Getting too high quantizers.

[gusarapez2000]

Hello,

I am trying to encode a quite old B&W movie from a not so very good quaility DVD. I have set the encoder so that it uses 1000 kbps for a 512x368 frame, which gives a quality factor of about 0.228.

The graph for the xvid status during the second pass looks like this:

http://img190.exs.cx/img190/9919/xvid4nt.jpg

You see that all the I-frames are being encoded with a 5-6 quantizer. As you can imagine, the resulting video looks horrible, full of blocks.

Encoder setting are as follows:

AS@L5
MPEG Matrix
Adaptive Quantitation
Q-Pel
Packed bitstream
Max consecutie BVOPS 2
Max and minimum values for I-, P- and B-frames are 1-31
UltraHigh Motion search
VHQ Mode 1
Use chroma motion
Greyscale encoding

According to my limited experience, I would think that having a quality factor of 0.2 should be enough for having quantizer of 2 for the I-frames. It could be that the original video is not very clean and that therefore it can't be efficiently compressed. If this is the case, I would appreciate guidance on how can I improve the quality of the rip keeping the same bitrate.

Thanks

[mikeX]

You could use a denoising filter, to smooth the picture a bit, that should help a lot with bitrate reduction, but you should judge for yourself if it helps with quality or not.
You can also switch to H263 quantization, enable VHQ 4, trellis, gmc, and VHQ for B-VOPS. Chroma motion doesn't work if Greyscale is enabled, so you might as well turn it off. As you can see from the screenshot, the avg bitrate is still ~600 kbps, so you should encode a larger clip, large enough for the bitrate to average your desired value, before you judge the results.

[Sergei_Esenin]

You might also turn off AQ. Personally I've never liked its appearance with B&W films, though I haven't tried it with them for many releases.