Interlaced video stuttery

[rlevis]

Hi.

I'm using the Handbrake front-end which uses x264. I tried to post this question on their forum but the moderator refused to accept it!

I'm encoding videos recorded from my Sony HD camera 1440 x 1080 25i. The encoded 25p progressive video is very stuttery during panning. The original interlaced video is smooth.

In Handbrake I'm using the "Slowest" deinterlacing method, and a high bitrate.

I know that 24p bluray movies are not stuttery, so I'm wondering where the problem is. Anyone know?

Thanks.

[GodofaGap]

Movies are generally more "blurry" in high motion which makes the motion appear more smooth at the cost of detail. I don't know if handbrake allows you to put on a similar kind of motionblur or if you'd prefer to have a 50p version.

[rlevis]

I see. Motion blur would be better, but 50p could be better still. Are there x264 options I could add to force motion blur or 50p encoding? Handbrake does provide for additional parameters to be entered.

[GodofaGap]

This is not x264 related and should be handled on the filtering side, but never having used handbrake I can't comment.

[Didée]

One of the first & easiest things to try would be using a "double rate" deinterlacer (aka "bobbing"), instead of a "normal" deinterlacer (aka "single rate" deinterlacing).

[Hagbard23]

Maybe the wrong field order? Check whether your CAM uses BFF or TFF. If you feed BFF Material to a processing chain which is expecting TFF or vice versa, you get really ugly stuttering. But unless you start using AVISYNTH, you will get problems in changing the parameters.(ComplementParity() would be the right filter for you if field order is swapped - you also can use the command: AssumeTFF() or AssumeBFF() ... depends on your source-video and your expected target).

http://avisynth.org/mediawiki/Interlace_detection
http://avisynth.org/mediawiki/AssumeBFF


I do not know handbrake - so i can't give you support on that, but maybe you consider MeGUI, if you are in the need of something more "visual".

After that(setting the correct field order) i would recommend a good deinterlacer - my favourite is YADIF.DLL, but there are several other good options. Nevertheless it depends on your video. If you got really much motion, it is -like Guru-Didee says- the best option to use a bob-based Deinterlacer and leave the framerate on 50p. But if there is not so much motion (a lot of "standing" Pictures, like in interviews or similar) it maybe a better solution to blend fields somehow or you use a mix of several deinterlacer methods.

Use the forum search to find your best deinterlacer.

AND DO NOT FORGET: Set the right field order! It is the first step of deinterlacing. Processing software without options to manipulate/set the field order correctly is absolutely NO Option for you!

[nm]

Unfortunately HandBrake doesn't expose a bobbing deinterlacer to the user, so you'll need to look elsewhere. MEncoder has yadif and mcdeint (-vf yadif=3,mcdeint=0:0:10), which gives decent quality, or you can use AviSynth and Didée's TempGaussMC.

Another option is encoding as interlaced. Then you'll need to bob on playback (with a GPU) and quality will not be quite as good as with TGMC.

If you want Blu-ray/standalone player compatible video, you'll need to choose between encoding as interlaced at the original 1080i25 resolution, or downscaling and bobbing to 720p50. Currently 1080p50 is only suitable for PC playback.

[2Bdecided]

It depends what you want to use the resulting files for. For home movies, I always keep the original files (HDV = MPEG-2 1440x1080i25 25Mbps in my case) - and my PC, STB, and TV play these fine (I just bob-deinterlace in VLC player on the PC during playback). If I edit them, I might render to lossless or low-loss intermediate, but always keep an HDV copy too.

If you need to encode for some other use, then that other use will determine what you should do. I only drop to 25p for web use, because (as you say) it's stuttery - though some people like that look. 1080p50 is more than my PC can handle.

Cheers,
David.

[rlevis]

It's mainly to save some space. I can generally get less than half the size at no perceived quality difference using a slow encode/ max quality settings.

The thing is 24p blu-ray movies are not stuttery, so 25p should not be either. It must be a deinterlacing issue. My PC and HTPC can handle 1080p50 with no problems.

I've noticed that the original 25i is also stuttery when playing in Windows Media Player but very smooth when playing in MediaPortal and the Sony PBM utility which came with the handycam.

[GodofaGap]

The thing is 24p blu-ray movies are not stuttery, so 25p should not be either. It must be a deinterlacing issue.
It is not so much a deinterlacing issue as a recording issue. You can get very different shutter speeds when you record something at 24 Hz instead of 50Hz. What you would like to do is emulate the 24Hz behavior, but you can't do this by deinterlacing alone, and you probably can't do it perfectly.

[rlevis]

I suspect the shutter speed is 50hz, being a PAL camera, and the fact that panning in the original interlaced video is very smooth.

[rlevis]

As a matter of interest, Handbrake is using YADIF.DLL, and the field order is not the issue.