Transcode to Xvid, good stills, HORRIBLE motion.. help

[boogieq]

I have the latest version of GBPVR and have been messing with the automatic transcode option. I have been able to get a a 2.5gig recording to 800 or so megs in Xvid format.

When nobody is moving, it looks FANTASTIC.. as soon as anything motion related occurs, it gets VERY BLOCKY.

Also, this file seems a bit big for 1 hour of video. Most 1 hour video recordings I find over bittorent are 350megs and look perfect.

Is there a way to change the default settings for the xvid encode or no? I tried chaning the settings in the Xvid Encoder (it's in start > programs > xvid after you install the latest version) and that had no effect.

I would be happy with 500megs as I do not remove the comercials... or even the 800 meg, but the horrible motion compression is killing me.

Ideas?

System:
GBPVR
150 PVR from Hauppague
320gig Raid array
Athlon XP 1800+
512 ram

[daveid]

that is huge.. i guess you are using mencoder which apparently has the advanced features hidden somehow. your bitrate should be around 700-800kbps for xvid encodes, my 20minute episodes come to 120mb (i use vorbis as my audio which allows for better compression than mp3 though) which would mean an hour should be around that 350 you stated.
the settings for xvid need to be changed in the encoder you use, if the one you are using does not give you access to these options, you will need to use a different one. for an outline of what i do to get my (wonderful looking and sounding - BTW) encodings done see this thread -
http://forums.nextpvr.com/showthread.php?t=14140
i have found over the years i have been compressing video that programs that require little interaction and experience to use, provide much poorer quality than learning to do it the hard way..

[boogieq]

Thanks for the reply!

I know, I kept the bitrate up thinking that may fix it, and it did not. The motion was just horrific.

I'll scope that link when I get home and test it out.

I have NO idea what I am using for encoding. I simply went into the GBPVR config area and told it to transcode to xvid. Whatever it does after that is what it did.

[daveid]

i am attaching two clips (one simpsons one married with children) they are short, and small, but give a good example of what is possible if you put effort into encoding to xvid. they are .mkv and will require a matroska splitter, either haali or gabests (my top pic), or just use media player classic. you will also need a vorbis decoder, i choose radlight ogg vorbis directshow filter as it allows connection to other filters (such as ac3filter for upmixing and normalizing audio).. i suggest using ffdshow for the video decoding & spp deblocking with automatic quality control set to the second slider level (deblock H & V for luminance), i also set (under picture properties) luminance level fix & full range & chroma only, to get better contrast..
the attachment feature is not working so here is a link to the file:
http://www.mytempdir.com/610382

[sgilani]

By default GBPVR uses ffmpeg to transcode to xvid. You can get very good quality with either ffmpeg or mencoder, you just need to change the settings. Open up the config.xml and find the xvid commandline and tweak the settings.

I use GBPVR exclusively with my TV and out of personal preference, I make the resolution 640 x 480 to preserve aspect ratio and avoid scaling down the picture too much. For this, I use a bitrate of 1500 and it comes out looking actually better than the MPEG2 (because I use ffdshow to decode the xvid's and they do a better job at playback then any mpeg2 decoders do with the original stream)

You might find it nice to add this to the ffmpeg commandline:
-s 512x384

This will scale it down to 512 x 384, which is a fairly decent size. Just start out with a bitrate of 800 or so (-b 800) and see if you like the result. Make sure audio bitrate is 128 for now (-ab 128)