2-pass and decomb filter

[redlenses]

I'm encoding TV Show DVDs to H.264 for playback on a PS3

When I used the defaults in Handbrake or RipBot, I'm getting noticeable combing.

My question is: What are the negatives of using the decomb filter and/or 2 pass encoding? Why wouldn't one want these options on all the time? The default Handbrake PS3 profile does not include them.

[LoRd_MuldeR]

I guess with "Decomb" you either mean Deinterlacing or Inverse-Telecine (IVTC). Anyway: That is not related to the encoding mode! Given that your source is interlaced/telecined and you don't want to encode it as interlaced, you must deinterlace/IVTC the video before encoding. So that is pre-processing. Encoding modes are a completely different thing! If you want the best quality for a given target filesize (or target bitrate), then you should use 2-Pass mode. If you want to retain a certain level of quality (and don't care about the filesize), then you should use CRF mode. But none of these encoding modes works better/worse with interlaced/telecined material. You must apply the proper pre-processing and choose the suitable encoding mode...

[redlenses]

Handbrake says that it's "decomb" setting does the following: When a frame shows a significant amount of combing, decomb runs a tweaked version of HandBrake's "Slower" deinterlacing filter. That's yadif, a spatially (within one frame) and temporally (between several frames) aware deinterlacer. The tweak is that it uses a looks at more pixels when generating the spatial predictions.

When a frame is only very slightly combed, decomb runs a blending deinterlacer called a lowpass-5 filter. This preserves more detail from the image than yadif, and in particular prevents noticeable deinterlacing artifacts on progressive video.

OK so to refine my question: Why wouldn't someone run things through a decombing pre-process step before encoding? Handbrake doesn't have this selected by default for the PS3 profile.

[Guest]

The handbrake guys ripped off my name "Decomb" from me. My next filter will be called "Handbrake".

[LoRd_MuldeR]

OK so to refine my question: Why wouldn't someone run things through a decombing pre-process step before encoding?

Because somebody has an interlaced/telecined source and wants to encode it as progressive ???

Handbrake doesn't have this selected by default for the PS3 profile.

So what? Whether deinterlacing/IVTC is required or not depends on the type of source, NOT on the target playback device...

[nm]

The handbrake guys ripped off my name "Decomb" from me. My next filter will be called "Handbrake".
Imitation is the sincerest form of flattery. :)