How is the Automatic Bitrate calculated ?

[cribber]

Hi, someone else had asked this in a different thread but I thought i'd make a specific thread about it.

How is the Bitrate calculated ? Why doesn't it add bitrate so that the quality advisor is at the highest point in the green section ? I ask this because I converted a DVD to a MKV, I looked at the Automatic Quality Advisor and the needle was in the green but not the maximum. When I viewed the converted file, I noticed some pulsing/flickering pixels on peoples faces and in the background/on trees etc. (due to not enough bitrate). It's only minor, but it's not on the original. So why doesn't the quality advisor set the maximum ?

[Coral]

Cedric will have to explain this. Since the bit rate is automatically calculated for optimal value wihout disc space wastage.
In a way it is not exactly CBR or VBR. I prefer to let the user decide what to use as bit rate and just have a file size indicator.

[cedric]

Hello,

Quality advisor doesn't set the maximum bitrate to save disk space.
Some users complained of too big file size, that's why the bitrate use the best quality/output size ratio we found.
I can't satisfy the users wanting best quality and not regarding filesize and the users wanting to keep a low file size in same time...

The best way to fix this request is to add a "bitrate coefficient" as global settting allowing user to change how the video bitrate is computed.
This coefficient will be a value from 0.5 to 1.5 and will allow user to increase or decrease the video bitrate originally computed.
For example, if user set 1.5 as bitrate coefficient and average bitrate is computed as 4Mb/s, video bitrate used will be of 6Mb/s (4 x 1.5).

Regards,

[cribber]

So just out of interest, is this "bitrate coefficient" option coming soon because I didn't see it in the recent v1.1.0.17 ?

Also, if you increase the bitrate to the maximum on the quality advisor scale and then save it, if you go back to the edit screen the scale has gone back to normal but the bitrate is what was saved (so you can increase it again). You can keep doing this so I think there's a bug in the quality advisor.

[Claire]

bitrate coefficient not yet integrated is coming,

the other bug about conversion advisor has now been entered, thanks for pointing it out
http://bugs.vso-software.fr/view.php?id=7241

[cedric]

Hi all,

Video bitrate factor option implemented in last beta version (1.1.0.19) :

http://forums.vso-software.fr/new-vso-v ... 17272.html

I'm waiting for your feedback...

Regards,

[cribber]

I've only given it a quick test, if for example, you add 10% on the new 'bitrate coefficient' slider, when going to the Quality Advisor it doesn't show any difference in the bitrate amount or the estimated file size. I have no idea what the new bitrate or filesize will be. It would be good if you could see the before and [b]after[/b] information (like res, fps, bitrate, filesize etc) in the main conversion window on the selected clip to convert.

Also, when I make a custom profile and I change the framerate, if I exit and load the program again and go back to my custom profile settings the framerate has gone back to 'Same as Source'.

Thanks.

[Coral]

Somthing like this will be most welcomed. The controls on the values determine the file size.

[cedric]

Hello cribber,

Please give me more details about your test.
For your information, if you set manually the video bitrate in Video editor then save your changes, bitrate factor option will not have any effect after.
What output profile do you use?

Regards,

[cedric]

Sorry coral but I don't think the setting page you sent as screenshot is more clear than quality advisor...
Can you select more than one audio/subtitle tracks in your program?
Do you have an idea about final video quality?
Can you copy the video/audio or subtitle streams (remux), if yes how is computed the final file size in this case?

Regards,

[Coral]

Hello Cedric,
The bit rate calculator on those setting is intended to give a close estimate of file size at a given bit rate.
It was just an example.

[cedric]

Ok but, why you said "Something like this will be most welcomed"?

[cribber]

[quote="cedric"]Hello cribber,

Please give me more details about your test.
For your information, if you set manually the video bitrate in Video editor then save your changes, bitrate factor option will not have any effect after.
What output profile do you use?

Regards,[/quote]

Hi, my quick test was :-

If I leave the new bitrate slider at default 0 then check the edit options quality advisor and make a note of the bitrate and projected filesize.
I then add 10% on the new bitrate slider then check the edit options quality advisor, the bitrate and projected filesize are the same as before. It doesn't show me how much difference the 10% extra is on the bitrate and projected filesize.

It would be good if you could see the clips information (like res, fps, bitrate, filesize etc) in the main conversion window on the selected clip to convert, and next to it it would show what the converted clips info will be.

Also, when I make a custom profile and I change the framerate, if I exit and load the program again and go back to my custom profile settings the framerate has gone back to 'Same as Source'.

[Coral]

Ok but, why you said "Something like this will be most welcomed"?

Because changing one paramiter gives you a close indication of the file size and bit rate.
In other settings you can choose between CBR or VBR. (not shown here)

In the VSO Converter you will have to set the max bit rate by using the Output formats > Coustom profiles then moving to the Video editor > Quality adviser.
It would have been more simple if all the file settings were on one page and saved as a profile. This is just my opinion.

Edit:
I have noticed the Video quality/File size factor setting on V. 1.1.0.19. I quite like it. But again moving from one place to the other to fine tune your settings is rarther boring.

[Claire]

Hi, my quick test was :-

If I leave the new bitrate slider at default 0 then check the edit options quality advisor and make a note of the bitrate and projected filesize.
I then add 10% on the new bitrate slider then check the edit options quality advisor, the bitrate and projected filesize are the same as before. It doesn't show me how much difference the 10% extra is on the bitrate and projected filesize.

in 1.1.0.20 I cannot reproduce, values are always adjusted accordingly.