Hi Terry

As John has said MPEG4 is a much more efficient but complex compession. The smaller bandwidth for the same quality is why MP4 is becoming de rigeur for streaming and mobile devices and HD broadcasting.

The long GOP of sometimes more than 100 frames in some profiles, means there are only a few frames with full information compared to MPEG2 although professional formats are now using Long GOP MPEG2 (at high bitrates) compression for lower hardware requirements when processing and editing.   

BTW - did you encode the DVD using the MP4 file in a new project or from the original timeline? Were there any titles in the MP4 and how did they look on DVD quality. Do you see much aliasing on titles or pictures after it is scaled to SD? (see my earlier topic about DVD from HD).

Peter

John, Peter: thanks both, understood.

Peter,

I followed my usual procedure, as follows. Each day of an 18 day holiday was a separate project, complete with its own titles, narrative, music, etc. Each was exported as MP4, with settings unchanged since the last recent set of detailed screenshots I showed you:
https://dl.dropboxusercontent.com/u/4019461/MEP2013-YT-NormaExport-Full.jpg

I then imported each of these MP4s into a new project and made a few minor edits, such as changing the sound volume on a couple of days. I also made another short introductory 1920x1080 MP4 (with a program called BluffTitler) and inserted that into the full project. Finally I added just one simple MEP title over the top of that intro, moving up from off screen.

I exported that project as the final MP4 version. After viewing it over a glass of wine on my TV wirelessly via WDTV, I was satisfied with it. (Well, the usual balance between satisfaction and impatience to start the next one.) So I then imported USA2012.mp4 into a new project, USA2012-DVD-1.MVP. I specified 18 chapters, authored the menus and rendered the DVD, with settings at their usual:

https://dl.dropboxusercontent.com/u/4019461/MEP-AdvBurnSettings.jpg

(Note in particular that I don't have Interlace Mode set to Progressive. I'm technically out of my depth here, but presumably i would only use that if the majority of my source material used it too?)

So, regarding 'aliasing' in the DVD result, then yes, if I'm correctly recognising this I do see some. But I'd prefer you to assess this directly if possible, so here are two comparative screenshots with self-explanatory filenames:

https://dl.dropboxusercontent.com/u/4019461/MP4inVLC.png

https://dl.dropboxusercontent.com/u/4019461/DVDinVLC.png

Please specify any other info I can give you that might be helpful: screenshots, video extracts, settings, etc. I'd be happy to change settings if you spell out exactly what you'd like to compare.

--
Terry, East Grinstead, UK

Thanks Terry for the added info.

So if I understand correctly the material stayed in MP4 at HD res untill the new project which I presume was set in Movie settings to 720x576 PAL 16:9.

I was interested as to whether the HD titles became aliased or jagged edged after the downscaling which is one thing I have experienced a lot. From what I have read, it is a common problem in video circles to the point that some prefer to added the titles in the final project at the SD DVD resolution. Yours look pretty good however but it is something that occurs a lot with me both from the original HD timeline > SD or when taking the HD export and creating an SD project for the burn. Sometimes it does not occur but I have not yet been able to identify what is making the difference.

The aliasing in the picture when the disc is played is a little hard to convey as it does not show on a freeze frame or screen shot.

I notice your MP4 export does not have any B frames set but I presume you have some set in your DVD export > advanced MPEG settings > advanced Video settings Tab. Maybe a shot of that tab would be interesting. It is just that I tried converting the HD encode to SD through a program called PC User HD DVD and while the title came out without the aliasing, a Mediainfo analysis showed there were no B frames in the DVD output file and I felt the picture quality had suffered as a result of compression losses and artifacts.

Just as an aside, during my endless searching I have found that Magix support2.net (com?)  are recommending that jpegs be scaled down in a photo editor to nearer the project resolution prior to bringing them to the timeline, in an effort to stop aliasing / flickering.

Peter

Hi Peter,

The DVD export settings (most of which are technically beyond me) are shown here:

https://dl.dropboxusercontent.com/u/4019461/AliasingDiscussion-DVDExportSettings.jpg

https://dl.dropboxusercontent.com/u/4019461/AliasingDiscussion-DVDExportSettings-AdvAdv.jpg

Maybe you can comment on them in relatively simple terms!

I've also uploaded an edit of the first part of USA2012.mp4, with some MEP text added:

https://dl.dropboxusercontent.com/u/4019461/AliasingDiscussion-1.mp4 (35 MB)

Within that, is the section showing the title originally added in my day 1 MP4 export exhibiting the effect(s) you're focusing on? Here it is as an extract. Playing it in a loop allows me to see the blurriness and artifacts around the text.

https://dl.dropboxusercontent.com/u/4019461/AliasingDiscussion-2.mp4 (3 MB)

BTW, when I view the DVD disc on my TV it always seems 'better' than on my PC. In fact my wife seems bemused by my insistence on showing my videos via WDTV "...to get better quality" !

Here's the (zipped) DVD folder from the above:

https://dl.dropboxusercontent.com/u/4019461/AliasingDiscussion-1.zip

Let me know what else might be useful to you in isolating the problem. And please advise any conclusions you reach or any settings of mine I can change to improve my results.

--
Terry, East Grinstead, UK

Hi Terry

Those export settings look Ok to me and should give good results. I have read a few posts from the German magixinfo experts and they have advised some posters that they should not go above the defaults or perhaps a Bitrate of 7500 and quality 13 for a disc but I have not seen any evidence in my tests or research that says this would cause a problem.

In your MP4 I can see some blocking pixelation and interlace combing in the background around the 3D text but the text looks good. This appears to be due to the transition of the background and is possibly due to quite a low bitrate setting for the MP4 export. This does however look better on the WDTV. There is some pixellation on the place names on the map but this is probably due to zooming on a low resolution map.

What interests me is the way the MEP text you added "for discussion" looks bloated, jagged and low res on the zipped VOB on my computer. This is akin to what I am seeing frequently on my mpeg2 exports and DVD burns but as I have stated, this appears random and the text can look quite like the HD version in some cases. I just can not determine what is making the difference.....!!!! grrrr. This does however look cleaner on my WDTV player (probably because the TV deinterlaces better than the computer) although the thickness of the black outline is greater relative to the HD MP4. Just to be perfectly clear on this - did you add the text for discussion to the USA2012-DVD-1.MVP( which is I presume has 720x576 res set in the Movie settings) just prior to exporting the zipped file?

Peter

Hi terry

. . . . I then imported each of these MP4s into a new project . . . .

That causes problems for me with repeating the last 10 - 15 secs of the mp4 on the finished DVD / BD; plus a loss of quality on anything wth sharp edges eg titles and other sharp edges in the movie

I export as mxv for use in a mulrti-movie project whcih we covered in a previous question IIRC on multi movie menus.  That way I do not ppear to lose any quality or get the last 10 - 15 secs repeated..

John

Hi Peter,

Just to be perfectly clear on this - did you add the text for discussion to the USA2012-DVD-1.MVP

Effectively, yes, but to be strictly accurate this discussion demo project was called AliasingDiscussion-1.MVP, as you see from the screenshot below, to distinguish it from my full project.

( which is I presume has 720x576 res set in the Movie settings) just prior to exporting the zipped file?

 

No, why would I do that? The movie is still 1920 x1080. The burn settings for standard DVD are of course 720x576, as shown in my earlier screenshots (Advanced MPEG Settings window). Or have I misunderstood your question?

Or for better quality: https://dl.dropboxusercontent.com/u/4019461/AliasingDiscussion-ProjectForDemoDVD.jpg

--
Terry, East Grinstead, UK

. . . . I then imported each of these MP4s into a new project . . . .

That causes problems for me with repeating the last 10 - 15 secs of the mp4 on the finished DVD / BD

Hi John,

Can you say more on that aspect please? I've not had that problem AFAIK. Do you mean this duplication arises only the burned disc?

plus a loss of quality on anything wth sharp edges eg titles and other sharp edges in the movie

I export as mxv for use in a mulrti-movie project whcih we covered in a previous question IIRC on multi movie menus.  That way I do not ppear to lose any quality or get the last 10 - 15 secs repeated..

I'll try MXV instead of MP4 shortly and see if I get the same improvements.

--
Terry, East Grinstead, UK

Hi Terry

No, why would I do that? The movie is still 1920 x1080. The burn settings for standard DVD are of course 720x576, as shown in my earlier screenshots (Advanced MPEG Settings window). Or have I misunderstood your question?

The reason I am interested is that if I export (via the File > Export) from an HD project to a lower resolution SD format I get a warning that my "project resolution does not match my export settings and that I may get "black stripes" or "wobble"....." which may be a warning that I may see aliasing. I suspect titles would be a good candidate for problems as we are experiencing. As I mentioned in some discussion recently the professionals often go as far as redoing the titles in a new SD project in front of the HD material before exporting in the scaled SD format. In other words the project setting match the export settings and while the footage is still HD any titles created in the new SD project are created in SD and not subject to scaling during the export therefore avoiding aliasing issues on the titles, as least.

The other thing that occurs to me is that the reason the scaled text looks different when scaled from the HD project is that the thicker outlines may be due to the fact that the outline thickness is set in pixels, so 2 pixels in a SD 720 x 576 format would look proportionately a lot thicker than 2 pixels in a 1920x1080 project. The riddle then is why have I been able to reproduce those outlines in the right proportions on some SD exports and not others. 

John has raised a good idea worth persuing, with the MXV codec as an intermediate. I know some of the German members use this a lot to get over various quality issues. I have often wondered why Magix have clung to this format when it appears to be without use for most of us and in my recent test I did an export to SD from my HD project using it. I was disappointed with the quality when I dragged the new file into a new project so didn't take it to the conversion to MPEG2 and burn stage. I will try this. I will also export an HD MXV and then do the scaling to SD and export to DVD in another project.

Thanks Terry and John for you further input.

Cheers

Peter

Hi Terry

. . . . Do you mean this duplication arises only the burned disc? . . . .

Yes this occurred in the seven movie project I finished recently.  Each movie was created individually, exported as mp4 then re-imported into the final project.  In each case about 10 - 15 secs of the end of the movie was repeated on the DVD and BD discs and was present  in the image files created for burning.

The theory was that as they were H.264 mp4 there would be no recoding taking place for Blu-ray.

In practice this was not the case for BD and the recoding for DVD lost some of the quality on edges etc due to decompression / recompression and down sizing.

John

Well I have encoded a segment of my 1080 50p project using several different MXV profiles:

1080 50p, 1080 25p, 1080 50i BFF, (720 x) 576p 16x9DVD res, 576p 4x3DVD res.

The HD res MXVs retained their HD titles with nice thin outlines but the lower DVD res MXVs titles became low res with thick outlines. The 4x3 DVD (with 16x9 pictures now letterboxed) had even changed the line breaks so that the title was now on 3 lines instead of 2 to make it fit. Not quite what I had expected. It seems that MEP automatically resizes and reformats the text to suit the Export resolution! I guess this explains to some degree the MEP warning I mentioned in the previous post. It is trying to warn you to set the project settings to your target export settings so you can see what changes may take place after export.

I put all of these in a new project at 720x576 16x9 DVD movie settings and exported to DVD. Surprisingly the titles in the resulting disc / file retained the High res look of the 1080 HD clips and the SD clip titles of course stayed the same. So using an intermediate file does seem to be a workaround to retain the characteristics of an HD title albeit with some softening.

Alas I was not so impressed with the picture sharpness / quality of the MXV route and the files it produces are huge for 1080 50p. 3.5GB for about 1 minute with the quality slider on 100%.

All the final DVD output files and the DVDdisc play fine on my computer except for the interlaced file which exhibits the same tearing on diagonal lines and aliasing (in all the video material - titles are OK) as I see on my disc player. None of these above files show without this video disturbance when the same disc is played in my DVD player. Very frustrating as I am trying to distibute some copies of my daughters wedding. Don't know what to try next.....

Peter

Hi Terry

. . .  . The HD res MXVs retained their HD titles with nice thin outlines but the lower DVD res MXVs titles became low res with thick outlines . . . .

That is to be expected as you are expanding the size of the DVD pixels to fit a HD screen ie you are increasing the horizontal resolution of the pixels by 1920/720 ie by ~ x 2.7 and the vertical by 1080/576  ie x 1.9 hence you get the 'thicker' lines.

This has absolutely nothing to do with what you use as intermediate export it is the simple fact of 'upscaling' and you cannot defeat the physics of making a small pixel larger.

What to do next? - difficult one - I now create a 'boxed set' of two discs - one DVD and the other Blu-Ray (or BD burned to DVD when the movie is less than 30 mins long) when needed.

HTH

John

Hi John

I think you meant Peter not Terry.

Your explanation does not explain my earlier comment though:-

I put all of these in a new project at 720x576 16x9 DVD movie settings and exported to DVD. Surprisingly the titles in the resulting (SD) disc / file retained the High res look of the 1080 HD clips (titles) and the SD clip titles of course stayed the same. So using an intermediate file does seem to be a workaround to retain the characteristics of an HD title albeit with some softening.

Also:-

It seems that MEP automatically resizes and reformats the text to suit the Export resolution!

The point I am making here is that if the title is created on the timeline by MEP's title editor in an HD project, it appears in the preview screen as HD and if you export as an HD intermediate it becomes "baked in" and retains the characteristics (save for some softening), if the complete movie is put into an SD project and exported as SD.      

It appears that the title editor is smart enough to tell if the export is in a different size / resolution and adjusts the title to fit the export format properly during export rendering. Another key to this theory is that the texts outline becomes relatively thicker compared to the size of the characters of the text, after an SD Export from an HD project. 

Thanks for the suggestion about giving everybody an HD and SD version but I do not think any of my friends and family have Bluray players at present.

Peter