Mpeg2 -> Divx

[Enak]

Hi,

I want to covert some MPEG2 video I have to DIVX.

The video needs slight editing (begining and end cutting) and also aspect ratio correcting.

What is the best way to go abouts this?

Thanks

[Dr Mordrid]

I've had the best restults doing the following;

1. convert to a HuffYUV *.avi.
2. encode to the new format.

I've used this method when converting both from DivX 5.02 to MPEG and vice-versa. While a bit more involved this method encodes relatively clean in several scenes that otherwise pixelize badly when going straight from one format to the other.

Dr. Mordrid

[Enak]

What software do you use?

Thanks

[Peter B]

using your editing software, Media Studio, Premiere, etc and export from the timeline aftre triming your ends, beginings etc save as an avi file with HuffYUV compression.

Encode using Virtual dubb, i would do the aspect ratio cahnge with Virtual dubb as well as it will be quicker. note you may need a fair amount of hard drive space for the HuffYUV file if it is a long video segment and if over 4GB save to an NTFS drive

[Evildead666]

HuffYUV is a lossless compression technique.
I had no idea it could be used as a transition step inbetween MPEG2 and DivX 5...
Would this sort of step work with DVD to AVI? (i don't see why not...)
I'll give it a go tonite..
let you know if it is better than my current encoding...(looking for max quality image, and Dr Mordrid is God in this matter )

[Dr Mordrid]

DV is an *.avi format already, or at least it's in an *.avi wrapper.

An intermediate lossless codec (HuffYUV, uncompressed RGB *.avi's etc.) is very useful when transcoding if one or both sources uses a codec that has temporal compression. Examples are MPEG, WindowsMedia, DivX etc. This is especially the case if you plan on adding effects like subtitles, title overlays etc.

Of course lossless files are often very large, so NTFS volumes are also extremely useful.

Dr. Mordrid

[Enak]

OK... I'm getting the hang of it now... currently converting to HuffYUV in MediaStudio 6.5.

Another question though...
Will Virtual Dub allow me to go from MJPEG -> MPEG2

[Dr Mordrid]

No. VirtualDUB is for converting from one Video for Windows *.avi format to another. Ex: MJPeg to Cinepak, Indeo etc. It doesn't do MPEG, as its docs clearly state.

If you want to convert to MPEG the most usful tool around is TMPGEnc Plus. A trial version will let you do MPEG-2 for a trial period, but it's best to register it IMO. TMPGEnc's price is a total steal given its high end features.

In the case of MJPeg and DV I'd go straight from these formats to TMPGEnc Plus since neither uses temporal compression. It's this temporal compression that increases artifact generation the most in the transcoding process.

When encoding DV with TMPGEnc you should browse to its Options/Environmental setting.../General tab and check the box labeled "Interpolate YUV from 4:1:1 to 4:4:4". This forces DV files to be upsampled to a higher color sample level, which also helps prevent artifacting during the encoding process. This isn't a cure for artifacting, but it helps some.

Temporal compression: the use of GOP's (groups of pictures). In a GOP you may only have 1 real bitmap out of 15 frames with the rest being mathematical constructs of various kinds. This is how MPEG, WindowsMedia and DivX can achieve such high compression ratios.

Problem is temporal compressions were never designed to be edited or transcoded to another format; they were intended to be only a distribution format. This is why a lossless transitional codec is so useful. A lossless transitional codec like RGB or HuffYUV converts the entire video to nothing but uncompressed bitmaps. In this form they can be edited, composited (effects, titles & overlays applied) and transcoded with little additional loss.

Yes, this means editing in MPEG is not generally a good idea for quality reasons. Edit in a higher quality format then use MPEG, DivX or WindowsMedia as the distribution format.

http://www.tmpgenc.net

Dr. Mordrid

[Enak]

That's another thing I would like to do... convert everything I have to DV... What tools should I use to do this. The video I have is in MJPEG and MPEG2.

Where can I get TMPGEnc Plus from?

Thanks

[Dr Mordrid]

Check the edited post. It's URL is right above my name

Don't convert everything to DV as it too is lossier than MJPeg. DV has half the horizontal color samples that MJPeg has plus you'd introduce artifacts in the conversion process.

Why give quality up if you don't have to?

Dr. Mordrid

[Enak]

Most of the MJPEG clips I have are off of an old camcorder anyway... so low quality already.

The difficulty I have is that MJPEG is not a default codec so when I transfer files to my mates they cannot play them.
I would also like to shrink the size of the files I have as my video drive currently occupies about 90Gb... I running out of space and can't afford more drives.

Given the following question, what would you recommend:

What is the best format to use to convert my video files to so they can be edited easily without sacrificing too much quality. While still be easy to convert to MPEG2/ DIVX.

[Enak]

I can't seem to find the plus version at that URL..

Am I missing something?

[smok3]

I want to covert some MPEG2 video I have to DIVX.

without big intermidiate files:

matrox mpeg2 -> dvd2avi - save as project (choose demux audio)-> open with gordianknot -> choose resolution, save as urfile.avs (avisynth), -> open that file in virtualdub and encode into divx. | take demuxed audio file and feed it into lame to get mp3-> multiplex divx avi + mp3 with nandub.

(gordian knot is avaliable at doom9.org, i think dvd2avi is included in the package)

[Enak]

OK... I've got XMpeg... I can encode my MPEG2 -> DIVX, but I want to cut the beginning and end off the file.

How do I do this as XMpeg has no facility to edit the files.

Thanks

[smok3]

divx can be cut on keyframes without recompresion, iam using virtualdub/nandub for that. (basicaly u make the selection, check that video and audio are set to 'direct streaming copy' and click save as avi.)