Banding and sparkles in low motion x264

[DJRumpy]

I've been running a few encodes, thinking about backing up my DVD collection to the media PC. I've tried this using both Nero Recode, and MeGUI. I'm noticing something odd. In low motion scenes, with neutral, mid-scale colors (like wood, or gray backgrounds, or a wallpaper with little/no designs), I'm getting sparkle and banding. Initially I assumed there was a bit shortage, but when I started increasing this to 2000kbps for a 720x352 project, I'm a bit doubtful. Especially for this coded, as it continues to amaze me in it's capacity for compression. The sourc is straight from DVD. These are recent movies as well, not a noisy analog 80's flick. The weirdest thing is that this issue shows up on very low motion scenes. If it was high motion, you would never even see it, however, when two people are sitting at a table having a conversation, and the background 'glitters', it has me puzzled. I typically leave the AVS with Minimal Noise (UnDot filter) enabled unless my source DVD was shot in true digital.

Source: DVD
Output Resolution: 720x352
2-Pass, HQ-Slow profile (tried with Turbo disabled as well)
Bitrate 1000-2000
Deblocking: Enabled
Deblocking Strengh: -2
Deblocking Threshold: -1
AVC Profile: High Profile
AVC Level: Unrestricted
Zones: None defined
VBV Buffer Size: Auto
VBV Max Bitrate: Auto
VBV Initial Buffer: .9
Bitrate Variance: Tried 1.0 and 2.0
Quantizer Compression: .6 (also tried .5)
Temp. Blur of est Frame Complexity: .5
Chroma M.E: Enabled
M.E. Range: 12
Scene Change Sensitivity: 40
M.E Algorithm: Multi-Hex (also tried Exhaustive)
Subpixel Refinement: 6-RDO (Slow) (also tried 7)
Keyframe Interval: 240
Min GOP Size: 24
Noise Reduction: 0 (also tried 100-500)
Min Quantizer: 10
Maximum Quantizer: 51
Maximum Quantizer Delta: 4
Credits Quantizer: 40
Factor between I and P frame Quants: 1.4
Factor between P and B frame Quants: 1.3
Chroma QP Offset: 0
Trellis: 1 - Final MB
Number of reference frames: 3 (mixed Enabled)
CABAC: Enabled
No Dct Decimation: disabled
No Fast P-Skip: Enabled
Quantization matrix: None
Macroblock Optoins: All
# of B-Frames: 3
Adaptive B-Frames: Enabled
B-Pyramid: Enabled
RDO for B-frames: Enabled
Weighted B-Prediction: Enabled
Bidirectional M.E.: Enabled
B-frame mode: Auto
B-frame bias: 0

Any ideas as to what could be causing it?

[GMaq]

Hi,
What revision of x264 are you using in MeGUI? They update x264 on an hourly basis!! Or it seems that way anyway. Do you see the same artifacts with Nero AVC as well? If DVD is your source I would forget about the UnDot filter as well and maybe try an encode with one of Sharktooths presets.

[DJRumpy]

I've seen this issue across all of the recent revisions I've tried (I check every time I launch it). The current revision I'm on is 0.2.3.2192.

[Soopafresh]

This gives me good results. I have seen that issue on flat surfaces. Give it a try, maybe it'll work, maybe not

x264.exe --progress --no-psnr --scenecut 40 -I 250 -i 25 -t 1 --threads 1 --me hex --sar 1:1 -r 1 --nr 0 -f -2:-2 -b 2 --direct "temporal" --b-bias 0 -w --ipratio 1.400000 --pbratio 1.300000 -A p8x8,b8x8,i8x8,i4x4 --8x8dct -B 1700 --qpmin 10 --qpmax 51 --qpstep 4 --qcomp 0.600000 -m 5 --aq-strength 0.75 -o "output.mp4" "input.avs"

[DJRumpy]

Those settings appear to be identical to mine for the most part, although I don't see where in your command line as to what mode this is. I wish they would add a settings export that was an easier format to read than XML.

What resolutions are you encoding with these settings?

Can you save your settings as a profile, and paste it here so I can see everything your using, or do you know which of your settings seems to help resolve this?

The UnDot filter still has uses, even with a DVD source, as video shot with an Analog process still contains mesquito noise, while a true digital movie like Star Wars EP3 or a Disney CG flick has none.

It's almost as if it's seeing motion where there is none, or it's degrading the bitrate in those locations too far. I'm sure the bitrate settings under the Rate Control or possibly the Mostion Estimate settings could resolve this, but I'm not familiar enough with x264 yet to tweak these to an optimal setting. I would think the defaults should be 'safe', yet they obviously are not, or there is a flaw in the codec itself that needs to be worked out.

[Soopafresh]

Consider replacing Undot with RemoveGrain(mode=1) from kassandro's RemoveGrain package. It has SSE performance optimizations and the results are identical. Better yet, try your transcode without either. Remove as many possible culprits from your troubleshooting workflow.

I added "--aq-strength 0.75" to the command line, per a Doom9 thread regarding a similar issue.

I'm using these setting for 720x400 downsized from 720p source (-LOST- ota transport stream capture)

The above command can be saved as a batch file and executed by doubleclicking. Just save the text as RUNX264.BAT and make sure your X264.exe file is in the same folder as the batch file.

[DJRumpy]

I'll give it a try. I'd be curious to see how well it performs on something like War of the Worlds.

[DJRumpy]

No glory on the RemoveGrain. I'll post a few samples of what I'm seeing. I've resorted to encoding test runs of the same 5 minute clip to see what helps. No luck as of yet.

[DJRumpy]

Deband in ffdShow took care of this to a satisfactory level. Apparently it is handled differently by various decoders.