Example of my DV problem

[Daminator]

Hello gang

Can anyone explain to me why this ....

(small section of screen, but not zoomed)

turns into this ...


When I compress using DV as the codec?
I've tried the same bit of video using MPG2 at DVD quality settings and it looks perfect. Shouldn't MPG2 at DVD settings be much lower quality than DV?

I have also tried a couple of different DV codec, and have tried exporting through both Premier and VirtualDub. The same effect always occurs.

Below are links to the source files (vary small, just 6 frames) if anyone could take a look for me. I'd very much appreciate it if anyone can work this out. DV was sounding like the perfect way for me to archive my work, but MPG2 seems better at the moment?

www.daminator.com/misc/uncompressed.zip
www.daminator.com/misc/windows_DV_AVI.zip

(All in PAL by the way)

Hope some genius can put their finger on it!

[redwudz]

What format are you archiving from? DV is questionable as a codec to use to save video to, unless you plan to use a DV camcorder and tape to put the files on. MPG has the advantage of multiple encoding passes, and quite a few options, to my knowledge DV does not.

[MpegEncoder]

The DV codec is not perfect.

Follow this link:
http://www.adamwilt.com/DV-FAQ-tech.html

then search for "Artifacts"

[x21x]

If at all possible, I would suggest you archive your work on DVD or tape. If you try to compress the video, it will loose quality. I go from camera to uncompressed AVI(edit), back to camera or to mpg2(DVD).

[FOO]

The most difficult thing in the world to compress is a
maximum range step function , which is what you have.
Max white to max black in one pixel.

[Daminator]

Thanks for the replies all.

The source material is my animation that comes rendered as a TGA sequence out of my animation package. As pure as pure can be Lovely and lossless, but very big.

I liked the idea of using DV because although I'm quite happy with the MPG2 archives I've got, they really don't like being put back into an editing package and messed around with should I want to do any editing with them or anything. AVI's seem to handle that much better.

I've tried 'huffhuy' (if that's the right name) compression, and it's sometimes fine, but sometimes leaves horrible vertical glitches all over everything.

I'm still quite surprised that DV is so inferior to DVD quality MPG2 in this circumstance. I thought it was supposed to be much better.

Ah well, back to the drawing board.

Open to any of your suggestions of codec??

[racer-x]

First, DV and text don't go well together.
Second, DV-avi is interlaced (hence the artifacts)

Render that DV-avi to M-peg 2 and all will be well. If you're going to use it in a video, you have 2 options, Uncompressed RGB and DV-avi. Either will work fine.

Personally, I put my text in with a Titler during editing, that way it gets renderd out directly to Mpeg along with the animation.

[Anonymous65]

I use the Mainconcept DV codec, and if the Fast option is checked, I get the same artifacts. Uncheck the fast option in the codec and the artifacts should go away, they did for me. If you use another codec, see if there is a "fast" encoder option, or a "low quality" option. In that case, uncheck it. It will use more CPU power, but the quality will be better.

[Daminator]

I've just downloaded and tried the 'MainConcept' DV Codec. The results with those few test frames were exactly the same. Still the same at the lower speed setting too.

[MpegEncoder]

If at all possible, I would suggest you archive your work on DVD or tape. If you try to compress the video, it will loose quality. I go from camera to uncompressed AVI(edit), back to camera or to mpg2(DVD).

DV is ALREADY compressed by the camcorder. So even if you save it uncompressed it's still going to suffer from this artifact problem.

[Daminator]

DV is ALREADY compressed by the camcorder. So even if you save it uncompressed it's still going to suffer from this artifact problem.

I have already said that my source is not from my camcorder. The source material I'm using is rendered output from my animation program. As pure as pure can be. No compression whatsoever.

The above artifacts seem quite poor to me for something that's supposed to be much higher quality than MPG2 (at DVD settings at least ... which handles the same few frames without any visible artifacts)

[MpegEncoder]

DV is ALREADY compressed by the camcorder. So even if you save it uncompressed it's still going to suffer from this artifact problem.

I have already said that my source is not from my camcorder. The source material I'm using is rendered output from my animation program. As pure as pure can be. No compression whatsoever.

The above artifacts seem quite poor to me for something that's supposed to be much higher quality than MPG2 (at DVD settings at least ... which handles the same few frames without any visible artifacts)

OK, let me try again. DV IS compressed and DV compression does not handle text or animation very well. If that's what you are doing, then don't use the DV codec. Use huffyuv or mpeg-2 or anything but DV.

[The_Doman]

I can see the exact same artifacts when i use my DV-passthrough of my D8 camcorder (PAL) . It sometimes shows up with certian white subtitles when i record TV-programs with it. When recording a TEST-picture from TV i can also observe those artifacts in the fine vertical test patterns.

[The_Doman]

Intresting problem this is.
I did some short tests, and i think the problem lies in the DV decoder.
I recorded a short DV video (Type2) from TV with my D8 Camera where those artifacts are visible.

When playing it with the standard mediaplayer the artifacts are visible.
But when loading the clip in VirtualDub using Mainconcept DV Codec 2.4.4 the artifacts are totally GONE!. Also i made a MPEG2 clip of it with Canopus Procoder and there were also no artifacts visible.

So maybe using another DV codec can help?

Daminator:
I tried to load your clip in VirtualDub with the Mainconcept codec and there are NO artifacts visible!!. I just looks fine.

[racer-x]

DV-AVI is fine for animation, though Uncompressed RGB is a better choice. I use both with my animations and they both work just fine. Text is another matter. DV doesn't do well with text, unless it's 3D text.

The best aproach would be to:

1) Render your animation to DV or Uncompressed RGB.
2) Import your animation into your video editor.
3) Use the Titler to create your Text. You can also animate your text if you have a good video editor like Premiere.
4) Output the edited video to Mpeg-2. (encode as progressive if using CG graphics).

The quality should be perfect if you did it corectly.

[Daminator]

Hmm
Back to the drawing board then.
MPG2 is what I've been using in the past, but it's not good for re-editing when it comes to creating showreels etc.
I guess DV just can't do what I thought it would be able to. Thought it sounded too good to be true
I've had poor, corrupt results with huffyuv in the past, so I guess I'll just stick to having an MPG2 version, a DivX version and an uncompressed version (zipped away somewhere for editing purposes) of everything I produce.

[The_Doman]

What software /codec combination are you using when viewing the DV-avi?
Because when I open your avi file with mainconcept and VirtualDub there are NO artifacts visible at all. Only when using the standard MS directshow codec the artifacts show up.

[Daminator]

Hi The_Doman, sorry it's taken me so long to get back to this thread.

I'm not sure what's going on with my setup. I just tied to open my DV'ed video in VirtualDub and it just told me that it couldn't because the direct show filters were not suitable.

So maybe that it the problem?

Can anyone confirm this and confirm the that DV compressed file doesn't have artifacts if you don't view using Direct Show?

And if that's the case, how do I not use direct show?

[The_Doman]

You are probably using TYPE 1 DV avi files which cannot be used with virtualdub.

To use the Mainconcept (or other DV codecs) you have to use TYPE 2 DV avi files. There are tools to convert type 1 to type 2.

I tried different DV codecs (mainconcept/canopus) and the artifacts only show up with the directshow MS DV codec.

And it's difficult to disable the MS DV codec, which will also play type 2 DV avi files when you use the mediaplayer. This is a really annoying problem!!

[Daminator]

I thought I had tried the mainconcept DV codec. Although maybe I only tried it as an encoder but still was using whatever the default is to decode.

This is a really annoying problem!!

Sure is! I thought DV was going to be the perfect format for archiving my work. I'm pretty much resigned to using MPG2 and DivX for general storage and huge zipped up uncompressed AVI's and/or TGA sequences for when I need to re-edit things .. unless anyone comes up with a simple solution.

[Daminator]

I just did a quick test to see if it was the playback or not ...

I put the 'artifacted' DV file into Premier, then exported it as an uncompressed AVI file.

The artifacts were still there.

Does that mean that it's not just the DirectShow playback, or will DirectShow have been used to import the file into Premier?

[The_Doman]

Premiere uses standard the MS DV codec. So the files will be decoded with the artifacts.

And it's a real pain to disable the MS codec. You can find some info about it here. http://www.abcdv.com/article/articleview/10/1/79/

[Daminator]

That does seem like a hell of a lot of faf, but if it fixes the problem I may give it a go.

Can anyone who has done this please put my DV file into premier and export it as an uncompressed AVI and tell me if the artifacts are still there?

If this is the problem, there must be an easier way around it?? Is there any way that I could frame serve the DV files into Premier (or any package I want to use!) using a different DV codec?

[bottle-necked]

I'm no expert but I tried it. Here's my result frames copied out of VirtualDub to Clipboard, to Windows Paint, then converted to JPG in PhotoSuite4.

A frame from your original uncompressed AVI for comparrison...



A frame from my DV conversion. VirtualDub, MainConcept TrialWare DV Codec. Nothing special except unchecking the 'Fastest' box.



I tried a couple other DV codec but MainConcept did the best.

Hope this helps.
Good luck.

[Daminator]

Ok, now we're getting somewhere!

I've just converted to DV using a mainconcept codec in VurtualDub, and if I play the resulting AVI in media player, the artefacts are there, but if I put it back into VirtualDub (just to check in the preview window), they are gone!!

So...

A) Is there a media player that can play using your selected decoder?

B) Is there a free DV codec that anyone produces that would be artefact free? Mainconcept has a logo in the corner. I've not looked at how expensive it is.

C) Is there a way of Frame serving the good DV file into other programs (eg Premier and TMPGEnc) so that it is imported using an artefact free codec rather than second rate Microsoft poison?

[bottle-necked]

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