What the F….rame skip – stick?

[Johannes Schwarz]

Tried PCM and failed this afternoon.
But I’m trying the suggested variable bitrate now. The first file (for a reason beyond me) seems to have overcome the error. I’m trying to confirm with a 2nd one. After all I got 72 sequences…. 😛
Will report back

[Johannes Schwarz]

Ok. It does defy everything I know about things, but the problem on my machine seems to be that the Mainconcept Encoder in AME seems to deliver something pretty indigestible when in CBR – even though it is only 5.5 Mbps – at least in some files (making it even more mysterious)

When I use the standard 1 Pass VBR, the problems almost disappear. They are gone in the part they were troubling before and to a lesser degree have appeared at another place.

So it has something to do with the codec and the bitrate. Already this afternoon I noticed that when I re-encoded a certain file at 6 Mbps the problems were gone. I almost thought I had the solution, but it was premature. Other files did not improve at 6 Mbps.

I’m still at a loss and I’m not satifsfied. How much better things will be with VBR I will find out tomorrow morning, when the encoder is done

[Daniel Ludwig]

johannes,
you didn´t answer my question yet! what is your source-material HD 1080? shot on what kind of cam? AVCHD? P2? what resolution? 1920×1080 or 1440×1080?

if you shot in HD, you should scale-down before encoding to SD PAL MPEG2, and heaven – forget about PCM or MPG audio importing into encore! you need to transcode to AC3, never use the automatic transcoding!

by the way – encore will allways transcode to lower field first, even if you´ll have HD with upper first – there is no automatic field-shift !!

if you´ve recorded 1080psf25 (progressive segmented frame) – you are 1080i50, so you need to care about interlaced lines prior downscaling, and you need to downscale interlaced, not progressive, otherwise you´ll get interlaced trouble!!

cheers

danny (from germany – PAL-country 😉 )

[Johannes Schwarz]

Hallo Daniel,

well the source is non camera, animation 1080p @ 23,976 (so Bluray will be an option later)
Of course I scaled it down and interpreted it 25p to fit a 25p DV PAL timeline to work with it in Premiere. Since the animation had no audio there was no difficulty in just having a slightly shorter animation.

So the process was as follows:
– The FullHD footage is not from a camera but an animation.
– the raw animation was combined with 4k green screen (actually white screen double layer for hand and real shadows) photo-sequences to give the impression that the cartoon is drawn on paper.
– this was imported into premiere, interpreted to 25p DV PAL Widescreen etc as stated above. Voice and SFX were added and the animation cut and adjusted to fit the voice.
– This was exported to mpg2s (all working fine on its own – as do the mp4s online)
– Then I put it into Encore which now manages to get an occasional stutter into the video files if I use CBR. And from 3 test files it appeast that VBR solves the issue. Will know more in a few hours.

But:
There should be no issue with interlace, because the “footage” was produced progressive, never saw a cam and all settings in all programs it went through made sure that does not change. Even Encore meekly states as soon as I drop a clip into a timeline, that (since it promises not to encode) it will stay “no fields (progressive scan)”

As I said, I think there is something wrong (corrupted) with my MainConcept Encoder that seems to produce an occasional stutter when I use CBR. To verify that theory I need to test it with different footage, but right now the AME in full with files I need for the project.

Since you speak German you can actually take a peek at what the project looks like here: https://www.3mc.me/de/index_de.html
🙂

Cheers,
Johannes

[Eric Pautsch]

Maybe this link will shed some light:

https://forum.grassvalley.com/forum/archive/index.php/t-17953.html

Personally Id just make an NTSC 23.98 title and be done with it. NTSC discs are all over Europe.

[Johannes Schwarz]

Hi Eric,

thanks for the link. I’ll give it a read.

Originally (after asking on this forum) I planned to go all NTSC as you suggest and distribute it as such in PAL land. But in the early tests I felt that the loss of image resolution was bad enough to stick with PAL for most of the countries I’m distributing in. The series is a 2D line animation – not film. And so the extra lines of resolution mean a cleaner picture when the drawings are small (at least for PAL people). At an estimate of 100.000 PAL copies within the first year (note: I’ve already received 20.000 pre-orders over the last 2 weeks for the German edition alone) I think it is worth the trouble to go the extra mile (or resolution)

Cheers,
Johannes

[Eric Pautsch]

I hear you….We’ve done it in the past to save on replication costs.

No one will care about the extra lines of resolution….but then again, thats what is takes to be a professional so I agree and understand your point.

Can you post a sample of the issue youre seeing?

Here’s another thread to read:

https://forums.creativecow.net/thread/155/870715#870746

Also remember that there is no true progressive in DVD….DVD is over 20 years old so it predates any progressive video technology Only interleaved fields.

i wish I had a definite answer but Ive done several PAL title years ago and they were all interlaced

From the Spec

A disc has one track (stream) of MPEG-2 constant bit rate (CBR) or variable bit rate (VBR) compressed digital video. A restricted version of MPEG-2 Main Profile at Main Level (MP@ML) is used. SP@ML is also supported. MPEG-1 CBR and VBR video is also allowed. 525/60 (NTSC, 29.97 interlaced frames/sec) and 625/50 (PAL/SECAM, 25 interlaced frames/sec) video display systems are expressly supported. Coded frame rates of 24 fps progressive from film, 25 fps interlaced from PAL video, and 29.97 fps interlaced from NTSC video are typical. MPEG-2 progressive_sequence is not allowed, but interlaced sequences can contain progressive pictures and progressive macroblocks. In the case of 24 fps source, the encoder embeds MPEG-2 repeat_first_field flags into the video stream to make the decoder either perform 2-3 pulldown for 60Hz NTSC displays (actually 59.94Hz) or 2-2 pulldown (with resulting 4% speedup) for 50Hz PAL/SECAM displays. In other words, the player doesn’t “know” what the encoded rate is, it simply follows the MPEG-2 encoder’s instructions to produce the predetermined display rate of 25 fps or 29.97 fps. This is one of the main reasons there are two kinds of discs, one for NTSC and one for PAL. (Very few players convert from PAL to NTSC or NTSC to PAL. See 1.19.)

Because film transfers for NTSC and PAL usually use the same coded picture rate (24 fps) but PAL resolution is higher, the PAL version takes more space on the disc. The raw increase before encoding is 20% (480 to 576), but the final result is closer to 15%, depending on encoder efficiency. This translates to an increase of 600 to 700 megabytes on PAL discs compared to NTSC discs.

It’s interesting to note that even interlaced source video can be rendered as progressive-structured MPEG pictures by a good encoder, with interlaced field-encoded macroblocks used only when needed for motion. Most film sources are encoded at 24 frames per second (the inverse telecine process during encoding removes duplicate 2-3 pulldown fields from the videotape source, and the remaining field pairs, although technically in interlaced form, can be re-interleaved by a progressive player). Most video sources are encoded at 25 or 30 interlaced frames per second. These may be mixed on the same disc, such as an interlaced-source logo followed by a progressive-source movie.

[Daniel Ludwig]

johannes,
there is an workflow-issue, no more, no less!

you´ve wrote:
this was imported into premiere, interpreted to 25p DV PAL Widescreen etc as stated above

there it is: DV-PAL never is progressive!! DV PAL is lower field first – allways (because of the specs of the codec itself)

so if you encoded your material progressive this is definitivly wrong!

by the way – to use DV-PAL-codec is the worst thing you can do, as it significantly reduce picture-quality, you´ll see this especially on typos. DV-PAL only is 4:2:0 instead of 4:2:2 or 4:4:4 for uncompressed video.

your workflow should be like this:

1.) 1080p23.98-> interprete footage as 25fps while importing into premiere
2.) create a new user-sequenz-setting that has no interlace and no DV within the settings, not even in the preview-function, 720x576px PAL Widescreen

3.) edit your film

4.) export to selfcontained movie (MOV or AVI) with no default-setting, you need to create a progressive user-setting

if you are on MAC choose apple PRO RES HQ (or use sequenz-settings), if you are on PC use AVI uncompressed YUV8bit

5.) use AME to transcode your progressive video to M2V and AC3.

6.) import it into encore and author.

cheers

danny

PS: you might get in touch with me on skype, here´s my nick: dannyoman

[Johannes Schwarz]

Hi Daniel,

Hmm. Maybe I did not use the DV-PAL terminology correctly. I used these settings: screen-prog.jpg which would indicate the progressive is do-able from within the DV-PAL settings. My timelines and resulting files show up as progressive. No apparent problem

Also: the problems I had seemed to affect only certain sequences. Playing with bit rates solved it in some and switching to VBR solved it for all.
Since all my 72 time lines were just copies of each other, if the problem was progr vs interlaced mixed in the process at some point the problem would have to have been across all of my files (and having worked with mixed footage, I’ve know the pain of the resulting “jitters”). So I really think this is not a frame rate or field order mismatch issue.

In your workflow: I’m curious. Why would you do step 4 and not export with the right settings from Premiere (via AME)? Eg. Uncompressed AVI my 72 files would fill 2 TB. Even today this still is quite some “real estate”. What is the benefit of that intermediary step?

At any rate. I shipped the Masters out today. They played fine on my PC and on a DVD-Player. No jumps, no jitter. No on to the other 6 languages 🙂

[Daniel Ludwig]

Johannes,
sorry for the misunderstanding – I´m mainly a MAC-user, and the best way to work on mac is to use apple PRO RES, as it´s a high quality codec at a very low bitrate (similar to avid dnx). when I wrote the post – I´ve forgotten you could use other codecs instead of uncompressed AVI, for example avid DNX or quicktime-export to photo-jpeg.

the problem that you had could have more than one reason, so I started with the most common one.

other possibilities: bad media, wrong GOP-structure and also to preview a 25fps-disc on a computer is no good, as the player mostly deinterlacing the picture and finally – computermontiors could not playback 25fps correctly, as they are pepared to show 60Hz or 70hz.

and could be possible that I have been misinterpreting premiere-sequenz-settings – as I´m mainly a FCP-user. could be possible that DV-PAL just a declaration for the aspec-ratio – and similar to AfterEffects you are setting the output-codec and the field-dominance within the output-module to export the film. within FCP you have a dedicated sequenz with field-dominance and the dedicated codec that you use.

cross my fingers that everything will be fine on the replicated disc.

cheers

danny