CQ vs Bitrate - does that Increase the Compression?

[ak47]

This probly been posted before, but i can't find it. On Cq the higher the max bit rate and the same Cq does that increase the compression.

[kwag]

Quote:

Originally Posted by ak47

This probly been posted before, but i can't find it. On Cq the higher the max bit rate and the same Cq does that increase the compression.

Yes, and worse quality. In other words, the farther apart MAX bit rate is from a fixed CQ value, the worse the quality. It's equivalent to decreasing CQ while maintaining a fixed MAX bit rate

-kwag

[nicksteel]

Quote:

Originally Posted by kwag

Quote:

Yes, and worse quality. In other words, the farther apart MAX bit rate is from a fixed CQ value, the worse the quality. It's equivalent to decreasing CQ while maintaining a fixed MAX bit rate

-kwag

Given this, what is a good rule of thumb or method to use to get optimum output?

[kwag]

Quote:

Originally Posted by nicksteel

Given this, what is a good rule of thumb or method to use to get optimum output?

File size prediction

-kwag

[nicksteel]

Quote:

Originally Posted by kwag

Quote:

File size prediction

-kwag

I do use File size prediction (Predictor). During the course of sizing, CQ is modified. How does the sample file size relate with the max bitrate? I just use the bitrates preset in KVCDx3. For instance, if CQ moves from 60 to 90 based upon sampling, is the max bitrate still ok?

A lot of probably dumb questions, but I am trying to increase my skills. Could you also look at my decomb question under Capture? I would really appreciate.

[ak47]

Sorry i couldn't respond faster, but heres my second question. If my dvd player supports 9000kbs should i use 9000 or 2500 for the max kbps.

[kwag]

Quote:

Originally Posted by nicksteel

I do use File size prediction (Predictor). During the course of sizing, CQ is modified. How does the sample file size relate with the max bitrate? I just use the bitrates preset in KVCDx3. For instance, if CQ moves from 60 to 90 based upon sampling, is the max bitrate still ok?

The KVCDx3 is set to 2,500 on purpose, because its a value that most DVD players can handle in VCD mode. If your player can handle 3,000 to 3,500, then I suggest you go up to that, as you will get higher quality in high speed scenes. If you use file prediction, it doesn't matter what value you use for MIN or MAX, because file prediction will adjust CQ accordingly. So for optimal quality at 352x240, try to use MAX=1,800Kbps. For 352x480, MAX=2,500Kbps and for KVCDx3, and if your player can handle it, go for 3,000-3,500Kbps.

-kwag

[kwag]

Quote:

Originally Posted by ak47

If my dvd player supports 9000kbs should i use 9000 or 2500 for the max kbps.

You don't need to go that high. You'll never fit your movie on one (or two ) CDs with that 9000Kbps bit rate. You really don't need to go over 3,500 with KVCDx3 (528x480)

-kwag

[ak47]

thanx kwag your always alot of help.

[J-Wo]

Is there any benefit to increasing MIN bitrate, if I have space on a CD at CQ 90?

[JoZ]

Quote:

Originally Posted by kwag

The KVCDx3 is set to 2,500 on purpose, because its a value that most DVD players can handle in VCD mode. If your player can handle 3,000 to 3,500, then I suggest you go up to that, as you will get higher quality in high speed scenes. If you use file prediction, it doesn't matter what value you use for MIN or MAX, because file prediction will adjust CQ accordingly. So for optimal quality at 352x240, try to use MAX=1,800Kbps. For 352x480, MAX=2,500Kbps and for KVCDx3, and if your player can handle it, go for 3,000-3,500Kbps.

-kwag

Finally someone wrote it clear. Thanks!

I knew from before 352x240 max=1.8mbps because black prince
mentioned it in his guide and I was using max=2.5mbps for all the other
templates because it was the default one. Thanks for clarifying it again,
kwag!

OK how can I find out what my dvd player can handle? Is that written in
the book that comes with the player or do I need to make tests with
samples and cd-rw?

[dazedconfused]

Quote:

Originally Posted by J-Wo

Is there any benefit to increasing MIN bitrate, if I have space on a CD at CQ 90?

Well, one benefit of increasing MIN bitrate would be greater compatibility on some players that require a bitrate higher than the kvcd templates' default MIN setting (300kbps). My player handles kvcd's with 300kbps MIN just fine, but I've tested these same discs in other players and they glitched up during some of the credits and during very dark scenes (and I'm pretty sure this is due to the bitrate dropping too low during these scenes for these players to handle them properly).

Quote:

Originally Posted by JoZ

OK how can I find out what my dvd player can handle? Is that written in the book that comes with the player or do I need to make tests with samples and cd-rw?

Indeed, it would be very nice if manufacturers included this info on MIN/MAX acceptable bitrates in the owner's manual, but in my experience, they usually don't. You could try doing a Google search, or looking at your dvd-player company's website and/or emailing them (if they have a friendly customer-service department, maybe they'll be helpful...but I wouldn't hold my breath!). I would first try doing a search for your player at http://www.dvdrhelp.com/dvdplayers.php (formerly vcdhelp.com) to see if other people have already done some tests and reported their results (but keep in mind that some user-reports can be innacurate...also, sometimes companies use different parts for different batches of the same model dvd player, so 2 players that are identical on the outside might not be identical internally...APEX is notorious of doing this). So if someone says that something works on their XYZ-player, it isn't necessarily guaranteed to work on your XYZ-player. But it's worth a shot.

Of course, running some tests of your own is always the most surefire method!

Regards,
-d&c

[JoZ]

Quote:

Originally Posted by dazed&confused

Indeed, it would be very nice if manufacturers included this info on MIN/MAX acceptable bitrates in the owner's manual, but in my experience, they usually don't. You could try doing a Google search, or looking at your dvd-player company's website and/or emailing them (if they have a friendly customer-service department, maybe they'll be helpful...but I wouldn't hold my breath!). I would first try doing a search for your player at http://www.dvdrhelp.com/dvdplayers.php (formerly vcdhelp.com) to see if other people have already done some tests and reported their results (but keep in mind that some user-reports can be innacurate...also, sometimes companies use different parts for different batches of the same model dvd player, so 2 players that are identical on the outside might not be identical internally...APEX is notorious of doing this). So if someone says that something works on their XYZ-player, it isn't necessarily guaranteed to work on your XYZ-player. But it's worth a shot.

Of course, running some tests of your own is always the most surefire method!

Regards,
-d&c

Well I do agree!

Nothing in my manual

www.dvdrhelp.com formely www.vcdhelp.com is my favorite site. This is
how I found out about kvcd.

I'll make some tests just because It should support up to 3,200kbits/s.
Good, bad... no idea. I guess bigger's better (as usual) because if you
want can go to 1,800 or 2,500 or more but from the other side if you
would like to be more compatible with all ddvd players have to follow the
standart.

Thanks for the very nice reply and sorry for describing the word manual.
As you can see from my english I'm not an american.

[Bytecode]

So would it be better to encode at CQ 90 - 2500kb/s or CQ 75 - 3500kb/s

My dvd player will support very high bitrates on vcds, but I'm having a hard time figuring out which settings I should focus on to increase quality.

Higher Resolution = Better quality, so go with the highest resolution you can afford?

Higher CQ = Better quality, but should you sacrafice CQ to go to a higher bitrate?

I'm just trying to come up with a generic basis to use when trying to decide what I want to encode my movies at.

Thanks,

-BC