Poor Results on DivX

[sjdean]

Im looking for the best way to maximising quality of DivX's without bloating the file size.

Trying to create a DivX Library for my XBMC and pack away my DVD's in storage somewhere.

I don't know whether I have higher standards, but unless I encode at somewhere approaching the source bit rate, I get what I consider to be bad blocking - mostly streaking and wash out of similar colours, which to be fair you have to get up pretty close to the TV to watch, but even from a distance, clarity wise, they just don't seem right.

Some of the DVD's are very basic transfers to DVD, interlaced and 4Mbps. But even on movies at 1024x576 Im going up to 3000kbps before things look half way adequate.

For party mode, 1726kbps looks OK at a distance and gives good sizes I can play the resultant files on a range of equipment (eg phone, tablet). But there's a grey area between 1726 to 3000 that I just don't think DivX's are much up to scratch. Given that I've heard about people creating these excellent DivX's, I figured I must be doing something wrong?

But posting to another forum suggests Im not. On another forum, I've been told I've used the wrong bit rate, the wrong software, there's something in my playback and of course Im going to notice on a 37inch Hi Def TV, to the source file isn't any good and DivX isn't that miraculous at all.

Im sure I can get better results than what Im getting, less blocks, more clarity, at half or less the bitrate of the original MPEG2. If not, just what is the fascination of DivX?

Using DivX Plus Converter.

Any other recommended tools I think should be capable of Audio passthrough.

Thanks
Simon

[MatLz]

I figured I must be doing something wrong?
Yeah, first, you are thinking in bitrate, and second, you are using divx.

If you are limited to use asp for compatibility reasons, use at least xvid.
Choose a value of quant which is acceptable to you and never change it.
And as it is only one pass, you gain a lot of time.





Or use x264 if possible...

[sjdean]

Oh thank you for a sensible reply.

On another forum I've been told the profile is wrong, the bit rate is too low, the source is poor, and the TV is too large and that I shouldn't expect miracles.

Don't expect miracles, just what most people suggest they get when converting and how they can get files a fraction of the size of a vob with brilliant results, not hyper compressed block washed out garbage.

What programs do you recommend for converting to DivX, and I presume the next format up would be mpeg4 10? H264?

I'm looking for a program that can do audio passthrough without having to convert the aac audio. Hopefully something that supports subtitles. And you mention quant?

I'm just going to trial staxrip and I have handbrake.... either of those good?

[manolito]

First of all I have to admit that I was totally ignorant about XBMC, but a little googling took care of this...;)

Since XBMC does support MPEG4-AVC (H.264), I see no reason at all to use MPEG4-ASP (DivX or XviD) any more. H.264 is a much more efficient format compared to DivX or XviD, the only drawback are much longer encoding times. And many folks on this forum and elsewhere say that MPEG4-ASP in an AVI container is obsolete these days.

You mentioned Handbrake and StaxRip, and both are good choices. Handbrake is much easier to use, but StaxRip offers more control to the user. Audio passthrough is supported by both. Maybe you should start with Handbrake and move on to more advanced programs later...

Both programs use X.264 for H.264 encoding, and this encoder is not only free, it also delivers first rate quality. The preferred encoding method is 1-pass quality based. You have to specify a CRF value (defaults vary, but 20 to 22 will give you excellent quality). If your source is 16:9 you should encode in anamorphic mode. Handbrake comes with predefined presets which generally work quite well. For highest quality you would want to use the High Profile preset. As a container format you have to choose between MP4 and MKV. In the Windows world the Matroska format is probably more desirable, but this is also a matter of taste.


Hope this helps...
Cheers
manolito

[kalehrl]

I'd suggest you google 'scene rules' for best advice when it comes to encoding in xvid or h264.
For encoding in xvid, I'd suggest you use AutoGK which can handle subtitles as well leave audio unchanged.
For h264 encoding - MeGui.

[hello_hello]

If you're converting to AVI I still think AutoGK (http://www.autogk.me.uk/) is a good choice. It's easy enough to load a DVD, run a single pass encode at 100% quality (although 75% is probably adequate) and you'll know the resulting encode is as good as Xvid can do (which is probably as good as, or little better than DivX). The file size/bitrate will be whatever it needs to be.

If you still see too much blocking, then as suggested anamorphic x264 encoding is the way to go. My personal preference for an encoding GUI is MeGUI (http://sourceforge.net/projects/megui/). I encode using a CRF value of 19 for DVD, but it's all personal preference.
Of course MeGUI will also encode using Xvid. Instead of a running a single pass, 100% quality encode as you would with AutoGK, you configure the Xvid encoder to run a single pass, constant quantizer encode. A CQ of 2 = AutoGK's 100%.

I'd agree. Xvid/Divx AVIs are pretty much obsolete.

[mike20021969]

Any other recommended tools I think should be capable of Audio passthrough.
VidCoder/Handbrake.

[sjdean]

Oh yeah, thanks all for thes suggestions. Producing a H264 MKV file using HandBrake and CQ20 gives a really really excellent video, superior quality to DivX at a smaller size! Barely any noticeable pixellisation/blocking.

Only problem is, flaming things don't play well on my Galaxy Tab. Grrr.

As the main reason is for an XBMC library, presuming I carry on using HandBrake, would you recommend deinterlacing DVD's, and if CQ is substantially less than a DivX , is it worth specifying a target video size just to ensure that it uses as much file space as I want it to use?

I guess I could always knock the CQ down/up to 19.

I'll check out AutoGK.

Cheers
Simon

[sjdean]

I get much better results using H264 in an MP4 container as opposed to MKV. Doesn't seem to quite cut it on the Samsung Galaxy Tab (NVidia Tegra 2) very chopper. But MP4 perfect. Yaaaay. Thanks guys! Plus in MP4, the galaxy correctly resizes the video to proper 16:9 but MKV is still stretched heightways even though both encodings were done using Anamorphic Strict.

[manolito]

Congratulations...:)

Cheers
manolito

[hello_hello]

As the main reason is for an XBMC library, presuming I carry on using HandBrake, would you recommend deinterlacing DVD's, and if CQ is substantially less than a DivX , is it worth specifying a target video size just to ensure that it uses as much file space as I want it to use?

I guess I could always knock the CQ down/up to 19.

Yes, deinterlacing is a good idea.
Unless you need to manage the file size for a particular reason, there's no real benefit to picking a file size when using the x264 encoder. Encoding takes a lot longer and you're basically pre-determining the quality without knowing what it'll be. Using CRF encoding you're picking the quality instead and the file sizes will vary accordingly.
When it comes to the CRF value, just in case you're not aware, the lower the value the higher the quality and the larger the file size.

[sjdean]

Loving handbrake so far and x264 encoding. But on large TVs and certain DVD conversions, some background elements still look very heavily compressed and I can still see streaks. I half wonder if that's because some DVDs simply don't have z high enough bit rate to begin with?

Handbrake is also tempremental in sometimes not including the specified vob subtitles. Grrr. Time to crack open stax rip

Any further thoughts on really maximising quality?

Thanks
simon

[manolito]

Regarding quality it happened to me more than once that after I was disappointed with the result of a conversion I found out that all these artifacts were already present in the source.

With Handbrake all you can do is make sure you selected "High Profile" and lower the CRF value even more (maybe 18 to 16).

Staxrip gives you access to many more X.264 settings. In addition to the CRF value you can also "tune" your conversion for film, anime, grain, psnr, ssim and more. But as I said before, it has a higher learning curve than Handbrake.

For H.264 conversions you should probably also try out Ripbot264.


Cheers
manolito

[sjdean]

I've reduced the crf to 16, but it seems not to have any effect upon banding. Think you're right about blockiness. Most blockiness is on the source, but when there are flat areas of colour, I notice I get quite horrendous colour banding.

Any thoughts on this?

Thanks
Simon

[hello_hello]

Have you tried MeGUI? I have no idea which x264 settings would increase colour banding, or whether it's anything to do with the programs you're using for conversion etc, but I do know I've encoded many DVDs using a CRF value of 19 or 20 without introducing any colour banding. At least not that I've noticed (although I have noticed it a few times when looking at other people's encodes, so next time I'll pay more attention to the program they used for encoding). With a CRF value of 19 or 20 I can't see any significant difference between the DVD and the encode, if I can see any difference at all. A CRF value of 16 seems a bit extreme. You must be producing some largish encodes.

As a bit of an experiment the other day, I took a couple of 720p Bluray encodes and re-encoded them at 720p, except I took the file size from 2.1GB down to 400MB. I fully expected them to look horrible (it was just an experiment) but was surprised how good they looked considering the file size reduction. Yes there was a bit of blocking in places but other than that they looked okay. I didn't seem to introduce any colour banding in the process. I wonder what causes it? Do you know what filters, if any, are being applied when you encode?

[manolito]

The current stable version of Handbrake (0.95) dates from January 2011 which means that the X.264 libraries are more than 10 months old. But I do not believe that X.264 encoding quality has changed a lot since then...

Otherwise Handbrake's philosophy is to shield the user from long command lines. If you use the High Profile preset then Handbrake defaults to a CRF of 20, and
b-adapt=2:rc-lookahead=50
is added to the X.264 command line. Everything else stays at the default settings.

Another thing which may have an influence on encoding quality is the use of HandBrake's built-in video filters (detelecine, decomb, deinterlace, denoise, deblock). To get reproduceable results it is probably a good idea to turn all these filters off.


Cheers
manolito