29.97 interlaced hollywood movie? why bother?

[drcl]

Not sure if is the appropriate forum but Donald seems to be an expert in these things so here goes....

I live in UK(pal) so I dont come in to contact with NTSC stuff until someone bought me back a DVD from the U.S.

The title is "Collateral". Its encoded as a 29.97fps interlaced, but i was under the impression films NTSC films were at 23.976 and then the dvd player did the telecine/pulldown/3:2 thingy.

So i load it in to DGindex and make an index file at 29.97 and one at 23.976 the 29.97 obviously is interlaced.

So what is the point of the producer of the film making it 29.97? You have 25% more frames to encode and its also interlaced which messes up the chroma doesnt it?

I managed to make a perfectly good copy at 23.976fps and a pal version at 25fps.

So why go to the trouble?

Maybe I'm missing something really obvious......

[neuron2]

You omitted the key information. Is 3:2 pulldown present, either as flags or as hard telecining? Your saying that you made a perfect copy at 23.976 suggests that pulldown is present. You have to look at the D2V file per-frame flags to see if flagging is present (the film percentage is also a good indicator). If it is not, then you have to step through the clip decoded with field operation none and see if you get a pattern of 2 interlaced frames followed by 3 progressive frames in motion scenes. The use of interlaced MPEG2 encoding is not definitive.

[drcl]

Yes I'm sure it is originally shot at 24fps slowed to 23.976 then hard telecined to 29.97 interlaced. It's a hollywood film for movie theatres.

All I'm asking is what is the point in doing that? Why not put it on to the disk at 23.976 with pulldown flags? I was able to do this with pulldown.exe. I'm just asking why didn't the studio do it? Are some DVD players not capable of applying pulldown?

[drcl]

i just finished reading the thread about 25>29.97fps and your tool for doing this. Its the same principle as what im asking. you dont want to change from progressive to interlaced on the mpeg so you get the player to do the work.

[neuron2]

Maybe the only master they had access to was already telecined. Or maybe they were inexperienced at DVD authoring. There's no good technical reason for it, as you observe.

[Trahald]

@drcl

id be surprised if that movie was interlaced. its rare to see that on new dvds and that movie is fairly new. did you check it the way don suggested?

[drcl]

i created 2 d2v files. one with no field processing, one with force FILM. When viewing the AVS files in Vdub, the former has a 2 interlaced/3 progressive cycle at 29.97, the latter is progressive at 23.976.

[manono]

It's not hard telecined. It's stored as 24fps on the DVD, with the flags set to output 29.97fps, as required by the NTSC television standards. It's encoded Progressive. It's not Interlaced. Nothing's being changed from Progressive to Interlaced.

First you don't give enough information, and then you pass along bad information to neuron2. You don't seem to be asking, but telling, with a very incomplete knowledge of the subject.

Read the FILM percentage at the bottom of the .d2v as neuron2 suggested earlier. Check for the telltale 0 1 2 3 0 1 2 3 within the .d2v itself.

[Leak]

Originally posted by manono
Read the FILM percentage at the bottom of the .d2v as neuron2 suggested earlier. Check for the telltale 0 1 2 3 0 1 2 3 within the .d2v itself.

Shouldn't using the "Raw Frames" option in DGIndex do the same? If there's still combing when it's used the video was hard telecined; if the combing's gone it was pulldown after all...

[neuron2]

Originally posted by Leak
Shouldn't using the "Raw Frames" option in DGIndex do the same? If there's still combing when it's used the video was hard telecined; if the combing's gone it was pulldown after all... Sure. All roads lead to Rome. The easiest and most direct way, however, is to just look for the flags in the D2V.

drlc, if you post a section of lines from the D2V file, we'll be able to see once and for all whether pulldown flags are present.

[drcl]

OK I'm stupid, I should have read the guides more. There's a 0123 pattern on the d2v. 100% FILM too. I dont see interlacing with raw frames field processing. So i think that means its 23.976 with pulldown flags.


DGIndexProjectFile08
1
24 G:\VIDEO_TS\Vts_02_1.vob

Stream_Type=1
iDCT_Algorithm=2 (1:MMX 2:SSEMMX 3:FPU 4:REF 5:SSE2MMX)
YUVRGB_Scale=1 (0:TVScale 1:PCScale)
Luminance_Filter=0,0 (Gamma, Offset)
Clipping=0,0,0,0 (ClipLeft, ClipRight, ClipTop, ClipBottom)
Aspect_Ratio=16:9
Picture_Size=720x480
Field_Operation=0 (0:None 1:ForcedFILM 2:RawFrames)
Frame_Rate=29970
Location=0,1,0,1351

c00 1 0 2048 0 0 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 77824 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 169984 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 262144 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 358400 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 448512 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 542720 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 696320 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 927744 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 1132544 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 1341440 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 1570816 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 1808384 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 2062336 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 2308096 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 2560000 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 2795520 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 3033088 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 3266560 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 3485696 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 3715072 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 3946496 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 4169728 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 4395008 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 4620288 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 4845568 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 5070848 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 5294080 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 5523456 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 5754880 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 5984256 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 6215680 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 6449152 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 6678528 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 6914048 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 7155712 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 7405568 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 7632896 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 7829504 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 8030208 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 8282112 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 8534016 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 8781824 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 9025536 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 9250816 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 9455616 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 9654272 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1
c00 1 0 9865216 1 1 92 f3 a0 f1 b2 e3 b0 f1 a2 f3 b0 e1 ff

FINISHED 100.00% FILM



Thankyou everyone for trying to explain to me. Form a queue, here are the rotten tomatoes............

One thing I still dont understand; when previewing or playing in DGIndex, why does the frame type rapidly alternate between progressive and interlaced? I borrowed another ntsc DVD(Hellboy) while I was trying to figure things out but it doesnt exhibit the same behaviour, yet it also has the 0123 pattern.

[manono]

...why does the frame type rapidly alternate between progressive and interlaced?

I get that when I've forgotten to set the -prog_frames flag when running pulldown. The Secrets Of Home Theater people explain it this way:

The most common problem with this is the hundreds of discs that have a common encoding error where the progressive_frame flag alternates off and on every other frame.... ... This problem in the flags was caused by a bug in an MPEG encoder, but that MPEG encoder was extremely popular, and is still in use...

http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html

It's in a section called What Can Go Wrong-Flag Reading vs. Cadence Reading about 3/4 of the way down.

[drcl]

thanks a lot Manono, very interesting. Thanks for not ripping in to me for wasting everyone's time. Hopefully it explains a little as to why i got confused. I wasnt sure if DGIndex was reading somekind of mpeg flag with reguard to the interlacing or it was determining it from the video picture itself.

[Trahald]

excellent article manono. very informative