Fight with blockiness creating SVCD

[deutschem]

I have:
Firewirecard
Dazzle Hollywood DV-Bridge for AVI-capture
MGI VideoWave 4 for AVI-capture
TMPGEnc 2.01 for conversion
UDMA-100
Duron 750

TMPGEnc settings:
- SVCD-Template (PAL)
- CBR
- Bitrate 2250
- Interlaced
- Highest Quality
- Number of P picture in GOP = 4 (is that right for PAL ?)
- I do NOT (because i hate it) use "Soften block noise"

On (slow) high motion (for example someone walk in normal speed from one corner in the room to another) i have many blockiness. The source (DV-AVI) is ok.
I tried some setting fly around this forum. I tried another release from TMPGEnc. I tried to find a solution

Can anyone help me ?
Which (for example in TMPGEnc) things have an effect on blockiness in SCVD ??? VCD is by the way 100% OK

ThanX
deutschem

[Shabubu]

I'd go with a lower setting of soften block noise ;P

On a serious note, try using multipass VBR, also try adding a smooth filter in vdub then framserve to TMPGEnc.

[SH0CKER]

look up my READ ME:


https://www.videohelp.com/phpBB/viewtopic.php?topic=65609&forum=8

[deutschem]

SHOCKER, Shabubu thanx for your reply.

What are you try to tell me ??
Do XSVCD/XVCD, do simple multiplex, do killing MPEG2 header ???

Shabubu, when i use multipass VBR i need for a 50min. AVI 13 hours to encode
(by the way, i realy hate SBN !!!)

[Shabubu]

The two pass will help TMPGEnc give more bitrate to the higer motion scenes, thus helping get rid of the blockiness. It's like raising the overall bitrate, but the filesize isn't larger as the bitrate for low motion scenes is reduced to compensate. Unfortunately it's a case of test, try again, test etc etc. I'm doing gladiator now for the 3rd time and I'm doing 4 passes (in CCE). But in the end it's worth it.

[RHODK]

Increase the bit rate to at least 2.700 (standard SVCD, the japanese template is "low and on the save side&quot. Open "setting" in TMPG, go to "Advanced", double-click "Deinterlace" and choose "Even-odd field (field, animation adoption...)".
Be patient, good quality takes time. Wenn Du nicht warten kannst kannst Du keine ordentlichen SVCDs machen.

[deutschem]

Thanx for your reply,

i've tried the two pass VBR (ich habe gewartet). Nothing has changed.
I think no one can help.

I try "soften block noise" and buy eyeglasses for the blurred result.

[deutschem]

But i feel that many people have this problem (look at the views)
Is there a chance to figure out this problem ?

[Truman]

I highly recommend to use a smooth filter. For example you could use Avisynth's SpatialSoften/TemporalSoften filter
http://www.videotools.net/default.htm
or the Spatial soften plugin by Mathias Born. Similar filters you will find for VirtualDub. Unfortunately it slows down the encoding process drasticly. You have to decide whether you go for speed or quality. I don't think it is necessary to do a VBR 2pass encoding if you use a relativ high bitrate like 2200-2700 kbps. CBR should be enough. Have you ever tried a lower frame resolution like 352x576 or even 352x288?

[Truman]

The link to M.Born's site is down. Get the SpatialSoften MMX 0.9 from Dividee's site if you like.

[deutschem]

Thanx Truman for your reply.

BUT:
- I don't use Vdub, because my Dazzle DV Hollywood Bridge would not recognized.
- no blockiness by resolution like 352x576 or even 352x288, but is that the solution ?
- the source is 100% ok

or is MGI VideoWave 4 the problem ? What do you think ?

(at this time i try soften block noise, thrilling, ouhh my blood pressure)

[Truman]

TMPGEnc tends to give blocky picture @ higher resolutions. Let's say you use a bitrate of 2200kbps to fit the mpeg onto one VCD.
480x576=1080 macroblocks-->2085 bits/second/macroblock, 352x576=792 macroblocks-->2844 bits/ second/ macroblock
-> +36%--> so a smaller frame size is the solution, although the picture get less sharp.
The 2nd way is to increase the bitrate.
I don't know anything about MGI VideoWave 4. However, this seems to be an encoder problem only.

Also one told me, that he got a better picture quality by using a higher number of I-Frames (GOP structure IBBPBBPBB or even IBPB) although this will result in a lower compression effeciency.

Btw, what is the source resolution?

[nimrodo]

Hi there Truman wondered if you could explain the calculation form resolution-->macroblocks-->bitrate/sec/macroblock
And what does it have to do with blockiness??

[Truman]

nimrodo, a macroblock is the smallest unit, that will be encoded. 1macroblock=16x16pixels.
480 pixel / 16 pixel=30 macroblocks
576 pixel / 16 pixel=36 macroblocks
30x36=1080 macroblocks
bitrate in this example is 2200 kbps
2200 kbps / 1080 macroblocks=2.037 kbps
2.037kbps x 1024=2085 bps
I forgot to divide by 25 frames per sec in the calculation above-->2085 / 25=83,5 bits / sec / macroblock.
Anyway, do this calculation with a 352x576 resolution, you will get 113,7 bits / sec / macroblock---> +36 %
This means, by decreasing the resolution from 480x576 to 352x576 you increase the average bitrate per macroblock.

The higher resolution you chose, the higher bitrate you need to avoid artifacts /blockiness/ whatever.
2200kbps@ 352x576 equals ~3070kbps@ 480x576. If your player can handle that high bitrate and you don't care about, that
you can fit ~33min video on a 80min CD-R only, go that way.

Why do we use high resolution like 480x576 or 720x576 at all? Higher resolution guarantees a more detailed i.e. a sharper image if the you have a high-quality, sharp, low (or non-) compressed source. Homemade videos hardly come close to studio quality, so a 352x576 resolution should be enough.
Hope it helps.

[nimrodo]

Thanks Trueman
So what would you say be the minimum bitrate per macroblock to avoid blockiness?
Is there anypoint leaving the source lets say a dvd 720x576 pal if i am encoding for a usuall television which has a max resolution which is much lower?

[Truman]

It depends on the source. A DV avi source should be encoded at 480x576@ 3000-4000 kbps or as 352x576 @ standard SVCD bitrates. If the source is a well encoded DVD, standard SVCD bitrates are more than enough.
If I convert a 1:2,35 widescreen DVD with CCE to SVCD 480x576, usually an average bitrate of 1500-1800 is enough without a quality loss compared to the original DVD (1215 vs 560 macroblocks and few other ways to "count the bitrate down". If you use TMPG, never use an average bitrate lower than 2000kbps.
PAL TV resolution is always 768x576.

<font size=-1>[ This Message was edited by: Truman on 2001-11-16 07:39:13 ]</font>

[deutschem]

OK.
After this setting i have 20% less blockiness:

Soften block noise
Intra=35
Non-Intra=40

But i think it is not enough to be satisfied (not sharp).

I continue playing around with the GOB structure.

Truman: the source is 768x576

What about Cinema Craft Encoder Light ? A chance ?

[Truman]

Hi deutschem, I found this topic on a german forum. Hope it helps.
http://dvdboard.wpf.de/showthread.php?s=5993a960d239244ccfe0d782211d9a91&threadid=26023

[Vorlon]

This may seem like a strange answer. But I was battling blockiness for the longest time and some of the problem was really pixelation, instead. (I hope my definitions are correct)

I consider blockiness the result of motion artifacts - the inability to render the video data - usually through too low bitrate. Faster bitrates correct this type. Some is plain noise - garbage in/garbage out. I used a line conditioner (also known as a UPS) to correct that - voltage dips, etc can play havoc on capturing and encoding.

Poor source material can only be corrected by using a different source material. Library tapes, rental tapes, and recordings from the home VCR done at less than SP speed or off the air antenna, are usually very poor sources. Signal to noise ratio is way too low - Television units filter out most of this noise, but digitalizing will pick up the noise with the signal and attempt to encode it also (causing blockiness).

The pixelation that I had was due to my DVD player being unable to play CDRW containing SVCD format properly. Burning the CDRW at a faster speed removed most of the pixelation, but it still occurred too often and at the wrong times for me. Rewinding and replaying sometimes removed the pixelation, but sometimes a small effect still remained.

When I used CDR instead of CDRW, my DVD player did not experienced the pixelation anymore for SVCD.

VCD format almost always has blockiness for me (too low bitrate) - the picture quality is below VCR for me. SVCD has a much better quality than VCRs. I can place about 68 min of VCD on a CD. I have a setting that gives me great quality and still allows me to place between 43 to 47 minutes of SVCD on a CD - enough for an hour show without commericals.

I had had a hard time finding the cause, because more than one factor was causing the problem. I had to eliminate each cause - one at a time.

I hope this helps point you to a possible solution.

[Nelson37]

I have also been battling pixelation for months and likewise have found multiple causes to eliminate. New cable from pole to house, digital cable box helped. 10db signal amplifier also helped. for encode settings, either IVTC or area-based deinterlace, along with changing field order and setting GOP to IBPB (all ones) - this is not logical but the file size difference was very minimal, less than 1%, try it -, and bitrates from 2350 to 2600 have got me to 99.9% of original quality, and 35 to 43 minutes per CD. Good Quality CD's (now using Memorex black) definitely made a difference also. a LOT of test, tweak, test again. enjoy!

[nimrodo]

Hi there Trueman again
1:2,35 widescreen DVD what does that mean?
And again what would be the minimal bitrate per macroblock per second to avoid blockiness- from this question we could adjust each resolution to get the minimal bitrate required and thus more filmtime per megabyte!

[Truman]

1:2,35 is a cinema ratio, many dvd's come with this format.
Usualy aspect ratio's are 4:3, 16:9, 1:1,85, 1:2,35

There is no rule of thumb how many bits per macroblock one should use. It depends on the source, which filters you use(if any), which encoder you use etc. Quite complex stuff.
My calculation above should only show a solution to get rid of blockiness.