DivX vs. RealVideo

[mum_video]

All the articles I have read in different resources over the net suggest that DivX has a better quality compared to RealVideo, but my experience shows the opposite!! How could it be?

I am using "RealProducer Basic 8.5" to capture and encode RealMedia files and I am comparing them to DivX files I get by capturing and encoding using VirtualDub 1.4.7 and DivX 4.11 codec.

In real media I capture in 352x240 30fps 512Kb/s and in VirtualDub I capture 640x480 30fps 1000Kb/s. Even when I increase the bit rate to 6000Kb/s the quality does not seem to improve very much.

Is there any thing I am missing?

Thanks
Payman

[salvius]

You must be missing something major becuase RealVideo quality is crap. Do share the exact procedure of your Divx making.

[tinycorkscrew]

Friends don't let friends encode to RealVideo.

[mum_video]

In VirtualDub I capture and encode using the following settings:

under video->compression I choose "DivX Codec 4.11" and configure it as:

Variable bitrate mode: 1-pass
Performance/Quality: Slowest
Output bitstream: 1000 (I have tested 500 - 6000)
Keyframe: 300

all the rest of the options: default

Are these the best choices, or is there any thing I can play with to improve quality?

Thanks
Payman

[Unibomber]

dont use divx 4.11 its a piece of crap

use 3.11 alpha

4.11 is based of source code from another form of divx

if u use 3.11 alpha u will see a difference in quality from 1000-6000

[RafNunes]

I think you should use Windows Media Player 6.4 and at File/Properties/Advanced menu select Divx decoder filter and press Properties. At postprocessing level, slide the bar to the max. I think quality will be improoved.

I hope it helps you.

[mum_video]

Thanks for all your recommendations. I tested it and it seems that DivX 3.11 indeed has a superior quality.

But can anybody tell me what is the optimal settings for capturing and encoding video in realtime?

We are digitizing some faculty lectures on different topics in an educational environment and we use S-Video input and a Matrox G450 eTV to capture video, we are willing to fit at least 3 hours of video per CD.

Any more comments??

Thanks
Payman

[Shabubu]

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR size=1 color=black></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2001-12-11 12:35:33, mum_video wrote:
Thanks for all your recommendations. I tested it and it seems that DivX 3.11 indeed has a superior quality.

But can anybody tell me what is the optimal settings for capturing and encoding video in realtime?

We are digitizing some faculty lectures on different topics in an educational environment and we use S-Video input and a Matrox G450 eTV to capture video, we are willing to fit at least 3 hours of video per CD.

Any more comments??

Thanks
Payman


People aren't going to like this...

Firstly If your wanting 3 hours to CD your going to have to use SBC encoding, it can be done because their shouldn't be too much motion, but it's worth putting in the extra time. If your going to use SBC then you'll need to re-encode your caps, thus capping to DivX is a bad idea, your better capping to PicVideo or huffyuv, then using that as a source for SBC.

To do SBC encoding you can either use the built in 2pass from DivX4.11 (easier), or get Nandub (modified vdub) and 2 pass encode with DivX 3.11. The guide for both are here:

DivX 4.11: http://www.doom9.org/divx4.htm
DivX 3.11: http://www.doom9.org/nandub.htm

Those guides were designed with DVD ripping in mind, but still apply for capture processing.

PM me if you have any questions


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[mum_video]

Thanks Shabubu,

What is SBC by the way?

Payman

[mum_video]

I have to correct my comment on the quality of DivX 3.11.

When I compared my samples more closely I noticed that they barely have any difference. There is a difference in quality between version 4.11 and 3.11 alpha, but they are almost the same.

So I disagree that 3.11 has a better quality or may be I have not done the right settings.

Can any body tell me what is the seetings that you are using for 3.11?

Thanks
Payman

[salvius]

Unless blindness is a factor, you're greatly misusing Divx as realvideo can't even compare in quality.

Get gknot and follow it's directions. All there is to it. Encode. If you can't spot the difference between RealVideo and Divx... Well, not to flame or anything, but I'd suggest visiting an optometrist.

<font size=-1>[ This Message was edited by: salvius on 2001-12-12 15:21:15 ]</font>

[guthrie]

Thanks for the suggestions; but no, blindness is not a factor!
And thanks for reinforcing the differences in quality that we should be getting; but in reality, we aren't; so we need some pointers on where to look for our mistake

We are using a one-pass encoding from VirtualDub, and tried both the 4.x and the 3.11 codecs; we didn't see any noticeable difference. We are encoding at 320x input, and output bit-rate of 9000KB, but also tried 1200, and higher. We did not see much improvement or change in quality with these bit rates. The RV encoding is at 512K, and is significantly clearer and smoother.

We also tried to encode at a higher input resolutin, (704x), but found that our vendor supplied tool can do that, but only to MPEG2, which was what we were then trying to re-encode to DivX, which we now realize was a mistake. IN fact changing from the intermediate MPEG2 coding was what gave a big boost to our RV quality (dare I say that here!?)

So we feel we must have a similar fatal flaw in our DivX methodology (as described above).

We are in process trying the suggested alternate SVHS->Huffyuv->SBC,
and also looking into gknot.

Should we be worried about the initial input resolution? We setup VirtualDub to code at 640x480, but it drops LOTs of frames, and this is on a FAST system (dual 1.4G Athalons, 512MB DDR, 266MB FSB). The vendor tool for capturing does fins, no dropped frames, but only captures to MPEG2.

We don't see a huge quality difference in the different resolution settings.

We'll post a sample of our results on a local FTP tomorrow, and could someone send us a sample of what we could/should expect for a compressions like this (goal = ~3 hours/CD).

We hope that this further information will help someone pinpoint whatever error we may have; since we are NOT getting the expected results.

Thanks for the support and expertise.

[disturbed1]

For ~3 hours on one cd will take a total bitrate of 512kbit (audio and video combined). With that low of a quality constraint, use a resolution of 320x240. Windows Media 8 was designed for such encodings. Download the codec and encoder here

http://download.microsoft.com/download/winmediatech40/wm8eu/8/w982kme/en-us/wm8eutil_setup.exe

And the GUI here

http://doom9.org/software2.htm#encoders
(direct link)
http://doom9.org/Soft21/Files/Encoders/WM8EGUI.zip

I use that method to archive TV shows for computer only play back. I find the quality of WM8 higher than Divx at lower bitrates.

Plus it isn't hacked/stolen, and it is a standard format.

[tinycorkscrew]

I'm with distubed1 on this one.

WMV might not be a popular format, but quality for size is very good.

[Shabubu]

SBC is smart bitrate control, it's like Multipass VBR for MPEG.

[mum_video]

Thank you disturbed1 for your recommendation, I am testing it to see the quality, but can anybody tell me how to make good DivX out of VHS video tapes, regardless of the file size?!!

[Greg12]

I've produced quality real media but the file was huge.

[Shabubu]

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR size=1 color=black></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2001-12-15 10:01:22, mum_video wrote:
Thank you disturbed1 for your recommendation, I am testing it to see the quality, but can anybody tell me how to make good DivX out of VHS video tapes, regardless of the file size?!!
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Get Avisynth and Virtualdub (also get greedyHMA, mpeg2dec and spatialsoftenMMX, these are avisynth plugins). All are available from doo9.org and videotools.net.

Capture in virtualdub at 352x480 (576 for PAL), anymore would be a waste for VHS, use HuffYUV or Picvideo at a high quality setting.

Use this avisynth script to frameserve to Nanbub:

LoadPlugin("C:\Program Files\GordianKnot\MPEG2DEC.dll&quot
LoadPlugin("C:\Program Files\GordianKnot\AVISynth_Spatial.dll&quot
LoadPlugin("C:\Program Files\GordianKnot\GreedyHMA.dll&quot

#AVISource("Dressed To Kill.AVI&quot

video=AVISource("Dressed To Kill.AVI&quot
audio=WAVSource("D:\Dressed To Kill\Dressed To Kill.wav&quot
Audiodub(video,audio)

GreedyHMA(0,0,1,0,1,0,0,0)

Crop(0,16,400,536)

#SpatialSoftenMMX(2,4,6,false,false,4,4,6,
TemporalSmoother(2,1)
#SpatialSoftenMMX(2,4,6,false,false,4,4,6,

Trim(800,171966)

BilinearResize(352,28

Extract the audio with CoolEdit and noise reduce it and normalize using cooledit. Then change the path names in the above script to your actual ones. Load this in Nandub (from Doom9.org again), and encode. Read the guides at doom9.org to find out how.

One tip, if your going to use these for archiving you may consider going to MPEG2 instead.. DivX is not a good source for making VCD's

[mum_video]

Thanks for your advice. I have actually setup a web page with the samples that I have created for RealVideo and DivX so I would like to invite you to have a look at my samples and comment!!

http://www.cs.mum.edu/video

If you feel that my DivX samples are good enough please write to me.

[w00kiee]

unfortunately, just like lots of people say divx is crappy compared to vcd - even more say real video is crappy compared to everything.

but its the same issues usually. after viewing twenty 10 meg RM episodes of cartoons (or real people) you begin to beleive thats the best it can do. but actually its just people skimping on bandwidth... a 10 meg mpeg1 of anything 22 minutes long would be just (actually more in my opinion) ugly than the RM of same size (2 mins of mpeg at vcd spec is ABOUT 12 megs)

rms can have much higher bitrates. just hardly anyone uses them

having said that, there is no good way to convert rm to vcd (tinra and eo video aint the answer) so a high bitrate RM can only be viewed by someone with a fast PC ... on a pc.. so its not much use if you wanna view it on tv