Tweaking Xvid Settings for Better Video Quality

[dbq-andersons]

Good Day Everyone,

I need a little help. This will be a bit lengthy, but I want to describe how I got here.

I've been ripping/encoding DVDs for a few years now. Handbrake has been my tool of choice with the h264 video codec and the AAC audio codecs doing very well for me over the years. Then I got a new 60" vizio smart TV for Christmas. My goal is to serve up all my movies via a DLNA server and stream to the TV. I've been running into a lot of road blocks though and am looking to the experts on this forum for help.

While my h264 videos work fine when loaded on a USB drive and attached directly to the TV, I cannot get them to stream via a DLNA server...unless they are shorter than about 23 minutes and 15 seconds. Any videos longer than that cause the TV to spit out audio and video codec errors, even though the same codecs (h264/AAC) work fine (gorgeous picture quality across all 60" of the TV) if they're shorter than the time mentioned above. I'm still researching/fighting that issue (anyone have any thoughts on that one?), but in the meantime, I've been exploring other codecs.

The Xvid codec seems to work fine (USB and DLNA streaming). I am using autoGK for encoding from my DVD VOBs and have taken all the defaults so far. The codecs play fine, but I am having issues with the video quality. I am seeing "blockiness" around the motion in the frame, especially when on the TV. Before I go tweaking settings, I'm looking for some help in determining what settings I might need to tweak. I am looking for the same (or at least nearly the same) video quality I have on the h264 codec videos I get from Handbrake. Movie size doesn't matter much since I have plenty of hard-drive space.

I have attached the autoGK log and a small sample of the "blockiness" I'm talking about.

So, that's where I'm at. Any advice/help anyone could give would be greatly appreciated.

Thanks,

Bill Anderson

[jagabo]

Xvid will require substantially more bitrate than your h.264 source.

Your trouble is DCT ringing artifacts, aka mosquito noise, not blockiness. Using more bitrate or a lower quantizer will help. There are custom quantization matrices that will reduce that too (if your TV supports custom matrices). Maybe someone who knows a good matrix will step in...

If your source has some DCT ringing using a less sharp resizer will help. Lanczos enhances those types of artifacts.

This won't help for your TV, but for playback on a computer you can turn on Xvid's deblocking and deringing filters.

[manono]

Xvid will require substantially more bitrate than your h.264 source.

He's doing a 1-pass CQ encode at 100% in AutoGK, so it's a quant 2 encode. AutoGK doesn't support any custom quant matrices but its own.

Maybe he's talking about the commonly seen 'dark blocks', seen in dark scenes and scenes with the same color (like walls and skies)? One possible fix for that is to make sure the TV is properly calibrated.

Movie size doesn't matter much since I have plenty of hard-drive space.

So, is there any reason not to just keep the DVD as-is? Or, at most, to convert it into a single VOB or MPG?

I don't see the video sample. Am I missing it? Oh, so the picture is the sample?

[jagabo]

so the picture is the sample?

That's what I assumed. Also, one can't tell what problems are caused by the JPG compression and what was in the Xvid video.

[hello_hello]

I don't know how much the typical Xvid blockiness in fast motion/flat areas would be effected by resolution, but maybe instead of resizing the DVD "down" (ie width of 720) it could be resized it "up" (ie width of 848). AutoGK only does mod16 so that'd be about the closest match for NTSC. I don't know if that'd make any difference, or make it better or worse..... just a thought.

Is it also possible AutoGK's inclusion of grain removal when encoding DVDs is potentially increasing the blocking? If so...... AutoGK doesn't add grain removal to the script when encoding via directshow.... but it'd probably be more messing around to get AutoGK to encode vob files directshow than it's worth (it can be done though). Given dbq-andersons appears to be encoding with Xvid in single pass mode at maximum quality the encoder GUI is probably less relevant. Maybe using something like MeGUI for the Xvid encoding..... I wonder if adding dithering to the script would reduce the blocking, or whether using dithertools for resizing rather than one of the usual resizers would help?
I don't encoding using Xvid much these days so I've not experimented along those lines.

[dbq-andersons]

Hey Everyone,

So.

I've taken a bit to digest things. When I read mamano's post, I had a major Homer Simpson/forehead-slap moment. D'oh! Since I'm not worried about storage space, it does make sense the just run with the raw VOB files. I have verified that raw VOB files work very well both USB-attached to my TV and DLNA streaming through Universal Media Server. Picture quality is awesome...much better than any of the Xvid encodes I was doing. Not as good as my 1080p-upconverting DVD player, but for the convenience of being able to pull up any movie in the collection with a few clicks of the remote, it's more than good enough.

In case anyone is curious, I have included a sample of the encode I did that generated the log files above.

Thanks everyone for the help.

Bill