mp4 size issue

[jethropr]

Sorry if this has been talked about already, I took a quick look around and didn't see anything.

I'm using the Zarx264gui. I have the settings at Constant quality, Quantizer 20, and 192 kbs audio.

The scrip I'm importing is

Code: Select all

AVISource("D:\Clips\an08\huffy.avi")
ConvertToYV12()
deen("w3d",1) 
tweak(sat=1.1,cont=1.0)
mftoon()
FastLineDarken(50)
crop(2,0,-2,0)
LanczosResize(720,384)

The video I'm encoding is 3:58 in length, and when I encode it with the above settings, the file size is 70mb. I was expecting something around the 50mb marker.

I thought that h.264 was suppose to allow higher quality with smaller file sizes... is there something I've over looked?

any help is appreciated.

[JaddziaDax]

if you compress and xvid (single pass) with the same specifications it would be over 100mb

you could choose a lower bitrate for your audio

[Mosc]

You're completely missing the point of constant quantizer, jethropr. Ignoring the fact that you should always use constant quality rather than constant quantizer, the number you specify will result in a certain quality value (the quantizer) for every single video you encode. That's the beauty of it. The fact that your video came out pretty large in size means that x264 thinks the video is rather complex and it needed a lot of bits to keep it at the quality level you yourself specified! You have three options:

• Reduce the constant quality by raising the quantizer value. You should use this new value for every other video you encode for consistency.
• Completely forget about constant quality and use the bitrate mode to achieve the filesize you want.
• Accept the fact that x264 knows better what filesize it needs to achieve a certain quality than you. In other words, you need to completely let go of your "the filesize is larger than what I expected, thus something must be wrong" way of thinking. Use the same quality level for every video, again for consistency (otherwise, you'd be better off using the bitrate mode).

[jethropr]

sounds good, I just wasn't sure if there was something I was missing.

[Zero1]

Try removing mftoon and then fastlinedarken. They both create high frequency noise that is hard to code, and requires a lot of information. Also IMO mftoon looks pretty awful. It won't look at sharp, but it will look more natural and more faithful to the source.

Really IMO sharpening is something that should not be done, unless the source is really terrible. These days, decoders and TVs have sharpening functions within them which people can change to suit their preference rather than being stuck with an oversharpened image for good.

Also yes, if you are wanting constant quality but then you also want 50MB, you are missing the point of constant quality. With constant quality, 2 videos can be the same resolution, same length, framerate etc. but the filesize can vary wildly on the actual content. If you must have 50MB, then you will want a video bitrate of about 1488 if the audio is 192.