I have edited some AVCHD 50i 24Mbit files (Sony HDR-CX730) with Vegas Pro 11. Now I want do create a standard definition DVD (PAL). When I set the Mainconcept encoder to upper field first (same a project and files) an 8Mbit constant rate, the video looks very bad (stairs in lines, Moire, flickering). When I use the 25p setting, the video is okay, but fast moves become very unsharp (as expected).
A year ago, I have converted MPEG2HD 50i files (JVC) to DVD 50i, and the results look much better.
Question: What settings (project and encoder) would you recommend for the job AVCHD 24Mbit 50i to SD-DVD 50i?
Thank you and please excause my poor Englisch!
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"a lot of people are better dead" - prisoner KSC2-303
Method of resizing is quite important here, for example if you resize your video in VirtualDub (filter resize, Lanczos3, interlace), you get much better result than Vegas would do for you, no flickering, stair affect for horizontal lines etc. This is valid for interlace resize. Progressive resize is ok.
Interlaced video has to be handled properly when resizing. Otherwise you get terrible artifacts.
If the conversion is from HD source to HD output, or SD source to SD output, a one-step render through the MainConcept Encoder is usually quite excellent. However, when the encoder is trying to down-convert from HD to SD while simultaneously trying compress to a different codec at a reduced size, you don't always get optimum results.
I don't know if this is true with 720p, but if the source is 1080i, you can't simply down-convert to 576i (or 480i) in a field by field fashion, as 1080 is not evenly divided by 576 (or 480 in our NTSC countries, for that matter). How the down-conversion is done in timeline editors like Vegas and Premiere, while the MainConcept encoder is performing the MPEG-2 encoding process, is unknown to me. Nevertheless, I know a good solution to your problem.
You're going to need to take a 2 step approach, with the first step being the HD to SD down-conversion, and the second being the encode to DVD-compliant MPEG-2. The first step involves rendering your HD project to a lossless intermediate SD (740x576 for PAL) codec, like Lagarith or HuffYuv, with the field setting to None (Progressive). I know that sounds wrong, but the interlacing situation will get straightened out in the 2nd stage. Make sure you have lots of drive space, as the lossless .avi file will be HUGE.
Finally, take that giant standard-definition intermediate .avi file and encode to DVD-compliant MPEG-2, either using that same MainConcept encoder or other MPEG-2 encoder. For DVD compliance, you need to set the encoder for interlaced, preferably Top Field First, since it is that way with HD source (although I don't know how relevant field order remains after the down-conversion stage).
Do a test on a short segment of your project, preferably one with good motion. See if this 2-step method works as fantastically well for you as it has for me (and others--from where I got the advice).
filmboss80 - you can frame serve your video from Vegas directly without creating huge intermediate file , like in that video:
I would not deinterlace 50i to 25p, you loose temporal resolution, not good, you might deinterlace to 50p (with QTGMC within Avisynth), resize down to 720x576 and then create 50i again right after, or you can resize within VirtualDub with that filter like is shown in that tutorial, it is not bad at all, it works for downcorversion to DVD very well
One more thing, it has nothing to do with OP question though, I author progressive 30p DVD if I have to make DVD (original video is 30p) and never got into problem, so am I lucky ?, not sure. I tested to load it into DVD Maestro, that checks for DVD compliance, and that old exceptional software accepted that 30p m2v file so I guess it is all right.
Though I'm not absolutely sure, as I understand it, 30p isn't officially DVD compliant. You would have to apply 1:1 pulldown flags to make it compliant (pulldown flags instruct the player on how to produce 60 fields per second from any progressive frame rate from 20p to 30p). But I haven't found a player that didn't play it.
As for encoding to 25p (or in our case, 30p, being NTSC), some of the tests we performed were in Vegas, going from an HDV 1080-60i project timeline to a DVD-compliant, NTSC widescreen MPEG-2 file; and one of those encodes had a field order setting of None (progressive). Indeed, this particular render provided better results than choosing an interlaced setting of either field order. (I have not seen a DVD player that could not handle 30p MPEG-2.) Still, the results we got from the 2-stage process, first using the lossless intermediate with no field preference set, followed by an interlaced MPEG-2 encode, provided the best results, hands down. In our case, we could create the large intermediates, as we had tons of drive space. That is certainly a consideration.
Run your own eyeball tests. That's the only thing that's going to convince you in the end.
It would probably help if you posted a short sample of your HD source and the resulting SD MPEG 2 file. People will be able to tell you if what you are seeing is expected, or what might be done to improve matters.
filmboss80 - I'm not sure now what you originally described. That intermediate file suppose to be 576p25 and then encoded 25i mpeg2 ?
HuffYuv (Video for Windows), 29.97fps; and in the box for Field Order, "None (Progressive)" is selected. (As an alternative, the Lagarith codec can be selected instead of HuffYuv. Either codec provides non-lossy compression; but be advised, they produce really, really big files.) For PAL video, you would do 720x576, 25fps, progressive.
Once I have that standard-definition intermediate, I can go into any MPEG-2 encoder of choosing, and select the NTSC profile (720x480), 16:9 display aspect ratio; and in the Field Order box, select Interlaced - Top Field First. (Again, a PAL profile would be 720x576 at 25fps.)
You mentioned frameserving, avisynth, and virtualdub. If you search the internet on the subject of converting HD video to SD MPEG-2, you will find what some other folks are doing and see what scripts they've written. I've also seen advice about using the Vegas sharpen filter at 0.0 to get a crisper-looking MPEG-2 file. (Yeah, they say using a setting of zero will still do a touch of sharpening.)
I would be interested to know how others are handling this issue of HD down-conversion to SD interlaced. At my business, we are mastering to HD for future-proofing purposes, but our buyers (educational institutions and libraries, mostly) always demand DVD -- never Blu-ray. This method we have hit upon is relatively efficient, and has given us great results so far; but we're always open to new ideas. (Hell, that's why I come to forums like this one. I really don't have time to be coming here and perusing this site, much less offering some of my own input. But I just can't stay away.)
Of course, we also have to see what process the OP will be comfortable employing.
Last edited by filmboss80; 17th Dec 2012 at 22:16. Reason: Had typed 740 instead of 720. Thanks, manono.
(I'll go back in and edit the previous post.)
UPDATE: Corrected the post. Actually they weren't typos in the sense that I hit the wrong key. It was actually a big fat brain fart. Too much on the mind. Nice catch, manono.
Last edited by filmboss80; 17th Dec 2012 at 22:43.