Any way to correct NTSC DVDs that are time compressed?

[PBear]

There seems to be a good deal of discussion here about converting PAL DVDs to NTSC, and vice-versa, but I haven't been able to find anything about whether there's a viable solution to all those badly produced, mostly poverty row DVDs that are alreadly themselves PAL to NTSC conversions, but for which nobody has bothered to correct the frame rate -- resulting in severe time compression (lengths usually decreased by 4-6 minutes from the film's original running time) and the unbearable effect it has on the actors' voices (movie stars you once knew and loved suddenly come out sounding like Mickey or Minnie Mouse!).

Is there an easy (or not so easy) way to transcode these DVDs that have already been converted to 29.97 fps, by using something like TMPGEnc XPress, to get them to come out like they should, at the right speed and running length, and have them play back smoothly, with the audio also slowed down and lowered in pitch -- and everything still in sync? (Another problem with a lot of these releases done on the cheap is that they're interlaced instead of the usual progressive encodes done by the majors, and I've read that interlaced sources add an additional layer of difficulty when it comes to changing playback rates.)

[manono]

Is there an easy (or not so easy) way to transcode these DVDs that have already been converted to 29.97 fps, by using something like TMPGEnc XPress, to get them to come out like they should, at the right speed and running length,

I correct probably 2 of these a week. I don't know if you'd call it easy, but if you plan on doing several of these, the only way to fix them is by using AviSynth unblending filters (I usually use RePAL), resetting the framerate to 23.976fps, and slowing the audio as well.

In the process of unblending they become progressive again. If for DVD, you also have to redo the chapters as both the timing and the framecount changes with the conversion. If you already know AviSynth, there's only work involved. If you don't know it, there's both learning and work involved.

[PBear]

Thanks, manono, I've used used AVISynth a few times in the past, but not for a long time and never extensively. It is currently installed, though.

Could you post, or direct me to, a script that will do what you describe above? I'm sure I can then find the needed plug-ins and get them installed without any trouble.

And I've quite forgotten what encoders work well with AVISynth scripts. I generally use FFmpeg for everything these days because it's so fast. Is it a feasible choice? I also have TMPGEnc Xpress installed but I don't think it gets along with .avs or .d2v files.

Regards.

[manono]

Well, for the video:

Yadif(Mode=1,Order=1)#if TFF
RePAL()
AssumeFPS(23.976)

For the audio, first load the AC3 into BeSweet, and then "Change Framerate from" 24975 to 23976 to slow it and produce a WAV file for you. I then use SoftEncode to convert the WAV file back to AC3 audio, but the freeware Aften with one of its GUIs can also do the job.

RePAL works nicely for probably 90% of my interlaced DVDs made from PAL masters, and I usually use MRestore for the rest. There are a few that can't be converted well.

I use CCE, but the freeware HCEnc is excellent and takes AviSynth scripts.

[Midzuki]

<OFF-TOPIC>
@ PBear:
your avatar is very ridiculous/annoying
</OFF-TOPIC>

[PBear]

Again, manono, thanks for the help. It was a lot of work but, following your instructions, my first attempt came out close to perfect! Just a couple of snags: Yadif not recognized as a valid AVISynth 2.5 plug-in (so I used LeakKernelBob instead) and resulting video file (.m2v) apparently not truly DVD compliant - it was rejected as an input file by Muxman (with no explanation, so have no idea why) and so I scuttled that plan and decided to re-author with TMPGEnc DVD Author (better idea anyway, since it was much easier to add menus and subtitles, and make corrections on the fly).

When re-authoring, TMPGEnc DVD Author insisted on re-encoding the file all over again (wouldn't accept it as compliant, even when I added the AC3 audio files to the initial source import before adding it as an asset to the project). It did a good job, though, without too much evidence of being a third-generation copy. The movie is now back from 86 minutes to its original 90 and sounds much better.

The only thing that still stymies me is where you get the "convert from" frame rate of 24975 for the audio (never seen that number anywhere before). I thought the original DVD was standard NTSC 29970. Your numbers worked, though, so I'm not complaining. (Had to do a similar thing when adjusting the timings of the ripped subs with Subtitle Workshop: instead of 29.97 to 23.976, I had to use 25 for input and 23.976 for output -- and still adjust for a slight misalignment near the end of the movie, but that was easy.)

Again, many thanks.

[AlanHK]

For the audio, first load the AC3 into BeSweet, and then "Change Framerate from" 24975 to 23976 to slow it and produce a WAV file for you. I then use SoftEncode to convert the WAV file back to AC3 audio, but the freeware Aften with one of its GUIs can also do the job.

You might also use Audioscale (and GUI here), which can stretch or squeeze an AC3 file directly, without going through WAVE conversion and reencoding.

[manono]

Just a couple of snags: Yadif not recognized as a valid AVISynth 2.5 plug-in (so I used LeakKernelBob instead)

The proper line for Yadif would be:

LoadCPlugin("C:\Path\To\Yadif.dll")

It's a C Plugin.

resulting video file (.m2v) apparently not truly DVD compliant

I figured it was understood that when encoding for 23.976fps you apply 2:3 (or 3:2) pulldown either during the encode in CCE, or afterwards using DGPulldown. That makes it play at 29.97fps (without changing the length), and makes it DVD compliant.

When re-authoring, TMPGEnc DVD Author insisted on re-encoding the file all over again

Don't you dare let TMPGEnc get its grubby paws on it. Apply pulldown.

The only thing that still stymies me is where you get the "convert from" frame rate of 24975 for the audio

If you check the framerate of the script after RePAL but before AssumeFPS(23.976) (VDub(Mod)'s File->File Information), you'll see the framerate is 24.975. It's because of the drop-frame flag. Just as:

29.97 is to 30fps, and
23.976 is to 24fps, so is
24.975 to 25fps

I thought the original DVD was standard NTSC 29970.

It is, but if a movie is made from a decent NTSC master, it's 23.976fps pulled down to 29.97fps to conform to NTSC DVD requirements. Or in your case, they took an original 25fps PAL master, resized it for NTSC, field-blended the heck out of it to go to 30fps, and with the drop-frame flag the 30 gets reset to 29.97 and the 25 to 24.975. Inside that NTSC interlaced 29.97fps DVD is a speeded up PAL movie yearning to be set free. Whoever made that DVD was too cheap to prepare a proper NTSC master for the NTSC DVD. Like I said, I see a ton of these things in my work.

Had to do a similar thing when adjusting the timings of the ripped subs with Subtitle Workshop: instead of 29.97 to 23.976, I had to use 25 for input and 23.976 for output

No, 24.975 to 23.976. Not doing it correctly explains them getting off by a little bit towards the end.

[manono]

AlanHK,

The AudioScale link no longer works and I can't find it anywhere. Maybe you can zip up your copy for upload here, please. I'd like to try it out

[PBear]

The proper line for Yadif would be:

LoadCPlugin("C:\Path\To\Yadif.dll")

It's a C Plugin.

OK, I'll try that with the next one I do.

Don't you dare let TMPGEnc get its grubby paws on it. Apply pulldown.

Yes, sir! I think I've finally got it.

Ran the .m2v file thru DGPulldown, then put it back into TMPGEnc DVD Author. Everything OK now: DVD Author just remuxes, no more re-encoding.

No, 24.975 to 23.976. Not doing it correctly explains them getting off by a little bit towards the end.

My problem with the subs was the drop-down choices for the frame rates in Subtitle Workshop (24,975 was not a choice). I see now you can type a value in there manually.

Thanks again. I'll stop bothering you now.