Question on force FILM option in dvd2avi, and SVCD fps.

[madhops]

What does this do, WHEN should I use it, and how should the .d2v file be encoded (using TMPGEnc)if I enabled this option (NTSC 23.97, or NTSC 29.97)? I've been making pretty good xSVCD's from my DVD's lately, and read somewhere that this is supposed to help with blockiness.

Finally, what is the normal framerate for NTSC SVCD's: 29.97, 25, 24, or 23.97? I'm thinking 29.97 and 23.97, but do standalone players have problems playing back 23.97 SVCD's?

Any help will be greatly appreciated. Thanks!

[smokingweed3000]

what template did you use?

[drmzacit]

Force film force the fps to 23.97. Normal framerate for NTSC SVCD is 29.97 so if u encode using 23.97, u should use pulldown

[RFontenot]

Wrong drmzacit, you do not use 3:2 pulldown with Force Film. If you do, you are undoing what Forced Film does.

Film movies run at 24 fps. To play a 24fps film on NTSC TV, the film is telecined to make it run at the NTSC standard of 29.97fps.

When a film movie is transfered to NTSC DVD, a repeat first feild (RFF) flag is added which causes certain frames to be repeated. In effect, the film is telecined on the fly by your DVD player.

Forced Film On tells DVD2AVI to ignore the RFF flag, returning the film to it's original 24fps. To encode this with TMPGEnc, you should use either the SVCD or VCD NTSCFilm template, which runs at 23.97 fps.

Don't use 3:2 Pulldown in TMPGEnc, if you do you'll just be encoding your 24fps movie back to 30 fps.

Most DVD players which support SVCD or VCD will support either 29.97 or 23.97 fps, as both rates are part of the standards for these formats.

The advantage of NTSCFilm is basically you are getting a 20% increase in bitrate, which helps to improve quality. For example, with VCD your max bitrate is 1150Kbps. That bitrate can be spread over 30 frames per second, or 24 frames per second.

Try it and see for youself if it makes a difference to you. Of course, YMMV.

RF

For more info on Force Film, go here:

http://arbor.ee.ntu.edu.tw/~jackei/dvd2avi/doc/issue.html

[wildcatfan]

RF if your doing svcd...you can use pulldown without quality loss just use the 3:2 flag in the stream. and 23.97 is NOT supported by some players as it is out of spec, but the pulldown is within the specs.

[RFontenot]

I stand corrected. 23.97fps isn't in the official SVCD spec. It is, however, in the official VCD spec.

Still, some players may support it just as they support higher than spec bitrates. In addition, TMPGEnc includes a NTSCFilm template for SVCD. You just have to try it and see.

RF

<font size=-1>[ This Message was edited by: RFontenot on 2002-01-13 12:43:29 ]</font>

[kinneera]

For MPEG1 (VCD/XVCD), 23.976 fps is supported, and should be used, since MPEG1 does not have a RFF flag. For MPEG2 (SVCD), it is optimal to apply the RFF flag, so that the video is encoded at 23.976 fps, but played at 29.97. In TMPGEnc, this is accomplished using the "2:3 pulldown on playback" option in the same dropdown as the Interlace/No-Interlace settings. It can also be accomplished with the pulldown.exe tool.

[RFontenot]

kinneera,

Thanks, you covered some important details. It also describes exactly how the SVCD NTSCFilm template is setup.

RF