

Thanks Ken, that's clear