Xvid VB

[AllstarElyar]

is there a way to get variable bitrate XviD with virtualdub or any other program?
also when i select two-pass option VDM give error.
what i can do?

[jagabo]

With Xvid, Two-pass encoding and Single Pass with Target Quantizer encoding are both VBR.

If you need files of a specific size use 2-pass. If you want files of a specific quality use Single Pass with Target Quantizer.

For 2-pass encoding first select "two-pass, 1st pass", encode, then select two-pass, 2nd pass" and encode again.

For single pass with target quantizer, select Single Pass. If the button below says Target Bitrate, press it to change to Target Quantizer mode. Select a quantizer value (lower values lead to higher quality). Encode. The encoder will use whatever bitrate is necessary for each frame to meet the specified quality.

[AllstarElyar]

thx
but in two-pass after selecting 1st pass what should i do
preview vbr? or save as avi?

[jagabo]

Set everything up the way you want. Set Xvid to Two Pass 1st Pass. Save as AVI. Set Xvid to Two Pass 2nd Pass. Save as AVI again. The AVI created during the first pass will not contain any video.

[AllstarElyar]

is there a way to have vbr wmv
and in which method ill get better video quality in low bitrate?
i mean the movies with lots of action or basketball games?
when i cap dvb,after converting there is always some dots surrond every player.even in 1500 kbps bitrate.
i want to get rid of this?

[manono]

...even in 1500 kbps bitrate.

There's nothing particularly high about 1500, especially for captures, and especially for fast moving sports. If you're using a reasonably high resolution (640x480 or so), this is even more true. Use a higher bitrate and/or a lower resolution. And make sure the artifacts aren't in the original capture.

[jagabo]

is there a way to have vbr wmv

I don't know about WMV.

and in which method ill get better video quality in low bitrate?

With 2-pass VBR you know what the final file size will be (average bitrate * running time) but you don't know the quality. With Target Quantizer you know what the quality will be but you don't know the size. When the two methods end up creating a file of the same size, the quality will be equal.

i mean the movies with lots of action or basketball games?
when i cap dvb,after converting there is always some dots surrond every player.even in 1500 kbps bitrate.
i want to get rid of this?

Dots? I suspect you are seeing interlace artifacts? Post a sample frame.

[AllstarElyar]

no thats not interlace line becuase i use deinterlace filter

source is:
mpeg-2 15 mbps bitrate 544*576

and i convert it to:
XviD 800 kbps 512*384(single pass)

i use 800 becuase some guys use the same or even lower and get better quality
and some use rmvb
is the source i cap isnt enough?

sample: http://rapidshare.de/files/29542399/123.avi

thx for your help

[jagabo]

I saw lots of macroblocks -- the result of too little bitrate for the video. High action sports with bright lighting will require higher bitrates than most movies (even action films have lots of slow and dark scenes that compress very well).

I didn't see much static noise in the sample so I would guess it was a digital satellite capture. There is probably a moderate amount of macroblocking in the source. Add to that the conversion to low-bitrate Xvid and you get very blocky video.

Here's a portion of frame 83, chosen at random, enlarge 4x with a nearest neighbor filter so the blocks aren't blurred by the enlargement:



You'll have to use a higher bitrate or a smaller frame size (smaller frames require less bitrate). With an MPEG source you shouldn't expect to get much more than a 4 fold reduction in bitrate without losing quality (unless you're also reducing the frame size).

[AllstarElyar]

I didn't see much static noise in the sample so I would guess it was a digital satellite capture. There is probably a moderate amount of macroblocking in the source. Add to that the conversion to low-bitrate Xvid and you get very blocky video.

yeah i cap from dvb-s and how can i get rid of thr macroblocks?
and you say that its blocky becuase of low bitrate XviD.i want to get smaller file size with the same quality as i can get now.what should i convert to ?rmvb?wmv?

[jagabo]

I don't think RMVB or WMV will do any better than Xvid. I know WMV will reduce the frame rate when action gets too high for the bitrate (rather than generating poor quality frames).

You might try h.264 (x.264 for a free, open source version). It can do better at low bitrates but with your source material there's a limit to what you can do.

There's a reason they broadcast as a 15mb/s MPEG2 stream -- if they could use less they would!

[AllstarElyar]

im gonna have a look at h.264
but when i watch a video in rm or rmvb format in 600 bitrate the quality is really good
but i cant find any guides here that how can i convert mpeg to rm or rmvb?
i use winAVI but there isn a lot of options.

[jagabo]

You can try the free RealProducer Basic:

http://www.realnetworks.com/products/producer/index.html

High action sports will not compress as well as movies.

[AllstarElyar]

realproducer doesnt support most avis and mpg(but divx)
btw i use x.264 and that works great.i encode mpeg-2 10mbps 704*576 to a 450kbps 320*240 avi and it looks very good without any blocking.maybe becuase this time source has more resolution.

[jagabo]

You're also encoding to a much smaller frame. 512x384 vs. 320x240 is 60 percent less video to encode. The Xvid encoding of your original 123.avi would have looked a lot better with the smaller frame.

By the way, you'll get better results with a 2-pass VBR encoding.