Two problems with avi -> DvD ffmpg

[abassili]

Hi all, I wanted to make a DVD that would play on my computers (mac and PC), as well as on my DVD player.

I put the avi in the "from" and then chose DVD ffmpg for the "to". After the conversion I burned the video_ts with Toast. I had 2 issues:
1) The video was choppy after the conversion (I tested it with mac DVD player, and burned it and tried it on a PC). However, it was NOT choppy on my TVs DVD player.
2) The image was skewed (ie the dimensions were out of proportion). I bet this one is easier to fix, but I don't really know how.

Thanks so much!
Adam

[Case]

1) If the framerate is 23.976 fps (NTSC Film), then your output file could be missing a 3:2 pulldown.
2) What is the aspect ratio (width÷height) of your source file?

[abassili]

Hi Case,
1) I did indeed have it set in NTSC Film. Should I change that to NTSC (or perhaps something else)?
2) I am not sure where I can retrieve this information. When I changed the aspect ratio from "default" to 4:3, 16:9, 16:10, 221:100, 5:4, and 1:1, it always changed the proportions (ie I do not think it is any of these). It appeared to be VERY close to 221:100.

[Case]

1) No, I would suggest a 3:2 pulldown. That is done with a simple checkbox if you use the DVD mpeg2enc preset in ffmpegX, but somewhat more of a hassle with DVD ffmpeg.
2) Open the AVI in QuickTime Player or VLC and do a Cmd-I. That should give you a width and height. (QTP) (VLC).

[abassili]

thanks so much Case!
1) That's fine, I'll use mpeg2enc for my repeat try, including the 3:2 pulldown. (is this done by checking set 3:2 in the "options" tab?)
2) 612 x 250 pixels is the "Normal Size" according to Quicktime. What step follows?

[abassili]

re: 2) in "video" options, do I manually put those dimensions into "Video Size?" Also, do I have to set "Autosize" to "Unconstrained?"

[Case]

1) That's fine, I'll use mpeg2enc for my repeat try, including the 3:2 pulldown. (is this done by checking set 3:2 in the "options" tab?)

Yes, tick the Set 3:2 checkbox.

2) 612 x 250 pixels is the "Normal Size" according to Quicktime.

That's odd, most codecs require the dimensions to be divisible by 16, and both 612 and 250 are not.
Is the "612x250" also visible in ffmpegX's Summary tab, in the Video field on the left side, when you drop the file on the From field?
Anyway, 612x250 gives an aspect ratio of 612:250 = 2.448:1, close to the cinema standard 2.35:1/2.39:1.

in "video" options, do I manually put those dimensions into "Video Size?"

No, DVD Video only supports a few resolutions, and the default (720x480) is fine for this. You'll want to letterbox your movie to make it 16:9, then encode that to a 16:9 widescreen DVD. To letterbox, you may use the Letterbox checkbox in the Options tab.

Also, do I have to set "Autosize" to "Unconstrained?"

No, set it to DVD 16:9.
That's about it.

[abassili]

Is the "612x250" also visible in ffmpegX's Summary tab, in the Video field on the left side, when you drop the file on the From field?

It says 588x240 in that field.

Ok so here is the summary of the changes I made:
1)Used mpeg2enc
2)Set Autosize to DVD 16:9
3)Set 3:2
4)Selected Letterbox

I'm encoding now, hopefully it works!
Are these changes that I should generally apply to all files that I convert?

Cheers

[Case]

I'm encoding now, hopefully it works!

Let us know how it turns out.

Are these changes that I should generally apply to all files that I convert?

If you have a source file close to 2.35:1 and with NTSC Film framerate, then you could apply these settings.

[abassili]

Well it seems to have worked, thanks so much!

I suppose my last question is how do I know if a file is NTSC Film Framerate? For example, the next file I wanted to convert defaulted to PAL (25). What protocol should I follow for this one?

[Case]

The default conversion framerate is a convenient indicator, but the Info button is safer (read: more accurate). 29.97 fps: NTSC; 25 fps: PAL; 23.976 fps: NTSC Film.
Not all north american set top players and/or tvs can handle the PAL framerate, so you may want to test (with a short clip, to save time) if your player-tv combo works with 25 fps material, or if your file needs framerate conversion.
There is no such thing as a pulldown for PAL, so when you convert to 25 fps, there is no need to Set 3:2.

[abassili]

thanks again! I am starting to understand the mechanics behind what I'm doing. So if the file is NTSC Film (based on the 23.976 fps in "info," what exactly is the 3:2 pulldown doing?

...Sets the framerate of the converted video. To avoid audio sync problems, don't try to convert PAL into NTSC or the opposite. PAL has only one value, though NTSC has two values (NTSC and NTSC FILM). Almost all NTSC DVDs are encoded at NTSC FILM rate, while TV or camera material is encoded at NTSC rate. mpeg-2 can also have 3:2 pulldown activated so video encoded at NTSC FILM will be played back at NTSC rate.

Assuming my set top doesn't cooperate with 25fps, what do I do with PAL files?

[Case]

what exactly is the 3:2 pulldown doing?

... mpeg-2 can also have 3:2 pulldown activated so video encoded at NTSC FILM will be played back at NTSC rate.

Like the quoted line says; the pulldown is a 'flag' to give instruction that the 23.976 fps progressive frames should be displayed as 29.97 fps interlaced frames for 29.97 fps equipment (e.g. a tv). There is this nifty scheme to make 4 frames into 5 frames (23.976/29.97 = 4/5), by splitting the NTSC Film frames in interlacing fields, and mixing them in a 2-3-2-3 ratio to create the extra frame in a way that your eye won't notice. (link) Which is applied in real time as the equipment receives the signal.

If you don't appy the pulldown, then you may experience some stuttering on some players (Apple DVD Player among them), I think because it plays some frames, then stops for the time of the frames it is 'missing' compared to 29.97 fps, as it catches up to the audio/built-in timing, then continues. It is like small pauses in the video.

Equipment that displays progressive content (e.g. a projector or monitor) is smart enough to detect the original 23.976 fps and show it non-interlaced, as the video itself is basically untouched.

[Case]

Assuming my set top doesn't cooperate with 25fps, what do I do with PAL files?

The funny thing is, a large selection of cheap import (read: from China) players, re-branded or not, are able to handle the conversion internally and on-the-fly. Most higher end players do not have such a feature, and require a display device compatible with the framerate of the disc.

To convert a PAL source file to NTSC or NTSC Film, set that target framerate in the Video parameters section of the Video tab in ffmpegX. After setting the framerate, re-activate the Autosize to set the size height to 480 (as the default for PAL is 576). I'm not sure how mpeg2enc handles that conversion on a frame level, but I found both NTSC and NTSC Film acceptable. I think I liked my NTSC test a bit better, as motion seemed to be a little bit more smooth, but my clip didn't have that much motion to make it very noticable. I had Decoding with Quicktime selected in my test, as QuickTime seems to handle timing so well in general, thus helping in keeping sync.

[abassili]

Case:

First off, thanks so much for all of your help. The NTSC Film stuff is working wonderfully!

I'm still a little wary of the PAL stuff. Is the conversion as simple as converting to "DVD ffmpeg," and then choosing NTSC Film for the framerate, followed by changing to DVD 16:9 autosize? (The file is 588x306).

I'm not clear on the "decode with quicktime" part, and if I do select that, should I letterbox the file?

[Case]

I'm not clear on the "decode with quicktime" part

In order to convert a file, it has to be decoded from its compressed form. ffmpegX allows the user to have a bit of influence over how that is done. With mpeg2enc, you have three decoders to choose from: QuickTime, mpayer or none of those two, which means using ffmpeg to decode.
When changing framerates, users have experienced sometimes losing sync between video and audio (regardless of conversion app). This seems to happen less with QuickTime based apps. Apparently the QuickTime team did something very good at the core of the QT architecture that helps in keeping sync.
So, I picked Decode with Quicktime for this conversion which also changed framerate, mainly in order to maintain lipsync. The other decoders may have worked just as fine (not tested), but I thought QT was my safest bet for this conversion.

... and if I do select that, should I letterbox the file?

You should letterbox any conversion to DVD that isn't either 16:9 or 4:3 to make them 16:9 or 4:3, because only those two are supported by the DVD standard. 588x306 has an aspect ratio of 1.92:1, which is wider than 16:9, thus should be letterboxed.

[Case]

I'm still a little wary of the PAL stuff. Is the conversion as simple as converting to "DVD ffmpeg," and then choosing NTSC Film for the framerate, followed by changing to DVD 16:9 autosize? (The file is 588x306).

ffmpegX by default sets the target framerate same as source (for PAL/NTSC/NTSC Film anyway). To change framerate during conversion, just select a different framerate.
The full PAL resolution (720x576) is different from the NTSC (Film) resolution (720x480), so the default video size value can be wrong if you do a framerate conversion. You could manually change the vertical resolution, but you'll want to set the Autosize to 'DVD 16:9' or 'DVD' anyway, which sets the video size for you, based on the framerate: Selecting an Autosize preset re-calculates the video size.
While the "DVD ffmpeg" preset is faster at encoding, you might prefer the "DVD mpeg2enc" preset instead, for two reasons. (1) "DVD mpeg2enc" allows for a 3:2 pulldown in the process. "DVD ffmpeg" has no such checkbox, but you could do it manually afterwards, using the Pull tool. (2) "DVD mpeg2enc" also creates MPEG files that Toast seems to recognize better (for authoring), although Toast burns VIDEO_TS folders just fine.

[abassili]

Hi Case,

I haven't been around in a long time but I wanted to let you know that your suggestions were very helpful. Your assistance here is much appreciated, so thanks!

Cheers
Adam