encoding .TS to 720p for smooth playback

[bengalih]

Hello all,

Specifically what I am trying to accomplish is to pull HD .TS off my DVR and encode into a file which will playback smoothly on my XBOX's processor (XBMC). I know this is capable, but I can't deduce all the steps. I am new to all of these tools and have been doing a lot of reading, but alot of guides I see are out of date, and it seems like the newest version of alot of these tools eliminate the need for many steps or other tools mentioned.

So far this is my process
- Pull .TS onto PC via firewire link and D-VHS drivers
- Use DGIndex to determine Pids, demux audio to AC3 and create .d2v file
- Load .d2v in GK and crop 8 pixels off the bottom (gray bar) and change output resolution to 1280x720.
- Use GK to launch Divx 3.1 encoding process and remux MP3 VirtualDub/VirtualDubMod/NanDub).

I also should probably note here that what I am pulling off is generally identified 29.97 Film Progressive by DGIndex. I use the FORCE FILM option when I create my .d2v file. I am taking movies off channels like HBO-HD, so I suspect I won't have alot of conversion problems that I am typically reading about with NTSC, telecining, and the like. My assumption is that since these are all "movies" they don't have any of the associated problems.

In the end I am getting a workable .AVI that looks pretty decent (playback on PC so far). However one main issue is size. My original 1 min .TS at 1080 is 107MB and when converted to AVI it is ~70MB. This means almost 6.5GB for a 1.5 hour movie. I have downloaded movies in 720p movies that take up only 1 4.7GB DVD.

So, I need to find out how I can be compressing this to fit onto a single DVD. Also, I have been told that the DivX codec gives the best playback when your CPU requirements are tight (XBOX processor). This is why I am using DivX instead of XviD.

I'm also a little confused as to what exactly the VirtualDub/VirtualDubMod/NanDub programs do. They all look the same to me and all seem to do the actual encoding from the AviSynth frameserver.

I think I've gotten pretty far on my own just reading around, but there is just too much (especially older posts) and I want to make sure I am doing this the latest and greatest way.

I really appreciate any help you can provide!

[Pookie]

You pretty much have the general idea correct, but there are a few things you need to change. I'm not an Xbox user, so I can't help you out in that regard.
Check and see what resolutions the Xbox can play.

Look at the stickie in the top of this section for converting HD to regular resolution.

VirtualDub/VirtualDubMod/NanDub are pretty similiar, although VirtualDubMod has a feature that allows you to modify your AviSynth script 'on the fly' and can also open up Mpeg2 files.

As far as Xvid vs Divx is concerned, you should try both and see which looks better. Don't rule out one or the other.

As far as fitting material onto a single DVD, it all comes down to bitrate and resolution.

[bengalih]

I realize that most of you don't have xbox specific info, and that's not exactly what I'm after. The XBOX is capable of 1080i, and there are a few games that actually run at that resolution. The problem is that the CPU/RAM in the xbox isn't capable of showing 1080i video without dropping frames(much like many people's PCs!).

I have spoken with others, who at this point I can't get more info from. However, based on their tests Divx 3.11 performs the best on the Xbox, I believe to a certain extent because it needs lower requirement (and therefore may not show the BEST image, but the best the XBOX can support).

So, my .TS are in 1080i and I reduce them to 720p, but can't seem to get good compression. The GK compressability test shows 1104.3% of 0.487.

In the long run, MY GOAL is to take a 1080i source .TS and encode it to fit on a single DVD (normal length movie) at a level that is a) playable on the xbox and b) significantly better quality than a standard DVD. The main point is to get better than DVD quality, which I thought I should be able to do as I am starting with a 1080i insteat of 480i/p source. If I can't get noticably better quality, there is no point to do it, as I could just buy the DVD.

[Pookie]

Gotcha. You might want to try 960x544, if Xbox permits that. Try the following:

1920x1080i --->Deinterlace/IVTC/etc--->Resize to 960x544 --->Encode at 2500kbps

Divx HiDef is 3000-4000kbps for 720p, going above that is a waste of space.

Keep the audio bit rate low as well, unless you're just remuxing the original AC3 to the new file. CBR MP3 at 256 is nice sounding and not too CPU intensive.

With the proper AviSynth Filters, you can also keep the crisp feel of HDTV.


Try playing the following 720p Divx files on your Xbox :

http://www.divx.com/movies/browse.php?categoryID=3&src=movietab_hd_from__movies_index_


These are just start off points, YMMV. Finding the sweet spot can be a lot of trial and error. I do know that if your source was 107MB and your target is 70MB that you're encoding at too high a bit rate.

[dlight]

I am pretty sure that even a modded XBOX will not be able to play HD res movies. I would check out XBMC (or something like that), these guys have put together a pretty slick media center type system that will run on an XBOX.

[bengalih]

Thanks guys,

Just added info, I am using the XBMC application for playback on the xbox. There has been alot of talk on those forums about getting HD video to play. I have been working with someone else on those forums (mostly his info I am using, as I am a newbie more or less).

We do have Divx 3.11 compressed video playback at 720p with no lost frames. I am just muxing back in the original AC3 stream and using digital/AC3 playback.

He provided me with his vcf file for nandub, but his Divx settings are set to 6500kbps. Are you telling me that this is overkill for Divx (3.11) and I should set it to less than 4000??

Also, he states that he uses DivX 3.11 as opposed to XviD or newer DivX versions because DivX 3.11 lets you set a maximum bitrate per frame, as opposed to a maximum average bitrate. This seems to be an important part of getting it to work on the xbox, since you need to be able to control the maximum PER FRAME so as not to overload the cpu.

Does this make sense? Are we on the right track. I hope I am not explaining it wrong as I am mostly relaying what I am being told.

The other problem I am seeing is that when I have text, like opening credits and titles at the beginning of the movie, I get little artifacts within the lettering. I find that I don't get these if I set to "Normal recompress", but I do get them in "Fast Recompress." However, I have read that "Fast Recompress" destroys the YUV colorspace. Is this correct? If so, what might be another way for me to get rid of these artifacts?