Block Noise

[stevemei]

I getting alot of block noise when viewing XVCDs. Is there any way of eliminating them. The resolution is great however.

I encode XSVDs using the following programs/methods:

1)DVD2AVI to get D2V file and wav file
2)Encode using TMPGenc 2.53 at 720x480 at a constant bit rate of 3361
Quantize Matrix tab with Soft block noise checked setting for both intra and non-intra blocks set at 100.

I read in this forum that one can use the filters in virtual dub such as Dynamic Noise Reduction, Static Noise Reduction, And 2D Cleaner. I then used VFAPIConv- to convert the D2V file into an AVI so I can use Virtual Dub. However, when I open up virtual dub. I can't find those filters.

I have tried using CEE and DVD2SVCDS in the past but both programs lockup for some reason. TMPGenc seems to work the best.

I would appreciate any help in this matter.

[vhelp]

stevemei,

quite frankly, you just using to highe a resolution (pending on your
source of course) but if anything else, you could up your bitate
for that resolution.
But, really, you need to look at your whole process, ie, ivtc
32pulldown, inversv32, etc. w/out utilizeing this, even higher
bitrates will foil your encodes.

but, i'm surprised that CCE didn't reduce your blocks.
What is your tv size 13" or 50" or hdtv, etc.

-vhelp

[stevemei]

What I meant was I tried using CEE. But was never successful in encoding anything because the program always froze up during the encoding process.

[ratt794]

A couple of things IO noticed about your settings:

Bitrate of 3300 is too low for full D1 resolution regardless of the encoder.
Broadcast Quality is 4000-6000 for D1.

I recomend 4000 or higher and use MPEG-2 not MPEG-1 as it is more efficient at compression.

Other things that can help is to lengthen the GOP sequence by increasing the B-Frames in particular as these compress the most. Just make sure to encode at highest quality, floationg Point and 10 bit precision.

I have used 5P, and 9B for a GOP length of 60 frames (2 Seconds) at bitrates as low as 3000 with good results although not perfect. Any high motion sequences may cause problems or blocks on a hi-res TV. Best option would be to keep the bitrate to at least 3500 and preferably 4000.

Also CQ VBR set to 100 quality works very well with longer GOP's.

The reason to use longer sequences is that B and P Frames compress more than I-Frames but You MUST use highest Quality encode to maitain accuracy otherwise the results will not look good. This allows a higher quality or lower bitrate to be used.

Hope this helps.

[ratt794]

Another thing I forgot - DVD is MPEG2 with VBR and a 9800 max bitrate.
DVD is also interlaced but I am not sure on the field order.

Re-Compressing to DV-AVI and then RE-Encoding to MPEG could also be the problem especially at the low bitrate of 3300. Multiple cascading codecs can only make matters worse unless it is done with EXTREME care. It will never look as good as the original even if the same bitrate is used.

If your target Bitrate has to be near 3300 then I recomend going to SVCD resolution 480x480. Quality loss is not that much and you will likely get rid of the "Blocks" you are experiencing. If you have to have the full 720 x 480 then the ONLY solution is Longer GOP + higher Bitrate.