Encoded mpeg4 AVC files are suddenly way bigger

[Jilocasin]

Hey folks

I used to work with 2.6.1 (Windows, 64 bit) and just recently tried to switch over to 2.6.5, but got stuck with a really weird behaviour with the video encoding.
Even with the exact same preset the Mpeg4 AVC encoder of 2.6.5 creates incredibly huge files, and is also considerably slower.
A 15 minute 1080p video used to have ~500mb in 2.6.1 (or even lower), but using 2.6.5 I had to cancel the render process after about 6% processing done, which already had over 200mb in size.

So, simply put, i assume that there is something wrong with the constant rate factor encoding. It almost looks like it ignores the quality slider or something and wants to encode it with quality 0. I have no clue, sorry

My two presets are attached, so you may check if I missed something important. But, as I said, there are pretty much the same settings. Can you tell me what's wrong here?

PS: Seems kind of similar to this.

[AQUAR]

This issue is being experiened by a few people.
See this thread  "Avidemux 2.6.4 - H.264 encode by video size is massively broken".

No answers yet for this behaviour.
Have you used the installer versions to update from 2.6.1 to 2.6.5?

Maybe collaborate at that thread with some info about your PC setup etc.

[cliffshit]

So, simply put, i assume that there is something wrong with the constant rate factor encoding. It almost looks like it ignores the quality slider or something and wants to encode it with quality 0.

I once had this issue too. A clean install solved the problem.
Uninstall the old version, delete all remaining files and folders, and then install the new version.

This issue is being experiened by a few people.
See this thread  "Avidemux 2.6.4 - H.264 encode by video size is massively broken".

This not seems to be the same problem: attached presets are for encoding by CRF ("AQ=22"), and not by video size or average bitrate.

[Jilocasin]

Actually I always prefer to use the zip versions, so you don't have to uninstall and install all the stuff for every new update. This may have lead to this inconsistency, although I don't understand how the encoder could be messed up like that, just by having two different (originally zipped) versions on your drive. That also means I basically can't uninstall them, because I never officially installed them in the first place. So I guess i will try to install the 2.6.5 properly and see what it does.

[AQUAR]

@ cliffshi?
The issue is "avidemux oversizing" and the event sample size is way too small to predict that this particular case is caused by a different trigger point.
This post does add information that the oversizing occurs on AVC encoding with a constant bit rate settings as well as variable bit rate settings (from the other thread).

@ Jilocasin
Thanks for the extra snippet.  I also simply unzip and use in place.
Since you have been running more than one version of 2.6.x this way, they may be accessing to same data area - possibly a problem. 
For windows 7 - look under users\user\appdata\roaming\avidemux and delete all contents in this avidemux folder. See if it now works okay.
Note "appdata" is a hidden system folder and so you need to unhide folders.
Could you also rename the executable by adding  _portable to the end of the name and see if running as a portable version works better.

[Jilocasin]

Thanks for all the feedback, guys!
I played around with the newest version and the nightlies and actually found the explanation for the behaviour I described, it seems.

The actual problem was in fact my preset, because it had interestingly some wrong settings. It seems, that after 2.6.1 the settings window for h264 has changed and some of the options are now available and will get imported from your preset. If you take a look at my posted 2.6.1 preset, you can see the following:

Code Select Expand

"ratecontrol" : {
"rc_method" : 0,
"qp_constant" : 0,
"qp_min" : 0,
"qp_max" : 0,
"qp_step" : 0,
"bitrate" : 0,
"vbv_max_bitrate" : 0,
"vbv_buffer_size" : 0,
"vbv_buffer_init" : 0,
"ip_factor" : 0,
"pb_factor" : 0,
"aq_mode" : 1,
"aq_strength" : 1,
"mb_tree" : true,
"lookahead" : 8
},

2.6.5 grabs all these settings and it will look like this: LINK.
On the left the h264 settings window of 2.6.5, on the right my old Avidemux 2.6.1.

So ...

It almost looks like it ignores the quality slider or something and wants to encode it with quality 0

I was kind of right. It just wasn't the quality slider on tab 1, but the quantiser settings were faulty. 
As you can see, simply put, the quantiser settings are completely messed up, after you import them from a preset, created with an Avidemux version, which did not export them correctly (for a reason I don't know).
All the settings not available (and thus set to default) in a former version, were exported as 0's, it seems.

So, after I adjusted the new preset it works like a charm. I am not sure if this is correlated to any other "avidemux oversizing" problem, but I will better double-check my advanced quantiser settings in the future

[mean]

Thanks for the info, probably will bump the version so that it doesnt happen with 2.6.6